Ages of Subsurface Stratigraphic Intervals in the Quaternary of Enewetak Atoll, Marshall Islands

1985 ◽  
Vol 23 (1) ◽  
pp. 54-61 ◽  
Author(s):  
B. J. Szabo ◽  
J. I. Tracey ◽  
E. R. Goter

Drill cores of Enewetak Atoll, Marshall Islands, reveal six stratigraphic intervals, numbered in downward sequence, which represent vertical coral growth during Quaternary interglaciations. Radiocarbon dates indicate that the Holocene sea transgressed the emergent reef platform by about 8000 yr B.P. The reef grew rapidly upward (about 5 to 10 mm/yr) until about 6500 yr B.P. Afterward vertical growth slowed to about 0.5 mm/yr, then lateral development became dominant during the last several thousand years. The second interval is dated at 131,000 ± 3000 yr B.P. by uranium series. This unit correlates with oxygen-isotope substage 5e and with terrace VIIa of Huon Peninsula, New Guinea, and of Main Reef-2 terrace at Atauro Island. The third interval is not dated because corals were recrystallized and it is tentatively correlated with either oxygen-isotope stages 7 or 9. The age of the fourth interval is estimated at 454,000 ± 100,000 yr B.P. from measured 234U238U activity ratios. This unit is correlated with either oxygen-isotope stage 9, 11, or 13.

1985 ◽  
Vol 24 (1) ◽  
pp. 73-86 ◽  
Author(s):  
Antony J. Sutcliffe ◽  
Thomas C. Lord ◽  
Russell S. Harmon ◽  
Miro Ivanovich ◽  
Angela Rae ◽  
...  

Cave sediments from Stump Cross Cave in northern England contain Pleistocene mammal remains. Uranium-series dating of calcium carbonate deposits closely associated with the fossiliferous horizons has established an absolute age of 83,000 ± 6000 yr B.P. for a faunal assemblage largely comprised of wolverines (Gulo gulo). This date lies firmly within the younger portion of oxygen-isotope stage 5. The occurrence of wolverines in the vicinity of Stump Cross Cave at ca. 83,000 yr B.P. indicates a significant climatic deterioration from ca. 120,000 yr B.P., when an Ipswichian interglacial fauna with hippopotamus was present in this part of northern England.


Boreas ◽  
2004 ◽  
Vol 33 (2) ◽  
pp. 164-180 ◽  
Author(s):  
Jiri Chlachula ◽  
Rob Kemp ◽  
Catherine Jessen ◽  
Adrian Palmer ◽  
Phillip Toms

2020 ◽  
pp. 1-19
Author(s):  
Vladimir Sheinkman ◽  
Sergey Sedov ◽  
Lyudmila S. Shumilovskikh ◽  
Elena Bezrukova ◽  
Dmitriy Dobrynin ◽  
...  

Abstract Recent revision of the Pleistocene glaciation boundaries in northern Eurasia has encouraged the search for nonglacial geological records of the environmental history of northern West Siberia. We studied an alluvial paleosol-sedimentary sequence of the high terrace of the Vakh River (middle Ob basin) to extract the indicators of environmental change since Marine Oxygen Isotope Stage (MIS) 6. Two levels of the buried paleosols are attributed to MIS 5 and MIS 3, as evidenced by U/Th and radiocarbon dates. Palynological and pedogenetic characteristics of the lower pedocomplex recorded the climate fluctuations during MIS 5, from the Picea-Larix taiga environment during MIS 5e to the establishment of the tundra-steppe environment due to the cooling of MIS 5d or MIS 5b and partial recovery of boreal forests with Picea and Pinus in MIS 5c or MIS 5a. The upper paleosol level shows signs of cryogenic hydromorphic pedogenesis corresponding to the tundra landscape, with permafrost during MIS 3. Boulders incorporated in a laminated alluvial deposit between the paleosols are dropstones brought from the Enisei valley by ice rafting during the cold MIS 4. An abundance of eolian morphostructures on quartz grains from the sediments that overly the upper paleosol suggests a cold, dry, and windy environment during the MIS 2 cryochron.


2005 ◽  
Vol 24 (1-2) ◽  
pp. 195-210 ◽  
Author(s):  
Qingsong Liu ◽  
Subir K. Banerjee ◽  
Michael J. Jackson ◽  
Chenglong Deng ◽  
Yongxin Pan ◽  
...  

2000 ◽  
Vol 24 (1) ◽  
pp. 27-39 ◽  
Author(s):  
Henning A Bauch ◽  
Helmut Erlenkeuser ◽  
Jan P Helmke ◽  
Ulrich Struck

1990 ◽  
Vol 34 (1) ◽  
pp. 86-100 ◽  
Author(s):  
M. Royd Bussell

AbstractCover beds on uplifted Quaternary marine terraces in the Taranaki-Wanganui area of New Zealand include organic deposits which yield abundant pollen. In the west at Ohawe, marine shore platform deposits are overlain by laterally extensive lignites and laharic breccia, interbedded with alluvium and capped by tephra-rich loess. Following a time of presumably interglacial marine deposition on the platform, a long period of glacial climate is suggested by pollen floras dominated by grass and shrubland taxa. Trees were sparse, but the abundance of podocarps, Nothofagus, and tree ferns increased during at least one interval, suggesting minor climatic amelioration. Near the top of the section, a major change in regional vegetation is recorded by a dominance of pollen derived from podocarp-hardwood forest taxa, including Ascarina, interpreted as indicating a fully interglacial climate. The marine platform, previously assigned to oxygen isotope substage 5e, is now placed in stage 7. The overlying deposits were deposited during glacial stage 6, while interglacial substage 5e is recorded by sediment and pollen assemblages near the top of the section.


2021 ◽  
Vol 20 (3) ◽  
pp. 22-35
Author(s):  
Ernar A. Estemesov

Purpose. The article describes the history and analysis of the main issues in the study of archaeological sites of the Saka period in Semirechye. They are presented by three main types on this territory: burial and memorial complexes, settlements and hoards. The first type of monuments includes numerous burial mounds, where the elite burials of “royal” type and ordinary burials are located. Both social groups are combined by the unity of funeral rites, and the main differences are the complexity of architecture, memorial practices, and richness of burial equipment in the “royal” type burial mounds. The second category of monuments is presented by the settlements that are mostly small in size. The constructions like half dugouts were discovered on them, which gave a rich ceramic material. The third type of monuments of the Saka period in Semirechye includes numerous hoards of bronze items. Some of them are represented by the cult objects (sacrificial tables, lamps and cauldrons) that mark the places of worship. A significant percentage of the hoards contain items of weapons, horse equipment and household purposes and, apparently, serve as offerings to the spirits. However, despite the considerable progress in the study of the Saka monuments of the Semirechye Region, the main problem is their cultural attribution at this time. Some researchers suggest that the independent Saka archaeological culture was formed and developed on the territory of Semirechye in the Early Iron Age, while others believe that the Saka monuments of this region belong to the broader historical and cultural community that also covers the neighboring regions of Kyrgyzstan and Xinjiang. Results Another important issue in the study of the Saka sites of Semirechye is to clarify the chronology of burial and memorial complexes. Up to now, the significant database of radiocarbon dates has been accumulated, which allows us to consider the chronological positions of a wide range of monuments in a new way. It was of great importance to obtain such dates from several burials of Karatuma necropolis, which showed that it belonged to the Saka period, since burial monuments of this appearance are traditionally dated back to the Wusun period. Conclusion. The necessity of solution of these problems is an urgent task for further research of burial and settlement objects of the Saka period in this region.


2018 ◽  
Vol 90 (3) ◽  
pp. 439-456 ◽  
Author(s):  
Adam Nadachowski ◽  
Grzegorz Lipecki ◽  
Mateusz Baca ◽  
Michał Żmihorski ◽  
Jarosław Wilczyński

AbstractThe woolly mammoth (Mammuthus primigenius) was widespread in almost all of Europe during the late Pleistocene. However, its distribution changed because of population fluctuations and range expansions and reductions. During Marine Oxygen Isotope Stage 2 (MIS 2), these processes were highly dynamic. Our analyses of 318 radiocarbon dates from 162 localities, obtained directly from mammoth material, confirmed important changes in mammoth range between ~28.6 and ~14.1 ka. The Greenland stadial 3 interval (27.5–23.3 ka) was the time of maximum expansion of the mammoth in Europe during MIS 2. The continuous range was soon fragmented and reduced, resulting in the disappearance of Mammuthus during the last glacial maximum from ~21.4 to ~19.2 ka in all parts of the North European Plain. It is not clear whether mammoths survived in the East European Plain. The mammoth returned to Europe soon after ~19.0 ka, and for the next 3–4 millennia played an important role in the lifeways of Epigravettian societies in eastern Europe. Mammoths became extinct in most of Europe by ~14.0 ka, except for core areas such as the far northeast of Europe, where they survived until the beginning of the Holocene. No significant correlation was found between the distribution of the mammoth in Europe and human activity.


Author(s):  
Alan Graham

The Quaternary Period encompasses the Pleistocene and the Holocene or Recent Epochs. The date used for the beginning of the Pleistocene depends upon which globally recognizable event is selected as representing a significant break with the preceding Pliocene Epoch. Candidates include the Gauss-Matuyama magnetopolarity boundary (~2.8 Ma; see Quaternary International, 1997); the initiation of widespread permafrost, a frigid Arctic Ocean, and rapid glaciation in the high northern latitudes (~2.4 Ma; Shackleton and Opdyke, 1977; Shackleton et al., 1984); or the African Olduvai paleomagnetic event between 1.87 and 1.67 Ma. The transition from hothouse to icehouse conditions was gradual, but the Pleistocene is typified at Vrica, Italy, as beginning at ~1.67 Ma (Aguirre and Pasini, 1985; Richmond and Fullerton, 1986; oxygen isotope stage 62), and that is the date used here. In the conterminous United States the Elk Creek till of Nebraska is 2.14 m.y. in age (Hallberg, 1986), and the onset of the full ice age is represented by the onset of repeated glaciations at ~850 Kya when glaciers extended down the Mississippi River Valley. Subsequently, glacial-interglacial conditions fluctuated until the latest retreat at ~11 Kya that began the Holocene or Recent Epoch. The chronology of ice age events began with the publication of Louis Agassiz’s (1840) Etudes surles Glaciers. In the absence of evidence to the contrary, a single glacial advance was envisioned as blanketing the high latitudes. In the 1940s Willard E Libby at the University of Chicago perfected the technique of radiocarbon dating, and Flint and Rubin (1955) applied this methodology of “isotopic clocks” to establishing the absolute chronology of drift deposits from the eastern and midwestern United States. Their radiocarbon dates showed evidence of two or more times of continental-scale glaciations; older organic material was “radiocarbon inert” and beyond the ~40-Ky range of the technique. A standard chronology eventually became established for North America that included four major glacial stages (Nebraskan, oldest; Kansan; Illinoian; and Wisconsin) separated by four interglacials (Aftonian, oldest; Yarmouth, Sangamon, and the present Holocene).


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