湖泊沉积有机质的地球化学记录与古气候古环境重建

与深海沉积与冰芯记录相比,湖泊沉积主要反映区域气候变迁史,可以揭示百年、甚至十年尺度的古气候事件,是高分辨率古环境、古气候重建的理想场所.传统的地质地球化学方法主要侧重于宏观物理 /化学特性描述和孢粉学的研究,近 10年来,沉积有机质分子碳、氢同位素地球化学技术的渗入,使研究工作从传统的宏观、微观层次向分子级水平发展,对诸如古生产率估算、C3/C4植被演替史、古二氧化碳分压及古温度计算等深层次问题解决提供了强有力支持.本文评述了湖泊沉积有机质分子与碳、氢同位素地球化学记录及其在区域古环境、古气候研究中的应用前景.

Lacustrine sediments as a record of changes of regional climate and environment

Compared to marine sediments and ice core, lacustrine sediments can reconstruct regional paleoenviron ment and paleoclimate with high resolution. The method of study changes from traditional geochemical method focusing on macr oscopic depiction of chemical/physical characters of sediments and pollen analys is to molecular stable carbon/hydrogen isotopes, which provides new evidence for reconstruction of paleoproductivity, the history of expansion of C4 plants, CO2 level of atmosphere and paleotemperature, etc. This paper summarizes the achiev ements of reconstructing paleoenvironment and paleoclimate using lacustrine sedi ments by application of biomarker and molecular carbon/hydrogen signatures, and evaluates the future development in this field.