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Origin and depositional environment of Archean particle-bearing sandstones in the Japanese Islands

日本列岛太古代含颗粒砂岩的成因及沉积环境

基本信息

批准号：
09304048
负责人：
ADACHI Mamoru
金额：
$ 18.94万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09304048/
关键词：
Archean clastic particle CHIME geochronology ICP mass spectrometric analysis Mino terrane Hida terrane Shimanto terrane zircon monazite シルコン始生代砕屑岩 ICP質量分析計希土類元素

项目摘要

Recent CHIME geochronological studies have revealed that the origin of the rocks in the Japanese Islands was as long as ca. 3000 Ma ago, namely during late Archean time (e.g. Suzuki & Adachi, 1991; Adachi and Suzuki, 1993). Since in East Asia, the distribution of the Archean rocks is restricted to part of North China, the Archean clastic particles in Mesozoic sandstones provide important key information as to the birth and tectonic evolution of the Japanese Islands. During these three years of the project, we have carried out the CHIME dating on detrial zircon, monazite, zenotime and allanite, together with ICP mass spectrometric analysis of the Mesozoic sandstones. The dating results have shown that ca. 2000 Ma detrial zircons are common in the sandstones of the Mino, Hida and Shimanto Terrenes, while Archean (older than 2500 Ma) zircons are not common and ca. 3000 Ma zircons are very rare. Although scarce, these rare zircons demonstrate an input of sediment from Archean rocks of northeastern China and Korea. Some fundamental analytical problems with the determination of rare earth elements (REE) that are contained in detrial zircon, monazite, etc. were also addressed.The origin and tectonic evolution of the Archean particle-bearing sandstones were discussed in the light of the newly obtained chronological and geochemical data, the distribution of the Archean rocks, and the Mesozoic tectonic setting of East Asia.

最近的CHIME地质年代学研究表明，日本群岛岩石的起源时间长达约1000年。3000 Ma前，即太古代晚期（如Suzuki &阿达奇，1991;阿达奇and Suzuki，1993）。在东亚，太古宙岩石的分布仅限于华北部分地区，中生代砂岩中的太古宙碎屑颗粒对日本列岛的形成和构造演化提供了重要的关键信息。在项目的三年中，我们对中生代砂岩进行了锆石、独居石、锆石和褐帘石的CHIME定年和ICP质谱分析。测年结果表明，CA。2000 Ma的碎屑锆石常见于美浓地体、希达地体和四万十地体的砂岩中，而太古代（大于2500 Ma）的锆石不常见，约为2000 Ma。3000 Ma的锆石非常罕见。虽然稀少，这些罕见的锆石证明输入的沉积物从中国东北部和朝鲜的太古代岩石。本文还讨论了锆石、独居石等矿物中稀土元素测定的一些基本问题，并结合新近获得的年代学和地球化学资料，结合太古代岩石的分布和东亚中生代构造背景，讨论了太古代含颗粒砂岩的成因和构造演化。