Datowanie muszli mięczaków metodą 14C

Teresa Goslar, Mieczysław F. Pazdur

Abstract


Omówiono zagadnienia związane z datowaniem muszli mięczaków metodą 14C, a zwłaszcza dokładność uzyskiwanych dat radiowęglowych oraz ich przydatność w geologii czwartorzędu. Opisano metodykę: datowali stosowaną w Laboratorium C-14 w Gliwicach oraz przedstawiono wyniki uzyskane na muszlach morskich z rejonu Billefjorden na Spitsbergenie.

DATING OF MOLLUSCAN SHELLS BY THE14C METHOD

The present state of studies on dating of molluscan shells by the HC method is summarized and a review of the published uses of results of the datings in geological studies, especially in reconstructions of sea level oscillations and changes of shore line is given. Basic principles and limitations of the I~C radiocarbon method arc specified, with attention mainly paid to limitations and errors made in dating of shells. The major difficulties encountered in dating of such material include relative easiness of pollution with extraneous carbon, underestimation of original concentration of isotope 14C, leading 10 origin of the so-called apparent ages, and isotope fractionation. There are also discussed geochemical mechanisms which represent source of errors in dating of shells, and the methods of elimination of these errors. Serious difficulties in introduction of correction for the apparent age of fresh-water molluscans indicate uselessness of these shells for chronometry. The method of dating of shells, worked out in the 14C Laboratory in Gliwice is presented and criteria for selection of samples for dating precised. The results of .dating of a series of marine shell samples from Spitsbergen are given as an example and compared with hypotheses put forward by G.S. Boulton (1979).


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