摘要
Cenozoic volcanism has been well studied in northern, eastern and southwestern Tibet (Coulon et al., 1986; Arnund et al., 1992; Turner et al., 1993, 1996; Deng, 1978, 1998; Miller et al., 1999, Wang et al, 2000). But the data of the Cenozoic post\|collisional volcanism in central and southern Tibet is limited (Coulon et al., 1986; Turner et al., 1996; Zhang, 1998). These potassic and ultrapotassic intrusive and extrusive rocks are regarded to be a key clue for the deep lithospheric process of the plateau after Indo\|Asian collision. Present here is the preliminary results of the rocks from Oiyug (Wuyu) basin, about 150km northeast to Shigatse. Major and trace elements of the rocks are studied and compared with the ultrapotassic and potassic (shoshonitic) rocks exposed in Lhasa block and Qiangtang terrane.(1) Geologic setting. The magmatic rocks studied are Gazacun formation of the lower part of the Pliocene Oiyug group (N 2 oy ). The cross\|section is situated in Gazacun village of Namling. Gazacun formation is underlain unconformable by the andesitic rocks of Linzizong Group [(K 2—E 2) ln ], and covered by the coarse\|grain layered sandstone and conglomerate of Zongdangcun formation. The Gazacun formation consists of mediate\|acidic volcanics, granite\|porphyry, coal\|bearing clastics, plants and sporo\|pollen.
Cenozoic volcanism has been well studied in northern, eastern and southwestern Tibet (Coulon et al., 1986; Arnund et al., 1992; Turner et al., 1993, 1996; Deng, 1978, 1998; Miller et al., 1999, Wang et al, 2000). But the data of the Cenozoic post\|collisional volcanism in central and southern Tibet is limited (Coulon et al., 1986; Turner et al., 1996; Zhang, 1998). These potassic and ultrapotassic intrusive and extrusive rocks are regarded to be a key clue for the deep lithospheric process of the plateau after Indo\|Asian collision. Present here is the preliminary results of the rocks from Oiyug (Wuyu) basin, about 150km northeast to Shigatse. Major and trace elements of the rocks are studied and compared with the ultrapotassic and potassic (shoshonitic) rocks exposed in Lhasa block and Qiangtang terrane.(1) Geologic setting. The magmatic rocks studied are Gazacun formation of the lower part of the Pliocene Oiyug group (N 2 oy ). The cross\|section is situated in Gazacun village of Namling. Gazacun formation is underlain unconformable by the andesitic rocks of Linzizong Group [(K 2—E 2) ln ], and covered by the coarse\|grain layered sandstone and conglomerate of Zongdangcun formation. The Gazacun formation consists of mediate\|acidic volcanics, granite\|porphyry, coal\|bearing clastics, plants and sporo\|pollen.
出处
《地学前缘》
EI
CAS
CSCD
2000年第S1期107-108,共2页
Earth Science Frontiers
