Geologic correlation of Southwest Japan and Korean Peninsula

Petrochemical and Rb Sr geochronological data are pesented for upper Cretaceous to Paleogenegranitic rocks in the South Eastern part of the Korean Peninsula. This study revealed the temporaland spacial variation on magmatism at the active continental margine. the Kajopluton situatedoutside of the Kyeongsang basin have whole rock isochron ages of about 85Ma and a high Sr initialratio of about 0.70840. The high initial Sr ratio are comparable with those of Ryoke-type Graniticrocks. While the Hwawan, Deokdong and Girimusa pluton, situated in the Kyeongsang basin，show whole rock isochron ages of 84 to 35Ma，low initial Sr ratio from 0.70542 to 0.70570. The initial Sr isotopic ratios within TheKyeongsang basin are compatible with those of the majority of the Cretaceous-Paleogene graniticrocks in the Kyeongsang basin，也可以compare well with those of Cretaceous-Paleogene granitic rocks in the San'in Belt andnorthern Kyushu, southwest Japan. This suggests that the Cretaceous-…More Paleogene granitic rocks in the southeastern part of Korea and in the southwestern partThe new and preveously reported of Japan were derived from isotopically similar source materials. The new and preveously reportedage data and initial Sr ratio suggest that the creataceous - paleogenemagmatism migrated to a narrowbelt along the East Sea （Japan Sea）in both Korea and southwest Japan. The geochronological and initial Sr isotope data obtained in thisstudy are consistent with the suggestions that the Eocene-Oligocene magmatism can be ascribed theupwelling of a mantle plume，the opening of the East Sea (Japan Sea)On the other hand，geochemical indication of provenance linkage and sedimentary environment of the Lower Cretaceous of the Lower CretaceousSouthwest Japan and Kyeongsang basin were considered. Shales from the Yoshimo and Sengoku formationin the back arc area in Japan and Hayang group of the Kyeongsang basin are upper Paleozoic in the back arc area in Japan and Hayang group of the Kyeongsang basin aresimilar to PAAS (Post Archean Australian shales) in REE.other trace elements. Th-Hf-Co and La-Th-Scternary diagrams. Geochemical similarity between the Kyeongsang basin and the Sengoku formation ofSouthwest Japan suggests their close linkage in the provenance. Present examination of relatively高供应内容和metal enrichment in这些shales indicates appearance of saline lakeenvironment in arid climate during the Lower Cretaceous. Less

Petrochemical and Rb・Sr geochronological data are pesented for upper Cretaceous to Paleogene granitic rocks in the South Eastern part of the Korean Peninsula. This study revealed the temporal and spacial variation on magmatism at the active continental margine. The Kajopluton situated outside of the Kyeongsang basin have whole rock isochron ages of about 85Ma and a high Sr initial ratio of about 0.70840. The high initial Sr ratio are comparable with those of Ryoke-type Granitic rocks. While the Hwawan, Deokdong and Girimusa pluton, situated in the Kyeongsang basin, show whole rock isochron ages of 84 to 35Ma, with low initial Sr ratio from 0.70542 to 0.70570. The initial Sr isotopic ratios within the Kyeongsang basin are compatible with those of the majority of the Cretaceous-Paleogene granitic rocks in the Kyeongsang basin, and also compare well with those of Cretaceous-Paleogene granitic rocks in the San'in Belt and northern Kyushu, southwest Japan. This suggests that the Cretaceous- … More Paleogene granitic rocks in the southeastern part of Korea and in the southwestern part of Japan were derived from isotopically similar source materials. The new and preveously reported age data and initial Sr ratio suggest that the Cretaceous-Paleogenemagmatism migrated to a narrow belt along the East Sea (Japan Sea), in both Korea and southwest Japan. The geochronological and initial Sr isotope data obtained in this study are consistent with the suggestions that the Eocene-Oligocene magmatism can be ascribed the upwelling of a mantle plume, which probably initiated the opening of the East Sea (Japan Sea)On the other hand, geochemical indication of provenance linkage and sedimentary environment of the Lower Cretaceous of Southwest Japan and Kyeongsang basin were considered. Shales from the Yoshimo and Sengoku formation in the upper Paleozoic in the back arc area in Japan and Hayang group of the Kyeongsang basin are similar to PAAS (Post Archean Australian shales) in REE.other trace elements. Th-Hf-Co and La-Th-Sc ternary diagrams. Geochemical similarity between the Kyeongsang basin and the Sengoku formation of Southwest Japan suggests their close linkage in the provenance. Present examination of relatively higher sulfer content and metal enrichment in these shales indicates appearance of saline lake environment in arid climate during the Lower Cretaceous. Less