Late Noachian to Hesperian climate change on Mars: Evidence of episodic warming from transient crater lakes near Ares Vallis
Late Noachian to Hesperian climate change on Mars: Evidence of episodic warming from transient crater lakes near Ares Vallis
复制标题
火星上诺亚纪晚期到西方气候变化：阿瑞斯山谷附近短暂的火山口湖间歇性变暖的证据
DOI：
10.1029/2009je003522
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Warner N
中科院分区：
文献类型：
--
作者：
Warner N
战神谷地区被高地地形所包围，其中包含退化和原始的大型撞击坑，这表明在晚诺亚纪-早期西方纪期间气候发生了变化，从温暖，潮湿的条件到寒冷，干燥的条件。然而，区域性出现的西方时代陨石坑出口通道表明，这一时期火星上的气候波动特征是短暂的变暖，促进了地表液态水的稳定。对该区域75个撞击盆地的形态和地形进行的广泛调查表明，在最大的退化陨石坑中，有4个陨石坑被发现有单一的出口通道，表明以前存在水填充。这些盆地缺乏入口，表明水流入可能来自地下水的枯竭。测得的陨石坑边缘高度与模型边缘高度的比较表明，这些陨石坑的深度/直径减少的大部分是由于填充，可能是沉积物。火山口统计表明，火山口降解和填充发生在短短的200 Ma的时间间隔在晚诺亚纪，从3.8 Ga到3.6 Ga。在3.6 Ga之后形成的陨石坑表现出接近原始的形态。我们的研究结果支持了在诺亚纪末期气候迅速变化的假设。然而，陨石坑出口通道和战神谷之间的地质关系表明，排水只发生在强烈的陨石坑改造期间，在西方（3.5-2.9 Ga）。这表明陨石坑的填充时间和排水时间之间存在延迟。
The Ares Vallis region is surrounded by highland terrain containing both degraded and pristine large impact craters that suggest a change in climate during the Late Noachian‐Early Hesperian, from warmer, wetter conditions to colder, dryer conditions. However, the regional occurrence of Hesperian‐age crater outlet channels indicates that this period on Mars was characterized by episodic climate fluctuations that caused transient warming, facilitating the stability of liquid water at the surface. An extensive survey of the morphology and topography of 75 impact basins in the region indicates that of the largest degraded craters, 4 were identified with single outlet channels that suggest the former presence of water infill. These basins lack inlets indicating that water influx was likely derived from sapping of groundwater. A comparison of measured crater rim heights to modeled rim heights suggests that the bulk of the depth/diameter reduction on these craters was the result of infilling, possibly by sediments. Crater statistics indicate that crater degradation and infill occurred during a short 200 Ma interval in the Late Noachian, from 3.8 Ga to 3.6 Ga. Craters that formed after 3.6 Ga exhibit a near‐pristine morphology. Our results support the hypothesis of rapid climate change at the end of the Noachian period. However, geologic relationships between the crater outlet channels and Ares Vallis indicate that drainage occurred only after the period of intense crater modification, during the Hesperian (3.5–2.9 Ga). This suggests a delay between the time of infill of the craters and the time of drainage.