Shortening, Gravity-Driven Compensation, and the Thermal Evolution of the East Greenland Caledonides

造山带内的伸展变形过程对碰撞山脉的发育具有重要意义。首先在喜马拉雅有充分的证据表明，当物理侵蚀不足以补偿挤压驱动的隆升时，这些伸展构造似乎提供了一种限制地形起伏和平均海拔的机制。通常与这些伸展特征联系在一起的是一种神秘的变质关系，其中变质等级是颠倒的，即向上增加。从热模拟可以清楚地看出，这些反向变质梯度只能通过快速冷却来保存。然而，这些系统的变形（压缩与伸展无顶调节）与地热收支（变质等级和压力-温度-时间路径）之间的时空和力学关系尚不清楚。本项目将研究东格陵兰加里东构造剥蚀和逆变质作用。该地区暴露出造山带较深的部分，其反向变质梯度呈现在与喜马拉雅类似构造不同的构造环境中。从技术上讲，所使用的高精度地质年代学技术能够更紧密地联系这一古老造山带的变形变质作用。本研究的预期结果包括更好地理解主动变形造山带的热行为，特别是对整体挤压造山带伸展期的反应。

9526659 Hodges The process of extensional deformation within orogenic belts is of considerable interest in the development of collisional mountain ranges. First well-documented in the Himalaya, these extensional structures appear to provide a mechanism for limiting the topographic relief and mean elevation when physical erosion is not sufficient to compensate for the compression-drives uplift. Commonly associated with these extensional features is an enigmatic metamorphic relationship in which the metamorphic grade is inverted, that is, increases upward. From thermal modeling it is clear that these inverted metamorphic gradients can only be preserved with rapid cooling. However, the temporal spatial and mechanical relationships between deformation (compression with extensional unroofing accommodation) and the geothermal budget (Metamorphic grade and pressure-temperature-time path) of these systems is not well understood. This project will study tectonic denudation and inverted metamorphism in the East Greenland Caledonides. This area exposes a much deeper part of an Orogen, and the inverted metamorphic gradient is present in a different structural setting from analogous structures in the Himalaya. Technically, the high-precision geochronologic techniques to be used are capable of more closely tying deformation metamorphism in this older orogen. The expected results of this research include a better understanding of the thermal behavior of actively deforming orogens, particularly in response to episode of extension in the overall compressional orogens.