scholarly journals Analysis Of The Late Pleistocene Environmental Changes In Dianchi Lake, Yunnan Province

1990 ◽  
Vol 2 (2) ◽  
pp. 25-30
Author(s):  
Xiao Jiayi ◽  
◽  
Wu Yushu
1991 ◽  
Vol 4 (3) ◽  
pp. 499 ◽  
Author(s):  
GI Jordan ◽  
RS Hill

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.


Author(s):  
Tony Hallam

We saw in Chapters 5 and 7 that the Quaternary was a time of low extinction rates despite a succession of strong environmental changes induced ultimately by climate. This began to change from a few tens of thousands of years ago with the arrival on our planet of Homo sapiens sapiens, which can be translated from the Latin as the rather smug ‘ultrawise Man’. It is widely accepted today that the Earth is undergoing a loss of species on a scale that would certainly rank in geological terms as a catastrophe, and has indeed, been dubbed ‘the sixth mass extinction’. Although the disturbance to the biosphere being created in modern times is more or less entirely attributable to human activity, we must use the best information available from historical, archaeological, and geological records to attempt to determine just when it began. Towards the end of the last ice age, known in Europe as the Würm and in North America as the Wisconsin, the continents were much richer in large mammals than today: for example, there were mammoths, mastodonts, and giant ground sloths in the Americas; woolly mammoths, elephants, rhinos, giant deer, bison, and hippos in northern Eurasia; and giant marsupials in Australia. Outside Africa most genera of large mammals, defined as exceeding 44 kilograms adult weight, disappeared within the past 100,000 years, an increasing number becoming extinct towards the end of that period. This indicates that there was a significant extinction event near the end of the Pleistocene. This event was not simultaneous across the world, however: it took place later in the Americas than Australia, and Africa and Asia have suffered fewer extinctions than other continents. There are three reasons for citing humans as the main reason for the late Pleistocene extinctions. First, the extinctions follow the appearance of humans in various parts of the world. Very few of the megafaunal extinctions that took place in the late Pleistocene can definitely be shown to pre-date the arrival of humans. There has, on the other hand, been a sequence of extinctions following human dispersal, culminating most recently on oceanic islands. Second, it was generally only large mammals that became extinct.


2008 ◽  
Vol 41 (2) ◽  
pp. 265-277 ◽  
Author(s):  
Anne de Vernal ◽  
Claude Hillaire-Marcel

ABSTRACT Palynological and isotopic analysis in a few deep-sea cores from the Labrador Sea reveals strong environmental changes related to the Late Pleistocene glacial fluctuations over eastern Canada. On the whole, the Labrador Sea was characterized by strong exchanges between North Atlantic water masses, Arctic outflows, and meltwater discharges from Laurentide, Greenland and lnuitian ice sheets. The penetration of temperate Atlantic waters persisted throughout most of the Late Pleistocene, with a brief interruption during the Late Wisconsinan. During this glacial substage, a slight but continuous meltwater runoff from the Laurentide ice margins grounded on the northern Labrador Shelf is indicated by relatively low 18O values and low-salinity (< 30‰) dinocyst assemblages. The calving of the ice margin, the melwater outflow and the subsequent dilution of surface waters offshore Labrador probably contributed to the dispersal of floating ice and, consequently, to a southward displacement of the polar front restraining the penetration of North Atlantic waters into the Labrador Sea. The advection of southern air masses along the Laurentide ice margins, shown by pollen assemblages, was favourable to abundant precipitation and therefore, high ice accumulation rates, especially over northern Labrador during the Late Wisconsinan. The déglaciation is marked by a brief, but significant, melting event of northern Laurentide ice shortly after 17 ka. The main glacial retreat occurred after ca. 11 ka. It allowed restoration of WSW-ENE atmospheric trajectories, increased phytoplanktonic productivity, and penetration of North Atlantic water masses into the Labrador Sea.


1981 ◽  
Vol 2 (2) ◽  
pp. 85-100 ◽  
Author(s):  
Kit W. Wesler

Arguments for Paleoindian overkill of Late Pleistocene megafauna have traditionally emphasized North America with little more than token reference to other areas. Other scholars reject human causation of Pleistocene extinctions, preferring to see in climatic and environmental changes a sufficient explanation for the losses of these forms. This paper discusses the idea of overkill with reference to a computer simulation by Mosimann and Martin (1975), and offers reasons for preferring an alternative formulation. It is also suggested that the case of South America should be reviewed separately, and that an environmental explanation of Pleistocene extinction may be more suitable there.


2010 ◽  
Vol 57 (3) ◽  
pp. 1341-1346 ◽  
Author(s):  
Jose R. Loaiza ◽  
Marilyn E. Scott ◽  
Eldredge Bermingham ◽  
Oris I. Sanjur ◽  
Richard Wilkerson ◽  
...  

1993 ◽  
Vol 59 ◽  
pp. 1-15 ◽  
Author(s):  
T. E. G. Reynolds

Whilst research has shown many faults with the Movius scheme of a Middle Pleistocene group of Chopper/Chopping tool industries in South-East Asia, it remains a fact that pebble tool industries are still the dominant characteristic of the South-East Asian record. Exploration has now revealed hundreds of Late Pleistocene and Holocene sites in Mainland South-East Asia and these are archaeologically very different from cave sites in Europe. Further problems exist with the current nomenclature of later industries, such as the Hoabinhian and the Neolithic, for there is a large amount of overlap between such assemblages. Should such factors as economy, site location, etc. be used to assist clarification of such problems?This paper outlines some of these issues and reveals that the pebble tool tradition as it is widely known in South-East Asia is a relatively recent phenomenon dating back to the Last Glacial Maximum (LGM). A possible reason for the change from flake to pebble tool industrial types and in the visibility of sites is the environmental changes and rise in sea level which submerged over half the available land area in the region during the Late Pleistocene. An existing broad spectrum system of exploitation was likely to have been intensified as a result of this.


Elem Sci Anth ◽  
2013 ◽  
Vol 1 ◽  
Author(s):  
Erle C. Ellis ◽  
Dorian Q. Fuller ◽  
Jed O. Kaplan ◽  
Wayne G. Lutters

Abstract Human use of land is a major cause of the global environmental changes that define the Anthropocene. Archaeological and paleoecological evidence confirm that human populations and their use of land transformed ecosystems at sites around the world by the late Pleistocene and historical models indicate this transformation may have reached globally significant levels more than 3000 years ago. Yet these data in themselves remain insufficient to conclusively date the emergence of land use as a global force transforming the biosphere, with plausible dates ranging from the late Pleistocene to AD 1800. Conclusive empirical dating of human transformation of the terrestrial biosphere will require unprecedented levels of investment in sustained interdisciplinary collaboration and the development of a geospatial cyberinfrastructure to collate and integrate the field observations of archaeologists, paleoecologists, paleoenvironmental scientists, environmental historians, geoscientists, geographers and other human and environmental scientists globally from the Pleistocene to the present. Existing field observations may yet prove insufficient in terms of their spatial and temporal coverage, but by assessing these observations within a spatially explicit statistically robust global framework, major observational gaps can be identified, stimulating data gathering in underrepresented regions and time periods. Like the Anthropocene itself, building scientific understanding of the human role in shaping the biosphere requires both sustained effort and leveraging the most powerful social systems and technologies ever developed on this planet.


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