Late Pleistocene Paleoenvironments Research Articles

Late Pleistocene paleoenvironment at a Middle Stone Age archaeological site in Equatorial Guinea: a paleopedological approach

Key evidence of human occupation in Africa during the Middle Palaeolithic (Middle Stone Age [MSA]) is available from the south and east of the continent, where semi-arid climate prevails. Rare evidence of MSA human occupation in the humid tropical region was recently reported from Equatorial Guinea. To identify if paleolithic human occupation occurred in the tropical forest, the stratigraphy of the recently discovered archaeological site “Mabewele I” was analyzed using a paleopedological approach. The properties evaluated along a vertical profile are: granulometry, magnetic susceptibility (K), free iron extractable with sodium dithionite (Fed), total organic carbon (TOC), chemical composition by X-ray fluorescence (XRF), X-ray diffraction mineralogy (XRD), ternary plot of the three main oxides (SiO2-Al2O3-Fe2O3), phytoliths and micromorphology. The predominant fraction is sand, with a significant clay content (> 30 %). The K and the Fed presented low values, as well as the TOC. XRF showed few variations along the sequence and XRD showed that the clays are mainly kaolinites, with a very low component of vermiculites. The phytoliths correspond to tropical vegetation with few changes in the vegetal composition between the deep and superficial zones. A charcoal from the lower part of the profile was dated between 12.57-12.24 ka cal BP, while the main artifact horizon was located at the bottom. The analytical results appear contradictory: on the one hand, there is evidence of intense chemical weathering under a humid tropical climate, but the clay cutans in the pores are very scarce and incipient and the iron nodules are mostly anorthic. This indicates that the sequence is composed of pedosediments associated with a high environmental dynamism, with short periods of erosion-sedimentation-pedogenesis. The results allow us to propose that humans inhabited the tropical forest during the MSA and that erosion-sedimentation processes could be related to anthropization processes.

A Late Pleistocene third molar of Hylochoerus (Suidae, Mammalia) from Rusinga Island, Kenya: paleoenvironmental implications and a note on the hypsodonty of African forest hogs

ABSTRACT African forest hogs (genus Hylochoerus) are extant Afro-tropical suids that inhabit a variety of forest environments and thick bushlands and are predominantly herbivores. Hylochoerus likely evolved from a Pleistocene Kolpochoerus majus-like ancestor, but its recent evolutionary history is virtually unknown. Here, we describe a partial right lower third molar from the Late Pleistocene Wasiriya Beds of Rusinga Island (~50-36 ka). The crowns are mesiodistally compressed in a bunolophodont fashion and arranged in columnar pillars that resemble those of extant Hylochoerus. We provide accurate data derived from computed tomography on the hypsodonty index (HI) of extant Hylochoerus and show that the Rusinga third molar crown was as tall as those of its modern counterpart (HI = 1.8–2.0). Stable carbon isotope analyses suggest that the diet of the Rusinga specimen (δ13C = −17.0 ‰) was also like that of extant forest hogs (δ13C average = −17.6 ‰). This extremely negative value contrasts strikingly with those of other fossil large herbivores at Rusinga (δ13C average = −0.7 ‰.). Among the potential explanations for this anomaly, the most likely is that the Late Pleistocene paleoenvironments were more heterogeneous than previously considered and may have included closed-canopy woodland in the highlands of Rusinga.

Late Pleistocene paleoenvironment of southern China: Clay mineralogical and geochemical analyses from Luna Cave, Guangxi, China

A number of important early Late Pleistocene human fossils have been found in southern China. These new data have contributed to a major revision of the traditional Out of Africa model that argues modern humans did not disperse out of Africa until after 60 ka. At the same time, these findings have attracted increased attention by paleoclimate specialists (e.g., vertebrate paleontologists, sedimentologists) interested in identifying the characteristics and understanding the living environment of the region in which these early Late Pleistocene modern humans lived in. Unfortunately, research focused on the reconstruction of the Late Pleistocene paleoenvironment in southern China is still very limited. Here, we present an analysis of the clay mineral assemblage and geochemical characteristics of the sedimentary deposits from Luna Cave, one of these important early Late Pleistocene modern human sites in southern China. The results from the sedimentological analyses are consistent with previous paleontological and geological studies that showed the paleoclimate was strongly influenced by the East Asian monsoon and that the Late Pleistocene environment was relatively stable warm and humid. Further studies of coeval sites from the region are necessary to determine whether this is a consistent pattern across southern China or specific to the Bubing Basin.

Reconstruction of Late Pleistocene Paleoenvironments Using Bulk Geochemistry of Paleosols from the Lake Victoria Region

The impact of changing environments on the evolution and dispersal of Homo sapiens is highly debated, but few data are available from equatorial Africa. Lake Victoria is the largest freshwater lake in the tropics and is currently a biogeographic barrier between the eastern and western branches of the East African Rift. The lake has previously desiccated at ~17 ka and again at ~15 ka, but little is known from this region prior to the Last Glacial Maximum. The Pleistocene terrestrial deposits on the northeast coast of Lake Victoria (94 to 36 ka) are ideal for paleoenvironmental reconstructions where volcaniclastic deposits (tuffs), fluvial deposits, tufa, and paleosols are exposed, which can be used to reconstruct Critical Zones (CZ) of the past (paleo-CZs). The paleo-CZ is a holistic concept that reconstructs the entire landscape using geologic records of the atmosphere, hydrosphere, lithosphere, biosphere, and pedosphere (the focus of this study). New paleosol-based mean annual precipitation (MAP) proxies from Karungu, Rusinga Island, and Mfangano Island indicate an average MAP of 750108 mm yr-1 (CALMAG), 800182 mm yr-1 (CIA-K), and 1010228 mm yr-1 (PPM1.0) with no statistical difference throughout the 11 m thick sequence. This corresponds to between 54 and 72% of modern precipitation. Tephras bracketing these paleosols have been correlated across seven sites, and sample a regional paleo-CZ across a ~55 km transect along the eastern shoreline of the modern lake. Given the sensitivity of Lake Victoria to precipitation, it is likely that the lake was significantly smaller than modern between 94 ka and 36 ka. This would have removed a major barrier for the movement of fauna (including early modern humans) and provided a dispersal corridor across the equator and between the rifts. It is also consistent with the associated fossil faunal assemblage indicative of semi-arid grasslands. During the Late Pleistocene, the combined geologic and paleontological evidence suggests a seasonally dry, open grassland environment for the Lake Victoria region that is significantly drier than today, which may have facilitated human and faunal dispersals across equatorial East Africa.

Reconstruction of Late Pleistocene paleoenvironments in southern Germany using two high-resolution loess-paleosol records

Two loess-paleosol sequences from the Heilbronn Basin in southwestern Germany, Frankenbach and Talheim, have been investigated to gain information about environmental conditions during the last interglacial-glacial cycle. Since paleoenvironmental research on terrestrial archives is crucial for a better understanding of past climatic and environmental conditions, the profiles were studied using a multi-proxy approach. Applied methods include the analyses of grain-size distribution, element contents, sediment color, rock magnetism, micromorphology, and black carbon (BC) via benzene polycarboxylic acids (BPCA). The data reveal that the two profiles show large variations in conservation due to their different geomorphologic positions. Moreover, the results imply a subarctic climate with stable conditions during the Middle Pleniglacial (MIS 3) in-situ soil formation phase while the Lower Pleniglacial (MIS 4) was characterized by erosion and reworking of Eemian and Early Glacial (MIS 5) material but also by accumulation of aeolian material during the late Lower Pleniglacial (MIS 4) in Frankenbach. The results further suggest that the Rhine River floodplain has been a major source for the accumulated material in the two profiles, which indicates westerly wind directions during the time of accumulation. The low GSI and U-Ratio of Upper Pleniglacial (MIS 2) sediments, supported by the overall high content of fine material, imply a larger distance to the source area. We give an overview of loess in the Heilbronn Basin and place it in a wider context of loess in Western Europe.

Paleoclimatic significance of the late Quaternary plant macrofossils from the Gokarna Formation, Kathmandu Valley, Nepal

Late Quaternary plant macrofossils from fluvial, fluvio-deltaic and lacustrine sediments of the Gokarna Formation in the Besigaon, Mulpani, and Dhapasi sections in the Kathmandu Valley, Nepal were analyzed. The obtained plant macrofossils allowed us to reconstruct the late Pleistocene paleoenvironment in central Nepal, which was influenced strongly by the SW Indian monsoon system and tectonic movements of the Himalayas. In total, 102 taxa from 52 families were identified to genus or species levels. The dominance of Eurya, Ficus, Morus, Zizyphus, Stephania, Rubus, Quercus subgen. Cyclobalanopsis, Pyracantha, and Carpinus in the lower and middle plant macrofossil assemblages indicates influence of a warm climate. In the upper plant macrofossil assemblages, the higher contents of cooler climatic taxa such as Abies, Pinus, Picea smithiana, Tsuga dumosa, Taxus wallichiana, Quercus subgen. Lepidobalanus, and Betula indicate a climatic deterioration. The higher diversity and common occurrence of aquatic plants indicate rich wetland vegetation in the Kathmandu basin. The plant macrofossil analysis shows at least three cycles of climate fluctuation between warm and cool phases during the deposition of the Gokarna Formation between 53,170±820yrs. BP and 49,300±2100/1700yrs. BP. These cycles seem to be fairly local or regional, but this can also be correlated with the overall global cooling context in GISP2 oxygen isotope curve in the late Pleistocene.

A joined rock magnetic and colorimetric perspective on the Late Pleistocene climate of Orlovat loess site (Northern Serbia)

This study represents the first detailed joined colorimetric and rock magnetic investigation on a loess–paleosol sequence in the Vojvodina region, Northern Serbia. The aim of this paper is to derive new information on the Late Pleistocene paleoenvironment from a high resolution multi-proxy assessment of the iron mineralogical composition at the Orlovat loess paleosol sequence. The Orlovat section is the first site from the Banat loess region analyzed for Quaternary paleoclimate information, and accordingly it is the easternmost loess section in the Serbian loess region studied. In contrast to other Serbian sites, the Orlovat site is not located in a plateau. Rock magnetic analysis and the luminescence-dating based chronology revealed active slope processes at this site during the Late Pleistocene. This is the most strikingly evidenced by the absence of a Middle Wurmian (MIS 3) interstadial pedocomplex, present as marker horizon in the Serbian plateau-loess sites.Nevertheless, important stratigraphic units and distinct pattern of the proxy records can be correlated to other key sites of the Vojvodina loess region. Hence, this section provides an opportunity to reconstruct local as well as regional environmental and climatic conditions during the Late Pleistocene. The applied multiproxy approach especially allowed valuable insight in the environmental conditions that prevailed during formation of the last interglacial pedocomplex. Accordingly, in the Eemian pronounced summer dryness prevailed. During the formation of the Eemian soil, the dry period was warmer and lasted longer or was characterized by less precipitation as during formation of the modern soil. Although the soil moisture deficit in the Eemian summers was most likely higher, the rainfall was more pronounced in the period of from spring to early summer/and or autumn as during the Holocene. These findings support previous observations from the Batajnica site, a key site of the Vojvodina loess region, and highlight the Eemian as potential past analogue to future climate warming in Serbia. This study points out the potential of a joined colorimetric or spectrometric analyses and rock magnetic analyses in paleoenvironmental investigations on loess paleosol sequences.

Paleoindian subsistence strategies and late Pleistocene paleoenvironments in the northeastern and southwestern United States: a tooth wear analysis

Paleoindians of North America entered a continent undergoing rapid climatic and environmental changes. This paper is a preliminary contribution toward obtaining a better picture regarding how climate and environmental change might have impacted the first settlers of North America. The Paleoindian sites we analyzed are, from the oldest to the youngest, Ingleside (Texas), Blackwater Draw Locality No. 1 (New Mexico), Hiscock Site (New York), and Plainview Quarry (Texas). Paleoenvironmental reconstruction involves identifying the dietary traits of ungulate species that might reflect the environmental conditions where they were living, and also where they might have been hunted by Paleoindians. Such an approach is realized through tooth microwear and mesowear analyses. Results indicate that a variety of food resources were available for the ungulates at these sites as well as the likely presence of mosaic environments around these sites which allowed Paleoindians to exploit resources in a large variety of habitats. The application of a method that allows for the estimation of the duration of occupation at archaeological sites reveals that results for Blackwater Draw and Hiscock Site indicate a long-term occupation of probably several months. However, during short events, Paleoindians were most likely hunting herds of horse and bison when these prey were available near the site. Results indicate that Plainview Quarry was likely used only for short-term occupations, with large game hunting focusing on bison. These patterns identified at the archeological sites studied are related to the fact that Paleoindians follow a high-technology forager model and frequently shifted their territory depending on the composition and distribution of the large mammal fauna.

The late pleistocene paleoenvironment and paleoclimate of the madaras section (South Hungary), based on preliminary records from mollusks

Abstract 24 species and 110 506 specimens of mollusks were collected and identified from 250 samples of the loess profile at Madaras, South Hungary. According to changes in the mollusk fauna, six malacological-paleoecological zones can be identified in this profile. The Quaternary malacological data from the Madaras loess section suggest that the Middle and Late Pleniglacial development of the mollusk fauna, and local climatic and environmental conditions in this area differed from other loess regions in Europe.

Spores of coprophilous fungi from under the Dawson tephra (25,300 14C years BP), Yukon Territory, northwestern Canada

Based on the analysis of pollen and macrofossils Zazula et al. [Zazula, G.D., Froesne, D.G., Elias, S.A., Kuzmina, S., la Farge, C., Reyes, A.V., Sanborn, P.T., Schweger, C.E., Smith, C.A.S., Mathewes, R.W., 2006. Vegetation buried under Dawson tephra (25,300 14C yr BP) and locally diverse late Pleistocene paleoenvironments of Goldbottom Creek, Yukon, Canada. Palaeogeography, Palaeoclimatology, Palaeoecology 242, 253–286.] reported an in situ riparian grassy meadow ecosystem, and regional well-drained steppe-tundra, buried by Dawson tephra (ca 25,300 BP) at Goldbottom Creek in the Canadian Yukon Territory. An additional study of fungal spores in pollen slides from that site was completed. Ascospores of the coprophilous Sordaria type, Sporormiella type and Podospora type, appeared to be of common occurrence, pointing to the former presence of herbivores. The analysis of the various spore types of coprophilous fungi in pollen slides is useful and may lead to further knowledge of the role of different herbivore taxa in past ecosystems.

Vegetation buried under Dawson tephra (25,300 14C years BP) and locally diverse late Pleistocene paleoenvironments of Goldbottom Creek, Yukon, Canada

Paleoecological research at Goldbottom Creek in the Klondike region of Yukon Territory (NW Canada) documents an in situ riparian grassy meadow that was buried during the winter or early spring by Dawson tephra, near the onset of Marine Isotope Stage (MIS) 2, ca. 25,300 14C years BP. Analyses of vascular plant macrofossils, bryophytes, pollen, insects and paleosols from the riparian meadow contrast with evidence for well-drained, upland steppe–tundra habitats obtained from fossil arctic ground squirrel middens within the same valley. The mesic valley bottom vegetation consisted of grasses ( Deschampsia caespitosa, Alopecurus), sedges ( Carex), horsetail ( Equisetum cf. palustre), diverse bryophytes and few forbs. Upland habitats with dry loessal soils along the valley slopes contained graminoids ( Elymus, Festuca, Kobresia myosuroides), sage ( Artemisia frigida) and diverse steppe and tundra forbs ( Phlox hoodii, Plantago cf. canescens, Anemone patens var. multifida, Bistorta vivipara, Draba). These paleoecological data highlight the effect of topographic position and moisture on substrates and their control on local-scale habitat variability. This study represents the first recorded in situ riparian surface from the unglaciated Pleistocene refugium of Beringia and provides well-documented evidence for local habitat heterogeneity and ecosystem structure within the mammoth–steppe biome. Other radiocarbon dated paleoecological data from our study sites indicate that full-glacial steppe–tundra habitats in west-central Yukon Territory were established during the later stages of the MIS 3 interstadial, by 29,000 14C years BP. The diverse data obtained through integration of multiple paleoecological methods at the site demonstrate the efficacy of interdisciplinary research in furthering our understanding of Beringian glacial environments.

Glacial–interglacial organic carbon record from the Makassar Strait, Indonesia: implications for regional changes in continental vegetation

Recent studies convincingly show that climate in the Western Pacific Warm Pool and other equatorial/tropical regions was significantly colder (by ∼3–4°C) during glacial periods, prompting a reexamination of the late Pleistocene paleoenvironments of these regions. This study examines changes in continental vegetation during the last two deglaciations (Terminations I and II) using a sediment core (MD9821-62) recovered from the Makassar Strait, Indonesia. Evidence based on the lignin phenol ratios suggests that vegetation on Borneo and other surrounding islands did not significantly change from tropical rainforest during the last two glacial periods relative to subsequent interglacial periods. This supports the hypothesis that the winter monsoon increased in strength during glacial periods, allowing Indonesia to maintain high rainfall despite the cooler conditions.

Fossil insect evidence for late pleistocene paleoenvironments of the lamb spring site, Colorado

AbstractThe study of Quarternary insect fossils has shown their value as paleoenvironmental indicators, especially during times of rapid climatic change, and this method is now being introduced into North America archeological studies. Abundant insect fossils have been recovered from 13,000 year old detrital organic materials from silty clays at the Lamb Spring site, south of Denver, Colorado. The spring deposits also contain bones of extinct camel and mammoth, thought to have been modified by human hunters.The late Pleistocene insect fauna from Lamb Spring comprises 71 identified taxa from 6 orders and 14 families, principally beetles, providing substantial paleoenvironmental data. The beetle fauna is a mixture of grassland and mountain elements, and they appear to represent an environment similar to that found today in high mountain valleys, such as South Park, Colorado. Based on this fauna, mean summer temperatures at 13,140 B.P. were probably 10°C cooler than present.