Carbonate Speleothems Research Articles

Determination of the evolutionary mode of Austrian alpine cave bears by uranium series dating

Middle and Late Pleistocene sediments in many caves in Central and South Europe contain large numbers of bones and teeth of the cave bear (Ursus spelaeus). The cave bear differs in many characteristics from the recent brown bear and shows a rapid evolution especially in the changes of the teeth due to adaptation to pure herbivorous nutrition. The shifts of the morphotype frequencies of the fourth premolar from the upper jaw were used as a measure of the evolution. The uranium series method is the only suitable tool for the absolute age determination of the fossil bones with ages beyond the time range accessible to the radiocarbon method. By applying this method to the Herdengel cave profile the evolutionary rate of the cave bears was determined. Uranium series data from the fossil bones were partly verified by an independent carbonate speleothem age. For both, bone layers and carbonate formation found in stratigraphic relation, the determined ages correspond to a normal time sequence. According to the rel...

Isolation of Uranium and Thorium from Pure Carbonate Speleothems for Uranium Series Age Determination

Isolation of Uranium and Thorium from Pure Carbonate Speleothems for Uranium Series Age Determination

ESR dating of carbonate speleothem rings and late quaternary climatic changes in the Ryukyu Islands, Japan

Twenty-two carbonate speleothems were taken from the Ryukyu Islands and dated by the ESR dating method. Most of the growth rings showed ages on and after 25,000 y B.P. The result of this study shows the speleothem has many layers, like tree rings, as influenced by climatic changes. This new approach seems to be a useful method to reveal the Quaternary climatic changes.

Cave Features: Information Concerning the Nature and Genesis of Soils

AbstractInformation about soils may be obtained from speleology, the study of caves. Some caves are shallow enough for roots of surface plants to be present in them. Cave maps and the distribution of stalactites on cave ceilings show that rock structure strongly controls the pattern of water movement through soil‐rock columns. Relatively pure samples of some secondary minerals, formed at temperatures similar to those in the lower parts of overlying soils, may be obtained from caves. Dolomite seldom forms in caves, but calcite and aragonite are common. Impurities, including quartz, clay minerals, and iron oxides, are present in carbonate speleothems. Many speleothems have repeating growth increments (segments, rings). Some of these may be annual. When understood, they may give clues to, and dramatically portray, seasonal changes in the rate of flow and the composition of percolating waters. Studies of percolating waters from undisturbed soil‐rock columns could be made using caves, but it would be difficult to tell what area and volume of soil and rock contributed to the percolate.