The first Sinomastodon (Gomphotheriidae, Proboscidea) skull of the Early Pleistocene, collected from the Renzidong Cave deposits in Anhui Province, Eastern China, is described here as S. jiangnanensis sp. nov. As the only brevirostrine trilophodont gomphotheriid known from the Old World, Sinomastodon was mainly indigenous to China from the Early Pliocene to the Pleistocene. Compared with a few single Pleistocene teeth previously found in China, S. jiangnanensis sp. nov. is represented by a relatively complete skull, mandible and dentition, which is the first discovery of a Quaternary Sinomastodon skull from China. With a brevirostrine, elephant-like skull, no lower tusks, and simple bunodont and trilophodont intermediate molars, the new species is morphologically distinct from other gomphotheres and should belong to the genus Sinomastodon. The new species is more progressive than S. hanjiangensis and the Pliocene type species S. intermedius in its skull and mandible morphology, but is evidently more primitive than the Pleistocene S. yangziensis in its molar morphology. The faunal analysis suggests that the emergence of S. jiangnanensis sp. nov. in Jiangnan area and its southward migration may have been related to a cooling event at the beginning of the Quaternary in Eastern China.

Recent carbonate sediments from Jamaican north coast fringing reefs display variation in constituent composition, texture, and mineralogy related to their location on the reef. Samples were collected along lines which traversed the back reef and fore reef (0.5m to 70m). The sediment is dominated by highly comminuted coral fragments, plates of the calcareous green alga, Halimeda, coralline algae, and the encrusting Foraminifera, Homotrema rubrum, with lesser amounts of other taxonomic groups (Foraminifera; molluscs; echinoderms). Relative abundances of these biotic components vary between sites. Q-mode cluster analysis indicates that constituent composition can be used to delineate the different reef zones which have been described from analyses of the macrofauna. For most sediment, grain-size frequency distributions indicate that greater than 90% (by weight) of the sample is contained in the interval of 0.125mm to 2.000mm. Mean grain size approaches 0.5mm for most sites with little depth related variation. Sorting, however, becomes progressively poorer from the shallow (5m) fore reef terrace to the upper deep fore reef (70m). X-ray diffraction and insoluble residue analyses indicate that total CaC03 in these sediments is generally greater than 95% by weight. Aragonite is the most abundant carbonate phase, followed by high-Mg calcite , and low-Mg cal cite. Amorphous siliceous sponge spicules and organic matter comprise the remaining non-carbonate fraction of these sands. Significant differences in the proportions of aragonite and high-Mg calcite between fore reef terrace sediments and sediments from other reef zones results from the contribution of high-Mg calcite to fore reef terrace sediments by coralline algae, Foraminifera (principally Homotrema rubrum) and echinoderms, which are relatively less abundant sediment constituents elsewhere on the reef. The 120,000y.b.p.(Sangamon) Falmouth Formation along the north coast of Jamaica displays variability in sedimentological and faunal components analogous to that of back reef and shallow fore reef environments of the modern Jamaican fringing reef system. X-ray analysis of the mineralogy of Falmouth limestones reveals that surface exposures of fore reef grainstones exhibit greater diagenetic alteration than surface exposures of back reef packstones. This indicates variability in diagenetic processes most likely related to original sediment textural characteristics.

Master of Science - Science / The South African hominin bearing caves have yielded a wealth of early hominin and other faunal material, which has been the subject of many studies. Little work, however, has been undertaken on the cave fills themselves, as the breccias are complex, poorly stratified, highly calcified, inadequately exposed and too old to date by conventional radiometric means (Partridge, 2000). Gladysvale Cave is an exception to this, as the younger, internal deposits are well exposed from mining, are extremely well stratified, and are preliminarily dated to between 200 and 250 kyr, making this an ideal location to document the three dimensional stratigraphy and sedimentology of a cave fill fan and to test other models of cave sedimentation. The chronostratigraphic approach of Moriarty et al. (2000) was used to divide the deposit at Gladysvale into flowstone bounded units (FBU). The younger, internal deposit at Gladysvale was shown to consist of six major FBU and two minor ones, which in general occur throughout the cave. Binding flowstones are not always present, and are limited to areas directly below and in close proximity to major palaeodrip sources. The majority of sediment entered the cave through a single, central entrance and then split into two lobes around a number of stalagmitic bosses. This entrance eventually choked, and final stage sedimentation entered through a slit-like entrance across the front wall of the cave. As accommodation space inside the cave is fixed, the morphology of the units is defined by their relative position in the cave and the topography of the underlying units. Six major facies types are described, and facies changes from the proximal to distal portions of the deposit are described. Facies changes in time were controlled by the sediment supply rates. A number of intercalated flowstones and stalagmites were dated via ICP-MS Uranium-series dating, and despite problems with detrital contamination, ten reliable and robust dates were acquired, only three of which required correction for excess 232Th. The internal fan deposit is between ~570 and 7 kyr, making it both older and younger than previously thought. The dated speleothems all grew in the recovery period following a full interglacial or major inter stadial, indicating that these were periods of increased effective precipitation, during which the cave entrance was restricted to incoming clastic sediment. The dated flowstones show good concordance with the rainfall record of the Tswaing Impact Crater, and this record was used to generate an age model for the undated flowstones and intercalated breccia units. Carbon and oxygen isotope analysis of the breccias and flowstones provided further climatic control. Oxygen isotopes are invariant between flowstone and breccia, and any original signature was most likely overprinted by the residence time of the groundwater in the dolomite host rock. Carbon isotopes show more variation, and there is clear partitioning between flowstone and breccia, and ä13C values are interpreted as representing changing amounts of C3 and C4 vegetation respectively. The C4 signal for the breccias is confirmed by the presence of granular soil micropeds seen in thin sections. The succession of flowstones and breccias, the U-series dates and the stable light isotope data provide a ~600 kyr record of terrestrial climate change, which is, to date, the oldest such record for southern Africa, and shows excellent concordance with various other climate change records, both global, local and marine. The synchronicity of these records suggests a strong allocyclic control, which is attributed to changes in atmospheric circulation, in particular the size and position of the circumpolar vortex above Antarctica. A climatically controlled model for the nature and rate of sedimentation at Gladysvale Cave is proposed, in which flowstones grow during the warm, wet recovery period following full interglacials, during which C3 vegetation dominates and cave entrances are restricted. Sediments are washed into more open caves, during arid, C4 dominated conditions, corresponding to glacial periods. As this model is climatically controlled, and the Cradle of Humankind World Heritage Site is a relatively small area, the other caves in the area would have experience the same conditions, and if open at the time should contain fills of similar ages. This study has shown the value of the cave fills themselves, which are often understudied. The breccias at Gladysvale are strongly climatically controlled, being deposited only once certain climactic thresholds are crossed, hence producing a highly punctuated record. The hominin and other faunal remains from these caves should be viewed within this context. Gladysvale Cave also contains a ~600 kyr record of climate change, which will contribute to our understanding of terrestrial climatic changes and the landscape’s response to them.

No description available.

The Quaternary (the approximately the last 2.6 million years) of North America is a tremendously exciting time period to study with respect to ecology. It saw periods of immense climatic turbidity - the expansion and retreat of continental ice-sheets and large swings in temperature, resulting in the wide scale restructuring of terrestrial ecosystem. It also saw widespread migrations of many species and out of Eurasia, mostly notably of modern humans. Ancient DNA offers powerful tools to examine the relationships and responses of megafunal species to these events, but has largely focused on cold-adapted species, and within radiocarbon-time (i.e. the last 50 thousand years). In this thesis I work to expand our understanding of the genetic landscape of Pleistocene megafuna in three ways. First, I describe the analysis of coprolites from Bechan Cave, Utah and characterize the mammoth inhabitants in the broader context of North American mammoths. Second, I characterize the diversity of American mastodons across the continent and through time, showing that their range likely repeatedly expanded and contracted in response to Pleistocene glaciations. Lastly, I begin to fill in some of the gaps in the American mastodon dataset from chapter 3, and begin to address some of the taxonomic and biogeographic questions about American and Pacific mastodons in Idaho. Understanding how North American megafauna responded to these climatic and anthropogenic stresses may help to explain why so many species went extinct at the end of the last glaciation, and how species may respond to present day warming. However, it is important to include taxa from warmer locales and environments to ensure our models and hypotheses are comprehensive. / Thesis / Doctor of Science (PhD) / Pleistocene North America was a time period of immense climatic turbidity, with temperature swings greater than 15°C in response to the expansion and contraction of continental ice-sheets. Despite these massive swings in temperature, many species managed to thrive on the continent and adapt to glacial-associated ecosystem restructuring. Ancient DNA from Pleistocene megafauna can serve as a very useful tool to answer many questions about the distribution of megafaunal species, and how they may have responded to these climatic events. However, most studies have largely focused on species adapted to cold environments and from the last fifty thousand years. In this thesis I extend our knowledge of the genetic landscape of Pleistocene proboscideans, characterizing the mammoth inhabitants of Bechan Cave, Utah, and producing the first look at American mastodon diversity through space and time. This work increases our representation of warm-adapted specimens and characterizes the effects of glacial cycles on megafauna populations.

The U/Th dating method has been applied to five archeological sites in France. The U/Th method relies upon the co-precipitation of uranium with calcium carbonate in speleothems formed in caves. Because 230Th forms in the calcite from the decay of 234U a radiometric clock is begun in the newly deposited calcite. Dates are derived from measuring the isotopic abundances of the uranium and thorium in the calcite. For many archeological samples, preroasting of the sample before analysis is necessary to improve the yields. Normally, relative dates for archeological sites are derived from the comparison of paleoclimatic interpretations determined from sedimentological, faunal, and palynological studies of the cave sediments with global climatic records. These methods have established that the Mousterian culture and Neanderthals appeared in Europe at the beginning of the Würm, 80 Ka BP. Absolute dates determined for samples from Lachaise, Montgaudier, Pech de l'Aze, Abri Vaufrey, and Grotte 13, where archeological or faunal material is associated stratigraphically with speleothems sampled, have established that there were several regional climatic phenomena experienced in southern France. These events are dated at 80 to 120 Ka BP, interpreted to be the Riss/ Würm interglacial, and at 38 to 50 Ka, interpreted to be the Würm I/II interstadial. Furthermore, archeological materials and human skeletal remains associated with these sites and the speleothems therein, have proven that the Nean~erthals must have evolved prior to 150 Ka BP, but that they did not develop their Mousterian culture until about 125 Ka BP. / Thesis / Master of Science (MSc)

No description available.

The Mississippi Sound is underlain by late Pleistocene aged sediments of the Biloxi, Prairie, and Gulfport Formations topped by an erosional unconformity, which was an exposed land surface during the sea level low-stand of the last glacial maximum. During that period, rivers and streams draining upland watersheds cut across the exposed coastal plain incising a network of distributary fluvial channels. Subsequent sea level rise covered the incised drainage network with a relatively thin (10-20 m) layer of reworked Holocene aged sediments. Here, an extensive database of archived and newly collected seismic reflection profile data, as well as archived core data, is analyzed to map the paleotopography and the paleo-drainage network of the Pleistocene-Holocene unconformity surface beneath the western Mississippi Sound. Approximately 255 km of seismic data was acquired with a 2-16 kHz chirp sub-bottom profiling sonar. Additionally, 978 km of seismic data was accessed through a United States Geological Survey archive along with over 20 historical cores. Results indicate that the Pleistocene-Holocene unconformity under the western Mississippi Sound is gently dipping to the southeast (<0.05°) and contains a complex network of incised paleofluvial channels with relief ranging from 5-10 m and widths ranging from 0.3–2 km. A conceptual model for paleo-channel incision and infilling as well as modern analogue depositional environments are presented.

No description available.

This doctoral thesis presents the results of the pioneering archaeological investigation conducted in the Northern Mexican Highlands with the aim to evaluate the existing indicators of the earliest human occupations at the end of the Pleistocene and discover new evidence of ancient cultural manifestations through a systematic exploration of an endorheic basic in the Zacatecas desert, a region never studied before. An exhaustive survey and analysis of the available literature on Mexican prehistory establishes the weak points of the local paradigms, differentiating between academic myths and objective realities. A complete historiography of the topic of the earliest humans in Mexico has been achieved, for the first time. The study of several collections of flaked stone artefacts, in different cities in Mexico, show new indicators of the presence of bearers of the Late Paleoamerican cultures, in regions where their presence had been weakly confirmed. The most important part of the research consisted in fieldwork realised during two long seasons; the first one dedicated to the surface explorations and the second one to excavations. Thirty-five new archaeological sites were discovered in the first phase, most of them open campsites reminiscent of hunter-gatherer societies, with a richness of stone artefacts on their surface. They indicate a long cultural sequence, going from the Late Pleistocene to the Late Holocene and the historic periods. Four sites were further studied by fourteen test excavation units: Dunas de Milpa Grande, San José de las Grutas, the Chiquihuite Cave and Ojo de Agua. Two new archaeological cultures were identified, one at Dunas (an interesting assemblage of limestone and basalt flaked stone tools) and another one at San José (a limestone concave-based points complex). First indicators of ʻolder than Clovisʼ human presence have also been obtained. The palaeoenvironmental data provide a preliminary reconstruction of the Late Pleistocene-Early Holocene landscape of the basin, based on geology, extinct fauna, phytolith and mollusc analyses. Radiocarbon and OSL results support a first cultural and paleoclimatic model for the study area. This investigation also discovered the first case of a “black mat” in Mexico: a black layer of sediment deposited under specific environmental conditions during the Younger Dryas cooling event.