The Cenozoic uplift of Qilian Mountains is critical to comprehend the uplift and extension of the Tibet Plateau as well as the formation of the first and second steps in China's topography. This study summarized d...The Cenozoic uplift of Qilian Mountains is critical to comprehend the uplift and extension of the Tibet Plateau as well as the formation of the first and second steps in China's topography. This study summarized dynamic stratigraphic realm comprehensively on the basis of stratigraphic correlation of different Cenozoic sedimentary basin regions of the Qilian Mountains and adjacent mountains. This facilitated the re-creation of the tectonic-sedimentary evolutionary process of the Qilian Mountains and their surrounding areas. The results indicate that during the Early Paleogene(Paleocene-Eocene), the Qilian Mountains were part of an uplift realm. During the Oligocene, Guide-Xining-Lanzhou-Linxia sag basin at the northern margin of the West Qinling Mountains came into being and was subjected to sedimentation. The Suli Basin located between the North and South Qilian paleo-uplifts began to form and undergo sedimentation. Intracontinental orogenic extrusion and basin detachment occurred at the Qilian Mountains during the Miocene, which caused successive uplifts of various mountains, including the Laji, South Qinghai,Jishi, Liupan, and South Shule Mountains. Until Pliocene, Qilian Mountains uplifted continuously and resulted in the shrink,extinction and being eroded of the basins, and aeolian red clay started to accumulate.展开更多
Many plateau-edge reefs and reef mounds of the Late Permian have been discovered in Linxi County and adjacent areas of Inner Mongolia, China. These reefs verify that the Hinggan-Inner Mongolia Area was an open and uno...Many plateau-edge reefs and reef mounds of the Late Permian have been discovered in Linxi County and adjacent areas of Inner Mongolia, China. These reefs verify that the Hinggan-Inner Mongolia Area was an open and unobstructed sea-trough in Late Permian. Facies and sequences of reef strata in Member 4 and Member 5 of the Linxi Formation were studied for information to reconstruct the closing process of the Linxi-Jiutai chasm in the sea-trough, i.e., to constrain subsidence, uplift, and final closing. Ages of the reef-bearing strata have been determined to be late and end of Late Permian, based on ranges or abundances of diverse fossils. Six reef-building organic assemblages were distinguished, representing different ecologic conditions, according to morphological functions and paleoecological adaptations of organisms including primarily sponges, bryozoans, and calcareous algae. Two types of shelf slopes, the gentle slope and the steep slope, have been interpreted for Member 4 and Member 5 of the Linxi Formation, based on the assemblages. The locations of outcrops, and types of these reefs delineate the north margin of Sino-Korea Platform, and define uplift and final closing of the Linxi-Jiutai chasm at the end of Late Permian.展开更多
基金supported by the China Geological Survey (Grant No. DD20160345-16)the National Natural Science Foundation of China (Grant Nos. 40382039, 41372020, 41372036, 41472035)
文摘The Cenozoic uplift of Qilian Mountains is critical to comprehend the uplift and extension of the Tibet Plateau as well as the formation of the first and second steps in China's topography. This study summarized dynamic stratigraphic realm comprehensively on the basis of stratigraphic correlation of different Cenozoic sedimentary basin regions of the Qilian Mountains and adjacent mountains. This facilitated the re-creation of the tectonic-sedimentary evolutionary process of the Qilian Mountains and their surrounding areas. The results indicate that during the Early Paleogene(Paleocene-Eocene), the Qilian Mountains were part of an uplift realm. During the Oligocene, Guide-Xining-Lanzhou-Linxia sag basin at the northern margin of the West Qinling Mountains came into being and was subjected to sedimentation. The Suli Basin located between the North and South Qilian paleo-uplifts began to form and undergo sedimentation. Intracontinental orogenic extrusion and basin detachment occurred at the Qilian Mountains during the Miocene, which caused successive uplifts of various mountains, including the Laji, South Qinghai,Jishi, Liupan, and South Shule Mountains. Until Pliocene, Qilian Mountains uplifted continuously and resulted in the shrink,extinction and being eroded of the basins, and aeolian red clay started to accumulate.
基金supported by the National Natural Science Foundation of China (Grant No. 41472027)the Chinese Geological Survey (Grant No. 1212011120927)
文摘Many plateau-edge reefs and reef mounds of the Late Permian have been discovered in Linxi County and adjacent areas of Inner Mongolia, China. These reefs verify that the Hinggan-Inner Mongolia Area was an open and unobstructed sea-trough in Late Permian. Facies and sequences of reef strata in Member 4 and Member 5 of the Linxi Formation were studied for information to reconstruct the closing process of the Linxi-Jiutai chasm in the sea-trough, i.e., to constrain subsidence, uplift, and final closing. Ages of the reef-bearing strata have been determined to be late and end of Late Permian, based on ranges or abundances of diverse fossils. Six reef-building organic assemblages were distinguished, representing different ecologic conditions, according to morphological functions and paleoecological adaptations of organisms including primarily sponges, bryozoans, and calcareous algae. Two types of shelf slopes, the gentle slope and the steep slope, have been interpreted for Member 4 and Member 5 of the Linxi Formation, based on the assemblages. The locations of outcrops, and types of these reefs delineate the north margin of Sino-Korea Platform, and define uplift and final closing of the Linxi-Jiutai chasm at the end of Late Permian.
