caa a22 4500 465791026 CHVBK 20180323112024.0 cr unu---uuuuu 170327e19900701xx s 000 0 eng 10.1007/BF01575616 doi (NATIONALLICENCE)springer-10.1007/BF01575616 Along-arc lateral variation of Rb−Sr and K−Ar ages of Cretaceous granitic rocks in Southwest Japan [Elektronische Daten] [Takashi Nakajima, Teruo Shirahase, Ken Shibata] Cretaceous granitic rocks were emplaced over a distance of 700 km along arc in Southwest Japan. Rb−Sr and K−Ar ages of a major group of these granitic rocks, with ilmenite series ore mineralogy, were examined. Rb−Sr whole rock ages of 92.8±4.0 Ma and Rb−Sr and K−Ar biotite ages of 80-88 Ma were obtained on one group of these granitic rocks from Kamo-Sera area of central Hiroshima Prefecture. The K−Ar ages of various minerals, combined with the Rb−Sr whole-rock age, give a smooth cooling curve, which suggests a 5 to 10 Ma time-lag between intrusion and cooling at 300° C for the Cretaceous granitic rocks. The Rb−Sr whole-rock and Rb−Sr/K−Ar biotite ages of these granitic rocks become younger eastward along the Southwest Japan arc, and the time-lag between the two systems remains constant at 5 to 10 Ma over the entire area. The along-arc age variation does not support the genetical relationship of the Cretaceous granitoids with steady-state subduction. The Cretaceous granitic province at the eastern margin of Eurasian continent was, at least partly, formed by an episodic event such as ridge subduction. Springer-Verlag, 1990 Nakajima Takashi Geological Survey of Japan, Higashi, 305, Tsukuba, Japan aut Shirahase Teruo Geological Survey of Japan, Higashi, 305, Tsukuba, Japan aut Shibata Ken Geological Survey of Japan, Higashi, 305, Tsukuba, Japan aut Contributions to Mineralogy and Petrology Springer-Verlag 104/4(1990-07-01), 381-389 0010-7999 104:4<381 1990 104 410 https://doi.org/10.1007/BF01575616 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01575616 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Nakajima Takashi Geological Survey of Japan, Higashi, 305, Tsukuba, Japan aut NATIONALLICENCE 700 1- Shirahase Teruo Geological Survey of Japan, Higashi, 305, Tsukuba, Japan aut NATIONALLICENCE 700 1- Shibata Ken Geological Survey of Japan, Higashi, 305, Tsukuba, Japan aut NATIONALLICENCE 773 0- Contributions to Mineralogy and Petrology Springer-Verlag 104/4(1990-07-01), 381-389 0010-7999 104:4<381 1990 104 410 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer