Late Cretaceous U/Pb zircon ages and Precambrian crustal inheritance in Ryoke granitoids, Kinki and Yanai districts, Japan
Late Cretaceous U/Pb zircon ages and Precambrian crustal inheritance in Ryoke granitoids, Kinki and Yanai districts, Japan
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日本近畿和柳井地区 Ryoke 花岗岩的晚白垩世 U/Pb 锆石年龄和前寒武纪地壳继承
DOI：
10.2343/geochemj.32.21
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发表时间：
1998
影响因子：
0.8
通讯作者：
Y. Hayasaka
中科院分区：
文献类型：
--
作者：
C. Herzig;D. Kimbrough;Y. Tainosho;H. Kagami;S. Iizumi;Y. Hayasaka
Kinki地区Ikoma-yama和Katsuragi-yama上的Ryoke花岗岩和柳井地区Yashiro-Jima上的Ryoke花岗岩具有晚白垩世锆石U/Pb同位素结晶年龄。Ikoma-yama上较老和较年轻的花岗岩侵位时间较短，介于81 Ma和82±1 Ma之间。位于Ikoma-yama南部的Katsuragi-yama上的年轻Ryoke花岗岩结晶年龄为75±3 Ma。伽玛诺花岗闪长岩和基塔-大岛花岗片麻岩的结晶年龄为95~96±1 Ma。这一结果支持了早先的观点，即伽玛诺和基塔-大岛岩石是同源的。本研究所分析的Ryoke花岗岩类中的某些锆石中存在前寒武纪(1855~1953 Ma)放射性成因铅的继承成分。这一结果表明，较古老的大陆物质被同化到花岗岩浆中。可能的来源包括前寒武纪基底或较年轻的上地壳岩石，其中含有回收的前寒武纪碎屑。
Ryoke granitoids on Ikoma-yama and Katsuragi-yama in the Kinki District, and on Yashiro-jima in the Yanai District, have Late Cretaceous zircon U/Pb isotopic crystallization ages. Older and Younger granites on Ikoma-yama were emplaced within a short time interval between 81 and 82 ± 1 Ma. Younger Ryoke granite on Katsuragi-yama, located south of Ikoma-yama, crystallized at 75 ± 3 Ma. The Gamano granodiorite and Kita-Oshima granite-gneiss on Yashiro-jima have overlapping crystallization ages of 95 to 96 ± 1 Ma. This result supports earlier ideas that the Gamano and Kita-Oshima rocks are cogenetic. An inherited component of Precambrian (1855 to 1953 Ma) radiogenic lead is present in some of the zircons from the Ryoke granitoids analyzed in this study. This result implies that older continental materials were assimilated into the granitic magmas. Possible sources include Precambrian basement or younger upper crustal rocks that contain recycled Precambrian detritus.
影响因子：
3.5
作者：
H. Kagami;S. Iizumi;Y. Tainosho;M. Owada
通讯作者：
H. Kagami;S. Iizumi;Y. Tainosho;M. Owada