Paleomagnetism of Early Cretaceous Pacific Seamounts

该奖项将支持德克萨斯农工大学的Sager博士参与一项关于日本海沟和夏威夷群岛之间的古土的形态、沉积历史和地球化学的研究。太平洋的这一地区被认为是独一无二的，其特点是在白垩纪广泛的火山活动期间开始形成许多海山链、环礁和古尤群。在“托马斯·华盛顿”号上的一个实地项目中，将收集的数据包括反射地震剖面、单个地层的重力和磁力，以及这些特征的采样。这些数据将用于研究火山活动的年龄序列、白垩纪太平洋板块运动、岩石圈弯曲和弹性/热厚度、火山的地球化学亲缘性和地幔来源、海山古纬度、盖特礁盖的厚度和内部地层学以及礁淹没的时间和原因等问题。这些数据将被用来检验这样一个假设，即在白垩纪时期，海底山链的“达尔文带”的西北端是由地幔和薄而热的岩石圈构成的，而这些岩石圈现在位于活跃的“达尔文带”的东南部分。这是一个合作项目，涉及斯克里普斯研究所、德克萨斯农工大学和麻省理工学院的科学家。该项目的数据对于规划该地区未来的海洋钻探非常重要。

This award will support Dr. Sager of Texas A & M university to participate in a study of the morphology, sediment history, and geochemistry of guyots which are located between the Japan Trench and the Hawaiian Islands. This area of the Pacific Ocean is known to be unique and is characterized by numerous seamount chains, atolls and guyot groups which began forming during a Cretaceous period of extensive volcanism. Data to be collected during a field program aboard the Thomas Washington include reflection seismic profiles, gravity and magnetics across individual guyots as well as sampling of these features. These data will be used to examine questions on the age sequences of volcanism, Cretaceous Pacific Plate motions, lithosphere flexuring and elastic/thermal thickness, geochemical affinities and mantle sources of volcanics, seamount paleolatitudes, thickness and internal stratigraphy of guyot reef caps, and the timing and causes of reef drowning. These data will be used to examine the hypothesis that the older northwest end of this "Darwin Belt" of seamount chains was underlain in Cretaceous times by the type of mantle and thin, hot lithosphere that now underlies the active, southeast part of the belt. This is a cooperative project involving scientist at Scripps Institution, Texas A & M University and the Massachusetts Institute of Technology. Data from this project will be important in planning future ocean drilling in this region.