Hydrovolcanic tuff rings and cones as indicators for phreatomagmatic explosive eruptions on Mars
Hydrovolcanic tuff rings and cones as indicators for phreatomagmatic explosive eruptions on Mars
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水火山凝灰岩环和火山锥作为火星上岩浆爆发性喷发的指标
DOI：
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发表时间：
2013
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影响因子：
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通讯作者：
E. Hauber
中科院分区：
文献类型：
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作者：
P. Brož;E. Hauber
水火山作用在地球上是一种常见的自然现象，在火星上也应该很常见，因为它的表面显示出火山作用和近地表水的广泛证据。我们调查了位于古代撞击盆地乌托邦南缘的Nephentes/Amenths地区的凹陷圆锥体的田野，这些区域以前被解释为泥火山。锥体场包含凹坑和破裂的锥体，以及与之相关的流状地貌。根据地层关系，我们确定了西方人或更年轻的模型年龄。我们验证了(水)火山起源的假设。根据详细的形态和形态计量学分析，以及区域背景的分析，这些锥体的火成岩成因是由云母岩浆喷发产生的水火山建筑物。有几条证据表明地下水冰的存在。凹陷的圆锥体显示出发育良好的宽阔的中央陨石坑，底部高度低于喷发前的表面。它们的形态和整体外观类似于陆地凝灰岩锥体和凝灰岩环。在同一地区也观察到的土丘类似于陆地熔岩穹顶。上升岩浆与地下水和/或水冰之间的火山作用可能解释了凹陷圆锥体的形成，尽管不能排除其他情况，如泥火山作用。与这些土丘一起，这些圆锥体可能代表了由熔岩穹顶、凝灰岩环、凝灰岩圆锥体和可能的马尔组成的单一成因火山场的热情洋溢和爆炸性的建筑物。
Hydrovolcanism is a common natural phenomenon on Earth and should be common on Mars, too, since its surface shows widespread evidence for volcanism and near‐surface water. We investigate fields of pitted cones in the Nephentes/Amenthes region at the southern margin of the ancient impact basin, Utopia, which were previously interpreted as mud volcanoes. The cone fields contain pitted and breached cones with associated outgoing flow‐like landforms. Based on stratigraphic relations, we determined a Hesperian or younger model age. We test the hypothesis of a (hydro)volcanic origin. Based on a detailed morphological and morphometrical analysis and an analysis of the regional context, an igneous volcanic origin of these cones as hydrovolcanic edifices produced by phreatomagmatic eruptions is plausible. Several lines of evidence suggest the existence of subsurface water ice. The pitted cones display well‐developed wide central craters with floor elevations below the preeruptive surface. Their morphometry and the overall appearance are analogous to terrestrial tuff cones and tuff rings. Mounds that are also observed in the same region resemble terrestrial lava domes. The hydrovolcanic interaction between ascending magma and subsurface water and/or water ice may explain the formation of the pitted cones, although other scenarios such as mud volcanism cannot be ruled out. Together with the mounds, the cones might represent effusive and explosive edifices of a monogenetic volcanic field composed of lava domes, tuff rings, tuff cones, and possibly maars.