Structure of Oceanic Crust Formed at 200 mm/yr. Spreading Rate

合作项目OCE 98-11948威尔逊OCE 98-12612加固建议的项目涉及资金，用于对科科斯板块中南部地区的洋壳进行广泛的地球物理调查，以支持ODP522-PRE提案。这一洋壳是由海洋磁异常记录到的最快的扩张速度形成的，在科科斯-太平洋板块边界南端13-17 Ma的扩张速度约为200毫米/年。这项调查将测量在这种非凡的扩张速度下形成的洋壳的基本性质。外推观测和理论变化与扩展速率的关系表明，地震第三层和岩脉-辉长岩的转换可能发生在1公里以下的浅层。利用多道地震反射和海底水听器地震折射，将以很高的分辨率绘制海洋上部地壳的结构图。将针对四个特定区域进行详细测绘，作为海洋钻探方案未来钻探的潜在地点。***

Collaborative Project OCE 98-11948 Wilson OCE 98-12612 Harding The recommended project involves funds for an extensive geophysical survey of oceanic crust in the south-central Cocos Plate region, in support of ODP Proposal 522-Pre. This area of the ocean crust was formed by the fastest spreading rate ever documented by marine magnetic anomalies, with a spreading rate of about 200 mm/yr at the southern end of the Cocos-Pacific Plate boundary from 13-17 Ma. The survey will measure the basic properties of oceanic crust formed at this extraordinary spreading rate. Extrapolating observed and theoretical variations with spreading rate suggests that seismic layer 3 and the dike-gabbro transition may occur at a depth shallower than 1km. Using multi-channel seismic reflection and ocean-bottom hydrophone siesmic refraction, the structure of the upper oceanic crust will be mapped at very high resolution. Four specific areas will be targeted for detailed mapping as potential sites for future drilling by the Ocean Drilling Program. ***