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.

该项目的目的是测试弧形碰撞事件是否修改了Timor岛作为测试案例的总体收敛率。东帝汶的山区岛揭露了典型的弧形碰撞的构造 - 地层截面，并带有来自覆盖的亚洲海洋/弧形板的元素，高压/低温变态岩石的楔形物和下层层状的澳大利亚大陆源自源自源质量序列。将产生岛上的准确地质图，描述岩石类型和结构的分布，这将构成平衡结构横截面的基础，而碰撞期间将其用于量化一旦沉积在边缘上的沉积岩石的数量。缩短的大小应与已俯冲的大陆壳量相关。古磁分析用于确定地层的古显着性，旋转和年龄。高温和低温热量数据将记录挖掘的幅度，变化和时机。在识别板构造的识别后，引入了威尔逊周期，以描述海洋盆地的创造和灭亡。最初的四个阶段？大陆裂谷，海底蔓延和形成海盆，通过俯冲的海洋岩石圈俯冲闭合海盆以及大陆碰撞 - 仍然是我们对构造过程的理解的基本基础。弧形碰撞标志着海洋内俯冲带的最终灭亡，是海洋闭合期间的常见现象。 通常假定浮力抑制了海洋岛弧下的大陆物质的明显不足，但大陆俯冲的幅度仍然不受限制。该项目将对已俯冲的大陆地壳大小提供估计，结果对地幔化学和动力学具有重要意义。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以及对美国和国际学生的培训的重要合作。