湖相介形类壳体微量元素在古环境重建中的应用

湖相介形类壳体微量元素（本文主要指Mg和Sr）是重建古环境的重要指标之一，可以定性或定量地反映湖水信息。自20世纪80年开始应用以来，经过30余年的发展取得了很大进展。在古环境重建过程中主要存在两类影响因素：（1）其宿生水体中M/Ca比值（M主要指Mg和Sr）的影响因素：季节变化、微环境差异和湖泊演化过程，这类因素通过对宿生水体中M/Ca比值来影响介形虫壳体中的M/Ca比值，进而造成古环境重建结果的误差增大或可靠性降低；（2）介形类壳体微量元素分配系数的影响因素：宿生水体中M/Ca比值、温度、碱度等，这类因素能够直接影响介形类壳体分泌、钙化的生命-化学过程的因素，是定量重建的重要影响因素。加强现代介形类生活习性和微量元素组成变化过程的研究可以消除或减小以上影响因素对古环境重建的影响，提高介形类壳体化石中微量元素组成在古环境重建研究中的精度和可靠性。

Trace elements in non-marine Ostracods and their application to paleoenvironment reconstruction

The trace elements(Mg and Sr in this paper)in non-marine Ostracoda could be used as proxies to reconstruct the paleoenvironment of paleo-lake qualitatively or quantitatively.Since their first application to paleoenvironmental reconstruction in the 1980s,great progress has been made in the past 30 years.There are two factors which influence the proxies.One is the changes in M/Ca ratio of the host water(M refers to Mg plus Sr in this paper),including seasonal changes,microenvironmental differentiation and lake evolution process.This type of factors affects the M/Ca ratio in Ostracoda shells through the changes in M/Ca ratio in the host water,and may lead to the increase in error or decrease in reliability of the reconstruction results.The other is the partition coefficient of Ostracoda shells,including M/Ca of host water,temperature,alkalinity and so on,which can directly affect the bio-chemical process of shell secretion and calcification.This type of influencing factors may severely influence the quantitative reconstruction of paleoenvironment.For improving the accuracy and reliability of the results of paleoenvironmental reconstruction,living habits of modern Ostracoda and their trace elements composition in different environments should be carefully studied as reference cases.