Pleistocene period

First attempts to date archaeological remains by their fluorine content were undertaken in Great Britain by J. Middleton in London and K.P. Oakley at the University of Oxford [21,76], where especially Oakley became well known for his work on the Piltdown Man . By comparing the total fluorine content of a skull and a mandible, which had deliberately been faked to simulate fossil specimens and secretly placed in a ditch in Sussex, with original remains from the Lower Pleistocene period found in the same ditch, he concluded that the questionable specimens must have been significantly younger, as they contained less fluorine [69]. The Piltdown Skull had widely been held as a crucial discovery of modern... 

Figure 2. CM pattern of the modern and old Nile sediments. The abscissa (M) is the median grain size (in microns) for the sediments the ordinate (C) is the size of the largest 1% of the grains. The Sahaba ( + ) and Dandara (%) formations are considered to be modern (since middle Pleistocene period) silts the Giran el-Ful ( ) formation is from the older Nile regime. Significance of regions designated by roman numerals is discussed in the...

The Lower Cretaceous sandstone aquifer (Kumub Group) contains, for the most part, saline water. However, in the Sinai and the southern part of Israel it contains brackish water due to the inflow of meteoric water which occurred during the humid Pleistocene periods. The recharge is believed to have taken place mainly in the sandstone outcrops in the central Sinai and to some extent in the erosion cirques of the Negev and Sinai (Issar et al., 1972) (Fig. 1). 

Zeuner, F.E. 1959. The Pleistocene Period Its Climate, Chronology and Faunal Successions. Hutchinson, London, 447pp. 

The most recent geological period of our planet Earth is called "Quaternary" which is divided into two subsections. The older one is named "Pleistocene" and the younger one "Holocene". The Pleistocene period started about 1.8 million years before now and ended just 10,300 years before now. Consequently, the Holocene period covers the last 10,000 years. The Pleistocene is also called Glacial epoch or formerly Ice age. 

In order to illustrate this situation with an example, I want to present a figure (Fig.l) which shows the extension of ice caps in northern Europe during the Pleistocene period [1]. 

Karstic landforms vary enormously in character, shape and size and are formed in wet climatic conditions at present or in the geological past. When developed in the past, surface features may be buried and hidden by more recent sediments deposited in a changed climatic environment e.g., in the Middle East, currently known for its hyper-arid conditions, widespread karstification has occurred during the wet Middle Pleistocene period (325,000-560,000 years ago) affecting the Eocene limestones (Sadiq et al, 2002). The presence of dissolution cavities and other karst-related hazards may not always be visible at the ground surface, but may have to be identified by site investigations specifically aimed at karstic features. 

The approach proposed to check the preservation of isotopic signals in fossil vertebrate bones and teeth is appropriate not only for Pleistocene cold and temperate areas, but also during geological periods before the... 

Two possibilities for the observed enriched values for many of the grazers, and the often concomitant but slight enrichment of browsers (Fig. 5.6), present themselves. Either these shifts represent atmospheric CO2 enrichment shifts at particular periods during the last -lOOKa represented (the Late Pleistocene), or a hitherto unknown or unrecognized fractionation process has taken place during burial and fossilization. The former hypothesis could be tested by comparison of observations from a larger sample set from the site, with CO2 concentration and carbon isotope data from Antarctic ice-core records or high resolution marine isotope records. 

In the million year range, however, there is clearer evidence for isotopic alteration which also apparently increases with age. Unfortunately, at present there are few reliable browser and grazer data beyond the Late Pleistocene, i.e., in the Middle Pleistocene, which would allow determination of the periods during which bone apatite and enamel begin to deviate. The indications are that the timing should be different. Material from the site of Florisbad falls within the late Middle Pleistocene ( 125-200 Ka), but at present carbon isotope data are only available for three species of uncertain and/or opportunistic diets (Brink and Lee-Thorp 1992), so that extent or direction of isotopic alteration is impossible to separate from dietary vagaries. 

Richards DA (1995) Pleistocene sea levels and paleoclimate of the Bahamas based on Th-230 ages of speleothems. PhD Dissertation. University of Bristol, Bristol, United Kingdom Richards DA, Smart PL, Edwards RL (1994) Maximtrm sea levels for the last glacial period from U-series ages of submerged speleothems. Nature 367 357-360... 

Gordon D, Smart PL, Ford DC, Andrews IN, Atkinson TC, Rowe PJ, Christopher NSJ (1989) Dating of late Pleistocene interglacial and interstadial periods in the United Kingdom from speleothem growth frequency. (Jrrat Res 31 14-26... 

Kashiwaya K, Atkinson TC, Smart PL. (1991). Periodic variations in late Pleistocene speleothem abundance in Britain. Quat Res 35 190-196... 

Loess settles when dust-laden winds slow down to speeds between 7 (on dry surfaces) to 14 meters per second (on moist surfaces). The pore distribution of loess lets it quickly be retained by capillary forces if it lands on a moist surface. The presence of a vegetation cover may also enhance the rate of loess deposition, and many authors maintain that the northern limit of loess deposition coincides with the northernmost extent of grass steppes during arid periods in the Pleistocene. 

Foraminifera are also important in marine geochemistry studies, and Li isotopes have been measured in the shells of a variety of these organisms. The first report of this kind (You and Chan 1996) gave data for four Pleistocene samples of H obliquiloculata 5 Li = +19.3 to +23.0 for two glacial period samples and +26.6 to +42.4 for two interglacial samples (data without blank correction). The species effect interpreted by Marriott et al. (2004) in corals has also been suggested for forams. In the study of Rosier et al. (2001), core-top (i.e., Holocene)P. obliquiloculata samples yielded isotopic compositions close to modem seawater (5 Li = +27.8 to +31.1), whereas samples of G. tumida from the same samples had values of up to +50.5. 

Fig. 15a comes from N. J. Shackleton, A. Berger, and W. R. Peltier, An Alternative Astronomical Calibration of the Lower Pleistocene Timescale Based on ODP Site 677 , Transactions of the Royal Society of Edinburgh Earth Sciences, 81 (1990), 251. Fig. 156 comes from J. Jouzel et al., Extending the Vostok Ice-Core Record of Palaeocllmate to the Penultimate Glacial Period , Nature, 364 (1993), 407. 

Carbon-isotopic (13C/12C) ratios of the combustible organic matter fluctuate, but these variations can be correlated with warm (interglacial) and cold (glacial) periods of the Pleistocene (3). 

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