Extensive Noachian fluvial systems in Arabia Terra: Implications for early Martian climate
Extensive Noachian fluvial systems in Arabia Terra: Implications for early Martian climate
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DOI：
10.1130/g38247.1
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发表时间：
2016-10-01
期刊：
影响因子：
5.8
通讯作者：
Gupta, S.
中科院分区：
文献类型：
--
作者：
Davis, J. M.;Balme, M.;Gupta, S.
山谷网络是早期(诺阿契亚；>；3.7Ga)火星上广泛河流活动的最强有力的证据之一。然而，据称在某些古老的地形上没有它们，如阿拉伯土地，与“温暖和潮湿”气候模型预测的降水模式不同。这种分歧促成了另一种“冰川高地”设想的发展，即高地冰盖融化形成山谷网络。在这里，我们通过区域地图显示，阿拉伯地形显示了广泛的曲折山脊网络的证据。我们将这些海脊特征解释为形成于诺瓦契的倒置河道，然后进行埋葬和折返。倒置河道发育在大面积的淤积洪泛平原上。由于倒置的水道既来自阿拉伯陆地，又横穿阿拉伯陆地，它们的形成与离散的、局部的水源不一致，例如来自高原冰盖的融水。相反，我们的结果与早期火星更一致，因为火星支持了广泛的降水和径流。
Valley networks are some of the strongest lines of evidence for extensive fluvial activity on early (Noachian; >3.7 Ga) Mars. However, their purported absence on certain ancient terrains, such as Arabia Terra, is at variance with patterns of precipitation as predicted by "warm and wet" climate models. This disagreement has contributed to the development of an alternative "icy highlands" scenario, whereby valley networks were formed by the melting of highland ice sheets. Here, we show through regional mapping that Arabia Terra shows evidence for extensive networks of sinuous ridges. We interpret these ridge features as inverted fluvial channels that formed in the Noachian, before being subject to burial and exhumation. The inverted channels developed on extensive aggrading flood plains. As the inverted channels are both sourced in, and traverse across, Arabia Terra, their formation is inconsistent with discrete, localized sources of water, such as meltwater from highland ice sheets. Our results are instead more consistent with an early Mars that supported widespread precipitation and runoff.