摘要
横向沙脊是火星独特风沙地貌类型之一,近20年来研究者们借助高分辨率火星遥感探测资料开展了系列研究。总结了横向沙脊的分布规律、形态特征、沉积物组成、形成过程及其形成时代等方面的研究成果。火星横向沙脊是高度为米级,间距为10 m级的风成床面形态类型,主要分布于赤道和低纬度地区,而且南半球较北半球多。高反照率和对称的截面形态是其突出的特征,与地球上的巨型沙波纹和反向沙丘的截面形态类似。横向沙脊沉积物粒度组成一般具有双峰型特征,表层为粗沙覆盖,但热惯性较低。目前关于横向沙脊的形成过程有3种假说:巨型沙波纹假说、反向沙丘假说和粉尘胶结假说,但支持巨型沙波纹假说的证据最多。火星横向沙脊与沙丘一样,属于新近的火星地貌类型,但其形成时间一般较沙丘早,多形成于近几百万年以来,所以常被胶结或岩化,不具流动性,但也有少数现代时期形成的活动性横向沙脊。横向沙脊的独特性使其成为最令人困惑的火星风沙地貌类型之一,以至于研究者们对其在风沙地貌分类系统中的归属尚有争议。针对横向沙脊研究的需要,未来火星探测亟需提供两个方面的高分辨率遥感信息,即横向沙脊沉积物组成和若干区域的综合集成勘测。
Transverse Aeolian Ridges(TARs) are among the unique aeolian bedforms of Mars,which witnessed a series of investigation for the last two decades thanks to the high-resolution remote sensing data. This paper summarized the understanding with respect to distribution,morphology,sedimentology,formation hypotheses and formation time of TARs. It is suggested that TARs are a kind of aeolian bedforms with meterscale height and decameter-scale wavelength. TARs are primarily distributed in the equator and low-latitude regions,being rare in high and mid-latitude regions,and more popular in the south hemisphere than in the north hemisphere. Higher albedo and symmetric cross-sections are the most outstanding features of TARs,being analogous to the megaripples and reversing dunes on the Earth. The grain-size distribution of TARs’ sediments is generally bimodal,with granule cover and low thermal inertia. Three formation hypotheses were proposed for TARs:Megaripple hypothesis,reversing dune hypothesis and dust induration hypothesis,with more evidences supporting the megaripple hypothesis. Similar to dunes,TARs are geologically recent morphology on Mars,but generally predate dunes,formed in the last few million years so that most TARs are indurated or lithified and are immobile. However,contemporary mobileTARs are also developed in some regions. The unique features of TARs make them the mostenigmatic aeolian bedforms of Mars. It is proposed that high-resolution information on TARs sedimentology and integrated regional surveying should be listed in the priorities of future Mars exploration with respect to TARs study.
作者
董治宝
吕萍
李超
胡光印
Dong Zhibao;Lü Ping;Li Chao;Hu Guangyin(Planetary Aeolian Research Institute,Shaanxi Normal University,Xi'an 710119,China)
出处
《地球科学进展》
CAS
CSCD
北大核心
2020年第7期661-677,共17页
Advances in Earth Science
基金
国家自然科学基金项目“塔里木盆地周围干燥剥蚀山地风化速率研究”(编号:41930641)
“沙丘动力学数值模型时间与空间尺度的确定”(编号:41871011)资助。
关键词
火星风沙地貌
横向沙脊
风沙地貌形态学
形成假说
Martian aeolian geomorphology
Transverse aeolian ridges
Morphology of aeolian bedforms
Formation hypotheses