RUI: Motion History and Tectonic Significance of Major Faults in Southeastern New England

该项目的目标是确定热历史，方向， 潜在的边界断层的运动方向和时间， 北方阿巴拉契亚山脉 区域地质状况良好 除了断层运动之外。 断层系统是 研究标志着东南部阿瓦隆区的西部边界 新英格兰，可能是一个断层系统的一部分， 北方阿巴拉契亚山脉。尽管这些断层被认为是 二叠纪碰撞缝合线，初步结果表明， 段经历了不同的运动历史。 整个系统 可能经历了志留纪（430-400 Ma.）左旋 具有推力分量的运动， 二叠纪时期为低角度正断层。 需要开展额外工作， 定义尚未研究的断层段的运动历史， 在具有不同运动的段之间建立关系 历史，调查断层运动之间可能的关系， 孤立产状的彭萨科拉变质沉积 并将这些结果与区域地质相结合。 将使用的技术将是标准的详细结构分析， 定向薄片的场分析和显微组织分析。 热历史将通过表征温度来建立 相平衡证实了相关的微观结构， 适用因 运动的时间将由结构确定 火成岩年代分析 学生参与将采取的形式 在两个野外季节中的每一个季节， 还有几篇“高级荣誉论文” 预计结果将有助于 限制了新英格兰一些火山岩的构造历史。

The goals of this project are to define the thermal history, direction, sense and timing of motion(s) on potential terrane-bounding faults in the northern Appalachians. The regional geology is reasonably well known with the exception of fault motions. The fault system to be studied marks the western boundary of the Avalon zone in southeastern New England and may be a segment of a fault system which spans the northern Appalachians. Although the faults have been proposed as marking a Permian collisional suture, preliminary results suggest that various segments have experience different motion histories. The entire system of faults may have experienced Silurian (430-400 Ma.) left-lateral motion with a thrust component and some segments were reactivated in Permian time as low-angle normal faults. Additional work is required to define the motion histories of fault segments not yet studied, to establish relationships between segments with different motion histories, to investigate possible relationships between fault motion and deformation in isolated occurrences of Pennsylvanian metasedimetary rocks and to integrate these results with the regional geology. Techniques to be used will be standard detailed structural analysis in the field and microstructural analysis on oriented thin sections. Thermal histories will be established by characterization of temperature dependent microstrutures corroborated by phase equilibria where applicable. Timing of motions will be established by structural analysis of dated igneous rocks. Student involvement will take the form of two undergraduate field assistants for each of the two field seasons and several "senior honors theses". Results are expected to help constrain the tectonic history of some of the terranes in New England.