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Ice Age megafauna have long been known to be associated with global cooling during the Pleistocene, and their adaptations to cold environments, such as large body size, long hair, and snow-sweeping structures, are best exemplified by the woolly mammoths and woolly rhinos. These traits were assumed to have evolved as a response to the ice sheet expansion. We report a new Pliocene mammal assemblage from a high-altitude basin in the western Himalayas, including a primitive woolly rhino. These new Tibetan fossils suggest that some megaherbivores first evolved in Tibet before the beginning of the Ice Age. The cold winters in high Tibet served as a habituation ground for the megaherbivores, which became preadapted for the Ice Age, successfully expanding to the Eurasian mammoth steppe. [ABSTRACT FROM AUTHOR]

Abstract: The East Asian climate history during the Neogene is a complicated and contentious issue, in particular because of its bearing on the development of the East Asian monsoon and Tibetan uplift chronology. Here we present a paleoprecipitation analysis based on mean molar tooth height (hypsodonty) of large herbivorous mammals to investigate the spatial pattern of climate zonation in East Asia during the middle Miocene. We show a generally humid and uniform situation before the late middle Miocene, replaced by a mid-latitude arid belt from the late middle Miocene, into the earlier part of the late Miocene. These findings are concordant with the global phenomena of the middle Miocene climate optimum and the subsequent cooling, and suggest that the predominant climate in East Asia for most of the Miocene was planetary rather than monsoonal. Our results support a late initiation of the East Asian summer monsoon, coincidentally with the beginning of eolian red clay deposition in the later late Miocene at 7–8 Ma. [Copyright &y& Elsevier]

Several large suid cranial remains attributed to Microstonyx major are part of a new Hipparion Fauna collection from the Hezheng area, Northern China. The new material confirms the presence of Microstonyx in the late Miocene of the area. The Chinese form belongs to a small-sized eastern population with reduced premolar row and clear sexual bimodality. Statistical comparison shows that Microstonyx major was a polymorphic species and reinforces recognition of Hippopotamodon as a separate genus, defined by relatively stout premolars resulting from a different underlying pattern of allometric growth. The presence of Microstonyx in North China and the distinct suid assemblage that lived there suggest biogeographic connections between Northern China and Western Eurasia in contrast to isolation from Southern China and the Indian subcontinent. The suid fauna of the late Miocene of Northern China seems to have been restricted to the later, more humid phase represented by the Red Clay faunas. [Copyright &y& Elsevier]

The spatiotemporal pattern of the late Cenozoic spread of C 4 vegetation is an important indicator of environmental change that is intertwined with the uplift of the Himalaya and Tibetan Plateau, and the development of the East Asian monsoons. To explore the spread of C 4 vegetation in China and shed new light on regional climatic evolution, we measured δ 13 C values of more than 200 small mammal teeth (primarily rodents and lagomorphs) using a laser ablation isotope ratio mass spectrometry approach. Small mammals are highly sensitive indicators of their environment because they have limited spatial ranges and because they have minimal time-averaging of carbon isotope signatures of dietary components. The specimens originate from four classic Late Miocene fossil localities, Lufeng, Yuanmou, Lingtai, and Ertemte, along a southwest-northeast transect from Yunnan Province to Inner Mongolia. In Yunnan (Lufeng, Yuanmou) and on the Loess Plateau (Lingtai), the small mammal δ 13 C values record nearly pure C 3 ecosystems, and mixed but C 3 -based ecosystems, respectively, in agreement with previous studies based on carbon isotopes of large herbivores and soil carbonates. In Inner Mongolia, the micromammalian tooth enamel δ 13 C record picks up the presence of C 4 vegetation where large mammal samples do not, indicating a mixed yet C 3 -dominated ecosystem at ~ 6 Ma. As a whole, the results support a scenario of northward increasing C 4 grass abundance in a pattern that mirrors northward decreasing precipitation of the summer monsoon system. The results highlight differences between large and small mammals as indicators of C 4 vegetation in ancient ecosystems, particularly the ability of small mammal δ 13 C values to detect the presence of minor components of the vegetation structure. [ABSTRACT FROM AUTHOR]

Abstract: The East Asian monsoons have fluctuated in concert with high-latitude warmth during the past several hundred thousand years, with humid summer monsoon-dominant climates characterizing warm intervals, including interglacials and interstadials, and arid winter monsoon-dominant climates characterizing cool intervals, including glacials and stadials. Of the states comprising the mid-Pleistocene to recent climatic regime, interglacials are most similar in terms of high latitude ice volumes and temperatures to those extant during the late Miocene and early Pliocene. Thus, an important question is whether Mio-Pliocene climates in northern China were analogous to a hypothetical ‘prolonged interglacial state,’ with increased summer monsoon precipitation and expansion of forest and steppe environments at the expense of desert environments. We utilize new and previously published carbon isotopic data from fossil teeth and soil carbonates to place constraints on paleovegetation distributions and to help infer the behavior of the monsoon system between ∼7 and 4 Ma. We find that plants using the C4 photosynthetic pathway—which today are largely grasses found in regions with warm season precipitation—were present in northern China by late Miocene time, demonstrating that the C4 expansion in China was not significantly delayed compared to the global C4 event. During the late Miocene–early Pliocene interval, soil carbonate and tooth enamel δ13C data indicate: 1) that nearly pure C3-plant ecosystems existed in the southern Chinese Loess Plateau (CLP), and therefore ecosystems there were dominated by woody dicot, herbaceous dicot, or cool-season grass vegetation (or a combination of these), and 2) that the CLP was characterized by a pattern of northward-increasing C4 vegetation and aridity. Utilizing a broadened conceptual model for interpreting δ13C data, and citing independent faunal, floral, and lithostratgraphic data, we suggest that these patterns reflect northward expansion of forest and steppe ecosystems and relatively humid monsoon climates during the late Miocene and early Pliocene. An important implication of this interpretation is that the forcing mechanism illuminated by the temporal correlation during the Pleistocene between warm high latitudes and strong East Asian summer monsoons is a robust feature of the Eurasian tectonic–climatic system that predates the Plio-Pleistocene climatic reorganization. [Copyright &y& Elsevier]

Abstract: Mammalian fossils, especially the Hipparion fauna, found in the Red Clay of the Loess Plateau, are of immense value for reconstructing late Neogene paleoecology and paleoclimatology in northern China. The lack of a precise chronological framework for these fossil sites has impeded our understanding of the evolution of the Chinese mammalian fauna, their correlation with European mammalian units, and the retrieval of paleoclimatic information. In this study, a field survey of regional stratigraphy in the Baode area of Shanxi was carried out and three profiles (Tanyugou, Yangjiagou-I and Yangjiagou-II) of Late Neogene deposits were selected for detailed investigation. A new chronological framework of the Late Neogene sequences in the Baode area is established by means of paleomagnetism. Our results show that the Red Clay accumulation in the Baode area began at least 7.23 Ma ago. Deposition continued to the superposed Jingle Formation. The most continuous and complete exposure of the Jingle Formation known to date was identified and dated to 2.72~5.34 Ma. A lithological distinction between the Jingle Formation and the underlying Baode Formation forms a clear boundary in the Red Clay that is not coincident with the Miocene/Pliocene boundary documented elsewhere. Three rich fossil layers are found in the Yangjiagou-II profile and dated to 6.43–6.54 Ma, 6.83–6.86 Ma and 7.15–7.18 Ma, respectively. With the application of three different demagnetization techniques, the Matuyama–Gauss geomagnetic reversal boundary was identified in a transitional unit between loess and typical Red Clay deposits. A lock-in depth of as large as 6.8 m (corresponding to ca. 65 ka) was inferred but remains unexplained. [Copyright &y& Elsevier]