Stress Field History, Cape Roberts, Antarctica: Collaborative Research

威尔逊OPP 9527394 Jarrard OPP 9527319 Zoback OPP 9527412该奖项支持一项合作研究计划，该计划旨在获得南极西南极裂谷系统内第一个经年龄校准的应力场历史。计划在罗伯茨角进行的国际钻探计划提供了获取应力数据的机会，罗伯茨角位于横贯北极的隆起山脉和维多利亚陆地盆地裂开的地壳之间的边缘。有关中、新生代裂谷盆地充填体古应力史的信息将从天然裂缝和断层的岩心和井下测井中获得。为了确定当代应力状态，将检查岩心是否有取心引起的应力裂缝，并将通过井下电视和倾斜仪检查井眼是否有因当代应力场重新激活的井眼破裂和裂缝。将对应力数据进行分析，以解决与南极板块的古构造和新构造演化有关的问题。这些结果将有助于解决诸如大陆异常地震的原因、横贯北极山脉和西南极裂谷系统之间的岩石圈边界的应力几何形状、南极板内应力场的演化及其与冈瓦瓦兰裂解相关的裂谷幕的关系等悬而未决的问题。通过该计划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范围的空白。

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.