Collaborative Research: ST. Elias Erosion/tectonics Project (STEEP)

合作研究：ST。

• 批准号: 0409162
• 负责人: Peter Koons
• 金额: $ 29.86万
• 依托单位: University of Maine
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-15 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0409162&HistoricalAwards=false
• 关键词: Collaborative; Research; ST.; Elias; Erosion

0409162KoonsThis is a multi-disciplinary study to address the evolution of the highest coastal mountain range on Earth - the St. Elias Mountains of southern Alaska and northwestern Canada. This orogen has developed over the past few million years as the Yakutat block, a continental-oceanic terrane, has attempted subduction beneath the eastern end of the Aleutian arc-trench system. The ~500 km-long, 150 km-wide St. Elias mountain range is the product of the dynamic balance between rapid uplift induced by crustal convergence and rapid exhumation by a regional system of large, fast-moving temperate glaciers. Most sediments are deposited either on a broad shelf or in deepsea fans and provide a complete record of the tectonic, climatic, erosional, and eustatic events that have accompanied the orogeny. The overarching goal of the project is to develop a comprehensive model for the St. Elias orogen that accounts for the interaction of regional plate tectonic processes, structural development, and rapid erosion. The focus of the study is on the partitioning of deformation within the system from upper mantle flow to near-surface faulting and exhumation. The study will investigate the geodynamics of oblique collision under a set of conditions that will allow the PIs to address several important and fundamental questions:- Has intense Quaternary glacial erosion redistributed mass in the orogen sufficiently to change regional deformational patterns, and has focused erosion along deep glacial valleys been sufficient to localize crustal strains?- How is deformation partitioned into lithospheric shortening and uplift versus lateral extrusion of the detached crust, and does intense erosion influence this partitioning?- Is the orogeny driven primarily by subduction of a buoyant oceanic plateau or by collision of a small microcontinental block attached to allochthonous ocean crust?Addressing these questions has broad implications for understanding the geodynamics of oblique collision in general, the role of different mechanisms in development of far-field orogenic effects, and the control of erosion on development of slip partitioning during oblique convergence. The project also has general implications for how subduction/accretion of small continental terranes versus oceanic plateaus contribute to deformation of the continents, and ultimately the fate of these fragments in construction of the crustal collage which is typical of virtually all continents. Specifically, the P.I.s propose a multidisciplinary approach involving seismologists (subsurface imaging and seismicity), geologists, geodesists, glaciologists, geochronologists, and geodynamic modelers.

0409162Koons这是一项多学科研究，旨在解决地球上最高的沿海山脉——阿拉斯加南部和加拿大西北部的圣埃利亚斯山脉的演化问题。 随着雅库塔地块（一个大陆-海洋地体）试图俯冲到阿留申弧海沟系统东端之下，造山带在过去的几百万年里不断发展。 圣埃利亚斯山脉长约 500 公里，宽 150 公里，是地壳汇聚引起的快速抬升与大型、快速移动的温带冰川区域系统快速折返之间动态平衡的产物。 大多数沉积物沉积在广阔的陆架上或深海扇中，提供了伴随造山运动的构造、气候、侵蚀和海平面上升事件的完整记录。 该项目的总体目标是开发一个圣埃利亚斯造山带的综合模型，解释区域板块构造过程、结构发展和快速侵蚀的相互作用。 研究的重点是系统内变形的划分，从上地幔流动到近地表断层和折返。 该研究将调查一系列条件下倾斜碰撞的地球动力学，这将使 PI 能够解决几个重要和基本的问题：- 强烈的第四纪冰川侵蚀在造山带中重新分布质量，足以改变区域变形模式，并且沿着深冰河谷足以定位地壳应变？-变形如何划分为岩石圈缩短和隆起与分离地壳的横向挤压，强烈的侵蚀是否影响这种划分？-造山运动主要是由浮力海洋高原的俯冲驱动的还是由附着在异地洋壳上的小型微大陆块的碰撞驱动的？解决这些问题对于理解一般倾斜碰撞的地球动力学、不同机制在造山运动发展中的作用具有广泛的意义。远场造山效应，以及倾斜收敛过程中侵蚀对滑移分区发展的控制。 该项目还对小型大陆地体相对于海洋高原的俯冲/增生如何导致大陆变形，以及最终这些碎片在几乎所有大陆典型的地壳拼贴构造中的命运具有一般意义。 具体来说，PI 提出了一种多学科方法，涉及地震学家（地下成像和地震活动）、地质学家、大地测量学家、冰川学家、地质年代学家和地球动力学建模师。