Cochran James R, Tinto Kirsty J, Bell Robin E
Lamont-Doherty Earth Observatory of Columbia University Palisades, New York, USA.
Geochem Geophys Geosyst. 2015 May;16(5):1421-1438. doi: 10.1002/2014GC005570. Epub 2015 May 22.
Inversion of NASA Operation IceBridge airborne gravity over the Abbot Ice Shelf in West Antarctica for subice bathymetry defines an extensional terrain made up of east-west trending rift basins formed during the early stages of Antarctica/Zealandia rifting. Extension is minor, as rifting jumped north of Thurston Island early in the rifting process. The Amundsen Sea Embayment continental shelf west of the rifted terrain is underlain by a deeper, more extensive sedimentary basin also formed during rifting between Antarctica and Zealandia. A well-defined boundary zone separates the mildly extended Abbot extensional terrain from the deeper Amundsen Embayment shelf basin. The shelf basin has an extension factor, , of 1.5-1.7 with 80-100 km of extension occurring across an area now 250 km wide. Following this extension, rifting centered north of the present shelf edge and proceeded to continental rupture. Since then, the Amundsen Embayment continental shelf appears to have been tectonically quiescent and shaped by subsidence, sedimentation, and the advance and retreat of the West Antarctic Ice Sheet. The Bellingshausen Plate was located seaward of the Amundsen Sea margin prior to incorporation into the Antarctic Plate at about 62 Ma. During the latter part of its independent existence, Bellingshausen plate motion had a clockwise rotational component relative to Antarctica producing convergence across the north-south trending Bellingshausen Gravity Anomaly structure at 94°W and compressive deformation on the continental slope between 94°W and 102°W. Farther west, the relative motion was extensional along an east-west trending zone occupied by the Marie Byrd Seamounts.
Abbot Ice Shelf is underlain by E-W rift basins created at ∼90 Ma Amundsen shelf shaped by subsidence, sedimentation, and passage of the ice sheet Bellingshausen plate boundary is located near the base of continental slope and rise.
美国国家航空航天局冰桥行动在西南极洲阿伯特冰架上空进行的机载重力反演以确定冰下地形，定义了一个伸展地形，该地形由南极/西兰迪亚裂谷早期形成的东西向裂谷盆地组成。伸展作用较小，因为在裂谷作用早期裂谷作用就跳过了瑟斯顿岛以北地区。裂谷地形以西的阿蒙森海盆大陆架之下是一个更深、更广阔的沉积盆地，该盆地也是在南极和西兰迪亚裂谷作用期间形成的。一个界限分明的边界带将轻度伸展的阿伯特伸展地形与更深的阿蒙森海盆陆架盆地分隔开来。陆架盆地的伸展因子为1.5 - 1.7，在现在宽250千米的区域内发生了80 - 100千米的伸展。这次伸展之后，裂谷作用以当前陆架边缘以北为中心并导致大陆破裂。从那时起，阿蒙森海盆大陆架似乎一直处于构造静止状态，并受到沉降、沉积以及西南极冰盖进退的影响。在大约6200万年前并入南极板块之前，别林斯高晋板块位于阿蒙森海边缘的海侧。在其独立存在的后期，别林斯高晋板块相对于南极的运动具有顺时针旋转分量，在西经94°处产生了南北向别林斯高晋重力异常结构上的汇聚以及西经94°至102°之间大陆坡上的压缩变形。在更西边，相对运动是沿着玛丽·伯德海山所在的东西向地带的伸展运动。
阿伯特冰架之下是约9000万年前形成的东西向裂谷盆地；阿蒙森陆架受沉降、沉积和冰盖作用影响；别林斯高晋板块边界位于大陆坡和大陆隆的底部附近。
