Investigation of an Early Proterozoic Crustal Boundary Zone in Western Arizona

本文建议研究亚利桑那州西部早元古代地壳边界带的性质和成因。这项研究是一个合作项目，将涉及地质、地球化学和地质年代学研究，目标如下：1)亚利桑那州金曼附近重要的表壳-花岗岩组合的测绘和结构分析。2)典型表壳层序的岩性分析。3)变质火山岩的喷发方式和地球化学特征。4)变质沉积岩的野外、岩石学和地球化学研究。5)用不动元素比值来约束镁铁质火成岩地幔来源的组成。6)长英质火山岩和花岗岩(同构造期至后构造期)的锆石U-Pb定年。总而言之，这些研究结果应该为限制亚利桑那州西部早元古代序列的起源和构造背景，以及评估西南部这一地区可能存在的早元古代碰撞事件的存在、位置和时间提供有价值的数据基础。

It is herein proposed to investigate the nature and origin of an early Proterozoic crustal boundary zone in western Arizona. The research is a collaborative project that will involve geological, geochemical and geochronologic studies with the following objectives: 1) Mapping and structural analysis of important supracrustal- granitic associations near Kingman, AZ. 2) Lithologic analysis of representative supracrustal successions. 3) Characterization of metavolcanic rocks in terms of modes of eruption and geochemistry. 4) Field, petrographic, and geochemical studies of metasedimentary rocks. 5) Use of immobile element ratios to constrain the composition of the mantle sources of mafic igneous rocks. 6) Selected U-Pb zircon dating of felsic volcanic and granitic rocks (syn-to post-tectonic). Collectively, results from these studies should provide a valuable data base to constrain the origin and tectonic setting of early Proterozoic successions in western Arizona, and to evaluate the existence, location and timing of a possible early Proterozoic collisional event in this part of the Southwest.