Early glaciation already during the Early Miocene in the Amundsen Sea, Southern Pacific: Indications from the distribution of sedimentary sequences
Early glaciation already during the Early Miocene in the Amundsen Sea, Southern Pacific: Indications from the distribution of sedimentary sequences
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南太平洋阿蒙森海早中新世时期的早期冰川作用：沉积层序分布的迹象
DOI：
10.1016/j.gloplacha.2014.06.004
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发表时间：
2014
影响因子：
3.9
通讯作者：
K. Gohl
中科院分区：
文献类型：
--
作者：
G. Uenzelmann‐Neben;K. Gohl
在南极大陆斜坡和隆起上观测到的地震地层序列的分布和内部结构是底流和冰盖的沉积物搬运和沉积的结果。通过分析地震反射数据，可以重建沉积物输入和沉积物迁移模式，并推断过去的气候和海洋学变化。我们观察到四个地震地层单位，它们的沉积中心的位置和形状有明显的差异，并以不同的沉积速率积累。我们使用了一个年龄-深度模型的基础上DSDP腿35站点324的Plio/更新世和地震反射特性的相关性从罗斯和别林斯高晋海，不幸的是有很大的不确定性。对于21 Ma之前的时期，我们解释了低能量输入的碎屑通过一个古三角洲起源于阿蒙森海大陆架的一个地区，其中一个古冰流槽（松岛槽东，PITE）位于今天，和沉积这种材料的海冰覆盖下的大陆隆起。在21-14.1 Ma期间，我们假设西南极洲这一部分的腹地发生了冰川侵蚀，这导致了更大的沉积中心和大量运输沉积物的增加。在中新世中期气候最适期的变暖导致了多温冰盖，并导致了较高的沉积物供应沿着一个广泛的前沿，但重点是通过两个古冰流槽，PITE和Abbot槽（AT）。大部分的冰川碎屑被运送到东部阿蒙森海隆，在那里它被再循环的底流塑造成堤坝漂流。14 Ma后气候变冷开始后，深海沉积物积累减少，表明沉积物供应减少，这可能是由于冰盖变冷变干。4 Ma以来的动态冰盖主要通过AT和松岛槽西（PITW）向近海输送物质。这一冰川碎屑与西向底流的相互作用导致阿蒙森海东部和中部堤坝漂移的持续形成。
The distribution and internal architecture of seismostratigraphic sequences observed on the Antarctic continental slope and rise are results of sediment transport and deposition by bottom currents and ice sheets. Analysis of seismic reflection data allows to reconstruct sediment input and sediment transport patterns and to infer past changes in climate and oceanography. We observe four seismostratigraphic units which show distinct differences in location and shape of their depocentres and which accumulated at variable sedimentation rates. We used an age–depth model based on DSDP Leg 35 Site 324 for the Plio/Pleistocene and a correlation with seismic reflection characteristics from the Ross and Bellingshausen Seas, which unfortunately has large uncertainties. For the period before 21 Ma, we interpret low energy input of detritus via a palaeo-delta originating in an area of the Amundsen Sea shelf, where a palaeo-ice stream trough (Pine Island Trough East, PITE) is located today, and deposition of this material on the continental rise under sea ice coverage. For the period 21–14.1 Ma we postulate glacial erosion for the hinterland of this part of West Antarctica, which resulted in a larger depocentre and an increase in mass transport deposits. Warming during the Mid Miocene Climatic Optimum resulted in a polythermal ice sheet and led to a higher sediment supply along a broad front but with a focus via two palaeo-ice stream troughs, PITE and Abbot Trough (AT). Most of the glaciogenic debris was transported onto the eastern Amundsen Sea rise where it was shaped into levee-drifts by a re-circulating bottom current. A reduced sediment accumulation in the deep-sea subsequent to the onset of climatic cooling after 14 Ma indicates a reduced sediment supply probably in response to a colder and drier ice sheet. A dynamic ice sheet since 4 Ma delivered material offshore mainly via AT and Pine Island Trough West (PITW). Interaction of this glaciogenic detritus with a west-setting bottom current resulted in the continued formation of levee-drifts in the eastern and central Amundsen Sea.
影响因子：
12.1
作者：
Livingstone, Stephen J.;Cofaigh, Colm O.;Jamieson, Stewart S. R.
通讯作者：
Jamieson, Stewart S. R.
影响因子：
64.8
作者：
Naish, T.;Powell, R.;Williams, T.
通讯作者：
Williams, T.