Structural evolution of the Northern Cerberus Fossae graben system, Elysium Planitia, Mars
Structural evolution of the Northern Cerberus Fossae graben system, Elysium Planitia, Mars
复制标题
火星极乐世界北地狱犬窝地堑系统的结构演化
DOI：
10.1016/j.jsg.2009.11.004
复制
发表时间：
2010
影响因子：
3.1
通讯作者：
G. Roberts
中科院分区：
文献类型：
--
作者：
J. Vetterlein;G. Roberts
为了确定北Cerberus Fossae （NCF）的构造演化是由冰冻圈融化和塌陷主导还是由断层相关沉降主导，我们利用MOC、THEMIS和HiRISE图像以及MOLA数据记录了沿走向垂直偏移的空间变化。深窝是火星表面的一系列裂缝，它们横切了诺亚纪、赫斯佩里纪，在某些地方，还有非常年轻的晚亚马逊地貌。来自MOLA数据的裂缝相关地形的连续横截面显示，裂缝穿过较老的地形时，垂直偏移量并不大，这表明自亚马逊河地形形成以来，偏移量已经积累。垂直偏移在裂缝系统的中心部分更大，剖面类似于单个断层系统。地堑底部保留了早期变形的地形特征，表明沉积物很少填充，因此MOLA高程测量限制了裂缝形成以来的总垂直偏移量。垂直偏移的缺陷发生在裂缝没有连接的地方，并且在接力带中保持成梯队，或者已经连接，留下了古地堑尖端。这表明，裂缝的痕迹沿着地表走向传播，并在一段时间内相交，可能在105 - 106年的范围内，而不是在一次塌陷事件中。与塌陷坑相关的地方也存在缺陷，表明这种塌陷是地堑边缘横向扩展的早期沉降阶段。我们利用这些观测结果认为，引起下沉的主要机制不是冰冻圈融化和崩塌，而是断层作用。
To determine whether the structural evolution of the Northern Cerberus Fossae (NCF) was dominated by cryospheric melting and collapse or fault-related subsidence, we used MOC, THEMIS and HiRISE images, and MOLA data to document spatial variations in vertical offset along strike. The Fossae are a series of fractures on the martian surface that cross-cut Noachian, Hesperian and, in places, very young Late Amazonian terrain. Serial cross sections across the fracture-related topography, from MOLA data, show that vertical offsets are not greater where fractures traverse older terrain, showing that offsets have accumulated since the formation of the Amazonian terrain. Vertical offsets are greater in the central portions of the fracture system with the profile resembling that for a single fault system. Topographic features that pre-date deformation are preserved on the graben floors suggesting little sediment infill, so the MOLA elevation measurements constrain total vertical offsets since the fractures formed. Deficits in vertical offset occur where fractures have not linked and remain en echelon across relay zones, or have linked, leaving palaeo-graben-tips. This indicates that the traces of the fractures propagate along strike at the surface and intersect over time periods that are likely to be in the range of 105–106years rather than in a single collapse event. Deficits are also in places associated with collapse pits, suggesting such collapse is the early stage of graben subsidence at propagating lateral graben-tips. We use these observations to argue that the primary mechanism causing subsidence is not cryospheric melting and collapse, but faulting.