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国际大洋钻探计划(IPOD)沿日本海沟横剖面的调查表明:在早白垩世——早第三纪板块聚敛俯冲期和晚第三纪晚期板块聚敛俯冲期之间曾存在一个没有岛弧火山活动的新生代中期构造作用时期。白垩纪至早第三纪早期聚敛的证据是与一大型向斜(或许为一弧前盆地)有关的安山质火山活动。该盆地向海—翼是一套因构造作用而增厚的沉积层系,推断为一套加积复杂体。这些弧、向斜和增厚的沉积层系的大小和构造,类似于加利福尼亚由大峡谷弧前盆地和弗朗西斯科加积复杂体组成的弧—沟体系,它们可能是虾夷地槽的延伸部分,与其有关的层系还向北出露于北海道。该弧—沟体系与毗邻的东京湾西南面的四万十弧—沟体系是同期形成的。早第三纪早期,火山活动停止,白垩纪至早第三纪增厚沉积层系的部分边缘出露呈一个160公里宽的陆块,在地震记录上可看出该陆块为早第三纪晚期的沉积物源。早第三纪末期,该陆块开始下沉,火山再次开始活动。但是火山活动起先短暂地位于东部,然后出现于本州北部现代火山弧一带的白垩纪弧以西。在多道反射地震记录上,陆块的侵蚀表面呈—清晰可见的角度不整合面;笔者根据深海钻探计划取得的岩芯,研究了晚第三纪沉积物的层系、火山喷发作用和底栖有孔虫组合所记录的从陆地条件到现代半深海这一沉降过程。白垩纪的俯冲作用似乎遣成了非常广泛的加积复杂体,而晚第三纪俯冲的结果则似乎是:在弧前地区几乎没有形成有效的加积,但却在聚敛边缘的前锋引起了大幅度的沉降和一定的侵蚀作用。
A survey of the cross-section of the International Ocean Drilling Program (IPOD) along the Japan Trench shows that there was an absence of island arc volcanoes between the convergent and subduction stages of the Early Cretaceous to Early Tertiary and the convergent subduction of the late Late Tertiary During the Cenozoic tectonic period. Evidence of the convergence from the Cretaceous to the early Tertiary is antrican volcanic activity associated with a large synclinal (perhaps pre-arcanic) basin. The basin to the sea - wing is due to a thickening of the sedimentary facies structure, inferred as a complex accretion body. The size and configuration of these arc, syncline and thickened sedimentary facies are similar to those of the arc-ditch system of California, which consisted of the Grand Canyon Precamboidal Basin and the Francisco Jr. complex, which may be an extension of the diurnal trough , The related strata are also exposed to Hokkaido to the north. The arc-groove system is formed in parallel with the 40,000-arc-groove system in the southwest of the adjacent Tokyo Bay. Early Early Tertiary, volcanic activity ceased. Cretaceous to Early Tertiary thickening of the sedimentary part of the edge of the exposed part of a 160 km wide block, the seismogram can be seen that the block is Early Tertiary Sediment source. As early as the end of the Tertiary, the landmass began to sink and the volcano re-started its activity. However, the volcanic activity first briefly occurred in the east and then appeared west of the Cretaceous arc in the vicinity of modern volcanic arcs in northern Honshu. On the multi-trace seismic records, the eroded surface of the block presents a clearly discernible angular unconformity. Based on the core obtained from the deep-sea drilling program, the author has studied the sediments of the Late Tertiary, the volcanic eruption and the bottom Permian foraminiferal assemblage recorded from the land conditions to the modern semi-deep sea of this subsidence process. The Cretaceous subduction seems to have evolved into a very wide range of accretionary complexes, whereas the results of the late Tertiary subduction seem to be that few effective accretions have been formed in the pre-arcuate region but have been caused by the striking front Substantial settlement and a certain degree of erosion.