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Chemostratigraphy of Flood Basalts in the Garzê‐Litang Region and Zongza Block: Implications for Western Extension of the Emeishan Large Igneous Province, SW China
Author(s) -
Long XIAO,
Yigang XU,
Jifeng XU,
Bin HE,
FRANCO Pirajno
Publication year - 2004
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/j.1755-6724.2004.tb00675.x
Subject(s) - flood basalt , craton , large igneous province , basalt , geology , geochemistry , mantle plume , deccan traps , igneous rock , permian , earth science , paleontology , lithosphere , tectonics , magmatism , volcanism , structural basin
The Late Permian Emeishan Large Igneous Province (ELIP) is commonly regarded as being located in the western part of the Yangtze craton, SW China, with an asymmetrical shape and a small area. This area, however, is just a maximum estimation because some parts of the ELIP were not recognized or dismembered and destroyed during the Triassic to Cenozoic tectonism. In this paper, the chemostratigraphical data of the Zongza block, the Garzê‐Litang belt and the Songpan‐Garzê block suggest that the Late Permian basalts in these areas have remarkable similarities to the ELIP basalts in petrography and geochemistry. Flood basalts in the Sanjiangkou area are composed of the lower part of the low‐Ti (LT) tholeiite and the upper part of the high‐Ti (HT) tholeiite, which is the same as the flood basalts on the western margin of the Yangtze craton. Flood basalts in the Zongza and Songpan‐Garzê areas, which are far from the Yangtze craton, consist of HT tholeiite only. This is the same as the flood basalts within the Yangtze craton. Therefore we argue that these contemporary basalts all originated from the Emeishan mantle plume, and the ELIP could have a significant westward extension with an outcropped area of over 500,000 km 2 . This new scenario shows that the LT tholeiite occurs on the western margin of the Yangtze craton, while the HT tholeiite overlying the LT basalts occupies the whole area of the ELIP.