诺亚人
火星探测计划
西方人
亚马逊河
地质学
火星人
沉积岩
天体生物学
自行车
沉积沉积环境
地球科学
撞击坑
气候变化
地球化学
古生物学
构造盆地
地理
海洋学
生态学
考古
亚马逊雨林
物理
生物
作者
W. Rapin,Gilles Dromart,B. C. Clark,Jüergen Schieber,Edwin S. Kite,Linda C. Kah,L. M. Thompson,O. Gasnault,J. Lasue,P. Y. Meslin,P. J. Gasda,N. Lanza
出处
期刊:Nature
[Springer Nature]
日期:2023-08-09
卷期号:620 (7973): 299-302
被引量:5
标识
DOI:10.1038/s41586-023-06220-3
摘要
The presence of perennially wet surface environments on early Mars is well documented1,2, but little is known about short-term episodicity in the early hydroclimate3. Post-depositional processes driven by such short-term fluctuations may produce distinct structures, yet these are rarely preserved in the sedimentary record4. Incomplete geological constraints have led global models of the early Mars water cycle and climate to produce diverging results5,6. Here we report observations by the Curiosity rover at Gale Crater indicating that high-frequency wet-dry cycling occurred in early Martian surface environments. We observe exhumed centimetric polygonal ridges with sulfate enrichments, joined at Y-junctions, that record cracks formed in fresh mud owing to repeated wet-dry cycles of regular intensity. Instead of sporadic hydrological activity induced by impacts or volcanoes5, our findings point to a sustained, cyclic, possibly seasonal, climate on early Mars. Furthermore, as wet-dry cycling can promote prebiotic polymerization7,8, the Gale evaporitic basin may have been particularly conducive to these processes. The observed polygonal patterns are physically and temporally associated with the transition from smectite clays to sulfate-bearing strata, a globally distributed mineral transition1. This indicates that the Noachian-Hesperian transition (3.8-3.6 billion years ago) may have sustained an Earth-like climate regime and surface environments favourable to prebiotic evolution.
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