Deep-sea pleistocene biostratigraphy

The first detailed paleontological analysis of a deep-sea pistoncore from the Caribbean Sea has been completed. The core, P6304-8, was raised from 3927 meters, east of Beata Ridge at 14 degrees 59'N, 69 degrees 20'W. Formerly, stratigraphic works in this area were based on studies of paleotemperature, measured by the oxygen isotope mass spectrometry method, or on micropaleontological analysis by means of rapid or cursory examinations. For core P6304-8, samples for foraminiferal analysis were taken at 10-centimeter intervals and split into smaller samples containing an average of 710 individuals (smallest sample, 517 individuals); all individuals were then identified and counted. By use of data derived from populations of this size, a statistical reliability was insured within a 5 percent limnit. Temperature oscillations, the best method of portraying Pleistocene stratigraphy, were shown by using ratios of the relative abundances of tropical and subtropical planktonic foraminifera to those found in temperate and cooler waters. These ratios correlate well with existing paleotemperature measurements for the same core, obtained by the oxygen isotope mass spectrometry method.     

Pacific pleistocene cores: faunal analyses and geochronology

Two cores from the eastern Pacific were analyzed faunally and dated by the ionium: thorium method. Comparison of the results of these and of similar studies of Atlantic cores indicate that faunal changes, representing changes between the glacial and interglacial stages of the Pleistocene, occurred in both oceans simultaneously.     

Mummified pleistocene ostracods in alaska

Preserved soft parts of ostracod specimens were recovered from beach and lagoon sediments from the Gubik Formation, of Quaternary age, at Barrow, Alaska.     

Polymorphism in pleistocene land snails

Under suitable conditions the colors and patterns of the shells of land snails may be preserved for thousands of years. In a late Pleistocene population of Limicolaria martensiana all the major color forms that occur in modern living snails may be distinguished, and the basic polymorphism is at least 8,000 to 10,000 year old.     

A cheetah-like cat in the north american pleistocene

The discovery of abundant skeletal remains of Felis trumani from a late Pleistocene deposit in Wyoming shows that it was as highly modified for cursorial locomotion as the cheetah (Acinonyx). Several other Pleistocene felids that have been regarded as pumas seem to be related forms. The late Pleistocene fauna of the Big Horn Basin in Wyoming is dominated by cursorial taxa.     

The agulhas current during the late pleistocene: analysis of modern faunal analogs

Analysis of micropaleontologic evidence in a deep-sea core in the south-west Indian Ocean indicates that the Agulhas Current was not a dominant feature of this region during glacial intervals. Interpretation of the fossil record, based on the analysis of modern faunal analogs, indicates that during glacial intervals the Agulhas Current was not the strong, year-round current that it is today. Evidence shows that during summer months a weak tropical current was present. During winter months the current was replaced by cool, high-salinity waters. This interpretation suggests that seasonal changes in circulation may have been more pronounced in the southwest Indian Ocean during glacial intervals than today.     

Methane-derived marine carbonates of pleistocene age

In some calcium carbonate-bearing sandstones from the edge of the continental shelf off the northeast United States, the deltaC(13) range is from -30 and -60 per mil for both aragonite and high-magnesium calcite. The deltaC(13) of co-existing shells of Modiolus sp. is normal (+ 1.7 to -2.7 per mil). The deltaO(18) values of around + 3.5 per mil in all samples suggest deposition at temperatures around 0 degrees C. Quaternary methane oxidized either chemically or microbiologically to carbon dioxide is the probable source of carbon in these carbonates.     

New dates on northern yukon artifacts: holocene not upper pleistocene

New radiocarbon dates on four artifacts that were thought to provide evidence for human occupation of the Yukon Territory during the upper Pleistocene indicate that all four are of late Holocene age. The original radiocarbon age obtained for one artifact (the so-called "Old Crow flesher") was in error by almost 26,000 years.