Collaborative Research: Retreating-trench, Extension, and Accretion Tectonics (RETREAT): A Multidisciplinary Study of the Northern Apennines

合作研究：后退海沟、伸展和增生构造（RETREAT）：北亚平宁山脉的多学科研究

• 批准号: 0207980
• 负责人: Frank Pazzaglia
• 金额: $ 29.96万
• 依托单位: Lehigh University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-10-15 至 2008-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0207980&HistoricalAwards=false
• 关键词: Collaborative; Research; Retreating; trench; Extension

0207980PazzagliaThe paradox of how horizontal contraction and extension can occur simultaneously in convergent mountain belts remains a fundamental and largely unresolved problem in continental dynamics. The Apennines represent one of the most accessible "type locality" areas of syn-convergent extension. Rollback - which describes the tendency of a subducting plate to retreat from the orogenic front - is commonly invoked as an explanation for syn-convergent extension, but this idea does not address how the retrograde motion of the subducting plate, which is a mantle-based process, causes horizontal extension in the overlying zone of crustal convergence, especially in light of the large accretionary fluxes typically associated with continental subduction.The goal of the project (project RETREAT) is to develop a self-consistent dynamic model of syn-convergent extension, using the Northern Apennines as a natural laboratory. This part of the Apennine orogen has been the site of relatively steady orthogonal convergence and 2D (plane strain) orogenic deformation since ~30 Ma. GPS measurements indicate that convergence is presently active, and tomography indicates that the full length of subducted slab is still intact to depths of 250 km. Syn-convergent extension has been active since at least 15 Ma. The Northern Apennines are well studied, and all important features of the orogen are onland and thus directly accessible for detailed geological and geophysical research.The specific objectives of project RETREAT are 1) to determine in detail the velocity field across the orogen, including deformation in the orogenic wedge, the motion of lithospheric plates, and the flow fields in the surrounding asthenospheric mantle, and 2) to use this kinematic information to develop and test specific dynamic models for deformation in the orogenic wedge and underlying mantle. The research techniques to be used include; geodesy, tectonic geomorphology, low-temperature thermochronometry, structural geology and tectonic syntheses, seismic studies, and geodynamic modeling. The RETREAT project links together a broad multidisciplinary group with eleven PIs from six institutions, plus some 27 foreign collaborators in Italy, Switzerland, Canada, and France.***

0207980Pazzaglia悖论如何在融合山带中同时发生水平收缩和延伸仍然是大陆动力学中的基本且在很大程度上尚未解决的问题。亚平宁山脉代表了同步范围扩展最容易访问的“类型局部性”区域之一。 回滚 - 描述了俯冲板从造山学界撤退的趋势 - 通常被调用为合成范围扩展的解释，但是这个想法不能解决俯冲板的逆行运动如何，这是一种基于底漆的俯冲板的逆行运动过程，是在地壳收敛的上覆的区域中的水平扩展，尤其是鉴于通常与大陆俯冲相关的大吸积通量。 ，使用北部亚平宁山脉作为天然实验室。自〜30 mA以来，亚平宁造山基因的这一部分一直是相对稳定的正交收敛和2D（平面应变）造山膜变形的部位。 GPS的测量表明，收敛目前是活跃的，断层扫描表明俯冲板的全长仍然完整到250 km的深度。 自从至少15 mA以来，合成范围的扩展一直活跃。 对北部的亚平宁植物进行了充分的研究，并且造山机的所有重要特征都是onland的，因此可以直接进入详细的地质和地球物理研究。项目撤退的特定目标是1）详细确定跨膜速度场，包括在内的速度场，包括在造山学楔形，岩石圈板的运动以及周围的软圈地幔中的流场以及2）使用此运动学信息来开发和测试特定的动态模型，以在造山学楔形物和下面的地幔中进行变形。 要使用的研究技术包括：地球，构造地貌，低温热相应，结构地质和构造合成，地震研究和地球动力学建模。 该务虚会与来自六个机构的11个PI以及在意大利，瑞士，加拿大和法国的约有27个外国合作者将一个广泛的多学科小组与11个PI联系在一起。***