摘要
轨道和就位探测在火星表面发现了广泛分布的含水矿物。这些矿物作为火星早期地壳被液态水改造的证据,记录了火星早期地质特征、水环境和宜居环境演化等重要信息。火星南部高地Tyrrhena Terra是火星上含水矿物出露最为广泛的区域之一,其多样的矿物组合表明该区域经历了复杂的水蚀变过程。本研究以Tyrrhena Terra地区东北部一个未命名撞击坑(6.65°S, 93.90°E)及其周边区域作为研究对象,利用火星高光谱数据识别了区域内的含水矿物类型,并结合形貌数据分析了含水矿物的分布特征,进而探讨了这些矿物可能的形成机制。结果显示,研究区内的含水矿物有Fe/Ca碳酸盐、方沸石、绿泥石和Fe/Mg蒙皂石,这些矿物分布在撞击坑中央峰、坑底和溅射物,且在中央峰与溅射物区域存在相似的矿物类型。分析表明,这些含水矿物可能是在火星地下经过热液蚀变或低级变质等过程形成,并因撞击事件被挖掘并暴露在地表;含水矿物形成时地下可能存在有热液系统,具有宜居环境的潜力;出露的碳酸盐可能是大气CO_(2)-水-岩石相互作用的产物,对火星早期大气成分及气候具有指示意义。
Orbital and in-situ exploration have discovered widely distributed aqueous minerals on the surface of Mars.These minerals are evidence of liquid water modification of the early crust of Mars,and record vital information about the aqueous environment,geological features,and evolution of the habitable environment.Tyrrhena Terra(0°~20°S,65°~100°E)in the southern highland of Mars is an area where aqueous minerals are widely exposed,with diverse mineral assemblages suggesting that the region underwent a complex process of aqueous alteration.This study focuses on an unnamed impact crater(6.65°S,93.90°E,referred to as impact crater S in this paper)and two smaller impact craters(6.20°S,93.60°E;6.90°S,94.40°E)distributed along its northwestern and southeastern margins in the northeastern Tyrrhena Terra.We used hyperspectral remote sensing data obtained by the Compact Reconnaissance Imaging Spectrometer for Mars(CRISM)to identify aqueous minerals in the region,along with morphological data from Context Camera(CTX)to analyze the spatial distribution of these minerals,and investigated their possible formation mechanisms.The S impact crater has a diameter of about 52 km and a depth of about 1.1 km.The northwestern(NW)impact crater has a diameter of about 28 km and a depth of about 2 km,with a central peak of about 0.7 km.The southeastern(SE)impact crater has a diameter of about 17 km and a depth of about 1.6 km.Ejecta from the NW impact crater covers a significant portion of the floor of the S impact crater.We analyzed four CRISM images covering the floor and edges of the S impact crater,the central peak of the NWimpact crater,and the floor of the SE impact crater.Data were processed using the CRISM Analysis Toolkit and an improved CRISM noise reduction tool,generating spectral parameter maps and extracting ratio spectra for comparison with laboratory spectra.The results reveal that the aqueous minerals in the study area include Fe/Ca carbonates,analcime,chlorite,and Fe/Mg smectites,distributed in the central peak,crater floor,and ejecta blankets,with similar mineral assemblages observed in both the central peak and ejecta blankets of the NW impact crater.The mineral distribution characteristics suggest that aqueous minerals may have been exposed at the surface as a result of impact excavation.The analcime-chlorite-Fe/Mg smectite assemblage may reflect low-grade metamorphic or hydrothermal alteration processes,and the presence of Fe/Ca carbonates may result from interactions between basaltic rocks and CO_(2)-rich fluids.These findings suggest that hydrothermal systems may be present in the subsurface of the study area at the time of the formation of the aqueous minerals,with potential for habitable environments.The carbonates may be the products of atmospheric CO_(2)-water-rock interactions,indicative of the composition of the early Martian atmosphere and climate.
作者
李柯仪
吴兴
武雨纯
刘洋
LI Keyi;WU Xing;WU Yuchun;LIU Yang(State Key Laboratory of Solar Activity and Space Weather,National Space Science Center,Chinese Academy of Sciences,Beijing 100190,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;Center for Excellence in Comparative Planetology,Chinese Academy of Sciences,Hefei 230026,China)
出处
《第四纪研究》
北大核心
2025年第4期903-911,共9页
Quaternary Sciences
基金
国家自然科学基金项目(批准号:42072337和42441832)资助。
关键词
火星
撞击坑
红外遥感
含水矿物
宜居环境
Mars
crater
infrared remote sensing
aqueous minerals
habitable environment
