Geochemical evolution of amino acids in dentine of Pleistocene bears.
نویسندگان
چکیده
A linear correlation was established between aspartic acid racemization ratio from cave bear dentine collagen and absolute dating. The high correlation coefficient obtained allowed age calculation through amino acid racemization. Aspartic acid and glutamic acid racemization kinetics have also been explored in dentine from a North American black bear (Ursus americanus Pallas). Three sample sets were prepared for kinetic heating experiments in nitrogen atmosphere: one water soaked, one with a water-saturated nitrogen atmosphere, and one without any moisture. It was possible to show that the presence of water is a factor controlling amino acid racemization rate. The aspartic acid in a heating experiment at 105 degrees C shows an "apparent kinetics reversal" which can be explained by a progressive hydrolysis of amino acid chains (proteins and polypeptides). Because of the low potential of collagen preservation over long periods of time, the apparent kinetics reversal phenomenon will not affect the dating of old material where no traces of collagen remain. An apparent kinetics reversal was not observed in glutamic acid, which racemizates more slowly.
منابع مشابه
Geochemistry and Tectonic Setting of Pleistocene Basaltic Lava Flows in the Shahre-Babak Area, NW of Kerman, Iran: Implication for the Evolution of Urumieh- Dokhtar Magmatic Assemblage
Pleistocene basaltic lava flows, consisting of trachybasalt and basaltic trachyandesite, cover an area north-northwest of Shahre-Babak in southeastern Iran. The whole rock chemistry indicates that the lavas are dominantly alkaline and mildly calc-alkaline. Variation diagrams of SiO2 with major and trace elements are consistent with fractional crystallization processes involving olivine, pyroxen...
متن کاملPaleobiological Implications of the isotopic Signatures C 3 C , 15 N ) of
An isotopic investigation of upper Pleistocene mammal bones and teeth from Scladina cave (Sdayn, Belgium) demonstrated the very good quality of coHagen preservation. A preliminary screening of the samples used the amount of nitrogen in whole bone and dentine in order to estimate the preserved amount of collagen before starting the extraction process. The isotopic abundances of fossil specimens ...
متن کاملPedosedimentary Evolution and Site Formation Processes in Mirak Mound 8, South of Semnan
Mirak is one of the open-air Paleolithic sites in the Iranian Central Plateau and the only Iranian archaeological open-air site which has been excavated extensively. The site is comprised of 8 mounds, located in a dry floodplain some kilometers south of Semnan in the northern fringes of the Iranian Central Desert, aka. Dash-I Kavir. Mirak mound no. 8 was selected for the excavation. The mound i...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Chirality
دوره 13 8 شماره
صفحات -
تاریخ انتشار 2001