火星古湖泊形成环境及天体生物学意义

火星是类地行星中与地球地质环境最为相似的天体。其表面发育的古湖泊盆地是研究火星地质与气候演化历史的重要载体，具有重要的天体生物学研究意义。但目前对火星古湖泊盆地的分布、水源和沉积物及所记录的气候环境特点研究明显不足，尤其缺少火星湖泊与地球上类似湖泊盆地的对比研究，导致现有对火星早期环境的认识及理论模型依据不足。本项目将利用比较行星地质学的理论方法，（1）调查火星古湖泊的时空分布和水源特点；（2）研究火星南部高原典型古湖泊盆地的宏观地貌地质特征；（3）研究古湖泊相连河道及盆地中沉积物成分特征及所反映的水体性质；（4）开展柴达木盆地内次级干涸湖泊沉积物及其中生物标志化合物的研究，并与火星遥感地质解译结果进行类比分析，揭示火星表面古湖泊盆地的演化过程和环境变迁历史。其成果将为揭示火星古湖泊盆地记录的地质与气候环境历史提供重要证据，为探索古湖泊盆地的天体生物学意义及火星生命探测选址提供参考。

Mars is the planet that is most similar to the Earth's geological environment. The amount of channels and dry lake basins on Mars surface are important carriers for studying its geological and climate environmental evolution history, and have important research significance for astrobiology. However, due to the limitation of the amount and accuracy of the previous exploration data, the recognition, distribution, duration and history of the late paleolake basins are lacking of research, which leads to a great controversy about the understanding of the ancient climate and environment of Mars. This project will use the theory and method of comparative planetary geology, to (1) establish recognition criteria of the ancient lake basins and clarify their spatial distribution; (2) study temporal and spatial variation of ancient basins using overlap relationships among geological units and crater statistical analysis method; (3) study compositional characteristics of sediments within basin and connected rivers, and to constraint the properties of water of ancient lakes; (4) carry out comparative study with secondary dry lakes and playas within the Qaidam Basin, reveal late stage degradation processes of ancient lake basins on Mars, analyze bio-signatures of the playa sediments, and explore their astrobiological significance. These results will provide important evidence for revealing the history of the formation and evolution of the ancient lacustrine basin, and the recorded geological and climatic environment history, so as to disclose their astrobiological significance and provide references for location selection of Mars life exploration.