火星地壳磁性的构造意义。
Tectonic implications of Mars crustal magnetism.
作者信息
Connerney J E P, Acuña M H, Ness N F, Kletetschka G, Mitchell D L, Lin R P, Reme H
机构信息
National Aeronautics and Space Administration Goddard Space Flight Center, Greenbelt, MD 20771, USA.
出版信息
Proc Natl Acad Sci U S A. 2005 Oct 18;102(42):14970-5. doi: 10.1073/pnas.0507469102. Epub 2005 Oct 10.
Mars currently has no global magnetic field of internal origin but must have had one in the past, when the crust acquired intense magnetization, presumably by cooling in the presence of an Earth-like magnetic field (thermoremanent magnetization). A new map of the magnetic field of Mars, compiled by using measurements acquired at an approximately 400-km mapping altitude by the Mars Global Surveyor spacecraft, is presented here. The increased spatial resolution and sensitivity of this map provide new insight into the origin and evolution of the Mars crust. Variations in the crustal magnetic field appear in association with major faults, some previously identified in imagery and topography (Cerberus Rupes and Valles Marineris). Two parallel great faults are identified in Terra Meridiani by offset magnetic field contours. They appear similar to transform faults that occur in oceanic crust on Earth, and support the notion that the Mars crust formed during an early era of plate tectonics.
火星目前没有源自内部的全球磁场，但过去肯定有过，当时地壳获得了强烈的磁化，大概是在类似地球磁场的存在下冷却时产生的（热剩磁）。本文展示了一幅新的火星磁场地图，它是利用火星全球勘测者号航天器在大约400公里的测绘高度获取的测量数据编制而成的。这幅地图提高的空间分辨率和灵敏度为火星地壳的起源和演化提供了新的见解。地壳磁场的变化与一些主要断层有关，其中一些断层此前已在图像和地形中被识别出来（塞伯鲁斯断崖和水手号峡谷）。在子午线高原，通过磁场等值线的偏移识别出了两条平行的大断层。它们看起来类似于地球上大洋地壳中出现的转换断层，这支持了火星地壳是在板块构造活动早期形成的观点。
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