Elysium Region, Mars: Tests of lithospheric loading models for the formation of tectonic features
Elysium Region, Mars: Tests of lithospheric loading models for the formation of tectonic features
复制标题
火星极乐世界：用于构造特征形成的岩石圈加载模型测试
DOI：
10.1029/jb091ib11p11377
复制
发表时间：
1984
影响因子：
--
通讯作者：
J. Head
中科院分区：
文献类型：
--
作者：
J. Hall;S. Solomon;J. Head
火星上第二大火山省位于极乐世界。与更大的塔尔西斯省一样，极乐世界的特点是地形上升和广泛的自由空气重力异常，并且还表现出复杂的构造和火山特征。我们检验了这样一个假设：极乐世界的构造特征是火星岩石圈载荷产生的应力的产物。我们考虑三种不同尺度的载荷：单个火山的局部载荷、岩石圈上方或下方的区域载荷以及塔西斯的准全球载荷。弯曲应力与岩石圈强度以及推断的最大断层深度的比较证实，极乐世界蒙斯周围的同心地堑可以解释为约 50 公里厚的弹性岩石圈响应火山载荷而局部弯曲的结果。然而，区域尺度上的火山载荷导致预测的应力与所有观测到的构造特征不一致，这表明厚平原沉积物的广泛侵位所产生的载荷并不是极乐世界构造演化的重要因素。许多大致西北-东南方向的线性伸展特征可能是极乐世界隆起规模的岩石圈弯曲隆起的结果。与塔尔西斯隆起支撑相关的全球应力场似乎影响了极乐世界许多构造特征的发展，包括塞伯鲁斯鲁佩斯和极乐世界东部和西部的山脊系统。极乐世界的应力模型与保存的构造特征的比较支持该地区不同时间运行的一系列应力场。虽然这些应力场的运行顺序无法从目前的地质观测中确定，但热学和力学论据支持这样一种假设，即地幔热异常引起的岩石圈弯曲隆起先于最大火山载荷的形成或与最大火山载荷的形成同时发生。
The second largest volcanic province on Mars lies in the Elysium region. Like the larger Tharsis province, Elysium is marked by a topographic rise and a broad free air gravity anomaly and also exhibits a complex assortment of tectonic and volcanic features. We test the hypothesis that the tectonic features in the Elysium region are the product of stresses produced by loading of the Martian lithosphere. We consider loading at three different scales: local loading by individual volcanoes, regional loading of the lithosphere from above or below, and quasi-global loading by Tharsis. A comparison of flexural stresses with lithospheric strength and with the inferred maximum depth of faulting confirms that concentric graben around Elysium Mons can be explained as resulting from local flexure of an elastic lithosphere about 50 km thick in response to the volcano load. Volcanic loading on a regional scale, however, leads to predicted stresses inconsistent with all observed tectonic features, suggesting that loading by widespread emplacement of thick plains deposits was not an important factor in the tectonic evolution of the Elysium region. A number of linear extensional features oriented generally NW-SE may have been the result of flexural uplift of the lithosphere on the scale of the Elysium rise. The global stress field associated with the support of the Tharsis rise appears to have influenced the development of many of the tectonic features in the Elysium region, including Cerberus Rupes and the systems of ridges in eastern and western Elysium. The comparisons of stress models for Elysium with the preserved tectonic features support a succession of stress fields operating at different times in the region. While the order in which those stress fields operated cannot be determined from present geological observations, thermal and mechanical arguments favor the hypothesis that any flexural uplift of the lithosphere by a mantle thermal anomaly preceded or occurred contemporaneously with emplacement of the largest volcanic loads.