Stress Field History, Cape Roberts Antarctica: CollaborativeResearch

摘要该奖项支持一项合作研究项目，该项目旨在获得南极西部南极裂谷系统中第一个年龄校准的应力场历史。获得应力数据的机会是由计划在罗伯茨角进行的国际钻井项目提供的，罗伯茨角位于隆起的南极横贯山脉和维多利亚地盆地的裂谷地壳之间的边缘。通过岩心和天然裂缝、断裂的井下测井，获得了中、新生代裂谷盆地充填体的古应力史信息。为了确定当前应力状态，将对岩心进行取心应力裂缝检查，并通过井下电视和倾角仪检查井眼，以确定当前应力场重新激活的任何井筒裂缝和裂缝。对应力数据进行分析，以解决与南极板块古构造和新构造演化有关的问题。这些结果将有助于解决一些悬而未决的问题，如大陆异常抗震的原因，横贯南极山脉和南极西部裂谷系统之间岩石圈边界的应力几何形状，以及南极板内应力场的演化及其与冈瓦纳大陆分裂相关的裂谷事件的关系。从这个项目中获得的当代应力数据将被添加到全球应力数据库中，并将有助于填补目前以南极板块为标志的全球应力覆盖的空白。

Wilson OPP 9527394 Jarrard OPP 9527319 Zoback OPP 9527412 Abstract This award supports a collaborative research program to obtain the first age-calibrated stress-field history within the West Antarctic rift system of Antarctica. The opportunity to acquire the stress data is provided by the international drilling program planned at Cape Roberts, which is located along the margin between the uplifted Transantarctic Mountains and the rifted crust of the Victoria Land basin. Information on the paleostress history of the Mesozoic and Cenozoic rift-basin fill will be obtained from the core and downhole logging of natural fractures and faults. To establish the contemporary stress state, the cores will be examined for coring-induced stress fractures and the borehole will be examined via downhole televiewer and dipmeter for any wellbore breakouts and fractures reactivated by the contemporary stress field. The stress data will be analyzed to address questions relevant to the paleo- and neotectonic evolution of the Antarctic plate. The results will contribute to the resolution of outstanding questions such as the cause of the anomalous aseismicity of the continent, the geometry of stresses along the lithospheric boundary between the Transantarctic Mountains and the West Antarctic rift system, and the evolution of the Antarctic intraplate stress field and its relation to rifting episodes associated with Gondwanaland breakup. Contemporary stress data obtained from this program will be added to the global stress data base, and will help to fill the current void in the global stress coverage marked by the Antarctic plate.