Discovery of a geomorphological analog to Martian araneiforms in the Qaidam Basin, Tibetan Plateau  

青藏高原柴达木盆地的类火星蜘蛛状地貌

作　　者：Shengxing Zhang Yiliang Li Wei Leng 张晟星;李一良;冷伟(中国科学技术大学地球和空间科学学院地震与地球内部物理实验室,安徽合肥230026;香港大学地球科学系,中国香港999077;中国科学院比较行星学卓越创新中心,安徽合肥230026)

机构地区：[1]Laboratory of Seismology and Physics of Earth’s Interior,School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,China [2]Department of Earth Sciences,The University of Hong Kong,Hong Kong 999077,China [3]CAS Center for Excellence in Comparative Planetology,Hefei 230026,China

出　　处：《中国科学技术大学学报》2024年第5期1-9,I0006,共10页JUSTC

基　　金：supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB41000000);the Fundamental Research Funds for the Central Universities(WK2080000144)。

摘　　要：Araneiforms are spider-like ground patterns that are widespread in the southern polar regions of Mars.A gas erosion process driven by the seasonal sublimation of CO_(2) ice was proposed as an explanation for their formation,which cannot occur on Earth due to the high climatic temperature.In this study,we propose an alternative mechanism that attrib-utes the araneiform formation to the erosion of upwelling salt water from the subsurface,relying on the identification of the first terrestrial analog found in a playa of the Qaidam Basin on the northern Tibetan Plateau.Morphological analysis indicates that the structures in the Qaidam Basin have fractal features comparable to araneiforms on Mars.A numerical model is developed to investigate the araneiform formation driven by the water-diffusion mechanism.The simulation res-ults indicate that the water-diffusion process,under varying ground conditions,may be responsible for the diverse aranei-form morphologies observed on both Earth and Mars.Our numerical simulations also demonstrate that the orientations of the saltwater diffusion networks are controlled by pre-existing polygonal cracks,which is consistent with observations of araneiforms on Mars and Earth.Our study thus suggests that a saltwater-related origin of the araneiform is possible and has significant implications for water searches on Mars.蜘蛛状地貌因有着蜘蛛状的结构而得名,它们广泛分布于火星南半球的高纬度地区。此前的研究提出干冰季节性升华驱动的气体侵蚀过程可以解释火星上蜘蛛状地貌的形成,但这种机理所要求条件特殊,无法发生在气温较高的地球上。在本研究中,我们报道了地球上首个类火星蜘蛛状地貌结构分布的地体,该地体位于青藏高原北部的柴达木盆地中的一个干涸湖泊上。我们通过对该蜘蛛状地貌分布的地体的研究,提出了一种新的模型来解释火星蜘蛛状地貌的成因。根据该模型,我们认为蜘蛛状地貌由上涌的地下卤水侵蚀地表而形成。几何形态学分析表明,在柴达木盆地发现的蜘蛛状地貌具有与火星蜘蛛状地貌接近的分形结构和维度特征。我们建立了相应的数值模型来进一步研究由水扩散机制驱动的蜘蛛状地貌形成过程。结果显示,水的扩散过程在不同的地形和地表结构条件下可以导致不同的蜘蛛状地貌形态,这也解释了火星上蜘蛛状地貌形态特征的多样性。数值模拟结果还表明,地表预先存在的多边形地体边缘的几何特征会影响卤水扩散形成的蜘蛛状网络的生长动力学,这与火星上的观测结果一致。我们的研究结果表明,蜘蛛状地貌的形成可能与地下卤水的上涌密切相关,这对研究火星近地表卤水的活动具有重要意义。

关 键 词：araneiform landform subsurface water Qaidam Basin Mars analog fractal simulations 

分 类 号：P931[天文地球—自然地理学]