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为了说明加拿大不列颠哥伦比亚西部胡安德富萨和美洲板块之间的相互作用,最近,我们对大陆边缘进行了研究。大陆坡平均宽度为70公里,由第四纪和上第三纪地层组成;这些地层形成了许多不对称的褶皱和北东向的逆断层。这种挤压构造可认为是北美板块之下胡安德福萨板块北东向发生俯冲断层形成的。较好地了解这些构造特点,对进行温哥华岛近海区域的油气的勘探来说,是很有益处的。该区1980年 COCRUST 计划的一个内容,就是获得150公里(从与大陆边缘垂直的胡安德福萨板块至深海大陆架)的局部换向的地震折射剖面。连续地震剖面是与32支气枪一起使用的;局部换向的放炮线是记录在四张洋底地震记录上的。旅行时间和振幅数据已用射线轨迹法和合成地震记录
In order to illustrate the interaction between the Juan de Fussa and the Americas plate in western British Columbia, Canada, we have recently conducted a study of the continental margin. The continental slope has an average width of 70 kilometers and is composed of Quaternary and Upper Tertiary formations; these formations have many asymmetric folds and a northeastward thrust fault. This squeeze structure can be thought of as a subduction fault in the northeast of the Juan de Fusa plate below the North American plate. A good understanding of these structural features can be very beneficial for the exploration of oil and gas in the offshore Vancouver Island. One of the elements of the 1980 COCRUST project is the seismic refraction profile obtained for a partial reversal of 150 kilometers (from the JFF plate to the deep shelf) perpendicular to the continental margin. The continuous seismic section is used with 32 air guns; the locally deflected shot is recorded on four ocean floor seismic records. Travel time and amplitude data have been ray traced and synthetic seismograms