权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

A study on growth history of reef terraces deduced from the U-series method of dating

U系列测年法推导的礁台生长史研究

基本信息

批准号：
08454148
负责人：
OMURA Akio
金额：
$ 5.06万
依托单位：
Kanazawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08454148/
关键词：
Quaternary Coral Reef Terrace Sea Level Change U-Series dating Kikai Island Philippine Islands Huon Peninsula Fiji Islands 完新世更新世伊良部島フィジ-諸島間氷期最終氷期後氷期

项目摘要

The growth history of coral reef terraces at Kikai Island (Ryukyu Islands), Huon Peninsula (Papua New Guinea), Philippine Islands, and Fiji Islands, which were formed during the last several tens of thousands years, has been elucidated by using U-series dates of corals as a time scale. The main results obtained in this study are outlined as follows :1. As the result of U-series dating and stratigraphic study, coral limestone younger than the isotope stage 5a was sporadically distributed at an altitude of ca. 10 to ca. 65 m in the Kikai Island. Such limestone overlies the fore-reef sediments assigned to stage 3 to 5e. These facts suggest that coral reefs have been formed on the sea floor being successively shallowed with the regression from isotope stage 5e to 3. In contrast, alpha-spectrometric ^<230>Th/^<234>U method was also useful for interpreting the growth history of Holocene coral reef terraces. The Holocene coral limestone at the island began to deposit at ca. 10 ka in water dep … More th of 5 to 10 m. Then the transgressive and highstand systems tracts were deposited during the times when sea level raised and attained to the maximum height (ca. 12 m) up to ca. 7.5 ka. As lowering of the sea level, the terriginous materials became gradually in short supply and a fringing reef started to grow around 7 ka.2. A buried coral reef implying that the sea level at the last glacial maximum was 126 m in water depth, was found beneath the outer edge of insular shelf off the Miyako Islands.3. It was explicated, from U-series dating and oxygen isotopic analysis of late Pleistocene corals at Huon Peninsula, that the rapid rise of sea level at ca. 140 ka has been interrupted at ca. 135-130 ka and restarted after it has been once lowered.4. The distribution of coral reef terrace formed during the stage 5e was confirmed at Panglao, Bohol, and Mactan Islands. A tidal notch of the stage 5e also occurred at the west side of Palawan Islands. The altitude of those indicators for paleo-shoreline denotes that some areas in the Philippine Islands have not uplifted, even though they are situated in the active margin in the western Pacific region. Less

本文以珊瑚的U系年龄为时间尺度，对琉球群岛的纪凯岛、巴布亚新几内亚的休恩半岛、菲律宾群岛和斐济群岛的珊瑚礁阶地的生长历史进行了研究。本研究取得的主要结果如下：1.根据铀系定年和地层学研究，在海拔约1000米处零星分布着年龄小于同位素5a阶的珊瑚灰岩。10到CA 65米在Kikai岛。这种石灰岩覆盖在3 - 5e阶段的礁前沉积物上。这些事实表明，珊瑚礁是在海底逐渐变浅的情况下形成的，其同位素阶段从5e退化到3。相比之下，α-能谱法的^<230>Th/^<234>U也适用于解释全新世珊瑚礁阶地的生长历史。岛上全新世珊瑚灰岩约于1980年开始存款。10 ka水深度 ...更多信息 5到10米。海侵体系域和高水位体系域是在海平面上升并达到最大高度（约100米）时沉积的。12米）至约。7.5 ka.随着海平面的降低，陆源物质逐渐减少，约7ka.2左右开始发育边缘礁.在宫古岛外的岛架外缘下发现了埋藏的珊瑚礁，表明末次盛冰期的海平面水深为126 m。通过对休恩半岛晚更新世珊瑚的铀系测年和氧同位素分析，阐明了海平面的快速上升是在约2000年左右。140 ka在ca被中断。135-130 ka，在降低一次后又重新开始.在邦劳、保霍尔和麦克坦群岛，证实了在第5 e阶段形成的珊瑚礁阶地的分布。在巴拉望群岛西侧也出现了5 e级的潮汐缺口。这些古海岸线指标的海拔高度表明，菲律宾群岛的一些地区没有隆起，尽管它们位于西太平洋区域的活动边缘。少