アミノ酸ラセミ化法による大阪湾南港底たい積層の年代測定

概要

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In order to deduce the age of the bed sediments at Nanko in Osaka Bay, the D/L ratios of amino acids contained in fossil 3hells buried in sediments were determined by glass capillary gas chromatography. Shells in the sediments were at the depth of (1)8.5m, (2)28.5m, (3)51.Om, and (4)64.5m, respectively. Shells were first washed with O.0 2N-HCl by ultra-sonication and then with ethanol. After hydrolysis of the shells with 6N-HCl at llO℃ for 20 h, amino acids were taken out by ion-exchange chromatography with Bio-Rad AG 50W-X8. After derivatization to their N(0)-TFA isopropyl esters, the enantiomeric mixtures of amino acids were separated by gas chromatography using a Chirasil-Val capillary column, As the racemization of Ala, Val, Phe, and Glu was found to proceed in proportion to age ,we could easily deduce the dates of the sediments. The corresponding ages of the 5ediments determined are as follows: (1)3000, (2) 14000, (3) 28000, (4) 30000 years. The present amino acid racemization method has some advantages over radiocarbon method, i.e.in measurable range and sample quantity required.
1983-05-05