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首页> 外文期刊>Geochemistry, geophysics, geosystems >Preglacial to glacial sediment thickness grids for the Southern Pacific Margin of West Antarctica
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Preglacial to glacial sediment thickness grids for the Southern Pacific Margin of West Antarctica

机译：西南极南太平洋边缘的冰川至冰川沉积物厚度网格

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摘要

Circum-Antarctic sediment thickness grids provide constraints for basin evolution and paleotopographic reconstructions, which are important for paleo-ice sheet formation histories. By compiling old and new seismic data, we identify sequences representing preglacial, transitional, and full glacial deposition processes along the Pacific margin of West Antarctica. The preglacial sediment grid depicts 1.3-4.0 km thick depocenters, relatively evenly distributed along the margin. The depocenters change markedly in the transitional phase at, or after, the Eocene/Oligocene boundary when the first major ice sheets reached the shelf. Full glacial sequences, starting in the middle Miocene, indicate new depocenter formation North of the Amundsen Sea Embayment and localized eastward shifts in the Bellingshausen Sea and Antarctic Peninsula basins. Using present-day drainage paths and source areas on the continent, our calculations indicate that an estimated observed total sedimentary volume of similar to 10 x 10(6) km(3) was eroded from West Antarctica since the separation of New Zealand in the Late Cretaceous. Of this, 4.9 x 10(6) km(3) predates the onset of glaciation and need to be considered for a 34 Ma paleotopography reconstruction. Whereas 5.1 x 10(6) km(3) postdates the onset of glaciation, of which 2.5 x 10(6) km(3) were deposited in post mid-Miocene full glacial conditions.
机译：南极洲周围的沉积物厚度网格为盆地演化和古地形重建提供了限制，这对于古冰片形成的历史非常重要。通过汇总新旧地震数据，我们确定了代表南极西部太平洋边缘冰川前，过渡和完整冰川沉积过程的序列。冰川前沉积物网格描述了1.3-4.0 km厚的沉积中心，沿边缘相对均匀地分布。当第一大冰盖到达陆架时，在始新世/渐新世边界或之后的过渡阶段，沉积中心的变化明显。从中新世中期开始的完整冰川序列表明，在阿蒙森海蕴藏以北有新的沉积中心形成，并在贝灵斯豪森海和南极半岛盆地发生了局部的东移。使用当今大陆上的排水路径和源区，我们的计算表明，自从新西兰在后期分离以来，估计的观测到的总沉积量已从西南极洲侵蚀了约10 x 10（6）km（3）。白垩纪。其中，4.9 x 10（6）km（3）早于冰川期，需要考虑进行34 Ma的古地形重建。尽管有5.1 x 10（6）km（3）距冰期开始时间较晚，但其中有2.5 x 10（6）km（3）距中新世中期冰川期较晚。

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