Collaborative Research: Australia Down Under: Quantification of Rates and Amount of Continental Subduction During Neogene Arc-continent Collision on Timor

合作研究：澳大利亚：帝汶新近纪弧大陆碰撞期间大陆俯冲速率和量的量化

• 批准号: 0948449
• 负责人: Nadine McQuarrie
• 金额: $ 33.24万
• 依托单位: Princeton University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-15 至 2011-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0948449&HistoricalAwards=false
• 关键词: Collaborative; Research; Australia; Down; Under

The objective of this project is to test whether arc-continent collision events modify overall convergence rates, with the island of Timor as test-case. The mountainous island of Timor exposes a tectono-stratigraphic section of a typical arc-continent collision, with elements from the overriding Asian oceanic/arc plate, a wedge of high pressure/low temperature metamorphic rocks and an underlying deformed Australian continental passive margin sedimentary sequence. An accurate geologic map of the Island, which describes the distribution of rock types and structures, will be produced that will form the basis for balanced structural cross-sections, which, in turn, will be used to quantify how much the sedimentary rocks once deposited on the margin have been telescoped during collision. The magnitude of shortening should correlate with the amount of continental crust that has been subducted. Paleomagnetic analysis is used to determine paleolatitude, rotation, and age of strata. High- to low-temperature thermochronologic data will document the magnitude, variability, and timing of exhumation.Shortly after the recognition of plate tectonics, the Wilson cycle was introduced in order to describe the creation and demise of ocean basins. The original four stages ? continental rifting, seafloor spreading and formation of ocean basins, closure of ocean basins by subduction of oceanic lithosphere, and continent-continent collision - still form a fundamental basis for our understanding of tectonic processes. Arc-continent collision marks the ultimate demise of an intra-oceanic subduction zone and is a common phenomenon during ocean closure. It is usually assumed that significant underthrusting of continental material under an oceanic island arc is inhibited by buoyancy but the magnitude of continental subduction remains unconstrained. This project will provide an estimate for the magnitude of continental crust that has been subducted, results that would have important implications for mantle chemistry and dynamics. The project involves a significant collaboration with researchers from Norway, Swiss, Australia, and Indonesia as well as training of U.S. and international students.

该项目的目的是以帝汶岛为测试案例，测试弧陆碰撞事件是否改变了总体收敛速度。多山的帝汶岛暴露出典型的弧陆碰撞的构造地层段，元素来自俯冲的亚洲大洋/弧板、高压/低温变质岩楔形和下伏变形的澳大利亚大陆被动边缘沉积序列。将制作一张准确的岛屿地质图，其中描述了岩石类型和结构的分布，这将成为平衡结构横截面的基础，而这些横截面又将被用来量化一旦沉积在边缘的沉积岩在碰撞期间被伸缩了多少。缩短的幅度应该与被俯冲的大陆地壳的数量相关。古地磁分析用于确定地层的古纬度、旋转度和年龄。从高温到低温的热年代学数据将记录出土作用的规模、变异性和时间。在认识到板块构造后不久，威尔逊旋回被引入以描述洋盆的产生和消亡。最初的四个阶段？大陆裂谷作用、海底扩张和大洋盆地的形成、大洋岩石圈俯冲造成的洋盆闭合以及大陆-大陆碰撞--仍然是我们理解构造过程的基本基础。弧陆碰撞标志着大洋内部俯冲带的最终消亡，是海洋闭合过程中的一种常见现象。通常认为，在大洋岛弧之下，大陆物质的显著俯冲受到浮力的抑制，但大陆俯冲的幅度仍然不受限制。该项目将对已被俯冲的大陆地壳的规模进行估计，这一结果将对地幔化学和动力学产生重要影响。该项目涉及与挪威、瑞士、澳大利亚和印度尼西亚的研究人员的重大合作，以及对美国和国际学生的培训。