Cenozoic episodic volcanism and continental rifting in northeast China and possible link to Japan Sea development as revealed from K Ar geochronology

Abstract Cenozoic volcanic rocks in northeast China comprise part of the volcanic belt of the western circum-Pacific rim and represent one of the presently active tectono-magmatic regions of the world. Over 590 volcanoes with erupted basalts covering an area of ∼50,000 km 2 are exposed in the Songliao graben and particularly on its flanks. K–Ar dating of the volcanic rocks sampled from a selection of eruption sites over the region reveals that the volcanism occurred episodically through the entire Cenozoic corresponding to the tectono-magmatic interactions particularly between the India, Eurasia and Pacific Plates. The volcanism initiated in the Songliao graben in late Cretaceous (∼86 Ma) and migrated flankward since ∼28 Ma. The magmatic propagation shows three major stages intimately associated with the evolution of Japan Sea and related to the geodynamic forcing of the India–Eurasia collision. Prior to Japan Sea rifting, volcanic eruptions were restricted to the Songliao basin. During Japan Sea opening, volcanism migrated into the lateral belts. After cessation of Japan Sea opening at ∼15 Ma, volcanism with greatest intensity occurred on both flanks particularly along the Yi–Yi fault system around 14–13 Ma and subsequently the Fu–Mi fault between 11 and 7 Ma. Continuing this trend of migration, eruptions scattered further away from the Songliao basin in the last 4.5 Ma. We suggest that the Cenozoic volcanic belt in northeast China and the Japan Sea backarc basin are competitive parts in the eastern-marginal magmatic system of the Eurasian Plate. The early stage of the volcanism in the Songliao basin may have resulted from mantle upwelling beneath the Songliao–Bohai basin belt. Rifting of the NE faults and relatively weak intensity of volcanism in northeast China during Japan Sea opening could be attributable to the lithospheric breakup in the Japan Sea and spreading of Japan Sea. The subsequent strong volcanism in northeast China after cessation of the Japan Sea opening implicates the easiest pathway for the melts of the magmatic system in the plate margin. The diversified volcanism in scattered localities during the Quaternary may indicate localized melting processes or notable modifications in smaller sized individual domains and possibly, a magmatically waning phase of the limited source in eastern China.

[1]  G. B. Dalrymple,et al.  Irradiation of samples for 40Ar/39Ar dating using the Geological Survey TRIGA reactor , 1981 .

[2]  T. Song.  Inversion styles in the Songliao basin (northeast China) and estimation of the degree of inversion , 1997 .

[3]  Yan Song,et al.  Isotopic characteristics of Hannuoba basalts, eastern China: Implications for their petrogenesis and the composition of subcontinental mantle , 1990 .

[4]  G. B. Dalrymple,et al.  40Ar/39Ar technique of KAr dating: a comparison with the conventional technique , 1971 .

[5]  Y. Tatsumi,et al.  Asthenospheric injection and back-arc opening: Isotopic evidence from northeast Japan☆ , 1988 .

[6]  Y. Tatsumi,et al.  Backarc extension versus continental breakup: petrological aspects for active rifting , 1991 .

[7]  L. Jolivet,et al.  Right‐lateral shear along the Northwest Pacific Margin and the India‐Eurasia Collision , 1990 .

[8]  N. Arndt,et al.  Pb isotopic compositions of Archean komatiites and sulfides , 1990 .

[9]  G. B. Dalrymple,et al.  40Ar/39Ar age spectra of some undisturbed terrestrial samples☆ , 1974 .

[10]  Yan Song,et al.  Geochemistry of Hannuoba basalts, eastern China: Constraints on the origin of continental alkalic and tholeiitic basalt , 1990 .

[11]  L. Jolivet,et al.  Japan Sea, opening history and mechanism: A synthesis , 1994 .

[12]  Xin-hua Zhou,et al.  Nature of the Lithospheric Mantle Beneath NE China: Evidence from Potassic Volcanic Rocks and Mantle Xenoliths , 2013 .

[13]  R. Zartman,et al.  Pb-, Sr- and Nd-isotopic systematics and chemical characteristics of Cenozoic basalts, eastern China , 1986 .

[14]  Shigenori Maruyama,et al.  Mechanism of backarc opening in the Japan Sea: role of asthenospheric injection , 1990 .

[15]  I. Wendt,et al.  The statistical distribution of the mean squared weighted deviation , 1992 .

[16]  M. McCulloch,et al.  Chemical geodynamics in a back arc region around the Sea of Japan: Implications for the genesis of alkaline basalts in Japan, Korea, and China , 1989 .

[17]  R. Arculus,et al.  Multiple magma sources involved in marginal-sea formation: Pb, Sr, and Nd isotopic evidence from the Japan Sea region , 1998 .

[18]  L. Jolivet,et al.  Neogene stress field in SW Japan and mechanism of deformation during the Sea of Japan opening , 1995 .

[19]  S. Foley,et al.  Parallels in the origin of the geochemical signatures of island arc volcanics and continental potassic igneous rocks: The role of residual titanates , 1990 .

[20]  Walter D. Mooney,et al.  Crustal structure of China from deep seismic sounding profiles , 1998 .

[21]  C. Petit,et al.  Paleostress reconstructions and geodynamics of the Baikal region, Central Asia, Part 2. Cenozoic rifting , 1997 .

[22]  Brian Taylor,et al.  Backarc basins : tectonics and magmatism , 1995 .

[23]  R. Armstrong,et al.  Cenozoic volcanic rocks of eastern China — secular and geographic trends in chemistry and strontium isotopic composition , 1982 .

[24]  K. Tamaki.  Opening Tectonics of the Japan Sea , 1995 .