Collaborative Research: High Field Strength Elements and Hf-Nd Isotope Systematics in Aleutian Lavas: Implications for Conservative Element Behavior in Subduction Zones

本文对阿留申岛弧火山岩中的高场强元素（Ti，Ta，Nb，Zr，Hf）和Lu-Hf同位素体系进行了研究。这项研究的主要目的是限制HFSE和相关的稀土元素行为在俯冲带的细节。具体来说，这项研究将评估的条件下，HFSE表现保守与非保守俯冲岩浆成因。将测量从沿着阿留申岛弧全长收集的熔岩中的高场强元素丰度和Hf-Nd同位素。分析方法将包括（1）在钢夹套Teflon容器中溶解样品;（2）用混合的94 Zr、176 Lu、180 Hf、180 Ta加标物加标样品;（3）用离子交换化学分离感兴趣的元素;以及（4）在多收集器ICP质谱仪上通过同位素稀释分析样品。这项研究将记录阿留申HFSE和Hf同位素地球化学的沿弧和跨弧变化。有据可查的物理条件的变化沿着弧，特别是推断的相对温度的俯冲板块和地幔楔在东部与西部阿留申群岛，和俯冲沉积物的存在或不存在的地幔源下的弧的不同部分，将提供解释所观察到的HFSE和Hf同位素变化的地质背景。

Yogodzinski EAR-0230145This is a study of high field strength element (HFSE; Ti, Ta, Nb, Zr, Hf) and Lu-Hf isotopic systematics in volcanic rocks of the Aleutian island arc. The main objective of the study is to constrain the details of HFSE and related rare-earth element behavior in subduction zones. Specifically, the study will evaluate the conditions under-which HFSE behave conservatively versus non-conservatively during subduction magma genesis. High field strength element abundances and Hf-Nd isotopes will be measured in lavas collected from along the full length of the oceanic Aleutian arc. The analytical approach will involve (1) dissolution of samples in steel-jacketed Teflon vessels; (2) spiking of samples with a mixed 94Zr, 176Lu, 180Hf, 180Ta spike; (3) separation of elements of interest with ion-exchange chemistry; and (4) analysis of samples by isotope dilution on a multi-collector ICP mass spectrometer. This study will document along-arc and cross-arc changes in Aleutian HFSE and Hf isotope geochemistry. Well-documented changes in physical conditions along the arc, in particular the inferred relative temperature of the subducting plate and mantle wedge in the eastern versus western Aleutians, and the presence or absence of subducted sediment in the mantle source beneath different parts of the arc, will provide the geologic context for interpreting the observed HFSE and Hf isotopic variation.