U.S.-China Cooperative Research (Geochemistry): U-disequili-bria in Northeast Asian Alkali Basalts.

这项为期两年的合作研究项目的目标是， 詹姆斯吉尔，加州大学，圣克鲁斯和梁 中国科学院地球化学研究所周成是 开展东北亚碱金属铀钍不平衡研究 玄武岩 调查人员将集中研究来自于 265年前中国北方的火山爆发。 通过 放射性同位素研究，研究人员将确定 中国玄武岩的来源，研究化学分馏过程中， 玄武岩的成因并确定样品的年龄。 铀钍不平衡 研究是研究火山岩起源的有用工具， 地幔的组成和形成地幔的过程 异质性 美国--中国的合作在几个方面都很重要。 U 不平衡研究需要“年轻”的岩石， 都能接触到中国的独家消息来源 分析将 在美国和中国的实验室进行， 实验室间样品校准。 研究成果将 进一步了解最近火山爆发的性质， 东北亚（日本、韩国和中国）及其与构造的耦合 该地区的活动。 共同努力，相辅相成 中国和美国实验室的设施满足了 美国的主要目标-中国计划;也就是说， 通过国际合作获取科学知识。

The objective of this two-year cooperative research project between James Gill, University of California, Santa Cruz and Liang Zhoucheng, Chinese Academy of Sciences' Institute of Geochemistry is to perform U Th disequilibrium studies of Northeast Asian alkali basalts. The investigators will concentrate on "young" basalts from volcanic eruptions in Northern China 265 years ago. Through radioactive isotopic studies the investigators will determine the source of the Chinese basalts, study chemical fractionation during basalt genesis and date the age of the samples. U Th disequilbrium studies are useful tools for studying the origins of volcanic rocks, composition of the earth's mantle and the processes causing mantle heterogeneities. The U.S.-China collaboration is significant in several respects. U Th disequilbrium studies require "young" rocks and the investigators will have access to a unique source in China. Analysis will be performed in both U.S. and Chinese laboratories thereby enabling inter-laboratory calibration of samples. Research results will advance understanding of the nature of recent volcanic eruptions in northeast Asia (Japan, Korea and China) and its coupling to tectonic activities in this region. The combined efforts, complementary facilities of the Chinese and U.S. laboratories fulfill the principal objective of the U.S.-China program; which is, to advance scientific knowledge through international collaboration.