著者

中川 昌治 M. Santosh 吉倉 紳一 原田 亜実 三浦 正裕 福田 照久 松田 靖正 桑田 泰宏 K. J. Mathew P. T. Ambujakshan H. Thampy

出版者

一般社団法人日本粘土学会

雑誌

粘土科学討論会講演要旨集 第48回 粘土科学討論会 (ISSN:24330566)

巻号頁・発行日

pp.23, 2004 (Released:2006-05-13)

---

南インドKerala州のTrivandrum近郊では,良質のカオリン粘土の鉱床が多く存在し,紙や衛生陶器用に採掘されている.カオリナイトと少量の石英からなる白色塊状粘土の層が第三紀層中に胚胎し,鉱床上部にはラテライト化した砂質カオリンが分布する.これらの粘土中のカオリナイトはXRDとSEMから結晶性が非常に高い.基盤岩(先カンブリア時代のアルミナ質グラニュライト)が強烈な風化変質作用を受けカオリン化し,近くの湖に堆積してできたと考えられる.

著者

M. SANTOSH 千秋 博紀

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.120, no.1, pp.100-114, 2011-02-25 (Released:2011-05-20)

参考文献数

50

被引用文献数

3 10

---

The history of supercontinents is briefly reviewed in relation to the origin of the Japanese Islands. The Japanese Islands formed part of the S. China Block, which was a part of supercontinent Rodinia at 1.0 Ga. Rodinia was rifted at 600 Ma, separating S. China Block, N. America, Australia and other continents, to generate the Proto-Pacific Ocean in between. On the other hand, the Hida and Oki islands belong to the N. China Block, which has much longer history than the S. China Block, extending back to 1.9-2.0 Ga with minor older rocks dating back to 3.8 Ga. The 1.8-2.0 Ga high-grade gneiss in the Hida and Oki belts may be part of the 1.8-1.9 Ga Nuna/Columbia supercontinent within which N. China-Japan occurred at the NE corner, as judged from key parallel belts of 1.8-1.9 Ga in N. China. The position of Japan at 1.0 Ga within Rodinia was at the center together with S. China and western margin of N. China. The oldest fossiliferous rocks in Japan may extend back to the Early Cambrian to Ediacaran formed during the rifting of Rodinia directly after Neoproterozoic snowball Earth. Initiation of subduction began ca. 520 Ma, and evolved through five Pacific-type orogenies along the southern margin of S. China. On the other hand, the Hida and Oki belts suffered the Triassic collision orogeny at 230-240 Ma, involving platform sediments up to the Carboniferous age. The final tectonic emplacement above the Jurassic accretionary complex may be related to the extensional event during the opening of the Japan Sea in the Miocene.