Neogene record of Antarctic Peninsula glaciation in continental rise sediments: ODP Leg 178, Site 1095
Neogene record of Antarctic Peninsula glaciation in continental rise sediments: ODP Leg 178, Site 1095
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大陆隆起沉积物中南极半岛冰川作用的新近纪记录：ODP Leg 178，Site 1095
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发表时间：
2002
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影响因子：
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通讯作者：
C. Pudsey
中科院分区：
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作者：
C. Pudsey
1095号地点是大洋钻探计划第178段期间钻探的三个大陆隆起地点中最远的一个。一段长(600米)的近连续剖面从全新世一直延伸到近10 Ma的沉积物，由细粒浊积岩、半长角砾岩和泥质等深岩组成。
剖面上部300m的沉积相、物性、成分、粒度等均表现出米级岩性旋回性，代表0~7 Ma。沉积物中的硅藻含量表明，只有在
更新世。细小的颗粒大小意味着，在过去的7英里内，海底洋流从未明显比现在更强。冰筏碎片的存在意味着南极半岛在“温暖的上新世”(3.2-4.5 Ma)期间没有任何重要的冰川消融。间歇性地向隆起供应细小的陆源沉积物与已发表的沉积模型一致，这些沉积模型表明冰川时期冰盖固定在陆架边缘。在某些时候，特别是在
晚中新世，与海底航道转换和瓣叶进积有关的过程可能掩盖了该地点沉积的气候控制。
Site 1095 is the most distal of three continental rise sites drilled during Ocean Drilling Program Leg 178. A long (600 m), near-continuous section extends from the Holocene down to nearly 10-Ma sediments, comprising fine-grained turbidites, hemipelagites, and muddy contourites.
Meter-scale lithologic cyclicity is seen in sediment facies, physical properties, composition, and grain size in the upper 300 m of the section, representing 0–7 Ma. The diatom content of the sediments suggests sea ice was a significant limitation on productivity only during the
Pleistocene. Fine grain size implies that bottom currents were never significantly stronger that at present during the last 7 m.y. The presence of ice-rafted debris implies the Antarctic Peninsula was not deglaciated for any significant period during the “warm Pliocene” (3.2–4.5 Ma). Intermittent supply of fine terrigenous sediment to the rise is consistent with published depositional models showing the ice sheet grounded to the shelf edge during glacial periods. At some times, particularly during
the late Miocene, processes related to submarine channel switching and lobe progradation may have masked climatic control on deposition at this site.