U-Th-Pb ages of zircon from the Ryoke metamorphic terrain, Kinki District
U-Th-Pb ages of zircon from the Ryoke metamorphic terrain, Kinki District
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近畿地区 Ryoke 变质带锆石 U-Th-Pb 年龄
DOI：
10.2465/ganko1941.62.191
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发表时间：
1969
期刊：
影响因子：
--
通讯作者：
K. Ishizaka
中科院分区：
文献类型：
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作者：
K. Ishizaka
测定了Kinki地区Ryoke变质带花岗岩和变质岩中三种锆石的U-Th-Pb年龄。花岗岩中两个锆石的Pb206/U238年龄约为90m.这与Rb-sr法在该变质地体的云母样品上获得的结果一致，表明花岗岩和变质岩的侵入作用可能发生在约90m.变质古生代沉积岩的碎屑锆石U-Pb年龄相当不一致，Pb207/Pb206年龄高达1792 Ma。这一结果可能表明，在所谓的二叠纪-石炭纪古生代岩区附近，可能在日本海附近存在前寒武纪的酸性结晶岩。
U-Th-Pb ages of three zircons of granitic and metamorphic rocks from Ryoke metamorphic zone in the Kinki district have been determined. Two zircons from granitic rocks yielded Pb206/U238 age of approximately 90 m. y. which is consistent with the results obtained by Rb-Sr method on mica samples of this metamorphic terrain, suggesting the intrusion of the granitic rocks and metamorphic may have taken place about 90 m. y. ago. Detrital zircon of metamorphosed Paleozoic sedimentary rock yielded quite discordant U-Pb age, Pb207/Pb206 age being as old as 1792 m. y.. This result may indicate the presence of acidic crystalline rocks of Precambrian age near the so-called Permo-Carboniferous Paleozoic rock region, probably in the Japan Sea.