Collaborative Research: Os, Nd and Hf isotopes in abyssal peridotites from Arctic Lena Trough: Continental lithospheric or asthenospheric mantle origin?

（0648567/0648409 Snow/Lassiter）智力优势：本研究旨在利用超镁质海洋基底岩石的地球化学特征来了解大陆分裂的原因。在最近前往勒拿海槽的游轮上收集的岩石将被分析和解释。勒拿海槽是北大西洋/北极分隔欧洲和北美大陆边缘的一个年轻裂谷带。从岩浆裂谷的橄榄岩幔岩中分离出的矿物将进行放射性同位素Os、Re、Nd和Hf的分析，以检验莱拿海槽基底是软流圈成因还是大陆岩石圈成因。如果岩石具有次大陆源，则同位素应显示非常低的Os同位素比率和分散的Nd和Hf值。年轻的软流圈起源将反映在Nd和Hf模式年龄和Os同位素组成中，它们与世界范围内深海橄榄岩的平均值相匹配。更广泛的影响：该项目通过支持两个机构的新实验室和设备，加强了科学基础设施。它还开发了一种通过直接注入测量Os同位素的新技术，改进了以前的喷射方法。这项工作将使本科生接触研究并培养研究生。我们将努力从一个在科学领域代表性不足的群体中招收研究生。

(0648567/0648409 Snow/Lassiter)Intellectual Merit: This research seeks to use geochemical signatures in ultramafic ocean-basement rocks to understand the cause of continental breakups. Rocks collected on recent cruises to the Lena Trough, a young rift zone in the North Atlantic/Arctic separating the continental margins of European and North America will be analyzed and interpreted. Mineral separates from peridotitic mantle rocks from this amagmatic rift will be analyzed for the radiogenic isotopes Os, Re, Nd, and Hf to test whether there is an asthenospheric or continental lithospheric origin for the Lena Trough basement. If the rocks have a subcontinental source, the isotopes should show very low Os isotope ratios and scattered Nd and Hf values. Young asthenospheric origins will be reflected in uniformly young Nd and Hf model ages and Os isotopic compositions that match the average worldwide abyssal peridotite value.Broader Impacts: The project enhances the infrastructure for science by supporting new laboratories and equipment at two institutions. It also develops a new technique to measure Os isotopes via direct injection which improves on previous sparging methods. The work will expose undergraduates to research and train a graduate student. Efforts will be made to recruit try and recruit the graduate student from a group under-represented in the sciences.