Back to Search
Start Over
Possible partial melting and production of felsic melt in a Jurassic oceanic plateau of the Izanagi Plate: Insights from 159 Ma plagiogranites from northern Japan.
- Source :
- International Geology Review; Mar2024, Vol. 66 Issue 5, p993-1022, 30p
- Publication Year :
- 2024
-
Abstract
- A small tonalite – dacite body has been discovered in the Nakanogawa Group, Hidaka Belt, northern Japan, which is a Palaeogene subduction complex formed in the palaeo-Japan trench along the northeastern margin of Eurasia. The tonalites are characterized by extremely low K<subscript>2</subscript>O (0.2–0.3 wt.%) and relatively flat chondrite-normalized rare earth element patterns (La/Yb<subscript>[N]</subscript> ~2.3), similar to plagiogranites in ophiolites. The major-and trace-element characteristics are consistent with low-pressure partial melting of oceanic crust outside the garnet stability field. Zircon U – Pb dating of the tonalite yielded a weighted-mean <superscript>206</superscript>Pb/<superscript>238</superscript>U age of 159.1 ± 1.6 Ma. Late Jurassic oceanic plateau-type basaltic rocks with a small amount of plagiogranitic rocks are distributed sporadically in subduction complexes along the palaeo-Japan arc – trench system. A similar zircon U – Pb age (151.6 ± 1.8 Ma) has been reported for greenstone in the Cretaceous subduction complex along the palaeo-Kuril arc – trench system. The tonalite – dacite block was probably derived from the subduction complex at the junction of the palaeo-Japan and -Kuril arc – trench systems. Thus, the greenstones and the tonalite body were likely part of a large oceanic plateau, which formed at the Izanagi – Pacific–Farallon ridge triple junction during the Late Jurassic – Early Cretaceous. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00206814
- Volume :
- 66
- Issue :
- 5
- Database :
- Complementary Index
- Journal :
- International Geology Review
- Publication Type :
- Academic Journal
- Accession number :
- 174973214
- Full Text :
- https://doi.org/10.1080/00206814.2023.2224426