"Proto-Japanese Islands" estimated by detrital minerals in Cretaceous sediments

中新生代日本海地层运动使日本列岛的地质带重新排列。我对白垩纪浅海和非海相沉积物和基岩的独居石和锆石进行了定年。我成功地确定了笹山群的精确沉积时代。此外，Himenoura群的碎屑独居石表明，该群物源中可能缺乏白垩纪花岗岩类。在三巴川带天龙地区进行了白垩系增生杂岩勘探。虽然该地区被认为是“严格意义上的三巴川元- ac”和“石曼托元- ac”的接触点，但我的研究结果清楚地表明，该地区的这两个单元都起源于晚白垩世增生杂岩。

The geologic belts in the Japanese Islands were rearranged by movement of Japan Sea formation in middle Cenozoic. I have conduced dating of monazite and zircon for Cretaceous shallow- and non- marine sediments and basement rocks. I succeeded to decide the precision sedimentary age of the Sasayama Group. In addition, detrital monazites from the Himenoura Group indicated a possibility that Cretaceous granitoids were scarce in the provenance of the group. Exploration of Cretaceous accretionary complex is conducted in the Tenryu area of the Sanbagawa Belt. Although the area was thought to be the contact of the "Sanbagawa meta-AC sensu stricto" and the "Shimanto meta-AC", the result of my study clearly indicate that both of the unit in the area originate from Late Cretaceous accretionary complexes.