Collaborative Research: Metamorphism and Deformation Associated with Late Cenezoic Strike-Slip Faulting in the Philippines

菲律宾断层是一个活跃的左旋走滑断层， 几乎横贯整个菲律宾群岛。 是 世界上几个主要的走滑断层系统之一， 倾斜会聚的洋内板块边界。 这个和一个 合作项目（EAR 87 -07345）将研究起源和 沿着断层的变质岩的侵位。 一些 这些变质岩--绿片岩相变质火山岩，角闪岩 和蛇纹岩--可能是在会聚缝合带形成的，但是我们 将检验一个假设， 完全是走滑相关过程的结果。 我们将使用 构造、年代学和地球化学技术， 变质岩的变形变质历史是 与它们沿菲律宾断层沿着的形成相一致，而不是 碰撞过程。 严重打滑的常见现象 现代斜向会聚边缘的断层表明， 在古活动陆缘，构造应是一种边界 组合，但很少有这样的结构已被确认。 这可能是 因为许多岩石学和构造学组合都是 会聚和走滑“缝合线”通常被认为是 只与前者有关。通过研究变质作用的起源， 岩石沿着一个活跃的走滑断层，也起到并列 我们希望建立一个框架， 用于在旧的电弧炉中识别这样的结构。

The Philippine Fault, an active, left-lateral strike-slip fault, transects almost the entire length of the Philippine Archipelago. It is one of several major strike-slip fault systems worldwide that occur at obliquely converging intra-oceanic plate boundaries. This and a collaborative project (EAR87-07345) will study the genesis and emplacement of metamorphic rocks that occur along the fault. Some of these metamorphic rocks-- greenschist-facies metavolcanics, amphibolites and serpentinites-- may be created at convergent suture zones, but we will test the hypothesis that at least some of them were generated entirely as a result of strike-slip related processes. We will use structural, geochronological and geochemical techniques to determine if the deformational and metamorphic history of metamorphic rocks is consistent with their creation along the Philippine Fault, rather than by collisional process. The common occurrence of major strick-slip faults at modern obliquely converging margins suggest that similar structures should occur as terrane boundaries in ancient active margin assemblages, but few such structures have been recognized. This may be because many petrologic and structural associations common to both convergent and strike-slip "sutures" are generally believed to be associated only with the former. By studying the origin of metamorphic rocks along an active strike-slip fault that also acts to juxtapose disparate terranes in the Philippines, we hope to establish a framework for recognizing such structures in old arc terranes.