scholarly journals Dietary responses of Sahul (Pleistocene Australia–New Guinea) megafauna to climate and environmental change

Paleobiology ◽  
2017 ◽  
Vol 43 (2) ◽  
pp. 181-195 ◽  
Author(s):  
Larisa R. G. DeSantis ◽  
Judith H. Field ◽  
Stephen Wroe ◽  
John R. Dodson
Keyword(s):  
Late Pleistocene ◽  
Population Biology ◽  
Late Quaternary ◽  
New Guinea ◽  
Middle Pleistocene ◽  
Dental Microwear ◽  
Southeastern Australia ◽  
Climate And Environmental Change ◽  
Arid Conditions ◽  
Monitor Lizards

AbstractThroughout the late Quaternary, the Sahul (Pleistocene Australia–New Guinea) vertebrate fauna was dominated by a diversity of large mammals, birds, and reptiles, commonly referred to as megafauna. Since ca. 450–400Ka, approximately 88 species disappeared in Sahul, including kangaroos exceeding 200kg in size, wombat-like animals the size of hippopotamuses, flightless birds, and giant monitor lizards that were likely venomous. Ongoing debates over the primary cause of these extinctions have typically favored climate change or human activities. Improving our understanding of the population biology of extinct megafauna as more refined paleoenvironmental data sets become available will assist in identifying their potential vulnerabilities. Here, we apply a multiproxy approach to analyze fossil teeth from deposits dated to the middle and late Pleistocene at Cuddie Springs in southeastern Australia, assessing relative aridity via oxygen isotopes as well as vegetation and megafaunal diets using both carbon isotopes and dental microwear texture analyses. We report that the Cuddie Springs middle Pleistocene fauna was largely dominated by browsers, including consumers of C4 shrubs, but that by late Pleistocene times the C4 dietary component was markedly reduced. Our results suggest dietary restriction in more arid conditions. These dietary shifts are consistent with other independently derived isotopic data from eggshells and wombat teeth that also suggest a reduction in C4 vegetation after ~45 Ka in southeastern Australia, coincident with increasing aridification through the middle to late Pleistocene. Understanding the ecology of extinct species is important in clarifying the primary drivers of faunal extinction in Sahul. The results presented here highlight the potential impacts of aridification on marsupial megafauna. The trend to increasingly arid conditions through the middle to late Pleistocene (as identified in other paleoenvironmental records and now also observed, in part, in the Cuddie Springs sequence) may have stressed the most vulnerable animals, perhaps accelerating the decline of late Pleistocene megafauna in Australia.

Late Quaternary Paleoenvironmental Reconstruction, Using Benthic Foraminifera and Ostracoda, of Marine Sedimentary Beds On the Southern Coast of Laizhou Bay, Bohai Sea, China

2018 ◽  
Vol 48 (2) ◽  
pp. 87-99 ◽  
Author(s):  
Xiaohui Cui ◽  
Shoujun Li ◽  
Hua Xu ◽  
Zhuo Zhang ◽  
Xiuli Zhao ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Bohai Sea ◽  
Late Quaternary ◽  
Middle Pleistocene ◽  
Small Scale ◽  
Laizhou Bay ◽  
Benthic Foraminifers ◽  
The Holocene ◽  
Subtidal Environment ◽  
Late Middle Pleistocene

Abstract Extensive studies of Quaternary transgressions have been conducted in Bohai Sea, but debates continue regarding the sedimentary evolution and timing of transgressions, especially in the Pleistocene section. Benthic foraminifers and ostracodes from three boreholes (GK138, GK111, GK95) at Laizhou Bay, Bohai Sea, were utilized to interpret the paleoenvironments of deposition and elucidate the coastal response to global sea-level changes since the late Quaternary. Benthic foraminiferal species identified included 32 species from 15 genera; ostracodes included 28 species from 16 genera. Three marine sedimentary beds were recognized based on sedimentary characteristics, down-core changes in environmental proxies (benthic foraminifers and ostracodes), accelerator mass spectrometry (AMS) 14C, and optically stimulated luminescence (OSL) dates. These three beds were interpreted as: marine sedimentary bed 3 (M3), deposited in the late-middle Pleistocene; marine sedimentary bed 2 (M2), deposited during the late Pleistocene; and marine sedimentary bed 1 (M1), deposited during the Holocene. Three microfossil assemblages were identified, all indicating nearshore conditions. Assemblage III indicated a fluvially influenced or paralic environment during a relatively small-scale late-middle Pleistocene transgression that produced bed M3. Assemblage II indicates an intertidal-subtidal environment where bed M2 was deposited during the late Pleistocene transgression. Assemblage I indicates somewhat more marine influence in a subtidal environment where bed M1 was deposited during the Holocene marine transgression.

Vegetation at the northern pole of cold during the climate extremes of the late Pleistocene: fossil records from the Batagay mega thaw slump, Yakutia

2020 ◽  
Author(s):  
Frank Kienast ◽  
Kseniia Ashastina ◽  
Svetlana Kuzmina ◽  
Natalya Rudaya
Keyword(s):  
Northern Hemisphere ◽  
Late Pleistocene ◽  
Late Quaternary ◽  
Plant Cover ◽  
Climate Extremes ◽  
Environmental Stability ◽  
Middle Pleistocene ◽  
Last Interglacial ◽  
Large Herbivores ◽  
Steppe Belt

<p>The Batagay mega slump is the largest active thaw slump on the planet. Enormously rapid thermal erosion gave access to permafrost sediments that deposited since the Middle Pleistocene. Permafrost is an excellent medium for the preservation of ancient organic matter. The Batagay exposure is well known for some spectacular findings of Pleistocene megaherbivore carcasses including the youngest steppe bison found in Eurasia so far, dated to 8.2 ka BP. The extraordinarily long sequence of Pleistocene deposits in Batagay is therefore an excellent archive of the palaeoenvironmental history in the Yana highlands - a region with uniquely stable cold-continental climate known as the pole of cold in the northern hemisphere. This region is regarded as refugial area for extrazonal steppe plants and now extinct large grazers together constituting the Pleistocene mammoth steppe, which covered vast areas in high and mid latitudes of the northern hemisphere during cold stages. Modern vegetation around the study site consists of light taiga mainly composed of larch, shrub alder, shrub birches and stone pine. To understand the processes that resulted in the demise of Pleistocene megafauna and in the biological turnover during the late Quaternary, we reconstructed vegetation and environmental conditions during the two climate extremes of the late Pleistocene, the onset of the last glacial maximum and the last interglacial using remains of plants and insects preserved in organic-rich material. The results from studies of plant material gathered in a fossil ground squirrel nest suggest that grassland vegetation corresponding to modern meadow steppes in Central Yakutia and northern Mongolia existed in the study area during the last cold stage. During the last interglacial, open coniferous woodland similar to modern larch taiga was the primary vegetation at the site. Abundant charcoal indicates wildfire events during the last interglacial. Zoogenic disturbances of the local vegetation were indicated by the presence of ruderal plants, especially by the abundant nitrophytic <em>Urtica dioica</em>, suggesting that the area was an interglacial refugium for large herbivores. Meadow steppes, which formed the primary vegetation during cold stages and provided potentially suitable pastures for herbivores, were a significant constituent of the plant cover in the Yana Highlands also under the full warm stage conditions of the last interglacial. Consequently, meadow steppes occurred in the Yana Highlands during the entire investigated timespan of the Pleistocene documenting a remarkable environmental stability. The documented fossil record also proves that modern steppe occurrences in the Yana Highlands did not establish as late as in the Holocene, as suggested by some scholars, but instead are relicts of a formerly continuous steppe belt extending from Central Siberia to Northeast Yakutia during the Pleistocene.</p>

Late Quaternary Ice Age Climates of Tropical Australasia: Interpretations and Reconstructions

1978 ◽  
Vol 10 (3) ◽  
pp. 279-309 ◽  
Author(s):  
P.J. Webster ◽  
N.A. Streten
Keyword(s):  
Late Quaternary ◽  
New Guinea ◽  
Circulation Pattern ◽  
Ice Age ◽  
Subtropical Zone ◽  
Ice Caps ◽  
Freezing Level ◽  
Southeastern Australia ◽  
Tropical Oceans ◽  
Upper Level

Paleoecological and paleogeographical evidence is used to mold a framework from which the basic parameters of the late Quaternary glacial-age climate of tropical Australasia can be inferred. The theory of physical circulations, a knowledge of present tropical circulation patterns, and a study of anomalous and extreme events in the present era are used to reemphasize the view of a less pluvial tropical and subtropical zone at that time. Cooler sea-surface temperature, cooler trades, and the effect of the then exposed land areas are indicated as instrumental in producing drier conditions. Tropical areas west of Cape York Peninsula and Torres Strait were subject to fewer tropical disturbances and were similar to the present tropical savannah of the northern interior of Australia. Such effects would exist even without shifts in major climatic zones, although they are shown to be consistent with an equatorward shift of the westerlies brought about by the increased pole to equator temperature gradient. Paleoenvironmental evidence from the New Guinea Highlands and southeastern Australia suggests that their climates were anomalous. Substantial data of the glacial period in New Guinea show snow lines to be 1000 to 1500 m lower than at present which matches a 6 to 8°C lowering of temperature in highland New Guinea. The deep-sea cores of the CLIMAP Project suggest a mere 2°C cooling of the surrounding tropical oceans. It is shown that it is highly unlikely that an upper-level decrease in temperature of 6 to 8°C could be maintained while the surface cools by only 2°C. It is suggested that either the temperature of the tropical oceans of the western Pacific were overestimated by CLIMAP or that cold air incursions from higher latitudes (for which some analogs exist today) were sufficiently frequent to allow the maintenance of a snow line well below the freezing level of the ancient ambient tropical atmosphere. It is shown that in southeastern Australia considerable evidence of aridity cannot be explained by merely displacing the westerlies more equatorward. To account for the aridity, a new circulation pattern is proposed. Noting that there is CLIMAP evidence of preferred equatorward extension of sea ice, a pattern is postulated that displays only small seasonal change and is characterized by an enhanced Indian Ocean trough, marked ridging at eastern Australian longitudes, and a further trough in the western Tasman. Such a basic flow is consistent with (i) a low rainfall over southeastern Australia, (ii) frequent cold outbreak conditions favorable for the maintenance of the New Guinea glaciers, and (iii) considerable precipitation to nourish the ice caps of Tasmania and the Australian and New Zeland Alps.

The response of periglacial landscape to Late Pleistocene active thrusting: evidences at the Po Basin-Northern Apennines hinge (Lombardy, Italy)

2020 ◽  
Author(s):  
Chiara Zuffetti ◽  
Riccardo Bersezio
Keyword(s):  
Late Pleistocene ◽  
Late Quaternary ◽  
Foreland Basin ◽  
Loess Soil ◽  
Sediment Flux ◽  
Middle Pleistocene ◽  
Fluvial System ◽  
Glacial Cycles ◽  
Passive Deformation ◽  
Basin Floor

<p>The palimpsest landscape and stratigraphic architecture of the Quaternary Po Foreland Basin record the tectonic pulses of the N-Apennines fold-and-thrust belt (the southern basin floor and active structural margin) and the glacial dynamics on the Alps (the northern basin floor and margin). Climate-controlled sediment flux from the glaciated Alpine side of the basin accommodated in the mobile setting driven by Apennine N-wards thrusting. Deciphering the nature, hierarchy and timing of landscape-changing increments at the Po Basin-Apennines hinge helps to describe the Late Quaternary tectonic modulation of landscape response to glacial cycles.</p><p>The study integrates different-scale geological, sedimentological, stratigraphic, geo-pedological, geomorphological and structural field surveys constrained by C<sup>14 </sup>and OSL age determinations, and subsurface reconstructions obtained from borehole logs and geophysical images. Focus is on the culminations of Apennine ramp-folds, the San Colombano (SC hereafter) and Casale-Zorlesco (CZ) isolated reliefs, which elevate above the terrace orders of the latest Pleistocene-Holocene plain. These selected key-sectors expose unconformities, morphological surfaces and stratigraphic units otherwise buried in the adjacent plain sectors, and show the involvement of Quaternary, alpine-sourced littoral, alluvial and glacio-fluvial succession in Apennine folding and faulting.          </p><p>Evidences of syndepositional tectonics are the location of unconformable stratigraphic vs. conformable morphological boundaries, pinch-out and cross-cut relationships among glacio-fluvial and alluvial sedimentary bodies, uplifted paleovalley fills, cannibalism of pre-existing alluvial clastics, colluvial wedges and soft-sediment deformation structures. During Early-Middle Pleistocene, the SC-CZ ramp anticlines underwent thrusting, which uplifted and folded the Gelasian regional unconformity between deep-marine Miocene and littoral Calabrian formations. Late Pleistocene, distal alpine-sourced glacio-fluvial units terraced the deformed marine successions giving origin to the composite Late Pleistocene unconformity. These units, time-constrained by OSL data to MIS6-MIS5, progressively wedge-out and amalgamate S-wards, suggesting confinement by the uplifting ancestors of the present-day hills. MIS4 glacio-fluvial system, fed from the Verbano-Lario glacial amphitheatres, fringed-out above a western uplifted culmination, while a braided glacio-fluvial system flowing South from the central-eastern Lario amphitheatre, terraced the eastern subdued structural highs. Relics of the corresponding  planation surface are uplifted at the present-day eastern SC and CZ hilltops. On the uplifted proto-hills, Late Pleistocene climate cycles are registered by polycyclic loess-soil sequences. Relics of syn-tectonic paleovalley fills, valley diversions, polygonal facets, alignments of windgaps and hanging valleys, suggest that differential uplift and wrenching occurred, plausibly driven by slip along the eastern dextral lateral ramp of the SC structure. The LGM, glacio-fluvial systems prograded S-wards terracing the existing reliefs. Tilting and faulting of these LGM terraces in correspondence of the faceted SC hill fronts, drainage diversions and polyphasic soil reworking at the same sites, imply passive deformation and collapse of the SC structure and hill. Entrenchment and abrupt diversions of the river network which cross-cut the mentioned geological and geomorphological elements, suggest that the Holocene lowermost terraces of the Po Plain formed during concurrent post-glacial increase of fluviatile discharge and tectonic uplift.</p>

Hominin transition to Upper Pliocene

2017 ◽  
Author(s):  
Francisco J. Ayala ◽  
Camilo J. Cela-Conde
Keyword(s):  
Brain Development ◽  
Late Pleistocene ◽  
Technological Progress ◽  
Homo Sapiens ◽  
Middle Pleistocene ◽  
Evolutionary Significance ◽  
Australopithecus Afarensis ◽  
Phylogenetic Significance ◽  
Homo Neanderthalensis ◽  
Surprising Discovery

This chapter analyzes the transition of the hominins from the Middle Pleistocene to the Late Pleistocene. Two alternative models are explored, the “Multiregional Hypothesis” (MH) and the “Replacement Hypothesis,” and how each model evaluates the existing relationships between the taxa Homo neanderthalensis and Homo sapiens. Next is the investigation of the transitional (or “archaic,” if this grade is taken into account) exemplars found in Europe, Africa, and Asia and their evolutionary significance. In particular, the comparison between H. erectus and H. sapiens in China and Java is investigated, as the main foundation of the MH. The chapter ends with the surprising discovery of Homo floresiensis and its description and interpretations concerning its taxonomic and phylogenetic significance. The correlation between brain development and technological progress is at odds with the attribution of perforators, microblades, and fishing hooks to a hominin with a small cranial volume, similar to that of Australopithecus afarensis.

Late Quaternary change in the mountains of New Guinea

Antiquity ◽  
1995 ◽  
Vol 69 (265) ◽  
pp. 818-830 ◽  
Author(s):  
Geoff Hope ◽  
Jack Golson
Keyword(s):  
Late Quaternary ◽  
New Guinea ◽  
Mountainous Areas ◽  
The South ◽  
Environmental Sequence ◽  
The North ◽  
Australian Continent

At the south and north limits of our region are mountainous areas very different from the open arid spaces of the Australian continent between. In the north, the high country of New Guinea offers a complex and well-studied environmental sequence as the arena for early and puzzling human adaptations, precursor of the extraordinary societies of the island today.

Late Pleistocene glaciation of the Mt Giluwe volcano, Papua New Guinea

2011 ◽  
Vol 30 (19-20) ◽  
pp. 2676-2689 ◽  
Author(s):  
Timothy T. Barrows ◽  
Geoffrey S. Hope ◽  
Michael L. Prentice ◽  
L. Keith Fifield ◽  
Stephen G. Tims
Keyword(s):  
Papua New Guinea ◽  
Late Pleistocene ◽  
New Guinea ◽  
Pleistocene Glaciation

Facies Composition and Stratigraphic Position of the Quaternary Upper Yenisei Sequence in the Tuva and Minusa Depressions

2021 ◽  
Vol 62 (10) ◽  
pp. 1127-1138
Author(s):  
I.D. Zol’nikov ◽  
I.S. Novikov ◽  
E.V. Deev ◽  
A.V. Shpansky ◽  
M.V. Mikharevich
Keyword(s):  
Late Pleistocene ◽  
Lacustrine Sediments ◽  
Alluvial Fan ◽  
Luminescence Dating ◽  
Middle Pleistocene ◽  
Mountainous Area ◽  
Gorny Altai ◽  
Stratigraphic Position ◽  
Geochronological Dating ◽  
Current Ripples

Abstract —The paper concerns the sediment sequence, which is widespread in the Yenisei valley and in the Tuva and Minusa depressions and also present in the valleys of the southern Chulym plain. The sediments of this sequence were previously described as “Neogene mud-shedding”, as well as moraines, alluvial fan deposits, alluvium of Middle Pleistocene high terraces, and lacustrine sediments. The giant ripple marks on the Upper Yenisei terraces was commonly interpreted as ribbed moraines; however, in recent studies, these ridges have been repeatedly referred to as marks of giant current ripples. Besides, some recently published papers provide description of geology of this sequence fragments suggesting its deposition by cataclysmic floods. Geomorphological analysis of the area shows Pleistocene glaciers to have been localized within the medium–high mountainous areas. The glaciers did not reach the Tuva and Minusa depressions and occupied large areas only in the Todzha basin and on the periphery of the Darkhat basin, forming a glacial dam at its outlet, which resulted in glacial-dammed lakes filling the basin completely. These lakes outburst, and the resultant flooding led to the deposition of megaflood sediments, which we refer to here as the Upper Yenisei sediment sequence. A detailed analysis of its facies architecture revealed similarity of these sediments to those of the Sal’dzhar and Inya sequences in Gorny Altai. Most of the Upper Yenisei megaflood sediments are localized in topographic lows of the Tuva and Minusa depressions. Beyond the Altai–Sayan mountainous area, the megaflood sediments of the Upper Yenisei sequence compose high terraces of the Yenisei, Chulym, Chet’, and Kiya rivers in the southern Chulym plain. The formation of Upper Yenisei sequence dates to the first half of the Late Pleistocene, inasmuch as it contains inset alluvial sediments of the second terrace of the Yenisei River. The available data allow suggesting that the Upper Yenisei sequence formed in the first Late Pleistocene regional glaciation. The Sal’dzhar sequence in Gorny Altai and the fourth terrace of the Ob’ River on the Fore-Altai plain are stratigraphic analogs of the Upper Yenisei sequence. The Upper Yenisei and Sal’dzhar sequences can thus be considered future regional markers serving as a link for the local stratigraphic schemes of the Altai–Sayan mountainous area and adjacent West Siberian plains. The results obtained call for verification by geochronological dating, first of all, by modern luminescence dating methods covering a wider chronological interval than radiocarbon dating.

Two new Banksia species from pleistocene sediments in western Tasmania

1991 ◽  
Vol 4 (3) ◽  
pp. 499 ◽  
Author(s):  
GI Jordan ◽  
RS Hill
Keyword(s):  
Plant Species ◽  
Late Pleistocene ◽  
Environmental Changes ◽  
Middle Pleistocene ◽  
Extinct Species ◽  
The Third ◽  
Taxonomic Groups

Subtribe Banksiinae of the Proteaceae was diverse in Tasmania in the early and middle Tertiary, but is now restricted to two species, Banksia marginata and B. serrata. Rapid and extreme environmental changes during the Pleistocene are likely causes of the extinction of some Banksia species in Tasmania. Such extinctions may have been common in many taxonomic groups. The leaves and infructescences of Banksia kingii Jordan & Hill, sp. nov. are described from late Pleistocene sediments. This is the most recent macrofossil record of a now extinct species in Tasmania. Banksia kingii is related to the extant B. saxicola. Banksia strahanensis Jordan & Hill, sp. nov. (known only from a leaf and leaf fragments and related to B. spinulosa) is described from Early to Middle Pleistocene sediments in Tasmania. This represents the third Pleistocene macrofossil record of a plant species which is now extinct in Tasmania.

scholarly journals Late Quaternary Fluvial Sedimentation in the Voidomatis Basin, Epirus, Northwest Greece

1991 ◽  
Vol 35 (1) ◽  
pp. 103-115 ◽  
Author(s):  
John Lewin ◽  
Mark G. Macklin ◽  
Jamie C. Woodward
Keyword(s):  
Mediterranean Basin ◽  
Late Quaternary ◽  
Radiometric Dating ◽  
Middle Pleistocene ◽  
The Mediterranean ◽  
Fluvial Sedimentation ◽  
The Mediterranean Basin

AbstractDetailed morpho- and lithostratigraphic investigations, allied with radiometric dating, in the Voidomatis basin, Epirus, northwest Greece, have identified four Quaternary terraced alluvial fills that range from middle Pleistocene to historic in age. Major-periods of alluviation during the late Quaternary were associated with valley glaciation (ca. 26,000–20,000 yr B.P.) and subsequent deglaciation (ca. 20,000–15,000 yr B.P.) in the Pindus Mountains during Late Würmian times, and more recently linked to overgrazing sometime before the 11th century AD. The late Quaternary alluvial stratigraphy of the Voidomatis River is more complex than the “Older Fill” and “Younger Fill” model outlined previously, and it is suggested that these terms should no longer form the basis for defining alluvial stratigraphic units in the Mediterranean Basin.

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