Crustal Formation and Assembly in the NW Pacific: Aleutians and Kamchatka

西北太平洋的地壳形成和组装：阿留申群岛和堪察加半岛

• 批准号: 9406195
• 负责人: Robert Kay
• 金额: $ 5.38万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-08-15 至 1996-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9406195&HistoricalAwards=false
• 关键词: Crustal; Formation; Assembly; NW; Pacific

9406195 Kay Throughout Tertiary time, Kamchatka has collected fragments of continental crust (terranes) that formed as oceanic island arcs and plateaus in the Bering Sea and the Pacific Ocean. Accretion of the fragments has resulted in a subcontinental mass. The process is thought by many to be the main mechanism of present day continental growth. Kamchatka is a particularly good site to study this type of continental growth due to its youth, due to the availability of information on similar but as yet unaccreted oceanic fragments (especially, the Aleutian islands) and due to widespread post-accretion magmatism that records conditions at depth. This investigation focuses on alkaline basaltic magmas that originate in mantle that lies under the Kamchatka terranes. Existing trace element data on these magmas lack typical signatures (e.g. high Ba/La, La/Ta ratios), and support delamination models that call fro wholesale replacement of mantle lithosphere by underlying Oceanic Island Basalt (OIB)-like asthenosphere. Isotope analyses (Pb, Sr, Nd) as well as additional trace element analyses will permit identification of mas reservoirs and quantification of mas fluxes related to fundamental processes of crustal growth and consolidation.

9406195 KAY在整个第三纪期间，Kamchatka都收集了大陆壳（地层）的碎片，这些碎片在白令海和太平洋中形成为海洋岛弧和高原。 碎片的积聚导致了次大质量。 许多人认为这一过程是当今大陆生长的主要机制。 坎奇特卡（Kamchatka）是一个特别好的网站，该地点由于其年轻而研究这种类型的大陆生长，这是因为有关相似但尚未确切的海洋碎片（尤其是阿留申群岛）的信息，并且由于经过广泛的后质量岩浆作用，记录了深度条件。 这项调查着重于碱性岩浆，该岩浆岩石起源于坎奇特卡人地下室的地幔。 这些岩浆上的现有痕量元素数据缺乏典型的特征（例如高BA/LA，LA/TA比），并且支持分层模型，这些模型可以通过基础海洋岛玄武岩（OIB）（OIB）（类似于Atthenosphere）来调用地幔岩石圈的批发批发。 同位素分析（PB，SR，ND）以及其他痕量元素分析将允许识别MAS储层以及对与地壳生长和巩固基本过程相关的MAS通量的量化。