Half Of MIS Research Articles

Major hydrological shifts in the Black Sea “Lake” in response to ice sheet collapses during MIS 6 (130–184 ka BP)

The Saalian was one of the largest glaciations during the Quaternary with an ice sheet extending considerably wider into the Eurasian continent than during other glacials. Orbital variations caused the ice sheet to switch between growing and shrinking. The partial retreat of the ice sheet and meltwater discharge resulted in global sea-level rise and increased lake levels of inland seas with broader environmental implications. During Marine Isotope Stage 6 (MIS 6), meltwater entered the formerly enclosed Black Sea at least twice as documented in a δ18O record from Anatolian speleothems. Here we present a sedimentary record from the Black Sea “Lake” covering MIS 6 and provide evidence for three meltwater periods coinciding with insolation maxima (BSWP-6-1: 180-167 ka BP, BSWP-6-2: 160-145 ka BP, BSWP-II: 133-130 ka BP). While δ18Oostracods and Sr/Caostracods point to pronounced meltwater supply and decreasing salinity, 87Sr/86Srostracods shed light on meltwater sources and pathways. During all three periods, meltwater drained most likely via the Dnieper and Volga into the Black and Caspian Seas and connected both basins. Relatively low 87Sr/86Srostracods values during the oldest meltwater period suggest melting solely of the eastern Eurasian Ice Sheet. In contrast, during the younger meltwater periods, exceptional high 87Sr/86Srostracods values point towards additional meltwater from the western Eurasian Ice Sheet. A surplus from melting glaciers in the Tian Shan and Pamir Mountains that finally entered the Caspian Sea via the Amu Darya and Sry Darya probably amplified the input of high radiogenic Sr-isotope water. We also show that higher temperatures and productivity suggest Dansgaard-Oeschger-like climate variability during the first half of MIS 6.

Каменные индустрии среднего палеолита из южной галереи Денисовой Пещеры: материалы раскопок 2003 года

Research work resumed in South Chamber of Denisova cave in Altai requires a complete introduction of previously obtained collections into scientific use and the refinement of the techno-typological characteristics in these stone tool industries. This publication presents the results of a technical and typological analysis of stone industries from layers 22-19 and 14 in the mouth area of the southern chamber. The initial stages of the settlement of the cave characterize materials from the upper part of layer 22 and from layer 21, which were formed during the periods of MIS 8 and MIS 7, respectively. These industries are characterized mainly by radial splitting, various types of toothed, notched, spinous tools and scrapers, an abundance of chips with ventral upholstery of the longitudinal edges and with a remote residual impact platform. Further development of the Middle Paleolithic is reflected in the materials materials from layers 20, 19 and 14, which were most likely formed at the end of MIS 6 and in the first half of MIS 5 after a break in sedimentation. In the industries of this time, planar parallel and radial cores were distributed. A small series presents Levallois cores for flakes and plates. In the tool set against the background of the predominance of different types of the scraper, a well-pronounced gear-notched component is preserved. There are products of the Upper Paleolithic group.

Leave at the height of the party: A critical review of the Middle Paleolithic in Western Central Europe from its beginnings to its rapid decline

The German Middle Paleolithic is marked by two stages with abundant archaeological sites: The Eemian Interglacial (MIS 5e) and the Weichselian Interpleniglacial (MIS 3). On the other hand, several stages were seemingly void of any human population (the second half of MIS 6 and MIS 4) and two long periods (MIS 8-6 and MIS 5d-5a) delivered very few archaeological sites, so far. The majority of all assemblages seem to belong to the latest part of the Middle Paleolithic, during the first half of MIS 3. Concerning this period, the layer G stratigraphic complex (“G-Komplex”) of Sesselfelsgrotte yielded the longest cultural sequence of late Middle Paleolithic unifacial-plus-bifacial industries (Keilmessergruppen, Micoquian in the sense of a “Mousterian with a Micoquian option”, MMO) in Central Europe. Information from this sequence permitted a reconsideration of the internal structure and the dating of the MMO. Evidence is presented for an earlier MMO stage with almost no Levallois technology (MMO-A) and a later stage (MMO-B) with Levallois technology, both occurring at the very end of the European Middle Paleolithic, between 60,000 and 43,000 (cal.) B.P. The vast majority of all Middle Paleolithic sites in Germany belong to the MMO-B which was, in Southern Germany, rapidly followed by the Upper Paleolithic Aurignacian from 42 ka (cal.) B.P. onwards without any Proto-Aurignacian interlude.

Abstract 11594: Reduction in Subtypes and Sizes of Myocardial Infarction With Ticagrelor in PEGASUS-TIMI 54

Objective: Ticagrelor reduced the risk of CV death, MI or stroke (MACE) in stable patients with prior MI in PEGASUS-TIMI 54. We investigated the efficacy of ticagrelor in reducing different subtypes and sizes of MI. Methods: MIs were adjudicated by the blinded TIMI Clinical Events Committee with definitions consistent with the Third Universal Definition of MI. Each MI was categorized by subtype and fold elevation of peak troponin (Tn) over the upper limit of normal (ULN). Results for both doses of ticagrelor were pooled in comparison to placebo. Results: A total of 1042 MIs occurred in the 21,162 randomized patients over a median follow up of 33 months. The majority (76%) of the MIs were spontaneous (Type 1), with demand MI (Type 2) and PCI-related (Type 4) accounting for 13% and 10% respectively (Figure Left); sudden death MI (Type 3) and CABG-related MI (Type 5) each accounted for <1%. Using fold elevation in Tn, half of MIs (520, 50%) had a peak Tn ≥10x ULN and 21% of MIs (220) had a peak Tn ≥100x ULN (Figure Right). A total of 21% (224) were STEMI. Overall ticagrelor reduced MI at 3 yrs (4.47% vs 5.25%, HR 0.83, 95% CI 0.72 - 0.95, p=0.0055). The benefit was highly consistent among the different subtypes of MI (Figure left) and with increasing size of MI by fold elevation of Tn (Figure right) and for STEMI (HR 0.60, 95% CI 0.46 - 0.78, p=0.0002). Conclusion: In stable outpatients with a history of MI the majority of recurrent MI events are spontaneous and associated with a high biomarker elevation. Ticagrelor significantly reduces the incidence of MI consistently among different subtypes and biomarker sizes, with the greatest absolute reduction in spontaneous MIs, large MIs, and STEMI.

Quaternary climatic instability in south‐east Australia from a multi‐proxy speleothem record

ABSTRACTMilankovitch‐scale Quaternary climatic oscillations within south‐east Australia are known to be characterized by relatively arid glacial and wet interglacial stages. However, terrestrial proxy records of environmental change are scarce, based largely on river terraces, dune sediments and pollen sequences. Here we present a speleothem‐based palaeoclimate record from Yarrangobilly caves, south‐east Australia. The oxygen isotopic composition of calcite (δ18Ocalcite) is taken to represent rainfall amount and used as an aridity index. High‐resolution trace element profiles and UV fluorescence support interpretations based on δ18Ocalcite, allowing further designation of key phases of speleothem growth into periods of relative aridity and moisture excess. A hiatus of approximately 37 ka duration divides the record into two key phases of growth which can be mapped onto marine isotope stages 5c–a and 3, respectively. Increasing aridity in the latter half of MIS 5 led to cessation of speleothem growth for the duration of MIS 4. Growth recommences during MIS 3, associated with greater moisture availability, enhanced vegetation and augmented biogeochemical cycling. This speleothem record provides a unique context of terrestrial environmental change and depicts hydrological conditions which fluctuate markedly over the 70‐ka period covering the time of megafauna extinction and human arrival on the continent.

Bonneville basin shoreline records of large lake intervals during Marine Isotope Stage 3 and the Last Glacial Maximum

Lacustrine shoreline depositional features in the Bonneville basin, western North America, were investigated to chronicle paleolake expansion and contraction in response to climate change. Based on stratigraphy, sedimentology, geomorphology, and radiocarbon dating, this study identifies multiple intermediate- to large-lake intervals during Marine Isotope Stage 3 and the Last Glacial Maximum. Timing and magnitude of the Bonneville basin lake size change are compared with those of hemispheric-scale climate-change events reported from the Greenland ice sheet, southwestern North America winter precipitation, and East Asian monsoon δ18O records. The amount of precipitation received by surface water systems in the Bonneville basin appears to have increased significantly during the Greenland stades throughout the last half of MIS 3 and early MIS 2. The lake also underwent rapid, large amplitude oscillations during the Last Glacial Maximum.

469 Vegetation change during the latter half of MIS 3 in the Abukuma Highland, Southern Tohoku, Japan

469 Vegetation change during the latter half of MIS 3 in the Abukuma Highland, Southern Tohoku, Japan

“Warm” stages in the West Siberian Late Pleistocene

The revised study of stratotypes and key sections of the Karginsky regiostage in the West Siberian Plain with the use of 230Th/U dating determinations and advanced 14C dating indicated that many 14C ages obtained in the 1960–1970s were incorrect, and revealed the pre-Karginsky age of the Karginsky regional substage stratotypes adopted in the modern Pleistocene stratigraphic schemes of West Siberia. The available 230Th/U and 14C data along with the new paleobotanical record provided substantial refinement of the Late Pleistocene succession of paleoclimatic events in the West Siberian Plain. The 5e5 and 5e1 optima corresponding to climatic events of the Greenland ice core and 5e2 and 5e4 pessima are revealed in boreal West Siberia. The obtained 230Th/U dating determinations, even with their wide tolerance interval, make it possible to recognize not only the major but certain minor climatic events within the Kazantsevsky interglacial in boreal West Siberia. Beds corresponding to MIS 5c are recorded in the middle reaches of the Ob River. The preceding cooling was comparable with that of the later stages of the Zyryansky glaciation and is correlated with MIS 5d, which suggests the beginning of the Zyryansky glaciation occurred in the second half of MIS 5. The obtained records do not require elimination or reducing of the range of the Karginsky regiostage. However, the stratotypes of its regional sub-stages, chosen mainly in the 1960–1970s, appear to be invalid.

Pleistocene glaciations of Central Asia: results from 10Be surface exposure ages of erratic boulders from the Pamir (Tajikistan), and the Alay–Turkestan range (Kyrgyzstan)

We have determined the timing of glaciations in the Pamir (Tajikistan) and the Alay–Turkestan Range (Kyrgyzstan) using 10Be surface exposure dating. Glacial advances in the area have occurred >93–136, ∼60–80, (40–55), ∼27–25, ∼22–20, ∼19–17, ∼16–15, ∼15–13, and 11–9 cal ka BP. All Late Pleistocene glaciers in the Pamir, and the Alay–Turkestan Ranges have been valley glaciers except for the most extended glaciers on the Pamir plateau, which have formed local piedmont glaciations. In the eastern Pamir, these are characterized by ELA depressions of ∼370–380 m (THAR 0.5). In the Turkestan Range and Alay Range, ELA depressions at the same time were >750 and 600 m, respectively. Late Pleistocene glacier advances all over western High Asia were contemporaneous with climatic cold phases rather than monsoonal maxima. Their maximum extent and that of the western hemisphere ice sheets were asynchronous, due to increasing aridity in the region over the course of the Last Glacial. Late Pleistocene climate in Central Asia seems to have been influenced by the interplay of the westerly circulation and the Siberian anticyclone. Some indirect monsoonal influence in the eastern Pamir may be responsible for the existence of some of the Lateglacial moraine stages in this area. High altitude glaciers seem to have reached their maximum extent earlier (MIS 5–4) than low altitude glaciers (first half of MIS 3), possibly due to prolonged glacial aridity imparting with moisture advection onto high altitude sites, inducing glacial retreat, but prolonged cold during the same time imparting with glacier ablation at lower altitude sites, inducing glacial advance.