Palaeoenvironmental implication of the Plio-Pleistocene loess deposits in southern Tarim Basin

The sedimentary characteristics, grain-size distribution, geochemical composition and surface characteristics of quartz grains, together with palaeoenvironmental reconnaissance, all point to an aeolian origin for the intercalated siltstone beds in the Plio-Pleistocene Artux and Xiyu Formations along the southern margins of the Tarim Basin, indicating that loess deposition in the region started, at least, in the Early Pliocene. Loess deposition in the southern Tarim Basin was a response to the global deterioration, which might be attributed to the uplift of the Tibetan Plateau.

Climatic changes from the late Pliocene to middle Pleistocene in and around central Japan reconstructed from plant macrofossil assemblages

We used composition of plant macrofossil assemblages obtained mainly from theOsaka Group in central Japan to reconstruct the palaeoclimate between the late Pliocene (about 3.3m.y. B.P.) and the middle Pleistocene (about 0.4 m.y. B.P.). The warmest climate of the periodwas before 3.0 m.y. B.P. Cool-temperate elements increased and subtropical elements decreasedbetween 3 m.y. B.P. and 2.7 m.y. B.P., indicating the first climatic deterioration. The firstoccurrence of subarctic elements characterizes the Plio-Pleistocene boundary as a severe coldstage. After 1.1 m.y. B.P., climatic fluctuation occurred at less than 100,000 year intervals. Asevere cold stage occurred just after the Jaramillo event (about 0.8 m.y. B.P.). The warmest stagein the middle Pleistocene occurred at about 0.5 m.y. B.P. With it evergreen broad-leaved forestexpanded into central Japan. The climatic curves reconstructed from plant macrofossils parallel theclimatic changes reconstructed from loess - paleosol stratigraphy in Central China, radiolarianfaunal stratigraphy in the north Pacific deep sea drilling core, oxygen-isotope data in the NorthPacific, and pollen spectra in western Europe.

Compositional Features of Fine Sediments Involved in the Montescaglioso Landslide(Southern Italy)

This paper presents the multidisciplinary study of the southern Italy Plio-Pleistocene sediments involved in the large Montescaglioso Landslide.The principal aim of the work is to assess the compositional characters(i.e.,grain-size,mineralogy,petrography and geochemistry)and some rheological features(Atterberg’s limits,plasticity index and activity)of these sediments to enrich our knowledge about the Montescaglioso fine sediments and correlation among the lithological properties studied.Two types of sediments,from a deep geognostic borehole and from the surrounding landslide area,were collected and analysed.No significant compositional differences have been found between the core and landslide area sediments.Conversely,some changes have been detected in sediments along the core.Particularly,the-15 to-20 m lithostratigraphic level hosts the highest percentages of phyllosilicates and clay fraction(CF),commonly considered as possible hazard factors for the landslide triggering.Further more,in the studied core sediments,the CF contents correlate with the Atterberg’s liquid and plastic limits and a CF value of about 38%was suggested as threshold value for the changing of index properties of sediments.Other factors,such as the weathering degree and clay mineral type,do not show significant correlations with the rheological properties of sediments here studied.

Global evolution of Equidae and Gomphotheriidae from South America

The contemporary South American mammalian communities were determined by the emergence of the Isthmus of Panama and by the profound climatic oscillations during the Pleistocene.Horses and gomphotheres were 2 very conspicuous groups of immigrant mammals from North America that arrived in South America during the Pleistocene.The present study compiles updated data on the phylogeny,systematics and ecology of both groups in South America.The horses in South America are represented by 2 genera,Hippidion and Equus,as are the gomphotheres,represented by Cuvieronius and Stegomastodon.Both genera of horses include small(Hippidi­on devillei,H.saldiasi,E.andium and E.insulatus)and large forms(Equus neogeus and H.principale),which dispersed into South America using 2 different routes.The possible model for this dispersion indicates that the small forms used the Andes corridor,while larger horses dispersed through the eastern route and through some coastal areas.In the case of gomphotheres,Cuvieronius and Stegomastodon reached South America in 2 inde­pendent dispersal events,and Cuvieronius dispersed across the Andean corridor,while large Stegomastodon spread along the eastern route.Horses and gomphotheres present values ofδ^(13)C from woodlands to C4 grass­lands.Hippidion present lower values ofδ^(13)C than Equus in the late Pleistocene,whereas the gomphotheres di­verge from value ofδ^(18)O,reflecting that Cuvieronius inhabited the Andean corridor and Stegomastodon dis­persed through eastern plains.The gomphothere and horse species recorded in South America became extinct around the time that humans arrived.