论化石氨基酸外消旋比率与纬度的梯度相关关系

RELATIONSHIP BETWEEN EXTENTS OF ISOLEUCINE EPIMERIZATION IN THE SAME PERIOD SEDIMENTS ACROSS REGIONS AND THEIR LATITUDE GRADIENT

成岩温度史不相同的剖面中,标本的氨基酸外消旋比率不可能直接进行对比.为了便于磺向对比,根据氨基酸外消旋动力学原理,对长白山孤山屯、陕西洛川、南京三山矶和福建占雷头4个剖面中贝壳化石及沉积物的异亮氨酸D/L比率进行了外推对比,发现同时代的跨纬度剖面中标本的氨基酸D/L.比率与其纬度的梯度成负相关关系.当前研究有可能为氨基酸外消旋比率的横向对比,跨纬度的不同区域的古温度、古生态的研究提供理论依据.

A direct comparison of alle/Ile ratios does not allow correlation of the sediments collected across various thermal regions (or different latitudes), since alle/Ile ratios in molluscs can only be compared between nearby areas with a similar thermal history up to now. The writer has obtained alle/Ile ratios in the fossil molluscs or associated sediments from Guleitou of Fujian, Sanshanji near Nanjing, Luochuan of Shaanxi and Gushantun in the Changbai Mountains Area.These areas have a different thermal history (and across different latitudes). The alle/Ile ratios from these study areas can be translated into relative ratios for the same period sediments in order to make a direct comparison across regions (or latitudes) with a different thermal history. The differences alle/Ile ratios in the same period sediments from different regions can be considered as resulitng from their respective different thermal history. This study indicates a negative relationship between the alle/Ile ratios, which are from the same period sediments across regions with a different thermal history, and their latitude gradient.