Collaborative Research: Investigation of Syncollisional Extension and Basin Development in the High Himalaya

合作研究：喜马拉雅高山同步碰撞伸展和盆地发育调查

• 批准号: 0438826
• 负责人: Michael Murphy
• 金额: --
• 依托单位: University of Houston
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-01 至 2009-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0438826&HistoricalAwards=false
• 关键词: Collaborative; Research; Investigation; Syncollisional; Extension

A team of scientists from the University of Arizona and the University of Houston are investigating the nature of the transition from contraction to extension in the Zada basin area of the Himalayan uplift. The Zada basin is the largest late Tertiary basin in the Himalaya and is broadly constrained to be Late Miocene to Pleistocene in age. The basin fill and its underlying basement are spectacularly exposed owing to incision by the Sutlej River, a major southward-flowing trans-Himalayan drainage. The basin currently lies at approximately 3500 m elevation in the hinterland of the Himalayan thrust belt and developed on top of a regionally extensive Early to Middle Miocene thrust system. The thrust system flanks a second major basin, the Kailas basin, which is considered to have developed during mid-Tertiary time, but remains poorly dated. Together, the Zada and Kailas basins archive the collapse of this region from high to relatively low elevation and the transition from erosional denudation to thick sediment accumulation in only a few million years. The multidisciplinary study is using structural analysis, thermobarometry, argon-argon thermochronology, basin analysis, and oxygen isotope paleoaltimetry to place constraints on: (1) geometry, kinematics, and magnitude of slip of the Qusum detachment, South Tibetan Detachment, and Great Counter thrusts; (2) provenance and subsidence history of the Kailas thrust basin and Zada basin; (3) paleoelevation history of the Zada basin; (4) pressure-temperature-time paths recorded in the rocks exhumed by the major faults; and (5) the depth to which the major structures operated. Results are being used to determine the: (1) timing of onset of high-elevation extension in this part of the Himalaya; (2) mode of kinematic accommodation of extension in and around the Zada basin; (3) rates of arc-perpendicular and arc-parallel extension; (4) elevation at which extension began, and the evolution of paleoelevation and paleoenviornments of deposition in the Zada basin in response to ongoing extension; and (5) date at which the paleodrainage pattern in Zada basin become integrated into the headwaters of the modern Sutlej River. By answering these questions, three theories to explain the transition from arc-normal contraction and to arc-parallel extension in major orogenic belts are being tested: (1) extension occurs in regions of overthickened crust; (2) extension is due to outward expansion of the arc-shaped thrust front; or (3) extension is caused by extrusion of the middle crust. The project involves undergraduate and graduate students in the research, collaboration with Chinese scientists, and education and outreach efforts in both the United States and China.

亚利桑那大学和休斯敦大学的一组科学家正在调查喜马拉雅隆起的扎达盆地地区的过渡到扩展的过渡。 Zada盆地是喜马拉雅山中最大的晚期三级盆地，并且在年龄上被限制为中新世晚期。由于Sutlej River的切口，Sutlej River是一个主要的向南流动的Himalayan排水，因此盆地填充物及其基础地下室被突出暴露。目前，该盆地位于喜马拉雅推力带的腹地约3500 m海拔，并在中新世的早期至中期推力系统的顶部开发。推力系统是第二个主要盆地凯拉斯盆地的侧面，该盆地被认为是在三级时间中期开发的，但约会前期很差。扎达（Zada）和凯拉斯盆地（Zada and Kailas）盆地共同存档了该地区从高海拔地区的崩溃，以及仅在几百万年内从侵蚀性剥夺到厚厚的沉积物积累的过渡。多学科研究是使用结构分析，热压体法，氩 - 阿贡热量学，盆地分析和氧同位素古藻类法对以下约束进行约束：（1）几何，动力学，动力学和Qusum脱离的宽度，南藏藏族脱离的巨大元素，南方西藏分离和巨大的对抗； （2）凯拉斯推力盆地和扎达盆地的出处和沉降历史； （3）Zada Basin的古升历史； （4）在主要断层挖掘出的岩石中记录的压力温度路径； （5）主要结构运行的深度。结果用于确定：（1）在喜马拉雅山的这一部分中高海拔扩展的发作时间； （2）Zada盆地内外的运动学延伸方式的模式； （3）弧形和弧线平行延伸的速率； （4）延伸开始的高度，以及响应持续的延伸时，Zada盆地古征和古征的演变； （5）扎达盆地古植物模式被整合到现代Sutlej河上游的日期。通过回答这些问题，正在测试这些问题，以解释从弧线正常收缩和弧线平行延伸的过渡。 （2）延伸是由于弧形推力前向外膨胀；或（3）延伸是由中壳的挤出引起的。该项目涉及本科生和研究生参与研究，与中国科学家的合作以及在美国和中国的教育和外展工作。