User:Marshallsumter/Keynote lectures (draft)/Dates

Dates are often the day of the month or year as specified by a number, including a particular day or year when a given event occurred or will occur. Sometimes they are the period of time to which an artifact or structure belongs. Then, there is a written, printed, or stamped statement on an item giving the day, month, and year of writing, publication, or manufacture.

Notations
Conventional dates may appear as

Notation: let April 27, 2016 by denoted as dd month year, or 27 April 2016.

Notation: let dd/mm/yy represent 27 April 2016 as 27/04/16.

Notation: let b2k represent years before J 2000.0.

Notation: let Mya represent millions of years ago, or millions of years b2k.

Precambrian
Def. "the time and geology dated before the Phanerozoic" or the "eon (or supereon) and rock formations dated before 541.0±1.0 million years ago, coinciding with the first appearance of the fossils of hard-shelled animals"

is called the precambrian.

Hadean
Def. "the geologic eon from about 4,600 to 3,800 million years ago; marked by the formation of the solar system, a stable Earth-Moon orbit and the first rocks" or the "eon before 4,000 Ma" is called the Hadean.

Eoarchean
Def. "a geologic era within the Archaean eon from about 4600 to 3600 million years ago; the first single-celled life began at this time" or the "era from 4,000 Ma to 3,600 Ma"

is called the Eoarchean.

Archean
Archaean is an alternate spelling of Archean.

Def. "the geologic eon from about 3,800 to 2,500 million years ago; comprises the Eoarchean, Paleoarchean, Mesoarchean and Neoarchean eras; marked by an atmosphere with little oxygen, the formation of the first continents and oceans and the emergence of simple life" or the "eon from 2,500 Ma to 4,000 Ma"

is called the Archaean, or Archean.

The rock, in the images at left and right, a tonalite gneiss, of the Acasta Gneiss exposed on an island about 300 kilometres north of Yellowknife in the Slave craton in Northwest Territories, Canada, was metamorphosed 3.58 to 4.031 billion years ago and is the oldest known intact crustal fragment on Earth.

The metamorphic rock exposed in the outcrop was previously a granitoid that formed 4.2 billion years ago, an age based on radiometric dating of zircon crystals at 4.2 Ga.

Paleoarchean
Def. "a geologic era within the Archaean eon from about 3600 to 3200 million years ago; the first aerobic bacteria appeared at this time" or the "era from 3,600 Ma to 3,200 Ma"

is called the Paleoarchean.

Mesoarchean
Def. "a geologic era within the Archaean eon from about 3200 to 2800 million years ago; stromatolites have existed from this time" or the "era from 3,200 Ma to 2,800 Ma"

is called the Mesoarchean.

The earliest reefs date from this era, and were probably formed by stromatolites. The surface temperature during the Mesoarchean was likely not much higher than modern-day temperatures. Atmospheric carbon dioxide concentration was only a few times higher than its pre-industrial value.

Pongola glaciation
The Pongola glaciation is dated "at 2.9 Ga".

Neoarchean
Def. "a geologic era within the Archaean eon from about 2800 to 2500 million years ago" or the "era from 2,800 Ma to 2,500 Ma"

is called the Neoarchean.

Hypozoic
Def. "older than the lowest rocks which contain organic remains" is called the Hypozoic.

Azoic
Def.
 * 1) destitute "of any vestige of organic life, or at least of animal life",
 * 2) anterior "to the existence of animal life", or
 * 3) formed "when there was no animal life on the globe"

is called the azoic.

Proterozoic
Def. the "eon from 2,500 Ma to 541.0±1.0 Ma, the beginning of the Phanerozoic, marked by the build up of oxygen in the atmosphere and the emergence of primitive multicellular life" is called the Proterozoic.

Huronian ice age
The Huronian Ice Age is known "mainly from Canada and the United States in North America, where dated rocks range from 2500 to 2100 million years old."

Makganyene glaciation
The "Makganyene glaciation begins some time after 2.32 Ga and ends at 2.22 Ga, the three Huronian glaciations predate the Makganyene snowball."

Paleoproterozoic
Def. the "era from 2,500 Ma to 1,600 Ma, marked by a dramatic increase in atmospheric oxygen" is called the Paleoproterozoic.

Mesoproterozoic
Def. "a geologic era within the Proterozoic eon; comprises the Calymmian, Ectasian and Stennian periods from about 1600 to 900 million years ago, when the Rodinia supercontinent was formed" is called the Mesoproterozoic.

Neoproterozoic
Def. "a geologic era within the Proterozoic eon; comprises the Tonian, Cryogenian and Ediacaran periods from about 1000 to 544 million years ago, when algae and sponges flourished" is called the Neoproterozoic.

Cryogenian ice age
The Cryogenian Ice Age, or the Stuartian-Varangian Ice Age, a "Late Proterozoic ice age was apparently the greatest of all. Glacial strata are known from all modern continents (except Antarctica) with an overall time range of about 950 to 600 million years old.

Phanerozoic
The Phanerozoic eon includes the Paleozoic, Mesozoic, and Cenozoic. It lasted from 542.0 ± 1.0 Mb2k to the present

Paleozoic
The Paleozoic era spanned 542.0 ± 1.0 to 251.0 ± 0.7 Mb2k.

Cambrian
The Cambrian lasted from 542.0 ± 1.0 to 488.3 ± 1.7 Mb2k.

Ordovician
The Ordovician lasted from 488.3 ± 1.7 to 443.7 ± 1.5 Mb2k.

Andean-Saharan ice age
The "Andean-Saharan [occurred] between 450 and 420 Ma […] did not achieve a global extent."

Silurian
The Silurian spanned 443.7 ± 1.5 to 416.0 ± 2.8 Mb2k.

Devonian
The Devonian spanned 416.0 ± 2.8 to 359.2 ± 2.5 Mb2k.

Karoo Ice Age
The "Karoo [occurred] between 360 and 260 Ma [but] did not achieve a global extent."

Carboniferous
The Carboniferous began 359.2 ± 2.5 Mb2k and ended 299.0 ± 0.8 Mb2k.

Mississippian
The Mississippian lasted from 359.2 ± 2.5 to 318.1 ± 1.3 Mb2k.

Pennsylvanian
The Pennsylvanian lasted from 318.1 ± 1.3 to 299.0 ± 0.8 Mb2k.

Permian
The Permian lasted from 299.0 ± 0.8 to 251.0 ± 0.4 Mb2k.

The Permian/Triassic boundary occurs at 248.2 ± 4.8 Ma (million years ago).

Mesozoic
The Permian/Triassic boundary occurs at 248.2 ± 4.8 Ma (million years ago).

Triassic
The Triassic/Jurassic boundary occurs at 205.7 ± 4.0 Ma (million years ago).

Jurassic
The Jurassic/Cretaceous boundary occurs at 144.2 ± 2.6 Ma (million years ago).

Cretaceous
"The Cretaceous period is the third and final period in the Mesozoic Era. It began 145.5 million years ago after the Jurassic Period and ended 65.5 million years ago, before the Paleogene Period of the Cenozoic Era."

Cenozoic
The Cretaceous/Cenozoic boundary occurs at 65.0 ± 0.1 Ma (million years ago).

In the image on the right, the finger is pointing to the K/Pg boundary clay in the Geulhemmergroeve tunnels near Geulhem, The Netherlands.

The second from the top image on the right shows the K-Pg boundary in the Badlands near Drumheller, Alberta, where glacial and post-glacial erosion have exposed the boundary.

The cliffs at Stevns, in the image at the top of this page, have the highest iridium occurrence in the Alvarez analysis.

The K-Pg boundary at Trinidad Lake State Park, Colorado, USA, in the fourth image on the right, occurs at the color change from dark gray or black to the Cenozoic light tans and browns.

"Our assessment of published radiometric dates suggests the following best biochronologic age estimates for Cenozoic Epoch boundaries: Pliocene/Pleistocene: <2 Ma; Miocene/Pliocene: ~5 Ma; Oligocene/Miocene: ~23.5 Ma; Eocene/Oligocene: ~37 Ma; Paleocene/Eocene: ~56.5 Ma; Cretaceous/Tertiary: ~66 Ma. The radiometric data on which these age estimates are based, especially in the Paleogene, are biased toward those obtained from high-temperature minerals; age estimates based on radiometric dates from glauconites tend to be younger, particularly in the Paleogene (for example, Odin and others, 1982)."

Tertiary
The Tertiary Period extends from 65.5 ± 0.3 to 2.588 x 106 b2k.

Paleogene
The Paleogene Period extends from 65.5 ± 0.3 to 23.03 ± 0.05 x 106 b2k.

Paleocene
The Paleocene dates from 65.5 ± 0.3 x 106 to 55.8 ± 0.2 x 106 b2k.

"Plesiadapis, the oldest known primate-like mammal, lived [58 million years ago.]"

"Infants were fully formed but helpless, so mothers must have provided a great deal of care. Resembling squirrel-like lemurs, Plesiadapis moms also spent a lot of time scurrying around the ground and in trees."

Danian
"Many correlation criteria are present at the GSSP of which the most useful are the meteorite impact evidence (iridium anomaly, Ni-rich spinel, etc.) and the mass extinction of plankic micro- and nannofossils."

The "GSSP of the K/Pg boundary [is defined] at the base of the boundary clay at the section near El Kef, Tunisia."

"The section [specifically shown in a closeup on the right] contains marine sediments and sedimentation was as continuous as it could be at a K/Pg boundary. There is a facies change from a grey marl to a black clay (Boundary Clay), at the base of which is a thin rusty layer. This is the fingerprint of continuous sedimentation over the K/Pg boundary interval."

"Neither magnetostratigraphy nor geochronometry are available at the section near El Kef."

"The GSSP section near El Kef contains one main feature that allows for a direct correlation of this marine section with continental sections: the Ir anomaly at the base of the Boundary Clay."

The Global Boundary Stratotype Section and Point for the base of the Danian Stage is also the base GSSP for the Paleocene, Paleogene, "Tertiary", and Cenozoic at El Kef, Tunisia.

"Although crinoids appear not to have been involved in the great change in diversity at the Cretaceous-Paleogene (K-Pg) boundary extinction event, it has been assumed that representatives of order Roveacrinida became extinct during this time. Well-preserved fossils from the Danian (early Paleocene) of Poland demonstrate that these crinoids survived into the earliest Cenozoic." Post-"Cretaceous ammonites of the genus Hoploscaphites have been found at Stevns Klint in Denmark (Machalski & Heinberg, 2005; Machalski et al., 2009)."

"The maximum age for Danian scaphitid survivors from the Cerithium Limestone at Stevns Klint, Denmark, has recently been estimated to be around 0.2 Ma following the K–Pg boundary event (Machalski and Heinberg in press). Assuming the Cretaceous– Paleogene boundary at 65.4 ± 0.1 Ma (Jagt and Kennedy 1994), the present study covers more than 4 Ma of the final stages in scaphitid evolution."

"Scaphitid material from subunit IVf−7 at the very top of the Meerssen Member [...] traditionally regarded to be uppermost Maastrichtian, has recently been reassigned to the lowermost Danian, based on microfossil and strontium isotope evidence (Smit and Brinkhuis 1996). According to Jagt et al. (2003), the scaphitid and baculitid ammonites preserved in subunit IVf−7 are early Danian survivors."

Above center are Hoploscaphites constrictus johnjagti subsp. nov., adult macroconchs, ammonites from the Danian: A. MGUH 27366, lowermost Danian, Stevns Klint, Denmark, in apertural (A1), lateral (A2, A3), and ventral (A4) views.

Ojo Alamo Sandstone
"A hiatus of about 8 m.y. separates Late Cretaceous from Tertiary rocks in the [San Juan] Basin. Most of the missing strata are from the Maastrichtian Stage. The unconformity is overlain by the Ojo Alamo Sandstone in the south and underlain by the Kirtland or Fruitland Formation at most other places in the basin."

The right femur of the hadrosaurian dinosaur is shown at left where the bone is in place in A and after excavation, preparation, and mounting in B.

"[P]ollen was the more accurate age indicator and therefore the Ojo Alamo dinosaurs were Paleocene in age. The conclusion was tentative because Paleocene pollen nowhere occurred at exactly the same locality as dinosaur bone. Paleocene pollen is present, however, in the Ojo Alamo near Barrel Spring, within one mile of the Alamo Wash bone locality [...]."

"A Cretaceous dinosaur bone collected from just below the Cretaceous-Paleogene interface yielded a U-Pb date of 73.6 ± 0.9 Ma, in excellent agreement with a previously determined 40Ar/39Ar date of 73.04 ± 0.25 Ma for an ash bed near this site. The second dinosaur bone sample from Paleocene strata just above the Cretaceous-Paleogene interface yielded a Paleocene U-Pb date of 64.8 ± 0.9 Ma, consistent with palynologic, paleomagnetic, and fossil-mammal biochronologic data."

"The second bone sample BB-1, a fragment of a large sauropod femur (Alamosaurus sanjuanensis) was collected from the Paleocene Ojo Alamo Sandstone. This bone shows much less geochemical variation than bone 22799-D and is very well preserved. The weighted average 206Pb/238U date of 64.8±0.9 Ma is interpreted to record the time of bone fossilization. Considering that fossilization times are typically less than a few thousand years, the age result from BB-1 confirms the existence of Paleocene dinosaurs. The strontium isotopic composition of both bones are relatively unradiogenic (0.70811±3 and 0.70860±3, respectively). The strontium content of both bones is remarkably homogeneous, in contrast to the chemical variability displayed by most elements, therefore we interpret the strontium isotope values to reflect the indigenous bone composition."

Eocene
The Eocene dates from 55.8 ± 0.2 x 106 to 33.9 ± 0.1 x 106 b2k.

Oligocene
The Oligocene dates from 33.9 ± 0.1 x 106 to 23.03 x 106 b2k.

Holarctic-Antarctic Ice Age
"This late Cenozoic ice age began at least 30 million years ago in Antarctica; it expanded to Arctic regions of southern Alaska, Greenland, Iceland, and Svalbard between 10 and 3 million years ago. Glaciers and ice sheets in these areas have been relatively stable, more-or-less permanent features during the past few million years."

Neogene
The Neogene dates from 23.03 x 106 to 2.58 x 106 b2k.

Miocene
The Miocene dates from 23.03 x 106 to 5.332 x 106 b2k.

Messinian
"The GSSP of the Messinian Stage, which per definition marks the base of the Messinian and, hence, the boundary between the Tortonian and Messinian Stages of the Upper Miocene Subseries, is Oued Akrech (Morocco) where the Messinian GSSP is now formally designated at the base of the reddish layer of sedimentary cycle no. 15. This point coincides closely with the first regular occurrence (FRO) of the planktonic foraminiferal Globorotalia miotumida group and the first occurrence (FO) of the calcareous nannofossil Amaurolithus delicatus, and falls within the interval of reversed polarity that corresponds to C3Br.1r. The base of the reddish layer and, thus, the Messinian GSSP has been assigned an astronomical age of 7.251 Ma."

"The correlation of characteristic sedimentary cycle patterns to the astronomical record resulted in an astronomical age of 7.24 Ma (Hilgen et al., 1995), in good agreement with the radiometric age estimates of Vai et al. (1993) and Laurenzi et al. (1997)."

The integrated magnetostratigraphy, calcareous plankton biostratigraphy and cyclostratigraphy of section Oued Akrech is diagrammed on the left.

Tortonian
The Tortonian lasted from 11.63 Ma to 7.246 Ma.

Gigantopithecus is an extinct genus of ape that existed from perhaps nine million years to as recently as one hundred thousand years ago, at the same period as Homo erectus would have been dispersed, in what is now India, Vietnam, China and Indonesia placing Gigantopithecus in the same time frame and geographical location as several hominin species. The primate fossil record suggests that the species Gigantopithecus blacki were the largest known primates that ever lived, standing up to 3 m and weighing as much as 540 - 600 kg,  although some argue that it is more likely that they were much smaller, at roughly 1.8 - 2 m in height and 180 - 300 kg in weight.

Prehistory
The prehistory period dates from around 7 x 106 b2k to about 7,000 b2k.

Pliocene
The Pliocene ranges from 5.332 x 106 to 2.588 x 106 b2k.

Zanclean
"The boundary-stratotype of the stage is located in the Eraclea Minoa section on the southern coast of Sicily (Italy), at the base of the Trubi Formation. The age of the Zanclean and Pliocene GSSP at the base of the stage is 5.33 Ma in the orbitally calibrated time scale, and lies within the lowermost reversed episode of the Gilbert Chron (C3n.4r), below the Thvera normal subchron."

MIS Boundary TG5/TG6 is at 5315 ka.

MIS Boundary TG4/TG5 is at 5301 ka.

MIS Boundary TG3/TG4 is at 5289 ka.

MIS Boundary TG2/TG3 is at 5266 ka.

MIS Boundary TG1/TG2 is at 5241 ka.

MIS Boundary T8/TG1 is at 5188 ka.

MIS Boundary T7/T8 is at 5165 ka.

MIS Boundary T6/T7 is at 5116 ka.

MIS Boundary T5/T6 is at 5094 ka.

MIS Boundary T4/T5 is at 5070 ka.

MIS Boundary T3/T4 is at 5038 ka.

MIS Boundary T2/T3 is at 5016 ka.

MIS Boundary T1/T2 is at 5002 ka.

MIS Boundary ST4/T1 is at 4985 ka.

MIS Boundary ST3/ST4 is at 4976 ka.

MIS Boundary ST2/ST3 is at 4952.5 ka.

MIS Boundary ST1/ST2 is at 4931 ka.

MIS Boundary Si6/ST1 is at 4904 ka.

MIS Boundary Si5/Si6 is at 4883 ka.

MIS Boundary Si4/Si5 is at 4860 ka.

MIS Boundary Si3/Si4 is at 4840 ka.

MIS Boundary Si2/Si3 is at 4821 ka.

MIS Boundary Si1/Si2 is at 4807 ka.

MIS Boundary NS6/Si1 is at 4778 ka.

MIS Boundary NS5/NS6 is at 4766 ka.

MIS Boundary NS4/NS5 is at 4737 ka.

MIS Boundary NS3/NS4 is at 4722.5 ka.

MIS Boundary NS2/NS3 is at 4702.5 ka.

MIS Boundary NS1/NS2 is at 4684 ka.

MIS Boundary N10/NS1 is at 4658 ka.

MIS Boundary N9/N10 is at 4648 ka.

MIS Boundary N8/N9 is at 4622 ka.

MIS Boundary N7/N8 is at 4603 ka.

MIS Boundary N6/N7 is at 45887 ka.

MIS Boundary N5/N6 is at 4570 ka.

MIS Boundary N4/N5 is at 4538 ka.

MIS Boundary N3/N4 is at 4523 ka.

MIS Boundary N2/N3 is at 4508 ka.

MIS Boundary N1/N2 is at 4487 ka.

MIS Boundary CN8/N1 is at 4457 ka.

MIS Boundary CN7/CN8 is at 4446 ka.

MIS Boundary CN6/CN7 is at 4420 ka.

MIS Boundary CN5/CN6 is at 4395 ka.

MIS Boundary CN4/CN5 is at 4371 ka.

MIS Boundary CN3/CN4 is at 4356 ka.

MIS Boundary CN2/CN3 is at 4335 ka.

MIS Boundary CN1/CN2 is at 4327 ka.

MIS Boundary Co4/CN1 is at 4303 ka.

MIS Boundary Co3/Co4 is at 4286 ka.

MIS Boundary Co2/Co3 is at 4259 ka.

MIS Boundary Co1/Co2 is at 4232 ka.

MIS Boundary Gi28/Co1 is at 4211 ka.

MIS Boundary Gi27/Gi28 is at 4192 ka.

MIS Boundary Gi26/Gi27 is at 4175 ka.

MIS Boundary Gi25/Gi26 is at 4146 ka.

MIS Boundary Gi24/Gi25 is at 4098 ka.

MIS Boundary Gi23/Gi24 is at 4085 ka.

MIS Boundary Gi22/Gi23 is at 4048 ka.

MIS Boundary Gi21/Gi22 is at 4029 ka.

MIS Boundary Gi20/Gi21 is at 4007 ka.

MIS Boundary Gi19/Gi20 is at 3978 ka.

MIS Boundary Gi18/Gi19 is at 3952 ka.

MIS Boundary Gi17/Gi18 is at 3939 ka.

MIS Boundary Gi16/Gi17 is at 3923 ka.

MIS Boundary Gi15/Gi16 is at 3912 ka.

MIS Boundary Gi14/Gi15 is at 3879 ka.

MIS Boundary Gi13/Gi14 is at 3862 ka.

MIS Boundary Gi12/Gi13 is at 3835 ka.

MIS Boundary Gi11/Gi12 is at 3822 ka.

MIS Boundary Gi10/Gi11 is at 3798 ka.

MIS Boundary Gi9/Gi10 is at 3768 ka.

MIS Boundary Gi8/Gi9 is at 3752 ka.

MIS Boundary Gi7/Gi8 is at 3742 ka.

MIS Boundary Gi6/Gi7 is at 3719 ka.

MIS Boundary Gi5/Gi6 is at 3705 ka.

MIS Boundary Gi4/Gi5 is at 3676 ka.

MIS Boundary Gi3/Gi4 is at 3660 ka.

MIS Boundary Gi2/Gi3 is at 3637 ka.

MIS Boundary Gi1/Gi2 is at 3619 ka.

Piacenzian
The magnetic field reversal to the present geomagnetic poles (Matuyama chron) occurred at 2,590,000 yr BP.

"The base of the beige marl bed of the small-scale carbonate cycle 77 (sensu Hilgen, 1991b) is the approved base of the Piacenzian Stage (that is the Lower Pliocene-Middle Pliocene boundary). It corresponds to precessional excursion 347 as numbered from the present with an astrochronological age estimate of 3.600 Ma (Lourens et al., 1996a)."

MIS Boundary MG12/Gi1 is at 3592 ka.

MIS Boundary MG11/MG12 is at 3578 ka.

MIS Boundary MG10/MG11 is at 3566 ka.

MIS Boundary MG9/MG10 is at 3546 ka.

MIS Boundary MG8/MG9 is at 3532 ka.

MIS Boundary MG7/MG8 is at 3517 ka.

MIS Boundary MG6/MG7 is at 3471 ka.

MIS Boundary MG5/MG6 is at 3444 ka.

MIS Boundary MG4/MG5 is at 3387 ka.

MIS Boundary MG3/MG4 is at 3372 ka.

MIS Boundary MG2/MG3 is at 3347 ka.

MIS Boundary MG1/MG2 is at 3332 ka.

MIS Boundary M2/MG1 is at 3312 ka.

MIS Boundary M1/M2 is at 3264 ka.

MIS Boundary KM6/M1 is at 3238 ka.

MIS Boundary KM5/KM6 is at 3212 ka.

MIS Boundary KM4/KM5 is at 3184 ka.

MIS Boundary KM3/KM4 is at 3167 ka.

MIS Boundary KM2/KM3 is at 3150 ka.

MIS Boundary KM1/KM2 is at 3119 ka.

MIS Boundary K2/KM1 is at 3097 ka.

MIS Boundary K1/K2 is at 3087 ka.

MIS Boundary G22/K1 is at 3055 ka.

MIS Boundary G21/G22 is at 3039 ka.

MIS Boundary G20/6G21 is at 3025 ka.

MIS Boundary G19/G20 is at 2999 ka.

MIS Boundary G18/G19 is at 2982.5 ka.

MIS Boundary G17/G18 is at 2966 ka.

MIS Boundary G16/G17 is at 2937 ka.

MIS Boundary G15/G16 is at 2913 ka.

MIS Boundary G14/G15 is at 2893 ka.

MIS Boundary G13/G14 is at 2876 ka.

MIS Boundary G12/G13 is at 2858 ka.

MIS Boundary G11/G12 is at 2838 ka.

MIS Boundary G10/G11 is at 2820 ka.

MIS Boundary G9/G10 is at 2798 ka.

MIS Boundary G8/G9 is at 2777 ka.

MIS Boundary G7/G8 is at 2759 ka.

MIS Boundary G6/G7 is at 2730 ka.

MIS Boundary G5/G6 is at 2704 ka.

MIS Boundary G4/G5 is at 2690 ka.

MIS Boundary G3/G4 is at 2681 ka.

MIS Boundary G2/G3 is at 2652 ka.

MIS Boundary G1/G2 is at 2638 ka.

MIS Boundary 104/G1 is at 2614 ka.

Paleolithic history
The paleolithic period dates from around 2.6 x 106 b2k to the end of the Pleistocene around 12,000 b2k.

MIS Boundary 103/105 is at 2595 ka.

The Paleolithic extends from the earliest known use of stone tools, probably by hominins such as australopithecines, 2.6 million years ago, to the end of the Pleistocene around 10,000 [Before Present] BP [12,000 b2k]. The Paleolithic era is followed by the Mesolithic. The date of the Paleolithic—Mesolithic boundary may vary by locality as much as several thousand years.

"Between 45,000 and 24,000 years ago [modern humans reached as far as 71° north latitude [at a site on the Yana River above the Arctic Circle in Siberia]."

"There were three coastal techno-complexes: the Fosna along the coast of southern Norway, the Hensbacka in southwest Sweden near Bohuslän and the Komsa in northern Norway, all with a forerunner in the late Paleolithic Ahrensburg culture further south (Ibid. 74)."

"By ca. 13,000 BP [13,000 b2k] long stretches of the Norwegian coast were ice-free but, as Hein Bjartmann Bjerck points out, there was “no certain evidence of human settlement in this rich arctic biotope” until near the end of the Younger Dryas (1,300 year cold snap) about 10,000 BP (2008: 65). The earliest evidence of human activity in Scandinavia is during the Early Mesolithic chronozone from 10,020-8,900 BP (9,500-8,000 cal BC); Bjerck lists 37 key sites in Norway (Ibid. 75-78)."

Quaternary
The "whole change elapsed just opposite the course of events that characterized the great glacial oscillations with sudden warming followed by slow cooling. Therefore, the two phenomena hardly have the same cause."

"In the Greenland ice cores, the Pleistocene–Holocene transition is chronologically constrained between two clearly defined tephra horizons: the Saksunarvatn tephra (1409.83 m depth) and the Vedde Ash (1506.14 m depth). These are dated at 10 347 yr b2 k (counting uncertainty 89 yr) and 12 171 yr (counting uncertainty 114 yr) b2 k, respectively."

Pleistocene
The Pleistocene dates from 2.588 x 106 to 11,700 b2k.

Gelasian
Some number of N tills occurred during the Olduvai subchron.

The magnetic field reversal to the present geomagnetic poles (Olduvai subchron) occurred at 2,000,000 yr BP.

The oldest till group, R2 tills, consists of till units with a reversed polarity and >77% of sedimentary clasts. Low amounts of expandable clays, substantial amounts of kaolinite, and the absence of chlorite characterize the clay mineralogy of R2 tills. The mineralogy of the silt fraction of R2 tills is rich in quartz and depleted in calcite, dolomite, and feldspar. This till group includes a till unit that underlies the 2.0-Ma Huckleberry Ridge ash, thus indicating deposition sometime between ~2.5 Ma (onset of Northern Hemisphere glaciations) (Mix et al., 1995) and 2.0 Ma.

The magnetic field reversal to the present geomagnetic poles (Reunion subchron) and back occurred at 2,080,000 yr BP.

The magnetic field reversal to the present geomagnetic poles (Reunion subchron) and back occurred at 2,140,000 yr BP.

"The base of the Quaternary System [shown in the image on the right] is defined by the Global Stratotype Section and Point (GSSP) of the Gelasian Stage at Monte San Nicola in Sicily, Italy, currently dated at 2.58 Ma."

"The astrochronological age of sapropel MPRS 250 (mid-point), corresponding to precessional cycle 250 from the present, is 2.588 Ma (Lourens et al., 1996), which can be assumed as the age of the boundary."

MIS Boundary 102/103 is at 2575 ka.

MIS Boundary 101/102 is at 2554 ka.

MIS Boundary 100/101 is at 2540 ka.

MIS Boundary 99/100 is at 2510 ka.

MIS Boundary 98/99 is at 2494 ka.

MIS Boundary 97/98 is at 2477 ka.

MIS Boundary 96/97 is at 2452 ka.

MIS Boundary 95/96 is at 2427 ka.

MIS Boundary 94/95 is at 2407 ka.

MIS Boundary 93/94 is at 2387 ka.

MIS Boundary 92/93 is at 2373 ka.

MIS Boundary 91/92 is at 2350 ka.

MIS Boundary 90/91 is at 2333 ka.

MIS Boundary 89/90 is at 2309 ka.

MIS Boundary 88/89 is at 2291 ka.

MIS Boundary 87/88 is at 2273 ka.

MIS Boundary 86/87 is at 2250 ka.

MIS Boundary 85/86 is at 2236 ka.

MIS Boundary 84/85 is at 2207.5 ka.

MIS Boundary 83/84 is at 2192 ka.

MIS Boundary 82/83 is at 2168 ka.

MIS Boundary 81/82 is at 2146 ka.

MIS Boundary 80/81 is at 2125 ka.

MIS Boundary 79/80 is at 2103 ka.

MIS Boundary 78/79 is at 2088 ka.

MIS Boundary 77/78 is at 2043 ka.

MIS Boundary 76/77 is at 2017 ka.

Huckleberry Ridge ash is dated at 2003 ka.

MIS Boundary 75/76 is at 1990 ka.

MIS Boundary 74/75 is at 1965 ka.

MIS Boundary 73/74 is at 1941 ka.

MIS Boundary 72/73 is at 1915 ka.

MIS Boundary 71/72 is at 1898 ka.

MIS Boundary 70/71 is at 1875 ka.

MIS Boundary 69/70 is at 1859.5 ka.

MIS Boundary 68/69 is at 1849 ka.

MIS Boundary 67/68 is at 1832.5 ka.

MIS Boundary 66/67 is at 1826 ka.

MIS Boundary 65/66 is at 1816 ka.

MIS Boundary 64/65 is at 1802.5 ka.

Calabrian
The magnetic field reversal to the present geomagnetic poles (Jaramillo subchron) occurred at 1,060,000 yr BP.

The magnetic field reversal to the opposite, back to the present, then opposite geomagnetic poles (Cobb Mountain subchron) occurred at 1,190,000 yr BP.

The magnetic field reversal to the opposite geomagnetic poles (Olduvai subchron) occurred at 1,780,000 yr BP.

"The [Calabrian] GSSP occurs at the base of the marine claystone conformably overlying sapropelic bed ‘e’ within Segment B in the Vrica section. This lithological level represents the primary marker for the recognition of the boundary, and is assigned an astronomical age of 1.80 Ma on the basis of sapropel calibration."

MIS Boundary 63/64 is at 1782 ka.

MIS Boundary 62/63 is at 1758 ka.

MIS Boundary 61/62 is at 1743 ka.

MIS Boundary 60/61 is at 1715 ka.

MIS Boundary 59/60 is at 1697.5 ka.

MIS Boundary 58/59 is at 1670 ka.

MIS Boundary 57/58 is at 1642.5 ka.

MIS Boundary 56/57 is at 1628.5 ka.

"The boundary falls between the highest occurrence of Discoaster brouweri (below) and the lowest common occurrence of left-coiling Neogloboquadrina pachyderma (above), and below the lowest occurrences of medium-sized Gephyrocapsa (including G. oceanica) and Globigerinoides tenellus."

In the image on the right, the Vrica section includes specifically the GSSP of the Calabrian Stage fixed at the top of layer 'e'.

Early Pleistocene
Early Pleistocene spans ca. 730,000-1,600,000 yr BP.

MIS Boundary 55/56 is at 1608 ka.

MIS Boundary 54/55 is at 1585 ka.

MIS Boundary 53/54 is at 1570 ka.

MIS Boundary 52/53 is at 1547.5 ka.

MIS Boundary 51/52 is at 1530 ka.

MIS Boundary 50/51 is at 1510 ka.

MIS Boundary 49/50 is at 1492 ka.

MIS Boundary 48/49 is at 1469 ka.

MIS Boundary 47/48 is at 1452 ka.

MIS Boundary 46/47 is at 1424 ka.

MIS Boundary 45/46 is at 1405 ka.

MIS Boundary 44/45 is at 1383 ka.

MIS Boundary 43/44 is at 1362 ka.

MIS Boundary 42/43 is at 1344 ka.

MIS Boundary 41/42 is at 1320 ka.

MIS Boundary 40/41 is at 1304 ka.

Mesa Falls ash is dated at 1293 ka.

MIS Boundary 39/40 is at 1286 ka.

MIS Boundary 38/39 is at 1264 ka.

MIS Boundary 37/38 is at 1244 ka.

MIS Boundary 36/37 is at 1215 ka.

MIS Boundary 35/36 is at 1190 ka.

MIS Boundary 34/35 is at 1141 ka.

MIS Boundary 33/34 is at 1114 ka.

MIS Boundary 32/33 is at 1104 ka.

MIS Boundary 31/32 is at 1081 ka.

MIS Boundary 30/31 is at 1062 ka.

MIS Boundary 29/30 is at 1031 ka.

MIS Boundary 28/29 is at 1014 ka.

Nebraskan glacial
Nebraskan glacial spans ca. 650,000-1,000,000 yr BP.

The magnetic field reversal to the present geomagnetic poles (Brunhes chron) occurred at 780,000 yr BP.

"The R1-till group includes two till units that overlie the 1.3 Ma Mesa Falls ash, thus indicating at least two glaciations between 1.3 Ma and 0.8 Ma."

The magnetic field reversal to the opposite geomagnetic poles (subchron) occurred at 900,000 yr BP.

MIS Boundary 27/28 is at 982 ka.

MIS Boundary 26/27 is at 970 ka.

MIS Boundary 25/26 is at 959 ka.

MIS Boundary 24/25 is at 936 ka.

MIS Boundary 23/24 is at 917 ka.

MIS Boundary 22/23 is at 900 ka.

MIS Boundary 21/22 is at 866 ka.

MIS Boundary 20/21 is at 814 ka.

MIS Boundary 19/20 is at 790 ka.

MIS Boundary 18/19 is at 761 ka.

MIS Boundary 17/18 is at 712 ka.

MIS Boundary 16/17 is at 676 ka.

Middle Pleistocene
Middle Pleistocene spans ca. 150,000-730,000 yr BP.

Aftonian interglacial
Aftonian interglacial spans ca. 600,000-650,000 yr BP.

"N tills [...] show the greatest amount of feldspar and carbonate minerals in the silt fraction. This group includes at least one till unit overlain by the 0.6 Ma Lava Creek ash, thus suggesting that some of these units were deposited between 0.8 and 0.6 Ma, but also later, as indicated by two sites with a till overlying the 0.6 Ma ash (Boellstorff, 1973). The N till group is considered to include the A1, A2, and A3 tills of Boellstorff (1973, 1978b)."

Lava Creek B ash is dated at 602 ka.

MIS Boundary 15/16 is at 621 ka.

The Yellowstone Lava Creek B ash is dated at 639 ± 2 ka ka.

"The Lava Creek B ash bed (0.64 Ma) originated from one of several Yellowstone Plateau plinian eruptions that produced extensive ashfall over much of the west-central United States (Izett and Wilcox, 1982)."

"The second, and geochemically analyzed, occurrence of Lava Creek B ash is in Kelso Gulch, along sloping hillsides slightly above the valley floor (Fig. 2). The tephra layer intermittently follows the contour of the hillslope at an elevation of 1,591 m. It is variably cemented with calcite and up to 5 cm thick. At this locality, geochemical confirmation of the Lava Creek B ash by co-author Wan (Table 1) comes from sample K06CO3, collected from an indurated, ca. 5-cm-thick ash bed exposed on a hillside (Fig. 2). This ash bed is thinly mantled by slope-wash."

"Processing, petrographic analysis, and geochemical fingerprinting of tephra sample K06CO3 and its identification as the Lava Creek B ash was performed at the USGS Tephrochronology Laboratory and the Electron Microprobe Laboratory in Menlo Park, California."

"The age of the [stag moose Cervalces] roosevelti type specimen is pre-Wisconsin (Aftonian)".

"Examples of pre–Illinoian sections [are in the images on the right]. (A) Two till units with paleosols separated by nonglacial silt and clay unit at site 19 (blow-up of units to left). (B) Lava Creek B ash (0.602 Ma) cropping out near site 4. (C) Two-till unit sequence capped by loess deposits at site 15. Lower till is truncated by sand and gravel unit whereas upper till is affected by paleosol development. Sandy diamicton is present between lower till and bedrock."

Kansan glacial
Kansan glacial spans 500,000-600,000 yr BP.

MIS Boundary 14/15 is at 563 ka.

MIS Boundary 13/14 is at 533 ka.

Yarmouthian interglacial
"Clay deposition in the Piauí River floodplain around 436 ± 51.5 ka occurred during a warmer period of the [Yarmouthian interglaciation] Aftonian interglaciation, corresponding to isotope stage 12 (Ericson and Wollin, 1968)."

"The extinctions and earliest known first occurrences of the 26 extant and 8 extinct cyst taxa in the three samples (with a minimum 430,000 yr BP Yarmouthian age) corroborate a likely assemblages with a maximum age of Illinoian (ca. 220,000-430,000 yr BP) in Unit I."

Yarmouthian spans 420,000-500,000 yr BP.

MIS Boundary 12/13 is at 478 ka.

MIS Boundary 11/12 is at 424 ka.

Illinois Episode glaciation
"Ages of sediments immediately beneath the oldest till (Kellerville Mbr.) in the bedrock valley average 160 ka and provide direct confirmation that Illinois Episode (IE) glaciation began in its type area during marine isotope stage (MIS) 6. The oldest deposits found are 190 ka fluvial sands on bedrock in the deepest part of the valley. These correlate to earliest MIS 6. We now correlate the lowest deposits to the IE (Pearl Fm.)."

The "last two glacial cycles [span] MIS 6 through 2".

"Illinoian [is] (ca. 220,000-430,000 yr BP)".

MIS Boundary 10/11 is at 374 ka.

MIS Boundary 9/10 is at 337 ka.

Marine Isotope Stage 9
MIS Boundary 8/9 is at 300 ka.

The base of the Pre-Illinoian stage has been correlated to the top of Marine Isotope Stage 9 at 300,000 BP.

Marine Isotope Stage 8
"The [Jebel Irhoud site] Moroccan fossils [...] are roughly 300,000 years old. Remarkably, they indicate that early Homo sapiens had faces much like our own, although their brains differed in fundamental ways."

"We did not evolve from a single 'cradle of mankind' somewhere in East Africa. We evolved on the African continent."

MIS Boundary 7/8 is at 243 ka.

Sangamon Episode interglacial
"OSL dates also suggest that last interglacial (MIS 5; Sangamon Ep.) fluvial deposits are preserved locally."

Age "assignment of Sangamonian (sense alto = 80,000-ca. 220,000 yr BP) [is] to Illinoian (ca. 220,000-430,000 yr BP)".

MIS Boundary 6/7 is at 191 ka.

Marine Isotope Stage 6
The base of the Illinoian stage and the top of the Pre-Illinoian stage correlates with the base of Marine Isotope Stage 6 at 191,000 BP.

Late Pleistocene
Late Pleistocene spans ca. 11,000-150,000 yr BP.

MIS Boundary 5/6 is at 130 ka.

Eemian interglacial
The "controversially split Eemian period, the predecessor of our own warm period about 125,000 years ago."

"The Eem interglaciation […] lasted from 131 to 117 kyr B.P."

Herning Stadial
MIS Boundary 5.5 (peak) is at 123 ka.

Brørup interstadial
The "Brørup interstade [is about] 100 ka BP". It corresponds to GIS 23/24.

MIS Boundary 5.4 (peak) is at 109 ka.

"More than 100,000 years ago in a Siberian cave there lived a child with a loose tooth."

"We only have relatively little data from this archaic group, so having any additional individuals is something we’re very excited about."

The "Denisova Cave [is] in the Altai Mountains [of Siberia where explorers] discovered the worn baby tooth in 1984."

"We think based on the DNA sequences that [the baby tooth] is at least 100,000 years, possibly 150,000 years old. Or a bit more. So far it makes it the oldest Denisovan. The baby tooth is at least 20,000 years older than the next oldest Denisovan specimen."

"This is four people in one cave and they have more variation than is in the Neanderthals, which are spread over 10,000 kilometers and over several hundreds of thousands of years."

Rederstall Stadial
MIS Boundary 5.3 is at 96 ka.

MIS Boundary 5.2 (peak) is at 87 ka.

MIS Boundary 5.1 (peak) is at 82 ka.

Wisconsinian glacial
Wisconsinian glacial began at 80,000 yr BP.

Odderade interstadial
The Odderade interstadial has a 14C date of 61-72 kyr B.P. and corresponds to GIS 21.

MIS Boundary 4/5 is at 71 ka.

Karmøy stadial
The Karmøy stadial begins in the high mountains of Norway about 60 kyr B.P. and expands to the outer coast by 58 kyr B.P.

The Schalkholz Stadial in North Germany is equivalent.

Oerel interstadial
The Oerel interstadial has a 14C date of 53-58 kyr B.P. and corresponds to GIS 15/16 with a GIS age of 56-59 kyr B.P.

MIS Boundary 3/4 is at 57 ka.

Ebersdorf Stadial
"Genetics suggests Neanderthal numbers dropped sharply around 50,000 years ago. This coincides with a sudden cold snap, hinting climate struck the first blow."

This corresponds to the Skjonghelleren Glaciation of Scandinavia where ice crosses the North Sea between 50-40 ka BP.

Glinde interstadial
The Glinde interstadial has a 14C date of 48-50 kyr B.P. and corresponds to GIS ?13/14 with a GIS age of 49-54.5 kyr B.P.

Moershoofd interstadial
The Moershoofd interstadial has a 14C date of 44-46 kyr B.P. and corresponds to GIS 12 at 45-47 kyr B.P.

Hasselo stadial
The "Hasselo stadial [is] at approximately 40-38,500 14C years B.P. (Van Huissteden, 1990)."

The "Hasselo Stadial [is a glacial advance] (44–39 ka ago)".

"One of two strongly rounded fragments of the mammoth maxilla from the Shapka Quarry in the southern Leningrad region was recently dated at 38450 + 400/–300 years (GrA-39 116) and rhinoceros remains (spoke bone), back to 38360 + 300/–270 years ago (GrA-38 819) [7]. The maxilla fragments occurred in sediments of the Leningrad Interstadial, which correspond to the transition between the Hasselo Stadial (44–39 ka ago) and the Hengelo Interstadial (38–36 ka ago)."

The Hasselo stadial corresponds to the Skjonghelleren stadial in Norway but to the Sejrø interstadial in Denmark.

"Paleomagnetic samples were obtained from cores taken during the drilling of a research well along Coyote Creek in San Jose, California, in order to use the geomagnetic field behavior recorded in those samples to provide age constraints for the sediment encountered. The well reached a depth of 308 meters and material apparently was deposited largely (entirely?) during the Brunhes Normal Polarity Chron, which lasted from 780 ka to the present time."

"Three episodes of anomalous magnetic inclinations were recorded in parts of the sedimentary sequence; the uppermost two we correlate to the Mono Lake (~30 ka) geomagnetic excursion and 6 cm lower, tentatively to the Laschamp (~45 ka) excursion."

"Some 41,000 years ago, a complete and rapid reversal of the geomagnetic field occured. Magnetic studies on sediment cores from the Black Sea show that during this period, during the last ice age, a compass at the Black Sea would have pointed to the south instead of north."

"[A]dditional data from other studies in the North Atlantic, the South Pacific and Hawaii, prove that this polarity reversal was a global event."

"The field geometry of reversed polarity, with field lines pointing into the opposite direction when compared to today's configuration, lasted for only about 440 years, and it was associated with a field strength that was only one quarter of today's field."

"The actual polarity changes lasted only 250 years. In terms of geological time scales, that is very fast."

"During this period, the field was even weaker, with only 5% of today's field strength. As a consequence, Earth nearly completely lost its protection shield against hard cosmic rays, leading to a significantly increased radiation exposure."

"This is documented by peaks of radioactive beryllium (10Be) in ice cores from this time, recovered from the Greenland ice sheet. 10Be as well as radioactive carbon (14C) is caused by the collision of high-energy protons from space with atoms of the atmosphere."

"The polarity reversal [...] has already been known for 45 years. It was first discovered after the analysis of the magnetisation of several lava flows near the village Laschamp near Clermont-Ferrand in the Massif Central, which differed significantly from today's direction of the geomagnetic field. Since then, this geomagnetic feature is known as the 'Laschamp event'."

The "new data from the Black Sea give a complete image of geomagnetic field variability at a high temporal resolution."

Hengelo interstadial
The Hengelo interstadial [is] > 35 ka BP".

The "Hengelo Interstadial [is] (38–36 ka ago)."

"An evolution with the coldest phases (coarsest grains) between 27,000 and 10,000 years B.P., 52,000 and 34,000 years B.P., and 76,000 and 60,000 years B.P. and relatively warmer intervals (finer grain size) in between is obvious. Apparently, they reflect a 21,000-year periodicity. This trend is superposed by much shorter oscillations of a duration of one to a few thousand years. Their duration is similar to the Dansgaard-Oeschger oscillations in the ice-core records. Some well-defined stadials and interstadials from the terrestrial records show also such a duration: for instance, the Hengelo interstadial around 37-38,500 14C years B.P. (Zagwijn, 1974; Kasse et al., 1995) and the preceding Hasselo stadial at approximately 40-38,500 14C years B.P. (Van Huissteden, 1990)."

Heinrich Event 4
Heinrich Event 4 "33-39.93 ka BP".

Huneborg interstadial
The Huneborg interstadial is a Greenland interstadial dating 36.5-38.5 kyr B.P. GIS 8.

The Denekamp interstadial corresponds to the Huneborg interstadial.

"GIS 8 (start) 35.716 [to] GIS 8 (end) 33.977 ka BP".

Stadial
"Stadial duration 0.642 ka".

GIS 7 interstadial
"GIS 7 (start) 32.896 [to] GIS 7 (end) 32.15 ka BP".

Stadial
"Stadial duration 0.932 ka".

Ålesund Interstadial
The Ålesund interstadial began with GIS 6 and ended after GIS 8.

"GIS 6 (start) 31.218 [to] GIS 6 (end) 30.849 ka BP".

Stadial
"Stadial duration 0.836 ka"

GIS 5
GIS 5 interstadial occurred during the Klintholm advance about 33.5 kyr B.P.

"GIS 5 (start) 30.013 [to] GIS 5 (end) 29.526 ka BP".

Klintholm advance
This advance occurred after the Møn and ended with GIS 6.

"Stadial duration 2.899 ka".

Møn interstadial
The Møn interstadial corresponds to GIS 4.

"GIS 4 (start) 26.627 [to] GIS 4 (end) 26.339 ka BP".

Stadial
Heinrich Event 3 (H3) "occurs at 26.74 ka BP, coincident with the start of the transition into GIS 4."

MIS Boundary 2/3 is at 29 ka.

"Stadial duration 0.768 ka".

GIS 3
The stronger GIS 3 interstadial occurred about 27.6 kyr B.P.

It begins abruptly at 29 ka and ends about 26 ka.

"GIS 3 (start) 25.571 [to] GIS 3 (end) 25.337 ka BP".

Letzteiszeitliches Maximum
This glacial advance begins about 26 ka and ends abruptly at about 23.4 ka.

"Stadial Duration 3.781 ka".

Laugerie Interstadial
The weak interstadial corresponding to GIS 2 occurred about 23.2 kyr B.P.

"GIS 2 (start) 21.556 [to] GIS 2 (end) 21.407 ka BP".

Heinrich Event 2 (H2) extends "22-25.62 ka BP".

The δ18O values from GISP-2 follow the diagram of Wolfgang Weißmüller. The positions of the Dansgaard-Oeschger events DO1 to DO4 and the Heinrich events H1 to H3 are also indicated. DV 3-4 and DV 6-7 are cold events marked by ice wedges in the upper loess of Dolní Veštonice.

Jylland stade
"After c. 22 ka BP [which is] during the Jylland stade (Houmark-Nielsen 1989), Late Weichselian glaciers of the Main Weichselain advance overrode Southeast Denmark from the northeast and later the Young Baltic ice invaded from southeasterly directions. Traces of the Northeast-ice are apparently absent in the Klintholm sections, although large scale glaciotectonic structures and till deposits from this advance are found in Hjelm Bugt and Møns Klint (Aber 1979; Berthelsen 1981, 1986). At Klintholm, the younger phase of glaciotectonic deformation from the southeast and south and deposition of the discordant till (unit 9) were most probably associated with recessional phases of the Young Baltic glaciation. In several cliff sections, well preserved Late Glacial (c. 14-10 ka BP) lacustrine sequences are present (Kolstrup 1982, Heiberg 1991)."

Lascaux interstadial
The Lascaux interstadial begins about 21 ka and extends to about 18 ka.

Heinrich event H1
This stadial starts about 17.5 ka, extends to about 15.5 ka and is followed after a brief warming by H1.

Meiendorf Interstadial
The period spans starting at the far right of the image on the right from Lascaux interstadial to Heinrich event H1, and to Meiendorf/Bölling warm stage, and Allegöd warm stage, to Younger dryas and early holocene.

The Meiendorf Interstadial is typified by a rise in the pollens of dwarf birches (Betula nana), willows (Salix sp.), sandthorns (Hippophae), junipers (Juniperus) and Artemisia.

The beginning of the Meiendorf Interstadial is around 14,700 b2k.

Oldest Dryas
"During the Late Weichselian glacial maximum (20-15 ka BP) the overriding of ice streams eventually lead to strong glaciotectonic displacement of Late Pleistocene and pre-Quaternary deposits and to deposition of till."

"The synchronous and nearly uniform lowering of snowlines in Southern Hemisphere middle-latitude mountains compared with Northern Hemisphere values suggests global cooling of about the same magnitude in both hemispheres at the [Last Glacial Maximum] LGM. When compared with paleoclimate records from the North Atlantic region, the middle-latitude Southern Hemisphere terrestrial data imply interhemispheric symmetry of the structure and timing of the last glacial/interglacial transition. In both regions atmospheric warming pulses are implicated near the beginning of Oldest Dryas time (~14,600 14C yr BP) and near the Oldest Dryas/Bølling transition (~12,700-13,000 14C yr BP). The second of these warming pulses was coincident with resumption of North Atlantic thermohaline circulation similar to that of the modern mode, with strong formation of Lower North Atlantic Deep Water in the Nordic Seas. In both regions, the maximum Bølling-age warmth was achieved at 12,200-12,500 14C yr BP, and was followed by a reversal in climate trend. In the North Atlantic region, and possibly in middle latitudes of the Southern Hemisphere, this reversal culminated in a Younger-Dryas-age cold pulse."

Bølling Oscillation
The "intra-Bølling cold period [IBCP is a century-scale cold event and the] Bølling warming [occurs] at 14600 cal [calendar years] BP (12700 14C BP)".

The "Bølling was originally defined as starting from 13000 14C BP (calibrated to ~15650 cal BP; Stuiver et al., 1998). [...] independent annual chronology indicate a much later onset of the Bølling (e.g., 14600 cal BP".

"During the IBCP and perhaps also IACP, δ 18O values inversely correlate with δ 13C, but during the OD δ 18O shows positive correlation with δ 13C, suggesting dry conditions with high evaporation, as well as cold."

The Bølling interstadial corresponds to GIS 1 as shown in the diagram on the right.

MIS Boundary 1/2 is at 14 ka.

Older Dryas
"Older Dryas [...] events [occurred about 13,400 b2k]".

"The most negative δ 18O excursions seen in the GRIP record lasted approximately 131 and 21 years for the [inter-Allerød cold period] IACP and [Older Dryas] OD, respectively. The comparable events in the Cariaco basin were of similar duration, 127 and 21 years. In addition to the chronological agreement, there is also considerable similarity in the decade-scale patterns of variability in both records. Given the geographical distance separating central Greenland from the southern Caribbean Sea, the close match of the pattern and duration of decadal events between the two records is striking."

In the figures on the right, especially b, is a detailed "comparison of δ 18O from the GRIP ice core24 with changes in a continuous sequence of light-lamina thickness measurements from core PL07-57PC. Both records are constrained by annual chronologies, although neither record is sampled at annual resolution. The interval of comparison includes the inter-Allerød cold period (12.9-13 cal. kyr BP) and Older Dryas (13.4 cal. kyr BP) events (IABP and OD from a). The durations of the two events, measured independently in both records, are very similar, as is the detailed pattern of variability at the decadal timescale."

Mesolithic
The mesolithic period dates from around 13,000 to 8,500 b2k.

The earliest traces of human settlement in Norway occur along the coast between 11,000 and 8,000 BC (13,000 to 10,000 b2k) during the Mesolithic, specifically the Younger Dryas period, include stone tools dated to between 11,000 b2k and 8,500 b2k.

Neolithic
The base of the Neolithic is approximated to 12,200 b2k.

Allerød Oscillation
The "Allerød Chronozone, 11,800 to 11,000 years ago".

"During the Allerød Chronozone, 11,800 to 11,000 years ago, western Europe approached the present day environmental and climatic situation, after having suffered the last glacial maximum some 20,000 to 18,000 years ago. However, the climatic deterioration 11,000 years ago led to nearly fully glacial conditions on this continent for some few hundreds of years during the Younger Dryas. This change is completely out of phase with the Milankovitch (orbital) forcing as this is understood today, and therefore its cause is of major interest."

"Excess 14C in Cariaco Basin sediments indicates a slowing in thermohaline circulation and heat transport to the North Atlantic at that time, and both marine and terrestrial paleoclimate proxy records around the North Atlantic show a short-lived (<400 yr) cold event (Intra-Allerød cold period) that began ca. 13,350 yr B.P."

Holocene
The Holocene starts at ~11,700 b2k and extends to the present.

"A timescale based on multi-parameter annual layer counting provides an age of 11 700 calendar yr b2k (before AD 2000) for the base of the Holocene, with a maximum counting error of 99 yr."

"The base of the Holocene Series/Epoch is defined in the NGRIP ice-core record [above] at the horizon which shows the clearest signal of climatic warming, an event that marks the end of the last cold episode (Younger Dryas Stadial/Greenland Stadial 1) of the Pleistocene [...]."

Younger Dryas
The "Alleröd/Younger Dryas transition [occurred] some 11,000 years ago [11,000 b2k]."

"The Younger Dryas interval during the Last Glacial Termination was an abrupt return to glacial-like conditions punctuating the transition to a warmer, interglacial climate."

"From former cirque glaciers in western Norway, it is calculated that the summer (1.May to 30.September) temperature dropped 5-6°C during less than two centuries, probably within decades, at the Alleröd/Younger Dryas transition, some 11,000 years ago."

Pre-Boreal transition
The last glaciation appears to have a gradual decline ending about 12,000 b2k. This may have been the end of the Pre-Boreal transition.

"About 9000 years ago the temperature in Greenland culminated at 4°C warmer than today. Since then it has become slowly cooler with only one dramatic change of climate. This happened 8250 years ago [...]. In an otherwise warm period the temperature fell 7°C within a decade, and it took 300 years to re-establish the warm climate. This event has also been demonstrated in European wooden ring series and in European bogs."

"The Pre-boreal period marks the transition from the cold climate of the Late-glacial to the warmer climate of Post-glacial time. This change is immediately obvious in the field from the nature of the sediments, changing as they do from clays to organic lake muds, showing that at this time a more or less continuous vegetation cover was developing."

"At the beginning of the Pre-boreal the pollen curves of the herbaceous species have high values, and most of the genera associated with the Late-glacial fiora are still present e.g. Artemisia, Polemomium and Thalictrum. These plants become less abundant throughout the Pre-boreal, and before the beginning of the Boreal their curves have reached low values."

Ancient history
The ancient history period dates from around 8,000 to 3,000 b2k.

The modern scientific discipline of astronomy focuses on reproducibility and physical theory to explain and describe observations. Many ancient observers produced remarkably reproducible calendars such as the Mayan Long Count calendar which apparently goes from August 11, 3114 BCE, to October 13, 4772, and beyond.

Ancient astronomical history is the aggregate of past observed astronomical events from the beginning of recorded human history to the Early Middle Ages. The span of recorded history is roughly 5,000 years, with Sumerian Cuneiform script, the oldest discovered form of coherent writing, from the protoliterate period around the 30th century BC.

And, on the telescope, there is this: "There are indeed ancient tablets that mention astronomers' lenses supported by a golden tube to enlarge the pupil, and in Nineveh a rock crystal lens was found (Pettinato 1998). Maybe one day a new archaeological excavation will find a Babylonian telescope for the first time."

Copper Age
The copper age history period began from 6990 b2k.

The "oldest securely dated evidence of copper making, from 7,000 years ago [6990 b2k], at the archaeological site of Belovode, Serbia."

The "Scandinavian one 2000 years earlier [8,000 b2k]."

Boreal transition
"In some cores a narrow band of clay interrupts the organic muds, at the horizon of the Boreal Atlantic transition."

Atlantic history
The "Atlantic period [is] 4.6–6 ka [4,600-6,000 b2k]."

"The last remains of the American ice sheet disappeared about 6000 years ago [6,000 b2k]".

Bronze Age
A general world-wide use of bronze occurred between 5300 and 2600 b2k.

"The first (purely typological) studies on Early Bronze Age (EBA) assemblages in the Jordan Valley settled on the turn of the 4th/3rd millennium BC [mark] the beginnings of the earliest Bronze Age culture (Albright 1932; Mallon 1932)."

"In the Chalcolithic/earliest Bronze Age I period (c. 4500±3000 cal BC), copper was mined in open galleries from the massive brown sandstone deposit, which consisted of thick layers of the copper carbonate malachite and chalcocite, a copper sulphide."

Iron Age
The iron age history period began between 3,200 and 2,100 b2k.

"The earliest known iron artefacts are nine small beads securely dated to circa 3200 BC, from two burials in Gerzeh, northern Egypt."

"Since both tombs are securely dated to Naqada IIC–IIIA, c 3400–3100 BC (Adams, 1990: 25; Stevenson, 2009: 11–31), the beads predate the emergence of iron smelting by nearly 2000 years, and other known meteoritic iron artefacts by 500 years or more (Yalçın 1999), giving them an exceptional position in the history of metal use."

The image on the left uses neutron radiography to show the metal underneath the corrosion.

"Bead UC10738 [in the image on the right] has a maximum length of 1.5 cm and a maximum diameter of 1.3 cm, bead UC10739 is 1.7 cm by 0.7 cm, and bead UC10740 is 1.7 cm by 0.3 cm. All three beads are of rust-brown colour with a rough surface, indicative of heavy iron corrosion. Initial analysis by [proton–induced X–ray fluorescence] pXRF indicated an elevated nickel content of the surface of the beads, in the order of a few per cent, and their magnetic property suggested that iron metal may be present in their body (Jambon, 2010)."

Early history
The early history period dates from around 3,000 to 2,000 b2k.

"About 280 B.C. [2280 b2k], ... Aristarchus of Samos proposed the hypothesis that the Sun is at rest, while the Earth and the planets rotate about the Sun." "Aristarchus also figured out how to measure the distances to the Sun and the Moon and their sizes."

The celestial sphere may have been produced very early: According to records, the first celestial globe was made by Geng Shou-chang (耿壽昌) between 70 BC and 50 BC. In the Ming Dynasty, the celestial globe at that time was a huge globe, showing the 28 mansions, celestial equator and ecliptic. None of them have survived.

Subboreal history
The "period around 850-760 BC [2850-2760 b2k], characterised by a decrease in solar activity and a sharp increase of Δ 14C [...] the local vegetation succession, in relation to the changes in atmospheric radiocarbon content, shows additional evidence for solar forcing of climate change at the Subboreal - Subatlantic transition."

The "Holocene climatic optimum in this interior part of Asia [Lake Baikal] corresponds to the Subboreal period 2.5–4.5 ka".

Subatlantic history
The "calibration of radiocarbon dates at approximately 2500-2450 BP [2500-2450 b2k] is problematic due to a "plateau" (known as the "Hallstatt-plateau") in the calibration curve [...] A decrease in solar activity caused an increase in production of 14C, and thus a sharp rise in Δ 14C, beginning at approximately 850 cal (calendar years) BC [...] Between approximately 760 and 420 cal BC (corresponding to 2500-2425 BP [2500-2425 b2k]), the concentration of 14C returned to "normal" values."

-5th Century
Apparently construction on the Parthenon is dated to have begun in 447 BC (2447 b2k) and was completed in 438 BC (2438 b2k) although decoration continued until 432 BC (2432 b2k).

A logboat from Ireland, Kilraghts, Co. Antrim, designated GrN-14743, has been radiocarbon dated to 2405 ± 20 BP or b2k.

-4th Century
The Hellenistic period is between the death of Alexander the Great dated to 323 BC and the Battle of Actium dated to 31 BC and the conquest of Ptolemaic Egypt dated to 30 BC.

The bronze statue imaged on the right is missing the feet, ankles, eyes, part of the crown and the palm branch originally brought in the left hand. The statue is supported by a stainless steel rod inserted in his right leg. It is dated from 340 until 100 BC.

Two logboats from Ireland, 124 Shapwick and 47 Ellesmere, designated Q-357 and Q-1246, have been radiocarbon dated to 2305 ± 120 and 2320 ± 50 BP or b2k, respectively.

-3rd Century
"Jastorf (La Tène) culture [3rd to 1st century BC] with bronze and iron technology. Rich building evidence in downtown Bremen."

A logboat from Britain 40 Clifton I, designated Q-1374, has been radiocarbon dated to 2250 ± 45 and 2275 ± 35 BP or b2k.

-2nd Century
The "fragments [of the Antikythera Mechanism] contain at least 30 interlocking gear-wheels, along with copious astronomical inscriptions. Before its sojourn on the sea bed, it computed and displayed the movement of the Sun, the Moon and possibly the planets around Earth, and predicted the dates of future eclipses."

The Winged Nike of Samothrace is made from Parian marble, ca. 190 BC? and found in Samothrace in 1863 by the archaeological expedition of Charles Champoiseau, 1863 and 1879.

Cleopatra II on the left was involved in the ruling of Egypt apparently from c. 175 BC to until she died in 116 BC.

A logboat, Eskragh, Co. Tyrone, from Ireland, designated GrN-14740, has been radiocarbon dated to 2165 ± 25 BP or b2k.

-1st Century
] The "Late La Tène time span [is] between the conquests of 55 BC and 54 BC [2055 and 2054 b2k] under Julius Caesar (100-44 BC) and the time of Christ. In the rare cases where pottery and tableware are attributed to Saxons of the 4th/5th c. AD, "astonishingly La Tène art styles [more than 300 years out of fashion] re-emerge as dominant in the northern and western zone." (Hines 1996, 260)"

"Stamped pottery has had a long and varied history in Britain. There have been periods when it flourished and periods when it almost totally disappeared. This article considers two variations of the rosette motif (A 5) and their fortunes from the late Iron Age to the Early Saxon period. [...] The La Tène ring stamps [which end in the 1st century BC; GH ] are found in a range of designs, from the simple negative ring (= AASPS Classification A 1bi) to four concentric negative rings (= AASPS A 2di). These motifs are also found in the early Roman period [1st century AD; GH]. [...] The 'dot rosettes' (= AASPS A 9di) on bowls from the [Late Latène] Hunsbury hill-fort (Fell 1937) use the same sort of technique as the dimple decoration on 4th-century 'Romano-Saxon' wares."

In "Šarnjaka kod Šemovca (Dalmatia/Croatia), e.g., contain 700-year-older La Tène and Imperial period items (1st century BC to 3rd century AD) [...]:"

"A large dugout house (SU 9) was discovered in the course of the investigation in 2006. Its dimensions are 4.8 by 2.1 metres, with a depth of 34 centimetres, and an east-west orientation, deviating slightly along the NE-SW line. It contained numerous sherds of Early Medieval pottery, two fragments of glass, and a small iron spike. Three sherds of Roman pottery [1st-3rd c. CE; GH] and ten sherds of La Tène pottery [ending 1st c. BCE; GH] were also recovered from the house."

"The contemporaneity of Rome’s Imperial period textbook-dated to the 1st-3rd century AD with the Early Middle Ages (8th-10th century AD) is also confirmed for Poland [in the stratigraphic table above]. There, too, Late Latène (conventionally ending 1st c. BC) immediately precedes the Early Medieval period of the 8th-10th c. CE."

"In [the Roman Empire] capital cities, Rome and Constantinople (Heinsohn 2016) [they] build residential quarters, streets, latrines, aqueducts, ports etc. only in one of the three periods—Imperial Antiquity, Late Antiquity, and Early Middle Ages—dated between 1 and 930s AD. In Rome, they are assigned to Imperial Antiquity (1st-3rd c.); in Constantinople, to Late Antiquity (4th-6th c.)."

"Roman churches of Late Antiquity and the Early Middle Ages [...] would suffice to confirm the existence of these two periods. The churches are there. However, we never find churches of the 8th or 9th century superimposed on churches of the 4th or 5th century that, in turn, are superimposed on pagan basilicas of the 1st or 2nd century. They all share the same stratigraphic level of the 1st and 2nd/early 3rd century. Moreover, the ground plans of the 4th/5th—as well as the 8th/9th—century churches slavishly repeat the ground plans of 1st/2nd century basilicas, as already pointed out 75 years ago by Richard Krautheimer (1897-1994). It is this period of Imperial Antiquity (with its internal evolution from the 1st to 3rd centuries) that alone builds the residential quarters, latrines, streets, and aqueducts so desperately looked for in Late Antiquity and the Early Middle Ages. Thus, Rome does not have more stratigraphy for the first millennium AD than England or Poland."

"Germanic tribes, not only Anglo-Saxons and Frisians but also Franks, had been competing with Rome for the conquest of the British Isles since the 1st century BC".

"1st century BC "Astonishingly LA TÈNE art styles" (Hines 1996) dominate pottery of SAXONS [and] Powerful LA TÈNE Celts with King Aththe-Domarous of Camulodunum [is the] greatest ruler."

"Saxons begin their attack on Britain as early as the 1st century BC. They compete with the Romans, who may have employed Germanic Franks as auxiliary forces. The Saxons invade from the East, i.e., from the German Bight."

From "the stratigraphy of the Saxon homeland, located around Bremen/Weser inside today’s Lower Saxony [it] is mainly inhabited by Chauci and Bructeri [...] Saxon tribes that are [...] at war with the Romans in the time of Augustus (31 BC-14 AD) and Aththe-Domaros of Camulodunum (Aθθe-Domaros, also read as Addedom-Arus; c. 15-5 BC)."

On the right is an Indian-standard coin of King Maues. On the obverse is a rejoicing elephant holding a wreath, a symbol of victory. The Greek legend reads ΒΑΣΙΛΕΩΣ&#32;ΒΑΣΙΛΕΩΝ&#32;ΜΕΓΑΛΟΥ&#32;ΜΑΥΟΥ (Great King of Kings Maues). The reverse shows the seated king Maues. Kharoshthi legend: RAJATIRAJASA MAHATASA MOASA (Great King of Kings Maues).

Gortgill, Co. Antrim, is the location of a logboat from Ireland, designated UB-268I, radiocarbon dated to 2060 ± 60 BP or b2k.

Classical history
The classical history period dates from around 2,000 to 1,000 b2k.

Imperial Antiquity
Imperial Antiquity lasts from 2,000 to 1,700 b2k.

In Felix Romuliana, "the construction [...] is [...] Imperial Antique (1st-3rd c.), and sometimes even late Hellenistic, [in] appearance."

1st Century
On the left is a Roman fresca of Venus standing on a quadriga of elephants from the Officina di Verecundus (IX 7, 5) in Pompeii, first century.

"[1st century AD] Saxon Chauci create rich building evidence. 50 m long houses (three aisles) with integrated stables are found all over the city and many suburbs; blacksmith shops; charcoal kiln technology etc."

"A succession of fires allowed the preservation of all the elements in place, when the inhabitants ran away from the catatrophe, transforming the area into a real little Pompei of Vienne [image on the right]."

"The fire brought the top floor, the roof and the terrasse of a sumptuous dwelling to collapse, both caved in floors being preserved, with the furniture left in place. The house, dating from the the second half of the first century and surrounded by gardens, was baptised "House of the Bacchae" because of a mosaic with a cortege of bacchae surrounding a Bacchus."

"With many others, a superb mosaic preserved in its near-totality in the "House of Thalia and Pan" has been lifted with much precaution earlier this week, to be restored at the ateliers of the gallo-roman museum of Saint-Romain-en-Gal."

"The Roman city of Vienne, in Southeast France, was at a crossroads of communications, between the Rhône River and the Roman province of Gallia Narbonensis, on a "highway" connecting Lyon, the capital of Gaul, to the city of Arles. Another axis of circulation had most probably preceded it and the excavations «provide also an exceptional opportunity to analyze the anterior states of the Roman road of Gallia Narbonensis, or Transalpine Gaul, "one of the most important of this time.""

"Besides the two luxurious houses, the neighborhood included shops dedicated to metalwork, food stores and other artisanal production; a warehouse full of jugs for wine; and a hydraulic network that allows for cleaning and drainage. The neighborhood appeared to be built around a market square, apparently the largest of its kind to be discovered in France."

A logboat from Britain 7 Baddiley Mere designated Q-1496 has been radiocarbon dated to 1980 ± 50 BP or b2k.

2nd Century
"[2nd/3rd century AD] Ptolemy’s PHA-BIRABON is identified with Bremen though there are other candidates, too. Rich evidence for Roman period. Settlements of 1st century are continued."

The last known celestial globe shown at the right dates from 1850 to 1780 b2k. The constellation illustrations from the Mainz celestial globe are shown at the left.

"After Octavian/Augustus (31 BCE – 14 CE) had, in 30 BCE, turned Egypt into an imperial province of the Roman Empire, Memphis continued to thrive. Suetonius (69-122) writes about the city in his Life of Titus (part XI of The Twelve Caesars)."

A 2nd-century sculpture on the right perhaps shows Phosphorus (the Morning star) and Hesperus (the Evening star) on either side of the Moon (Selene or Luna).

A logboat from Ireland Crevinish Bay l, Co. Femlanagh, designated HAR-1969, has been radiocarbon dated to 1860 ± 70 BP or b2k.

On the left is an image of the oldest extant diagram of Euclid's Elements, found at Oxyrhynchus and dated to c. 100 AD.

3rd Century
In the late imperial antiquity map on the right, provincial boundaries (dashed red lines) are approximate and, in many places, very uncertain.

"Many [British] building sequences appear to terminate in the 2nd and 3rd centuries [1900-1700 b2k]. [...] The latest Roman levels are sealed by deposits of dark coloured loam, commonly called the 'dark earth' (formerly 'black earth'). In the London area the 'dark earth' generally appears as a dark grey, rather silty loam with various inclusions, especially building material. The deposit is usually without stratification and homogeneous in appearance, It can be one meter or more in thickness. [...] The evidence suggests that truncation of late Roman stratification is linked to the process of 'dark earth' formation."

“Parts [of Londinium] / were already covered by a horizon of dark silts (often described as 'dark earth') / Land was converted to arable and pastoral use or abandoned entirely. The dark earth may have started forming in the 3rd century."

A logboat from Britain 168 Wisley designated Q-1399 has been radiocarbon dated to 1780 ± 45 BP or b2k.

Early Middle Ages
The Early Middle Ages date from around 1,700 to 1,000 b2k.

At left is an attempt to correlate the change in 14C with time before 1950. The different data sets are shown with different colored third order polynomial fits to each data set.

"The Δ14C values in a chronology can clearly be used to identify catastrophic gaps and catastrophic rises in carbon-14."

The first four gaps have a jump up in 14C with a fairly quick return to the calibration curve shown in the figure on the second left. However, from about 2000 b2k there is a steady rise in the Δ14C values.

4th Century
The House of Peter in Capernaum, Israel, has been dated to the 4th century.

"Recent archaeological excavations have focused on the late fourth and fifth centuries. The discovery of two young adult skeletons in a burial pit in the courtyard of the commander's house have been dated to the early fifth century. The bodies were not buried immediately after their deaths but were left [...] for animals to prey upon before they were thrown into the burial pit. The bodies of the young man and young woman have been radiocarbon dated to 140-430 AD cal. and 340-660 AD. Archaeologists believe that the commander's house was already in ruins at the time of their deaths, and the burial in the pit suggests the Roman community was no longer present at Arebia. The end of the occupation can be tentatively dated by two coins dated to AD 388-402 found on the floor of the commander's house. These coins are the latest Roman coins to be found anywhere along the northern Roman defenses. This last period of Roman occupation was active, with the fort's garrison and defenses consistently maintained. The fortress was remodeled or repaired in the same period since another coin dating to 388-402 was found in the resurfaced road of the rebuilt west gate. This combined data suggests that the fortress was occupied by the Romans until the end of the fourth century and that the end came rapidly."

A logboat from Ireland, Drummans Lower, Co. Leitrim, designated GrN-18756 has been radiocarbon dated to 1630 ± 30 BP or b2k.

5th Century
Ancient India was an early leader in metallurgy, as evidenced by the wrought-iron Pillar of Delhi in the image on the right, dated to about 415 or 1585 b2k.

"The Saxons tended to avoid Roman sites possibly because they used different farming methods."

"[We] learn from Prof. Fleming [2016] that Roman conquerors introduced many — perhaps as many as 50 — new and valuable food plants and animals (such as the donkey) to its province of Britannia, where these crops were successfully cultivated for some 300 years. Among the foodstuffs that Roman civilization brought to Britain are walnuts, carrots, broad beans, grapes, beets, cabbage, leeks, turnips, parsnips, cucumbers, cherries, plums, peaches, almonds, chestnuts, pears, lettuce, celery, white mustard, mint, einkorn, millet, and many more. These valuable plants took root in Britain and so did Roman horticulture. British gardens produced a bounty of tasty and nourishing foods. [...] Following the collapse of Roman rule after 400 AD, almost all of these food plants vanished from Britain, as did Roman horticulture itself. Post-Roman Britons [...] suddenly went from gardening to foraging. Even Roman water mills vanished from British streams. But similar mills came back in large numbers in the 10th and 11th centuries, along with Roman food plants and farming techniques."

"Wat's Dyke has recently been redated to the fifth century. The dyke runs parallel to the eighth-century Offa's Dyke in the Welsh Marches. This area marked the border between the British kingdom of Powys and Mercia in medieval times. Excavations at Maes-y-Clawdd near Oswestry have discovered a site along the dyke that contained the remains of a small fire and Roman-British pottery.  The charcoal from the fire had been radiocarbon dated to AD 411-561. It has been suggested that the dyke was associated with the Romano-British kingdom based on the city of Wroxter."

A logboat from Ireland Strabane, Co. Derry, has been dendrodated to 431 AD and radiocarbon dated 1610 BP or b2k.

Another Oxford Island, Co. Amlagh (Kinnegoe), has been dendrodated to 492 AD and radiocarbon dated 1590 BP or b2k.

6th Century
On the right is the Basilica Cistern in Constantinople, Turkey. It has been dated to the 6th century.

Dzibanche is an archaeological site which includes the Temple of the Owl pyramid. It is an ancient Maya site located in southern Quintana Roo, in the Yucatan Peninsula of southeastern Mexico.

Structures at Dzibanche include the Temple of the Captives, the Temple of the Lintels and the Temple of the Owl, on the left.

"AMS [Accelerator mass spectrometry] 14C dating [summarized on the left] indicates that the age [of Can Ferrerons, a Roman octagonal building in Premià de Mar, Barcelona, with an image of the Tepidarium on the right] is between CE 420–540, at 95.4% confidence level."

A logboat from Ireland West Ward I, Co. Tyrone, designated GrN-16863, has been radiocarbon dated to 1440 ± 30 BP or b2k.

7th Century
Sambor Pre Kuk, with its N16 Sanctuary imaged on the right, is an archaeological complex formed by the remains of the city of Isanapura, the capital of the kingdom of Chenla, an immediate predecessor of the Khmer Empire (pre-Angkorian).

This city was built during the reign of Isanavarman I (616-635). At this time, several constructions, clear predecessors of Khmer architecture, were erected in Angkor.

Cantona is a Mesoamerican archaeological site in the state of Puebla, Mexico. It was a fortified city with a high urbanization level at prehispanic times, probably founded by Olmec-Xicalanca groups towards the late Classical Period. It sat astride an old trading route between the Gulf Coast and the Central Highlands and was a prominent, if isolated, Mesoamerican city between 600 and 1000 CE. After Chichimec's invasions in the 11th century, Cantona was abandoned.

Cantona's inhabitants were mainly agricultural farmers and traders, particularly for obsidian, obtained from Oyameles-Zaragoza mountains surrounding the city. Additionally, they may have been supplying the lowlands with a derivative of the maguey plant, pulque. Cantona's population is estimated at about 80,000 inhabitants at its peak.

Cantona may well be the largest prehispanic city yet discovered in Mesoamerica. Limited archaeological work has been done at the site, and only about 10% of the site can be seen. The Pre-Columbian settlement area occupies approximately 12 km², distributed in three units, of which the largest is at the south, with a surface of 5 km². The site comprises a road network with over 500 cobblestone causeways, more than 3,000 individual patios, residences, and 24 ball courts - more than in any other mesoamerican site. It has an elevated Acropolis over the rest of the city in which the main buildings of the city were built. This was used for the ruling elite and priests, and was where the temples of the most important deities where located. These impressive buildings were constructed with carved stones (one atop the other) without any stucco or cement mortar. Cantona certainly was built with a definite urban design and walkways connecting each and every part of the city. The "First Avenue" is 563 meters in length.

8th Century
The Dunhuang map from the Tang Dynasty of the North Polar region at right is thought to date from the reign of Emperor Zhongzong of Tang (705–710). Constellations of the three schools are distinguished with different colors: white, black and yellow for stars of Wu Xian, Gan De and Shi Shen respectively. The whole set of star maps contains 1,300 stars.

The Dunhuang Star Atlas, the last section of manuscript Or.8210/S.3326. It is "the oldest manuscript star atlas known today from any civilisation, probably dating from around AD 700. It shows a complete representation of the Chinese sky in 13 charts with over 1300 stars named and accurately presented."

"The Dunhuang Star Atlas [above center] forms the second part of a longer scroll (Or.8210/S.3326) that measures 210 cm long by 24.4 cm wide and is made of fine paper in thirteen separate panels."

"The first part of the scroll is a manual for divination based on the shape of clouds. The twelve charts showing different sections of the sky follow these. The stars are named and there is also explanatory text. The final chart is of the north-polar region. The chart is detailed, showing a total of 1345 stars in 257 clearly marked and named asterisms, or constellations, including all twenty-eight mansions."

"The importance of the chart lies in both its accuracy and graphic quality. The chart includes both bright and faint stars, visible to the naked eye from north central China".

9th Century
There was an inscription which placed the foundation of the nilometer in 861.

Cobá is a former pre-Columbian Mayan city on the Yucatán Peninsula southeast of Valladolid located in the state of Quintana Roo, Mexico.

In Cobá, the temple pyramid Nohoch-Mul (also known as Castillo, or the climbing pyramid shown on the left) is 42 meters high.

The city was founded shortly after the beginning of the year and expanded into a city state that peaked between 600 and 800 (1400 and 1200 b2k).

10th Century
Visby was founded in the 10th century, on the then independent Baltic Sea island of Gotland. The Hansaetic League formed it during ensuing centuries, during which it came to Denmark. In 1645, it came into Swedish occupation, in which it has remained until today.

There is more about lenses more recently from Visby, Gotland.

"What intrigues the researchers is that the lenses are of such high quality that they could have been used to make a telescope some 500 years before the first known crude telescopes were constructed in Europe in the last few years of the 16th century."

"Made from rock-crystal, the lenses have an accurate shape that betrays the work of a master craftsman. The best example of the lenses measures 50 mm (2 inches) in diameter and 30 mm (1 inch) thick at its centre."

"The [Visby] Gotland crystals provide the first evidence that sophisticated lens-making techniques were being used by craftsmen over a 1,000 years ago."

High Middle Ages
The High Middle Ages date from around 1,000 b2k to 700 b2k.

"The first large-scale dike building activities commenced during the High Middle Ages, from the 11th to the 13th century. This marked a significant change in the relationship between man and nature. Whereas previously the sea flowed freely over the whole region during storm tides, it was now shut out. This provided an enormous boost to habitation and agriculture but when storm surges broke through dykes, people and cattle drowned in high numbers. These disasters were perceived as God’s aversion towards human wealth and corruption of moral standards, and had a lasting imprint on the mentality of the coastal population (Jakubowski-Tiessen, 2011)."

"Next to the building of dykes, the large-scale exploitation of the extensive peat lands between the clay areas and the sandy areas in the High Middle Ages also had a major impact on the coastal environment. In terms of water management, the construction of dykes and the exploitation of the peatlands cannot be considered separately (De Jonge, 2009). The exploitation together with the oxidising of the peat caused lowering of the level of the mainland behind the dykes which became a permanent challenge for drainage. Salt and peat mining also substantially contributed to the lowering of the marsh surface below the level of the sea."

11th Century
The star map on the right, which features a cylindrical projection, was published in 1092 and has a corrected position for the pole star using Shen Kuo's astronomical observations.

"All 5 pieces of the famous Swedish Överhogdal [tapestries such as the portion shown in the image on the right] were examined [by radiocarbon dating to 900 - 1100]."

Radiocarbon dating of charcoal fragments from Koumbi Salehin, a settlement in south east Mauritania, indicate the site was continuously occupied from the 8th/9th to the 13th centuries.

12th Century
Romanesque apses and brick towers of the Church of San Tirso, Sahagún, are shown on the right, dated to the 12th Century.

Recent dating of Sweden's oldest book, the Skara Missal [in the image on the left] shows that the book is just that: Sweden's oldest.

Researchers at Lund University concluded using radiocarbon dating that the book's pages are from the year 1150, i.e. at the time of the opening of the Skara cathedral.

Medieval Warm Period
The Medieval Warm Period (MWP) dates from around 1150 to 750 b2k.

"A proof-of-concept self-calibrating chronology [based upon the Irish Oak chronology] clearly demonstrates that third order polynomials provide a series of statistical calibration curves that highlight lacunae in the samples."

As indicated in the figures, the data used in the plots comes from radiocarbon dating of Irish Oaks.

Gaps occur near the 1070s and 1470s b2k during the rising Δ14C values.

"The number of suitable samples of wood, which connect Antiquity and the Middle Ages is very small [shown in the first figure on the left]. But only a great number of samples would give certainty against error. For the period about 380 AD we have only 3, for the period about 720 AD only 4 suitable samples of wood (Hollstein 1980,11); usually 50 samples serve for dating."

"The center of the graph [in the second image on the left] shows the time axis of conventionally dated historical events. Upper and lower coordinates show reconstructed time tables. The black triangles mark the phantom years."

"In Frankfurt am Main archaeological excavations did not find any layer for the period between 650 and 910 AD."

13th Century
The ruin tower on the right is apparently dated to the 13th Century and was built by the Anasazi.

The book was bound more than 100 years later with covers made of oak surrounded by leather, where the oak has been dated to 1264 using dendrochronology, and the oak trees used grew in the vicinity of Skara.

"In a meta-analysis of 1,434 radiocarbon dates from the region, reliable short-lived samples reveal that the colonization of East Polynesia occurred in two distinct phases: earliest in the Society Islands A.D. ~1025–1120, four centuries later than previously assumed; then after 70–265 y, dispersal continued in one major pulse to all remaining islands [15 archipelagos of East Polynesia, including New Zealand, Hawaii, and Rapa Nui] A.D. ∼1190–1290."

"The town of Tzintzuntzan, in addition to being a Pueblo Magico, is the heartland of Michoacan’s indigenous culture as it once served as the ceremonial center and capital of the Purépecha empire (Tarascan). The ceremonial center now is an outstanding archaeological site that contains five temples, called yacatas, which date back to the 13th century. Tzintzuntzan’s indigenous customs, traditions, and language are still very much present today."

Late Middle Ages
The Late Middle Ages extends from about 700 b2k to 500 b2k.

"Italy from the peace of Lodi to the first French invasion (1454-94): the era of equilibrium" is near the end of the late Middle Ages.

Charred materials from the Lake Pátzcuaro Basin, Mexico, were radiocarbon dated at 1170-1300 AD (680 b2k intercept), 1230-1315 AD (665 b2k intercept), 1300-1415 AD (605 b2k intercept), 1320-1535 AD (540 b2k intercept) and 1320-1435 AD (500 b2k intercept).

"During the late Middle Ages (a.d. 1000–1500), increased storm surges and tidal incursions allowed for extensive progressive erosion of inhabited peatlands, transforming the central Netherlands into the Zuyder Zee tidal lagoon. In the north-eastern quadrant of the expanding water body, medieval terrestrial geological and archaeological records fell prey to erosion, re-working and uptake into lagoon-floor deposits. These deposits have been intensively surveyed since the 1940s when the quadrant was reclaimed and made into arable land, and are revealed to contain spatially clustered late medieval archaeological objects."

14th Century
Italian humanism began in the first century of the late Middle Ages (c.1350-1450).

"The processed image at the right [in the images on the right] is the product of the application of digital filters. Digital filters are mathematical functions that do not add any information to the image, but transform it in such a way that information already present in it becomes more visible or easier to appreciate by the naked eye. The processed image was produced by inverting the brightness of the pixels in the positive image but without inverting their hue, and then by increasing both the brightness contrast and the hue saturation. Finally noise and so-called “salt and pepper” filters automatically removed the noisy information from the original image which hinders the appreciation of the actual face. To my knowledge the resulting image is the best available and indeed the only one that reveals the color information hidden in the original."

Radiocarbon dating of a corner piece of the shroud placed it between the years 1260 and 1390, in the High to Late Middle Ages, which is consistent with "its first recorded exhibition in France in 1357."

15th Century
"Italy from the peace of Lodi to the first French invasion (1454-94): the era of equilibrium" is near the end of the late Middle Ages.

A logboat from Ireland, Derryloughan A, Co. Tyrone, designated GrN-14737, has been radiocarbon dated to 570 ± 25 BP or b2k.

On the right is an image of an incense burner from the Tarascan culture, showing a deity with a "Tlaloc headdress", 1350 - 1521 AD, from the Snite Museum of Art.

The image second down on the right hangs in the interior of the ayuntamiento of San Cristobal de La Laguna, Tenerife.

The painting on the right shows the surrender of the Guanches kings of Tenerife to Ferdinand and Isabella. This appears to have occurred c. 504 b2k.

The painting on the left was painted in 1764. It depicts the surrender of the Guanches leaders Bencomo mencey with Tacoronte, Anaga and Tegueste to Governor Alonso Fernández de Lugo with his captains and noble friends, by bringing gifts to the governor.

16th Century
A logboat from Ireland (Derryloughan B, Co. Tyrone) designated GrN-14738 dates to 410 ± 35 b2k.

Angamuco "occupied 26 square kilometers of land instead of 13 square kilometers."

"That is a huge area with a lot of people and a lot of architectural foundations that are represented."

"If you do the maths, all of a sudden you are talking about 40,000 building foundations up there, which is [about] the same number of building foundations that are on the island of Manhattan."

Angamuco "had an unusual layout, with big structures like pyramids and open plazas situated around the edges rather than in the center."

"The Purépecha people existed at the same time as the Aztecs. While they are nowhere near as popular as their rivals, they were still a major civilization and had an imperial capital called Tzintzuntzan in western Mexico. Based on [...] LiDAR scans, though, Angamuco is even bigger Tzintzuntzan. It likely wasn't as densely populated, but [...] it's now the biggest city in western Mexico during that period that we know of."

"In I523 Cortes quietly appropriated for himself the great Tarascan-held silver district of Tamazula (Jalisco)."

"The central piece of information uncovered by de Waard was an entry in the unpublished journal of Isaac Beeckman, the rector of the Latin school in Dordrecht, and a friend of Descartes.37 Beeckman learned how to grind lenses for telescopes in an effort to obtain better instruments. In the early 1630's he took lessons from a spectacle-maker in Middelburg named Johannes Sachariassen, the son of Sacharias Janssen. Beeckman recorded in his journal that during one of these lessons Johannes Sachariassen told him that the first telescope in the Netherlands had been made in 1604 by his father, after the model of an instrument in the possession of an Italian. This instrument bore the date of 1590.38"

As many Italians were in the Netherlands fighting the Spanish, some with experience in grinding lenses for optical uses, it is likely a few carried with them optical transits such as the one dated to 1590 made in Italy which were so common as to be taken for granted by historians, modifiable into telescopes.

17th Century
The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s (the 17th century), using glass lenses.

"The central piece of information uncovered by de Waard was an entry in the unpublished journal of Isaac Beeckman, the rector of the Latin school in Dordrecht, and a friend of Descartes.37 Beeckman learned how to grind lenses for telescopes in an effort to obtain better instruments. In the early 1630's he took lessons from a spectacle-maker in Middelburg named Johannes Sachariassen, the son of Sacharias Janssen. Beeckman recorded in his journal that during one of these lessons Johannes Sachariassen told him that the first telescope in the Netherlands had been made in 1604 by his father, after the model of an instrument in the possession of an Italian. This instrument bore the date of 1590.38"

As many Italians were in the Netherlands fighting the Spanish, some with experience in grinding lenses for optical uses, it is likely a few carried with them optical transits such as the one dated to 1590 made in Italy which were so common as to be taken for granted by historians, modifiable into telescopes.