摘要
最近美国航空与空间计划署(NASA)开展的卡西尼—惠更斯外空探测计划发现,在直径为500km的卫星——土卫二上存在水冰和间隙泉的喷发活动。这一现象和在火星上工作的"机遇号"和"勇气号"漫游车所发现的液态水一起,证明了除地球以外的其他星球上过去和现在都存在水,其中的一些星体还有火山活动的证据,这意味着这些星球上可能存在过热液活动地质过程。讨论了火星、木卫二和土卫二可能存在的热液系统类型。这些热液系统类型是根据地球上的构造背景进行相似性研究后得出的,例如海底、火山和裂谷系统。将东非裂谷和贝加尔湖裂谷系统与火星Tharsis高原上巨大的水手大峡谷进行了对比,这些地区都是由地幔柱作用下构造—热液活动导致的地壳抬升、火山和裂谷作用。在火星上,地下冰或低温层会在火山活动和(或)小行星或彗星撞击作用下溶解而形成热液对流。
Recent images from the NASA Cassini-Huygens mission to the outer planets have shown evidence of water ice and geyser-like jets on Enceladus, a Saturnian moon, only about 500 km across. This, together with the data provided by numerous missions to Mars, including the Spirit and Opportunity rovers, are evidence that liquid water is, and was, present on planetary bodies other than the Earth in the solar system. Some of these bodies also contain evidence of volcanism, signifying that hydrothermal processes are, or may have been, active in their geological history. In this paper, we speculate on the types of hydrothermal systems that could have been and/or may be present on Mars, Europa （a moon of Jupiter） and Enceladus. These hydrothermal systems are modelled on terrestrial analogues, such as those on the seafloor, volcanic edifices, and in rift structures. Analogies are proposed between the East African Rift System and the Baikal Rift System with the Tharsis region of Mars, including the giant rift, Valles Marineris. Both regions are the result of mantle plume tectono-thermal activity that caused crustal uplift, volcanism and rifting. On Mars, we suggest that the subsurface ice, or cryosphere, was liquefied as a result of igneous activity and/or asteroid or cometary impacts, generating convecting cells of hydrothermal fluids. For Europa and Enceladus, published models of seafloorstyle hydrothermal systems may explain the features associated with these bodies.
出处
《地质科技情报》
CAS
CSCD
北大核心
2008年第1期1-12,共12页
Geological Science and Technology Information
