Stages Of Pleistocene Research Articles

Definition of the Quaternary Qiangtang Paleolake in Qinghai‐Tibetan Plateau, China

Abstract:Since the Quaternary, many lakes have been present in the Qinghai‐Tibetan Plateau. As peculiar geological processes in the evolution of the uplifting of Qinghai‐Tibetan Plateau, the distributions and evolutions of the Quaternary paleolakes in the Qinghai‐Tibetan Plateau have been the focus of interest among the international geosciences circle. Comparisons of the newly obtained and existing data from field surveys, remote sensing images, characteristics of tectonic landforms and distribution of the lacustrine strata, the author have, for the first time, defined a large‐sized Quaternary Qiangtang Paleolake. The paleolake starts from the east‐westerly direction at Rutog in western Tibet, passing through Gêrzê, and finally ends at Nagqu in eastern Tibet. Its length is approximately 1,200 km; it is about 420 km at its widest point (north‐southerly). The Paleolake forms an E‐W (or NWW) ellipsoid with an estimated area of 354920 km2. The Paleolake is bordered by the Mts. Gangdisê and Nyainqêntanglha to the south and the Karakorum Pass‐Tozê Kangri‐Zangbagangri‐ Tanggula Pass to the north. It generally appears as a basinal landform with low mountains and valleys in the central part (altitudes of 4400 m) and higher altitudes (5000 m) in the peripheries. The formation and development of the Paleolake was controlled by the nearly E‐W trending structures. There are three east‐westerly extending tectonic sutures inside the Paleolake area, from north to south: (1) the Shuanghu Suture; (2) the Bangong Co‐Nujiang River Suture; (3) the Shiquanhe‐Lhari Suture. These three sutures have generally controlled the spreading features of the Paleolake and act as the first grade lake‐controlling structures. In the southern Paleolake basin, there are a series of south‐northerly rift basins, which are controlled by the normal faults and exist as a series of south‐northerly grabens and semi‐graben faulted basins. The south‐northerly rift zones have clearly exerted control over the south margin of the Paleolake as well as the distribution of the residual lake basins after the Paleolake's break up. They are the secondary lake‐controlling tectonics. Discoveries of the lacustrine strata inside the Plateau, especially the successive discoveries of many high‐stand lacustrine strata, are direct evidence supporting the existence of the paleolakes in the Plateau. The dating results of the lake‐eroded travertine in the Dong Co in the hinterland of the Quaternary Qiangtang Paleolake have revealed that the lake‐eroded travertine is of Late Pleistocene sediments. By considering the analysis of the lacustrine strata as well, the researchers have revealed that the Quaternary Qiangtang Paleolake begins its embryonic form in the Early Pleistocene, successively develops till the Middle Pleistocene, and reaches its full blossom in the middle stage of the Late Pleistocene; it further shrinks and separates by the end of the Late Pleistocene, and finally ceases its whole life as the paleolake. After the Holocene, the huge Late Pleistocene Qiangtang Paleolake no longer exists, leaving a series of widely distributed smaller lakes on the Qiangtang Plateau. These smaller, isolated water systems receive the Holocene lacustrine sediments.

Changements environnementaux, dépositionels et culturels pendant le Pléistocène supérieur et l'Holocène ancien : la séquence de la Cinglera del Capello (Capellades, Espagne)

The correlation between environmental and cultural changes is one of the primary archeological and paleoanthropological research topics. Analysis of ice and marine cores has yielded a high-resolution record of millennial-scale changes during the Late Pleistocene and Holocene eras. However, cultural changes are documented in low-resolution continental deposits; thus, their correlation with the millennial-scale climatic sequence is often difficult. In this paper, we present a rare occurrence in which a thick archeological sequence is associated with a high-resolution environmental record. The Cinglera del Capello is a tufa-draped cliff located in the northeastern Iberian Peninsula, 50 km west of Barcelona. This cliff harbors several rock-shelters with Late Pleistocene and Early Holocene deposits. Together, the deposits of four rock-shelters span from 7000 to 70,000 years ago and provide a high-resolution record of the environmental and human dynamics during this timespan. This record allows the correlation of the cultural and environmental changes. The multiproxy approach to the Cinglera evidence indicates that the main cultural stages of the Late Pleistocene and Early Holocene (Middle Paleolithic, Upper Paleolithic and Mesolithic) are associated with significant changes in the environmental and depositional contexts.

Early Pleistocene landscapes and the colonization of Europe

The paleoecological context of hominin occupation in South Asia during the early and middle Pleistocene is virtually unknown. Attirampakkam, India, is an archeological site of global importance, with an early Acheulian occupation (age bracket of ~ 1.07–1.77 Ma) succeeded by Middle Paleolithic levels. Here we report on the recovery of phytoliths from artifact-bearing Quaternary deposits in excavated trenches. We focus on the reconstruction of past vegetation during hominin occupation of the site. The present study provides information on hominin microenvironments and local habitats in South Asia, situating them in a more tangible ecological context than so far achieved. Results show that this region was arid during the earlier stages of the early Pleistocene, and was occupied by hominins living in a landscape locally lacking woody plants. Herbaceous vegetation was dominated by C4 Chloridoid grasses. In the later phase of the early Pleistocene, the landscape was wooded and dominated by C4 Panicoid grasses, with a significant reduction of C4 Chloridoid grasses indicating a shift from a drier to a relatively more humid climate. A diverse husk and leaf phytolith assemblage of wild Oryza spp. (rice) occurring as natural annual or perennial components of the vegetation in the area, other herbaceous plants such as Cyperaceae (sedges), and the continuous presence of blackened phytoliths, suggest the establishment a grassland landscape with enclaves of wetland habitat affected by seasonal flooding and frequent fires. The transition from the early to the middle Pleistocene was marked by a moderately humid climate, with a shift toward aridity during the late Pleistocene, during which we note an environment dominated by C4 Chloridoid grasses, by a sharp reduction of C4 Panicoid grasses, and by a rise in woody taxa. During the middle to late Pleistocene, Middle Paleolithic populations would have witnessed water bodies near the site, as reflected by the presence of plants adapted to swampier conditions such as Cyperaceae and Oryza spp. The archeological record terminates in Layer 1, when human occupation decreased drastically, possibly because of increased aridity and/or greater environmental variability. The phytolith fingerprint at ATM sheds light on the co-occurrence of, vegetation, fire and early prehistoric land occupation. An important aspect is the evidence of Oryza spp., suggesting that wild rice occurred in the environment frequented by these early hominins.

Testing the correlation of fragmented pollen records of the middle and late Pleistocene temperate stages

Testing the correlation of fragmented pollen records of the middle and late Pleistocene temperate stages

The Early and early Middle Pleistocene context of human occupation and lowland glaciation in Britain and northern Europe

This paper reviews the stratigraphical and environmental contexts of early human occupation and lowland glaciation in Britain and northern Europe. It highlights the fragmentary nature of most of the critical sequences and the inadequacy of existing stratigraphical frameworks. The earliest archaeology known from NW Europe has been reported from Happisburgh 3, a site on the Norfolk coast. The flint artefacts from here were recovered from sediments previously assigned to the Pastonian Stage of the Early Pleistocene. However, the mammalian assemblage from Happisburgh 3 differs from other local sites attributed to the ‘Pastonian’, indicating a younger age within the Early Pleistocene. The sediments have reversed palaeomagnetic polarity and have palynological features inviting correlation with the Leerdam interglacial in the Dutch ‘Bavelian Complex’. The interglacials of the British ‘Cromerian Complex’ are compared and their archaeological record reviewed. At most of these sites, the archaeology includes hand-axes associated with a mammalian assemblage containing the water vole Arvicola but at Pakefield, Suffolk, a core-and-flake industry is associated with the ancestral Mimomys savini. This, together with the even older record from Happisburgh 3, indicates earlier periods of human occupation than previously known from NW Europe. At least five temperate episodes with distinct faunal assemblages are now recognized in the British early Middle Pleistocene but these are unlikely to equate directly with odd-numbered stages of the marine isotope record. This biostratigraphical framework conflicts with a ‘New glacial stratigraphy’ for East Anglia, which proposes glaciations during MIS 16, 12, 10 and 6. Evidence is reviewed from Sidestrand and Trimingham, where datable organic sediments occur directly beneath and above the Middle Pleistocene glacial succession, indicating that it was emplaced entirely during the Anglian glacial stage (MIS 12). A new stratigraphical framework is provided ranking British sites in order of relative age, which is then compared with a revised scheme for the Dutch late Early and early Middle Pleistocene succession. The revisions involve the relocation of the Waardenburg interglacial (‘Interglacial 1’) to the ‘Bavelian Complex’ and the use of the Brunhes-Matuyama palaeomagnetic reversal to define both the base of the Dutch ‘Cromerian Complex’ and the Early/Middle Pleistocene boundary. Moreover, following recent re-interpretation, the Noordbergum interglacial (‘Interglacial IV’) and ‘Glacial C’ are removed from the ‘Cromerian Complex’ and are correlated with MIS 11 and MIS 12 respectively. This scheme imposes greater consistency between the British and Dutch successions, as well as conformity with guidelines recommended by the International Stratigraphic Commission.

Late Pleistocene lineage divergence among populations ofNeolitsea sericea(Lauraceae) across a deep sea‐barrier in the Ryukyu Islands

AbstractAim Our goals were: (1) to assess the population genetic structure and demographic divergence history of a bird‐dispersed tree,Neolitsea sericea, endemic to East Asian land‐bridge islands; and (2) to interpret the results in the light of controversies over the dating and configurations of land bridges through the Japanese Ryukyu Island Arc.Location Japan–Ryukyu–Taiwan Island Arc and Chinese/Korean offshore islands.Methods We applied 10 nuclear microsatellites (nSSRs) and one chloroplast (cp) DNA sequence marker (psbA–trnH intergenic spacer) to 31 populations (397 and 326 individuals, respectively) from throughout the species’ range to infer current patterns of genetic diversity and structure, and pollen‐to‐seed migration ratios (r). A coalescent‐based isolation‐with‐migration (IM) model was applied to the combined nSSR/cpDNA data set to estimate lineage divergence times and population demographic parameters.Results The geographic structure of nSSRs and the distribution of most cpDNA haplotypes revealed two distinct lineages located in areas north and south of the ‘Tokara Gap’, a narrow (c. 37 km wide) but deep (> 1000 m) sea‐strait between the northern and central Ryukyus. Based on the IM analyses, we (1) dated the divergence of these northern and southern lineages toc. 0.07 Ma (90% highest posterior density interval: 0.02–0.38 Ma); (2) estimated a slightly smaller effective population size for the northern compared to the southern lineage; and (3) recovered only trivial signals of post‐divergence gene flow between them.Main conclusions The estimated divergence time for northern and southern lineages is consistent with geological evidence for the existence of land connections in the Tokara region during cold stages of the latest Pleistocene; it is thus incompatible with an ‘ancient sea‐barrier hypothesis’ for the Ryukyu Arc, where we would have expected much older divergences related to the initial formation of the Tokara and Kerama tectonic straits during the Pliocene. Multiple factors are likely to have had a role in the divergence ofN. sericea, including not only land‐bridge submergence, but also island configuration, and/or constraints on adaptation along a latitudinal temperature gradient.

Upper Palaeolithic hunter-gatherer subsistence in Mediterranean coastal environments: an isotopic study of the diets of the earliest directly-dated humans from Sicily

The subsistence of hunter-gatherers in the Mediterranean Basin has been the object of few studies, which have not fully clarified the role of aquatic resources in their diets. Here we present the results of AMS radiocarbon dating and of isotope analyses on the earliest directly-dated human remains from Sicily, the largest island in the Mediterranean Sea. The radiocarbon determinations show that the Upper Palaeolithic (Epigravettian) humans from Grotta di San Teodoro (15 232–14 126 cal. BP) and Grotta Addaura Caprara (16 060–15 007 cal. BP) date to the Late-glacial and were possibly contemporary. The diets of these individuals were dominated by the protein of large terrestrial mammalian herbivores, such as red deer ( Cervus elaphus). There is no evidence for the consumption of marine resources, which is probably the result not only of the oligotrophic nature of the Mediterranean, but also perhaps of the lack of adequate technology for exploiting intensively the resources from this sea. In spite of being contemporaneous and of the cultural and technological affinities present between the San Teodoro and Addaura humans, the carbon (δ 13C) and nitrogen (δ 15N) isotope composition of their bone collagen suggests that significant differences were present in their diets. In particular, the hunter-gatherers from Grotta di San Teodoro, in NE Sicily where coastal plains are backed by high mountain chains (Monti Nebrodi), probably had easy access to resources such as anadromous brown trout ( Salmo trutta), which might not have been similarly available in the NW of the island, where reliefs are noticeably lower and watercourses fewer and farther between. This study shows that the high biodiversity of this region, which results from the complex topography of Mediterranean landscapes, was probably exploited opportunistically by Late-glacial foragers. Our data also suggest that intensification and diversification of food acquisition in Sicily did not start in the closing stages of the late Pleistocene, as in other Mediterranean regions, probably because the island had only been (re-)colonized by humans around the Last Glacial Maximum.

Speleogenesis in highly geodynamic contexts: The quaternary evolution of Monte Corchia multi-level karst system (Alpi Apuane, Italy)

The Mt. Corchia karst system is one of the most important and famous caves in the World. Different from many other large caves, here the geological structure has had only a minor role on the vertical, multi-level pattern of the cave. A detailed geomorphic and morphometric analysis of the cave and a preliminary study of cave sediments, along with new datings of speleothems, allow us now to depict the multistage evolution of this cave, which produced at least three major paleo-phreatic levels related to different base-level stages. The analysis of the directions of cave passages shows that the three main phases have different orientations, which can be attributed to the different surface morphology during speleogenesis in former times.Chronological constraints and geomorphic features suggest that the upper part of Mt. Corchia Cave developed during the end of Pliocene in a stage of favourable climatic conditions and with a moderate tectonic uplift-rate. The morphological features and the nature of sediments in the upper paleo-phreatic level at 1350–1450m above present sea level (apsl) imply the occurrence of a wide allogenic catchment area. This drainage pattern persisted also in the following stage, during a significant but slow lowering of the base level, which allowed the formation and the intense vadose rearrangement of the epi-phreatic network around 1100–1250m apsl. An uplift stage in the Early Pleistocene caused the capture of the basins and the loss of allogenic feeding. A third epi-phreatic level was formed at around 900m (apsl) when the catchment area was reduced to the present extent of carbonate rock, more than 1Ma ago. The recent evolution is due to rapid uplift and to the progressive incision of surrounding basins, which led to the lowering of the local base level and to a readjustment of the cave system in order to adapt to a new equilibrium with the present elevation of the springs.

The Bulgheria canyon-fan: a small-scale proximal system in the eastern Tyrrhenian Sea (Italy)

The Bulgheria canyon-fan system in the eastern Tyrrhenian Sea displays well-developed, small-scale, fluvial-like features and has formed alongside the northern slope of the Sapri peri-Tyrrhenian basin. This study reveals, for the first time, the morphology and course of the present-day system as well as the buried elements based on a Digital Terrain Model and high-resolution seismic profiles interpretation. Two adjacent canyons (Infreschi and Luna) originate in the Cilento outer shelf at a short distance from each other and feed an intraslope basin fan through two main sub-parallel channels that run about 12 and 8 km, respectively. Channel and levee development seems to be controlled primarily by the local slope gradient and by Coriolis forces that induce a faster vertical growth of the right-side features, as is often observed in the Northern Hemisphere. Centrifugal forces, on the other hand, have induced episodic flow-stripping at the meander loops and bends, causing local destruction of the main channel levees rather than new levee growth at the outer bends. Overbank deposits are associated with overspill turbidite deposition in the mid fan where a topographic constraint occurs, whereas large-sediment, low-angle wave fields are mainly developed on the outer fan. Buried features and relict morphologies suggest that the Infreschi channel experienced at least two phases of re-incision since the final stages of the middle Pleistocene. Local re-adjustment of outer lobe growth due to channel avulsion and meander abandonment is possibly a consequence of relative base-level fluctuations. The sedimentary record of the mid and outer fan includes outrun mass wasting deposits from extensive failures of the Sapri slope. Indeed, a marked scar is present on the eastern side of the modern outer lobe that indicates the persistency of mass flow passages up to recent times. In addition to the environmental factors that are currently considered to cause canyon formation on the shelf margin, this study proposes the possibility that the head canyon branch close to the mainland was incised by massive and persistent underground freshwater flow from the adjacent aquifer when the sea-level was lower than at present.

Age and paleoenvironment of Xiaogushan fauna at Haicheng, Liaoning Province

A mammalian fauna composed of 40 species associated with Xiaogushan Man was unearthed during the archaeological excavations from 1981 to 2007 at Xiaogushan Paleolithic Site, Haicheng, Liaoning Province. The analyses of the fauna and comparison with other related faunas indicate that Xiaogushan fauna is very similar to that of Shanchengzi, Gulongshan and Yushu. It is a typical fauna of Northern Region. Its age is within the middle to late stages of the Late Pleistocene (80–20 ka). Influenced by cold period MIS4, the cold forms appeared in the fauna. Nevertheless the decrease in temperature was not very much and the climate was still a temperate one. The fauna’s environment was generally humid, with large forest, some water areas and grasslands. It is suitable for prehistoric human habitation during temperate seasons with considerable food and water resources. The cold period MIS4 might push prehistoric human southward to temperate areas or stimulate them to develop fire using and making techniques.

Early Wisconsinan (MIS 4) Arctic ground squirrel middens and a squirrel-eye-view of the mammoth-steppe

Fossil arctic ground squirrel ( Spermophilus parryii) middens were recovered from ice-rich loess sediments in association with Sheep Creek-Klondike and Dominion Creek tephras (ca 80 ka) exposed in west-central Yukon. These middens provide plant and insect macrofossil evidence for a steppe-tundra ecosystem during the Early Wisconsinan (MIS 4) glacial interval. Midden plant and insect macrofossil data are compared with those previously published for Late Wisconsinan middens dating to ∼25–29 14C ka BP (MIS 3/2) from the region. Although multivariate statistical comparisons suggest differences between the relative abundances of plant macrofossils, the co-occurrence of steppe-tundra plants and insects (e.g., Elymus trachycaulus, Kobresia myosuroides, Artemisia frigida, Phlox hoodii, Connatichela artemisiae) provides evidence for successive reestablishment of the zonal steppe-tundra habitats during cold stages of the Late Pleistocene. Arctic ground squirrels were well adapted to the cold, arid climates, steppe-tundra vegetation and well-drained loessal soils that characterize cold stages of Late Pleistocene Beringia. These glacial conditions enabled arctic ground squirrel populations to expand their range to the interior regions of Alaska and Yukon, including the Klondike, where they are absent today. Arctic ground squirrels have endured numerous Quaternary climate oscillations by retracting populations to disjunct “interglacial refugia” during warm interglacial periods (e.g., south-facing steppe slopes, well-drained arctic and alpine tundra areas) and expanding their distribution across the mammoth-steppe biome during cold, arid glacial intervals.

Upwelling Process of the Western Himalaya Mountains: Height and Velocity Estimation Evidenced by Formation and Evolution of the Zanda Basin, Tibet, China

Abstract:Based on field geological survey, stratigraphic section measurement and indoor comprehensive investigation, the Zanda Basin's tectonic location in the Himalaya Plate was ascertained, and the formation and evolution of the Zanda Basin during the Pliocene to Early Pleistocene was classified as six stages: (a) primary rift‐faulting stage, (b) quick rift‐faulting Stage, (c) intensive rift‐faulting stage, (d) stasis stage, (e) secondary rift‐faulting stage, and (f) secondary quick rift‐faulting stage. Based on this six‐staged formation‐evolution theory of the Zanda Basin, the upwelling process of the Western Himalaya Mountains from the Pliocene to Early Pleistocene was classified as the following five stages: (a) slow upwelling stage (5.4–4.4 Ma), (b) mid‐velocity upwelling stage (4.4–3.5 Ma), (c) quick upwelling stage (3.5–3.2 Ma), (d) upwelling‐ceasing stage (3.2–2.7 Ma), and (e) quick upwelling stage (2.7 Ma). Research has shown that in the duration from the Early Pliocene (4.7 Ma) to the End of Pliocene (2.67 Ma), which lasted 2.03 million years, the Himalaya Mountains had uplifted 1500 m at a velocity of 0.74 mm/a; this belongs to a mid‐velocity upwelling. During the 1.31 million years in the Early Stage of the Early Pleistocene, the Himalaya Mountains had risen up another 1500 m at a velocity of 1.15 mm/a; this is a rather quick upwelling. All of these data have shown that the upwelling of the Western Himalaya Mountains is along a complicated process with multi‐stages, multi‐velocities, and non‐uniformitarian features.

Integrated stratigraphy and astronomical tuning of lower–middle Pleistocene Montalbano Jonico section (southern Italy)

Astronomical calibration of the lower–middle Pleistocene Montalbano Jonico section located in the Lucania Basin (Southern Italy) is presented. Previous papers widely discussed the integrated stratigraphy (calcareous nannofossils, sapropel stratigraphy, benthic and planktonic oxygen stable isotopes) and the paleoenvironmental features of this section and its potential suitability for the selection of the Middle Pleistocene Global Stratotype Section and Point (GSSP). In this study, new planktonic δ 18O data, additional biostratigraphical constraints and new tephrochronology on volcaniclastic layers occurring within the studied record are reported. The new chronostratigraphic framework provides a robust base for correlation of the oxygen isotope stratigraphy for the Montalbano Jonico section with the glacial and interglacial fluctuations of the Oceanic and Mediterranean δ 18O reference deep-sea records. Specifically, the lower part of the Montalbano Jonico section (Interval A) provides correlation of the planktonic and benthic δ 18O cycles to Marine Isotope Stage (MIS) 36 to MIS 23. Interval A includes a distinct peak of left-coiled neogloboquadrinids, the Globoratalia crassaformis influx, the First Occurrence of Gephyrocapsa omega, and the First Common Occurrence and Last Common Occurrence of Reticulofenestra asanoi. These stratigraphical constraints support the tuning of five sapropel layers included in this part of the section to insolation cycles i-112, i-104, i-102, i-90 and i-86. The upper part of the section (Interval B), which includes the temporary disappearance (td2) of G. omega and tephra layer V5, Ar/Ar age dated at 719.5 ± 12.6 ka, is consistent with identification of MIS 22 to MIS 16 in the planktonic δ 18O pattern. The δ 18O time series of the whole section was reconstructed using the midpoints of individual sapropels and their correlative precession minima, visual comparison of the δ 18O pattern with the record available at the Mediterranean ODP Site 975, and, in the upper part of the section, the Ar/Ar age of tephra V5. The developed astronomical tuning revealed that the Montalbano Jonico section covers an interval from 1240 ka to 645 ka. A significant change in sedimentation rate occurs between Intervals A (0.53 m/ky) and Interval B (0.91 m/ky) at about 870 ka and is consistent with a sea-level drop from a bathyal to a circalittoral environment. Bioevents recognised in the Montalbano Jonico section have been dated according to the astronomical calibration, and age assignments of tephra V1–V4 and V6–V9 are also proposed. The Montalbano Jonico section fills the gap between the top of the Vrica section and the base of the Ionian informal Middle Pleistocene stage, and represents a Mediterranean reference section for the Mid-Pleistocene transition.

Early Pleistocene evolution of the Japan Sea Intermediate Water

AbstractThe Early Pleistocene fossil record of the Japan Sea reveals that the planktonic foraminifer Globorotalia inflata succeeded in expanding its range from the East China Sea to the Japan Sea during interglacial stages of the Early Pleistocene; however, the species is only found in surface sediment samples from the southwestern‐most part of the sea. Based on the ecology of G. inflata and the water mass structure of the Japan Sea, it appears that its geographical distribution is mainly controlled by the low temperature of the intermediate water, which is caused by the cool‐water mass of Japan Sea Proper Water. The temporal and spatial patterns of G. inflata occurrence indicate that the intermediate water at 200 m depth during interglacial stages between 1.46 and 1.3 Ma was warmest during the Quaternary. This warm intermediate water probably resulted from the influence of the low‐salinity nature of the Tsushima Current due to the large inflow of East China Sea Coastal Water. After 1.3 Ma, the intermediate water at 200 m depth became cooler in a step‐wise manner. This cooling can be explained by an intensification of thermohaline circulation in the Japan Sea associated with strengthening of the East Asian winter monsoon and an increase in salinity due to enlargement of the southern strait. Copyright © 2009 John Wiley & Sons, Ltd.

Global stages, regional stages or no stages in the Plio/Pleistocene?

Over recent decades, with extended exploration of all the oceans, with the study of ice cores from Greenland and Antarctica, with all the high resolution methodologies now available for integrated stratigraphy, there has been a tendency in several milieux to abandon the use of stages for the Plio/Pleistocene. We do not agree with this approach and consider the use of standard stages in the Plio/Pleistocene as appropriate as for older parts of the Phanerozoic. In the hierarchy of chronostratigraphic units (erathem–system–series–stage), stage is the unit of lowest rank, and of widest and longest usage. Moreover, stage is the only chronostratigraphic unit defined on the basis of a typological criterion: units of higher rank are usually defined on the basis of the hierarchical principle. In the Plio/Pleistocene there are three formalized stages: Zanclean, Piacenzian and Gelasian (oldest to youngest), all defined in the Mediterranean area, a small geodynamically active ocean basin, where uplift of coastal areas has exposed continuous successions of deep marine Plio/Pleistocene strata. The Zanclean GSSP is an example of event stratigraphy: the Pliocene transgression marking the sudden invasion by Atlantic water masses of the desiccated Mediterranean, terminating the Messinian salinity crisis. The other two Plio/Pliocene GSSPs are defined using multiple criteria, but mainly by reversals of the magnetic field polarity. Following the recent IUGS ratification of the formerly Pliocene Gelasian Stage as the oldest stage of the Pleistocene, formalization of younger Pleistocene stages is in progress, starting from the Calabrian. With just one name of precise and well controlled time significance and multiple criteria for global correlation, one can identify a defined time interval in both terrestrial and marine realms, independent of latitude, bioprovincialism and historical evolution.

Quaternary deposits of the Büyük Menderes Graben in western Anatolia, Turkey: Implications for river capture and the longest Holocene estuary in the Aegean Sea

The Büyük Menderes Graben is a seismically active depositional basin in the N–S extensional tectonic region of western Anatolia, Turkey. It extends in an E–W direction and is bounded by the Aegean Sea to the west. The infill of this tectonic basin comprises ca 850 m and 245 m thick clastic sequences of Neogene and Quaternary, respectively and the Quaternary part of the basin-fill is presented here by the help of seismic sections and boreholes. Results show that the studied succession was made of unconsolidated, mostly fine-grained clastic sediments of marine and continental sequences interfingered with each other. The marine counterpart forms three relatively short (approx. 30 km) and one long (approx. 100 km from modern coastline) sediment wedges representing sea transgressions onto the graben. The last one was a rapid incursion that occurred in the Middle Holocene, forming the longest estuary of the Aegean Sea in western Anatolia. The filling of this estuary caused the decline of some historical harbours and settlements in the region. While marine-based events occurred in the west of the graben, alluvial and fluvial processes produced marginal and axial deposits in the east of graben, respectively. In general, the continental succession of Quaternary is thinner than its marine equivalent, probably due to sea-level fluctuations. In addition, the sedimentation rate increased suddenly during deposition of the last marine sequence (estuarine deposits) in the Holocene. It is likely that this was the result of enlargement of the drainage area of the River Büyük Menderes due to a river capture that occurred in the latest stages of Pleistocene.

Chemical weathering intensity and element migration features of the Xiashu loess profile in Zhenjiang, Jiangsu Province

The chemical weathering intensity and element migration features of the Xiashu loess profile in Zhenjiang are studied in this paper. (1) The Xiashu loess profile underwent moderate chemical weathering. It seems that the precipitation is a more important factor than the temperature in controlling the process of the chemical weathering. (2) The major elements such as Si, K, Na, Ca, Mg, Mn and P were migrated and leached, while the elements Fe and Ti were slightly enriched. The migration features of the major elements reveal that the Xiashu loess finished the primary process of chemical weathering characterized by leaching of Ca and Na, and almost reached the secondary process characterized by leaching of K. Except the elements Sr and Ga, other trace elements such as Th, Ba, Cu, Zn, Co, Ni, Cr and V were enriched. It might be caused by both the biogeochemical process and the adsorption of trace elements by clay mineral and organic materials. (3) The difference of element migration down the Xiashu loess profile reveals that the climate was warm and wet at the early-middle stage of the middle Pleistocene. At the end of the middle Pleistocene, it became dry and cool. At the early stage of the Late Pleistocene, the paleoclimate became warm and wet again. As a whole, the paleoclimate generally became drier and cooler in this region from the beginning of the middle Pleistocene.

Remarks on the palynology-based chronostratigraphical subdivision of Pliocene terrestrial deposits in NW-Europe

The chronostratigraphical subdivision of the Pliocene and Early Pleistocene as applied in terrestrial deposits of Central and NW-Europe largely relies on the pollen analytical investigations. This subdivision is almost entirely based on the interpretation of quantitative changes of the vegetational cover as recorded by the pollen content of fluvial deposits in the Lower Rhine Embayment. The Early and Middle Pliocene stages are originally defined in the type areas near Susteren and Brunssum along the southern border of the roer valley graben (RVG). Late Pliocene and Early Pleistocene stages have been defined in the Venlo-Tegelen area on the Peel Block, just north of the RVG. A critical review of existing data has been carried out considering lithostratigraphical data, provenance studies and palaeogeography in comparison especially with the interpretation of palynological results. As a result, it is concluded that the existing subdivision of the Pliocene into stages and substages defined by pollen assemblages has not been executed correctly. As a consequence, the application of this subdivision in geological reconstructions and modelling reveals many problems and pitfalls.

An approach to the age of Huanghe River in shelf regions of Yellow Sea and Bohai Sea

There are two different opinions on the formation history of Huanghe (Yellow) River. One postulates that Huanghe River might have come into existence before Tertiary. The other supposes that it joined up into a long river only in the last stage of Late Pleistocene. The appearance of Huanghe River is believed to have close relation to the uplifting of Tibetan Plateau. It is not likely that it could have come into being before its high elevation riverhead was formed. Today Huanghe River occurred probably during the recession of the sea in glacial periods. In the last glacial age, the climate was very harsh in the area north of the modern estuary of Changjiang (Yangtse) River; some areas were permafrost and the others barren deserts. At that time, eolation was the major exogenic force on exposed shelf. Beginning from 12 Ka BP, the global climate warmed up, resulting in gradual disappearance of continental mountain glaciers retreated, and sea level rose. Consequently, Huanghe River was replenished with water to become modern river system. With continued rising of sea level, Huanghe River delta moved continuously eastward.

The movement age of hidden fault and analysis on width of its effect zone from shallow seismic sounding and drilling data

Field experimental seismic sounding permitted us to obtain optimal shallow seismic reflection sounding parameters. In process of data processing, we obtained a high-qualitative shallow seismic reflection sounding profile by using the techniques such as filtering, edition surgical blanking, prediction deconvolution, fitting static correlation of first arrival time, and velocity analysis. Comprehensive analysis on the information of reflection wave groups along the seismic sounding profile and the stratigraphic and neogeochronological data obtained from many drills near the sounding line reveals that the upper termination of the detected fault zone is located at depth of 75–80 m, in the Middle Pleistocene deposits dated to be about 220 ka BP. The continuity, discontinuity, increasing and decreasing amount of reflection wave groups and change of their configurations, in combination with geological columns of drills, permitted us to know that the width of upper termination of the fault zone is 100 m. It can be inferred from the variation of number of reflection wave groups along the profile that the scarp of hidden fault is 200 m wide and the fault is a synsedimentary active fault in the Early Pleistocene and the early stage of Middle Pleistocene. No tectonic movement, which offset the covering deposits, had occurred since the late stage of Middle Pleistocene.