Structural and Hydrological Evolution of the Central Oregon Accretionary Prism

增生棱柱体沿着深海向陆侧形成 海洋沉积物刮下的海沟 岩石圈俯冲 几个相互关联的因素影响 包括沉积物在内的厚层沉积物棱柱体的演化 成分、物理性质、俯冲速率和流体 在刮下的沉积物中脱水和迁移。 流体 运移和排驱作用在机械构造中起着重要作用 沉积物的行为、流体压力和岩化作用 变形带 目前的更新奖将完成结构的研究， 俄勒冈州增生边缘多道地震 技术. 在以前的资助下，获得了2000公里的数据 沿着这个边缘。 分析数据的进展一直是 好极了 流体的来源和运移途径都可以 在数据中成像。 继续分析和解释将 重点研究：1）基底地形在控制 断裂带的性质 沿着逆冲推覆作用发生; 3）斜向断层， 在数据的初始分析过程中发现;以及4）孔隙度 沉积物序列。 这些数据是主要ODP的基础 1992年年底在该地区进行钻探航行。

Accretionary prisms form along the landward side of deep sea trenches in response to offscraping of oceanic sediments during lithospheric subduction. Several interrelated factors influence the evolution of these thick sediment prisms including sediment composition, physical properties, rate of underthrusting, and fluid de-watering and migration within the offscraped sediment. Fluid migration and expulsion play an important role in the mechanical behavior, fluid pressure and lithification of sediments in the deformation zone. The present renewal award will complete study of the structure of the Oregon accretionary margin using multichannel seismic techniques. Under previous funding, 2000 km of data was acquired along this margin. Progress in analyzing the data has been excellent. Both the sources and migration pathways of fluids can be imaged in the data. Continued analysis and interpretation will focus on: 1) the role of basement topography in controlling structural evolution of the margin; 2) the nature of the fault zone along which underthrusting occurs; 3) oblique faults which were discovered during initial analysis of the data; and 4) the porosity of the sediment sequence. These data are the basis for a major ODP drilling cruise to the area in late 1992.