Environmental change since mid-Pleistocene recorded in Shangshan achaeological site of Zhejiang

At about 173 ka BP of the late period of mid-Pleistocene, the second terrace of the river had been formed as a result of uplift happening in Shangshan area because of the climate, sea level change and tectonic action. Between 173-75 ka BP, aeolian deposited on the terrace, a layer of reticulate red clayey soil about 80-100 cm thick deposited and developed under the warmer and higher temperature. In the last glacial period, the drop of the temperature and the decrease of the precipitation induced the dust-storms increased, A layer of Xiashu loess about 1.0-1.5 m thick accumulated on Shangshan terrace in the last glacial, which has the reticulate red clayey soil buried. At the beginning of the Holocene （11500 a BP-）, temperature went higher gradually and precipitation got more, the pre-persons moved on the Shangshan terrace （11,400-8600 a BP）, which is one of the most important archaeological sites, and can connect the paleolithic culture with Neolithic culture. It could be assumed from the results that the lower reaches of the Yangtze River are the home of rice cultivation, too. The lower place to the west of the Shangshan site experienced the two cycles process of the fluvial facies and the lacustrine facies, indicating that the water source of the pre-historical Shangshan is the river water or lake water. Two AMS 14C age proved the water source disappeared more than 1000 years ago.

Regional Environmental Differentiation in China Sincethe Mid-Pleistocene Inferred from Lake Recordsand Its Relation with East Asian Monsoons

Abstract: Comparative study of long lake records in different regions in China can provide some significant information about the regional differentiation of the environment and Asian monsoon activities. However, intensively studied lacustrine cores with a span of a few hundred thousand years are very rare in China. The available examples are only three long cores from the Zoigê basin in the eastern Qinghai-Tibet plateau, the Qaidam basin in the northern Qinghai-Tibet plateau and the Dianchi basin in the Yunnan plateau respectively. The results show that the regional environmental differentiation since the Mid-Pleistocene involved three stages, i.e. 780–480, 480–160, 160–0 ka B.P. In each of the three stages different regions of China had their own distinctive environmental characteristics, indicating that the uplift of the Qinghai-Tibet plateau played a major role in the environmental differentiation process.

Spratlies Archipelago as the Australasian Tektite Impact Crater, Details of Formation &Richard Muller’s Dust Cloud Explanation for the Mid-Pleistocene Ice Age Cycle Transition

Several significant events of a geological nature occurred approximately 800 ka before the present: (1) Australasian tektite fall (AA), (2) Brunhes-Matuyama geomagnetic reversal (BMR), (3) mid-Pleistocene changes in ice age cycles. Add to these the undated fault system (4) in the South-West (SW) of the South China Sea (SCS). Here we offer a unified cause for all four of these in (5), an impact in the SCS of a large, massive cosmic object, likely a comet, obliquely coming from the SW at an extremely shallow angle, striking the Sunda shelf yet unexploded with the shock of its compressed air bow wave, and causing the continual shelf and slope to collapse, resulting in the fault system (4), then traveling almost tangentially to the surface, exploding at impact with the sea surface, ejecting the tektites (1), creating the formation underlying the later atolls of Spratlies Archipelago (6), Nansha Islands in Chinese, & causing the BMR (2). An explanation of event (3) was Richard Muller’s hypothesis of planet Earth passing through an interplanetary dust cloud periodically due to ecliptic precession. Here we hypothesize this cloud actually is a belt of Australasian tektites ejected into space at super-orbital velocities that Earth encounters about every 100 ka.

The Mid-Pleistocene Climate Transition Recorded in a 1.6 Myr-Period Lacustrine Sediment Sequence from Mazatage, Tarim Basin

The mid-Pleistocene climate transition （MPT） has been widely reported in worldwide geological events. As a key issue of the Quaternary geology, it has attracted much attention from the paleoclimate community. MPT refers to a period lasting for several hundreds of thousand years, during which the dominant climate periodicity gradually extended from 41 kyr to 100 kyr （Ruddiman et al., 1989）,

Abrupt variations of the radiolarian fauna at Mid-Pleistocene climate transition in the South China Sea

Based on a detailed study of the radiolarian fauna, the abundance pattern of planktic foraminifera as well as on isotope and sedimentological records, the Mid-Pleistocene climate transition as a multiple transition phenomenon could be recognized at Core 17957-2 from the South China Sea. Distinct changes in the radiolarian/foraminfera ratio, the coarse fraction and the radiolarian assemblages can be related to the global climate cooling observed at the Mid-Pleistocene revolution (MPR) around 900 ka. A pronounced southward shift of the North Equatorial Current that leads to lower sea-surface temperatures in the South China Sea is documented by the shift of tropical to subtropical radiolarian assemblages at 900 ka. Increasing radiolarian abundance after the MPR can be interpreted as a result of stronger upwelling and nutrient supply. These abrupt variations could result from the northern trade wind system and East Asian monsoon circulation.

Did the modern Yellow River form at the Mid-Pleistocene transition?

The incision of the Sanmen Gorge marks the birth of the modern Yellow River,but its timing varies from the late Miocene-early Pliocene to the late Pleistocene(~0.15 Ma),and the suggested forcing mechanisms vary from the uplift of the Tibetan Plateau to global climate change.Here,we report sedimentologic,geochronologic,and provenance data from a drill core near the Sanmen Gorge,the last gorge along the main course of the Yellow River.Our results indicate that typical river channel deposits,with detritus from the Ordos Block in the upstream regions,started to accumulate in the Sanmen Gorge at~1.25 Ma.When integrated with river terrace evidence from the upstream and downstream regions,the results provide robust evidence that the final integration of the modern Yellow River occurred at~1.25 Ma,consistent with the beginning of the Mid-Pleistocene transition(MPT).We propose that the accelerated lowering of eustatic sea level during the MPT may play as important a role as tectonism in driving the birth and evolution of the modern Yellow River.

Age estimation of the mid-Pleistocene microtektite event in the South China Sea: A case showing the complexity of the sea-land correlation

The present study confirms the stratigraphical position of microtektite layer being clearly located below the Brunhes/Matuyama (B/M) boundary. Based on the sedimentation rate derived from the stable isotopic and magnetic data of ODP Site 772A, cores 17957 and 17959 in the South China Sea, the age of the mid-Pleistocene impact event was estimated at 10-12 ka earlier than the Brunhes-Matuyama polarity reversal. However, the microtektites were found above the measured B/M boundary in the loess profile due to the downward deviation of the measured B/M boundary from its true position. This demonstrates the complexity of paleo-magnetic records in the loess profiles which, in turn, causes the confusion in the sea-land stratigraphic correlation.

黄土-红粘土记录的构造尺度气候变化

晚新生代约5Ma以来，全球气候系统发生了一系列的重要转型，地球从单极（南极）常年有冰变为两极常年有冰，新生代从“温室”转为“冰室”的漫长历程至此完成。中国连续的黄土-红粘土沉积覆盖了约8—7Ma以来的时段，提供了完整的Pliocene-Pleistocene转型时期的陆相古气候记录，是研究晚新生代构造尺度气候变化和转型的重要记录。黄土-红粘土记录表明，其构造尺度变化既在相当程度上反映了晚中新世-上新世以来的全球变冷信号和Plio／Pleistocene转折、Mid．Pleistocene转折等重要构造事件，同时也对重要的区域构造和环境演化过程有显著的响应。今后需要通过对黄土-红粘土记录的研究，就上新世-更新世一系列的转型过程中重要气候系统成员的变化特征、高低纬气候系统相互作用特征以及转型机制等第四纪气候变化的根本问题作出有特色的回答。

Discovery and Analysis of the Fossilised Yuling-Man Skull

A fossilised paleoanthropological skull was discovered in November 1987, in the guily-head cliff on the east bank of Wenyu River near Xinza village, Yuling - town (hence the name Yuling-Man), Lingbao country, Henan Province, China. The skull, dated to an absolute U-isotope (U234 to U238 ) age of B. P. 156000 ± 13000 years, was found in the upper portion of the alluvial statum of the mid-Pleistocens Series, together with pateoliths of the Kehe Cutture System in the mid-late Paleolithic Periods. Although much research has been nomied out in this area, this is the first fossilised paleoanthropological skull in have been found. Therefore, this project, funded by the Natural Science Foundation/Henan Scientific Committee, is making new contributions to paleoanthropological research in China.

The older ice,the better science

Ice cores have revolutionized our views of the Earth system.They record past climatic and environmental parameters that range on time scales from synoptic events to hundreds of thousands of years.For instance,the Vostok ice core reached an age of 420 ka(thousand years)(Figure 1),revealing a close linkage between climate and greenhouse gas concentrations over the last four glacial-interglacial cycles(Petit et al.,1999).

Middle-Late Pleistocene Paleo-Climate and Paleo-Altimetry of the Centre of Tibetan Plateau Indicated by the Sporopollen Record of Well QZ-4

The core sample from well QZ-4 is an important climate archive for the central Tibetan Plateau in the middle-late Pleistocene. In this work, a detailed pollen analysis of it is carried out to provide a preliminary insight into the paleo-climate and paleo-altimetry change in the central Tibetan Plateau. It can be concluded that the pollen assemblage can be obviously divided into two pollen zones, Pollen zone I (251.1 - 314 m in depth, 120.0 - 345.8 ka BP.) and Pollen zone II (200 - 251.1 m in depth, 105.4 - 120 ka BP.). The paleo-climate during pollen zone I deposition period was comparatively colder and wetter than it during the pollen zone II deposition period. After Gonghe Movement, the center of Tibetan Plateau was uplifted about 300 m (from 3500 - 3700 m to 3800 - 4000 m in elevation). The wind was changed from horizontal or downward direction to upward direction, in the study area. In the central of Tibetan Plateau, the climate change seems to be mainly driven by global climate change, and that tectonic uplift may have been a subordinate influence at the middle-late Pleistocene.

Apennine–Pyrenees disjunct distribution: an unusual biogeographic pattern revealed in fea beetles of the Longitarsus candidulus species-group (Coleoptera, Chrysomelidae)

European mountain systems have played a crucial role in shaping the distribution of species and of their genetic diversity during the Quaternary climatic changes,with the establishment of allopatric patterns across main mountain ranges.Here we investigated the evolutionary history of fea beetles of the Longitarsus candidulus species-group showing an uncommon disjunct biogeographic pattern across the Apennine and the Pyrenees.We applied a multilocus molecular approach and multispecies coalescent models to establish a phylogenetic and systematic framework for this morphologically homogeneous species-group and to estimate the time of main cladogenetic events underlying the origin of the Apennine-Pyrenees pattern.We found strong support for the monophyly of the candidulus group with a sister relationship between Longitarsus laureolae and L.leonardii endemic to the Apennine and the Pyrenees mountains respectively.The timing of speciation events in the candidulus species-group coincides with 2 major climatic transitions during the Early and Middle Pleistocene which resulted in signifcant environmental changes in Europe and suggest a scenario of allopatric isolation and divergence on distinct mountain ranges.The split between the thermophilic species L.candidulus and the ancestor of the temperate species L.laureolae and L.leonardii is estimated at~3 Ma during the transition from Pliocene to Pleistocene and was probably triggered by their segregation in xerophilous and temperate habitats.The speciation between L.laureolae and L.leonardii,estimated at~1 Ma during the Mid-Pleistocene Transition,can be explained by the establishment of unfavorable conditions in West Alps and Central Massif underlying the onset of the Apennine-Pyrenees disjunct pattern.Finally,the strict association between members of the candidulus group and distinct Thymelaeaceae plants suggests further studies to address the hypothesis that speciation in these fea beetles might have been also associated with Pleistocene range changes of their host plants.

Transition of Quaternary glacial cyclicity in deep-sea records at Nansha,the South China Sea

High-resolution oxygen isotope records over the last 2249 ka (MIS 1-86) have been obtained from cores of the upper section (105.08 m) at ODP Site 1143 (water depth of 2772 m)drilled in the Nansha area, southern South China Sea. The sampling resolution is at about 2 ka intervals, resulting in one of the best oxygen isotope records over the global ocean. The oxygen isotope curves, displaying details in the Pleistocene glacial cycles, have revealed a nearly 300 ka long stage of transition from a predominant 40 ka to 100 ka periodicity. Therefore, the 'Mid-Pleistocene Revolution' should be considered as a process of transition rather than an abrupt change. Within the 100 ka glacial cycles, the changes in tropical sea surface water were found to lead those in high-latitude ice sheet. Our comparisons show that the ice sheet expansion and the glacial stage extension in the Northern Hemisphere with the 100 ka cycles must have been driven not by ice sheet itself, but by processes outside the high latitudes of the Northern Hemisphere.

Clay minerals in the Pliocene-Quaternary sediments of the southern Yangtze coast, China: Sediment sources and palaeoclimate implications

Clay mineralogy was used as an indicator of the sediment source and prevailing climate and five suites （I-V） were identified throughout the borehole. Smectite was dominant in the bottom suite of the borehole, indicating the sediment was mainly derived from the local basalt when the study area stood as uplands during the Pliocene. The sharp reduction of smectite in suites II and III （Early Pleistocene） reflects a broader sediment provenance due to neo-tectonic subsidence of the study area. Significant climate fluctuations are indicated by distinct variations in the ratios of illite versus smectite and kaolinite, and by the illite crystallinity in suites II and IV. Especially the suite IV, which forms mottled muddy sediments that underwent pedogenesis, possibly represents glacial/interglacial cycles during the Mid-Pleistocene climate transition （MPT）. The rare presence of smectite in suite V which formed during the Late Quaternary suggests a significant contribution of fine-grained sediment derived from the upstream of the Yangtze catchment. Such changes in sediment sources are consistent with the evolution of regional sedimentary environments, which evolved towards an open coast/ deltaic setting and imply that the study area became the depositional basin of the Yangtze fine-grained sediment due to the final submergence of the Wu-Nan-Sha and Fukien-Reinan Massifs since the Late Quaternary.

Two Necessary Conditions for the Glacial-Interglacial Cycles in the Quaternary

Milankovitch Theory shows that glacial-interglacial cycles in the Quaternary are related to the variation of solar insolation forcing linked to the earth＇s astronomical parameters.However,the summer insolation at northern high latitudes,usually considered as the main external forcing for the ice age as Milankovitch pointed out,is marked by the 19- and 23-ka precession periodicities,which is not consistent with the glacial-interglacial cycles.On the other hand,recent studies indicate that the annual mean insolation dominated by the obliquity is also an important external forcing in glacial cycles.In this paper,it is assumed that the glacial oscillation is regulated simultaneously by the annual mean insolation at northern high latitudes related to obliquity and the noon insolation at summer solstice at the ice-line latitude related to precession. Only when both of them exceed some thresholds,does the ice sheet start to melt continuously to induce the global warming and deglaciation.Furthermore,the periodicity transition of glacial cycles at mid-Pleistocene was a natural change when the ice sheet thickness altered.A conceptual model based on this idea gives encouraging results compared with the isotopic data.