摘要
Much remains to be discovered concerning the time of collision of the Paleoasian Ocean and the Late Paleozoic evolution in the Beishan orogenic belt. The insufficient research on the Late Paleozoic strata of the Beishan orogenic belt,to a great extent,limits the further discussion of the tectonic evolution. This paper shows that the LA-ICP-MS zircon U-Pb ages of the "Early Carboniferous Lvtiaoshan and Baishan formations"and the"Early Permian Shuangbaotang Formation"volcanics from the Hongshishan area are 296. 8 ± 3. 5Ma,314. 9 ± 3. 3Ma,and 299. 4 ± 5. 9Ma respectively,which belong to the Late Carboniferous-Early Permian Ganquan Formation of the Beishan orogenic belt. The relationship between the"Shuangbaotang Formation"and"Baishan Formation"should not be disconformable as thought before,which suggests an entire Carboniferous-Permian rift basin. And the unconformity between the "Lvtiaoshan Formation"and the Middle Devonian could be the one between the Ganquan Formation and the Middle Devonian,which implies the closure of the Paleoasian Ocean between the Middle Devonian and Early Carboniferous.