Carbonate Bank Development and Vertical Tectonic History of the Marshall Islands, Western Pacific: Ocean Drilling Program Related Research

马歇尔群岛是一个主要的地貌和地质 西太平洋的特点。 他们的起源被认为是 中生代太平洋板块经过热点地区， 交替地，发生广泛的，中板 火山作用 在比基尼环礁和埃尼威托克环礁进行钻探， 在邻近的海山和盖奥特进行疏浚， 在DSDP-IPOD操作期间进行的测试表明， 许多环礁和邻近的目前淹没的珊瑚礁覆盖的 海山是始新世和白垩纪（？）最近的 始新世-白垩纪生物礁生长（？）火山地基， 是在侏罗纪时期下沉的太平洋板块上爆发的 形态、内部相几何学和成岩历史 珊瑚礁下面的石灰岩部分， 淹没在水下的珊瑚礁被控制在海平面以下 冰川的消长引起的波动， 新生代 迄今为止的研究表明，马歇尔 岛屿区自白垩纪末以来沉降了约1500米， 始新世早期。 这种令人不安的快速下沉率， 早（？）侏罗纪被认为是 板块中部的热再生和板块的抬升。 该奖项支持的研究目标是 水深和地震测绘以及对水下、珊瑚礁、 覆盖着马歇尔群岛的海山和出海口。 这些 研究将提供确定沉降的数据 这一异常区域的历史，并确定相 生物礁的几何形状、成岩历史和停止时间 水下海山和出海口的增长，因为这些与 海平面波动。 这些数据也将用于规划 未来在该领域的发展。

The Marshall Islands are a major morphologic and geologic feature of the western Pacific. Their origin has been ascribed to the passage of the Mesozoic Pacific plate over hotspots or, alternately, to the occurrence of widespread, mid-plate volcanism. Drilling on Bikini and Enewetak atolls, surveying and dredging on neighboring seamounts and guyots, and ocean drilling carried out during DSDP-IPOD operations, have shown that the numerous atolls and adjoining presently submerged reef-capped seamounts are the result of Eocene and Cretaceous(?) to Recent reef growth on Eocene and Cretaceous(?) volcanic foundations that were erupted atop the subsiding Pacific plate of Jurassic age. The morphology, internal facies geometry, and diagenetic history of the limestone sections below the atolls and within the submerged reef-caps have been controlled be sea-level fluctuations induced by the waxing and waning of glaciers during the Cenozoic era. Studies to date indicate that the Marshall Islands region has subsided ~1500m since latest Cretaceous or Early Eocene time. This anomalously fast rate of subsidence on a lithospheric plate of Early(?) Jurassic age has been ascribed to a mid-plate thermal rejuvenation and uplift of the plate. Research supported in this award has as its objectives the bathymetric and seismic mapping and sampling of submerged, reef- capped seamounts and guyouts in the Marshall Islands. These studies will provide data with which to determine the subsidence history of this anomalous region and to determine the facies geometry, diagenetic history, and timing of cessation of reef growth of the submerged seamounts and guyouts as these relate to sea-level fluctuations. The data will also be used in planning future drilling in this area.