Provenance of Pleistocene sediments in the ANDRILL AND-1B drillcore: Clay and heavy mineral data
Provenance of Pleistocene sediments in the ANDRILL AND-1B drillcore: Clay and heavy mineral data
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ANDRILL AND-1B 钻芯中更新世沉积物的来源：粘土和重矿物数据
DOI：
10.1016/j.gloplacha.2009.03.018
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发表时间：
2009
影响因子：
3.9
通讯作者：
A. Zeoli
中科院分区：
文献类型：
--
作者：
G. Giorgetti;F. Talarico;S. Sandroni;A. Zeoli
麦克默多海峡地区的冰冻圈在过去 1 Ma 中经历了重大变化。因此，现代麦克默多冰架下方的沉积序列提供了地质数据，以重建由于冰期和间冰期期间冰盖延伸、接地线位置和主要冰流流动方向的变化而导致的陆源物质运输和沉积机制的变化。本研究旨在调查在 Windless Bight（罗斯岛南部）的 ANDRILL-McMurdo 冰架项目中回收的晚更新世冰下和冰海沉积物中的粘土和重矿物组合。分析表明，沉积物是来自南部和西部的麦克默多火山群（MVG）和横贯南极山脉（TAM）的碎屑的混合物。 MVG 衍生矿物优于 TAM 衍生矿物。岩心下矿物学变化是由烃源岩和沉积过程的变化决定的。钻探现场的沉积物受到来自南方的冰的滋养，这些冰从麦克默多火山地区带来了岩石；大量混积岩中 TAM 成分的富集证明冰盖收集了来自横贯南极山脉的碎片。当开放的海洋条件占主导地位时，只有来自当地的沉积物（即麦克默多火山岩）沉积下来。
The cryosphere in the McMurdo Sound region has undergone significant modifications during the last 1 Ma. Consequently, the sedimentary sequences underlying the modern McMurdo Ice-Shelf provide geological data to reconstruct variations in transport and depositional mechanisms of terrigenous material due to variations in ice sheet extension, grounding line position and main ice-stream flow directions during glacial and interglacial periods. The present study aims to investigate the clay and heavy mineral assemblages of the late Pleistocene subglacial and glaciomarine sediments recovered during the ANDRILL-McMurdo Ice Shelf Project in Windless Bight (South of Ross Island). The analyses show that the sediments are a mix of detritus from the McMurdo Volcanic Group (MVG) and the Transantarctic Mountains (TAM) from the south and west. MVG-derived minerals prevail with respect to TAM-derived minerals. The down-core mineralogical variations are determined by changes in the source rocks and the sedimentary processes. Sediments at the drill site are nourished by ice coming from the South which delivered rocks from the McMurdo Volcanic region; the enrichment of a TAM component in massive diamictites testifies that the ice sheet collected debris from the Transantarctic Mountains. When open marine conditions prevailed, only sediments from a local source (i.e. McMurdo volcanics) were deposited.