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Neogene Expansion of the Qilian Shan, North Tibet: Implications for the Dynamic Evolution of the Tibetan Plateau
Author(s) -
Pang Jianzhang,
Yu Jingxing,
Zheng Dewen,
Wang Weitao,
Ma Yan,
Wang Yizhou,
Li Chaopeng,
Li Youjuan,
Wang Ying
Publication year - 2019
Publication title -
tectonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.465
H-Index - 134
eISSN - 1944-9194
pISSN - 0278-7407
DOI - 10.1029/2018tc005258
Subject(s) - geology , neogene , thermochronology , cenozoic , paleocurrent , plateau (mathematics) , paleontology , paleomagnetism , fission track dating , late miocene , tectonics , clockwise , tectonic uplift , paleogene , magnetostratigraphy , structural basin , geomorphology , seismology , fold (higher order function) , clastic rock , mathematical analysis , mathematics , mechanical engineering , engineering
The Qilian Shan, at the northeastern frontier of the Tibetan Plateau, is a key area for studying the expansion mechanism of the Tibetan Plateau. Although previous thermochronology and paleomagnetic studies indicate Neogene northward expansion of the northern Qilian Shan, there is a distinct temporal gap in knowledge relative to the tectonic history of the southern Qilian Shan. This has hindered a complete understanding of the Cenozoic deformation pattern of the entire Qilian Shan. To study the growth history of the southern Qilian Shan, apatite fission track (AFT) data have been acquired from Zongwulong Shan and the Huaitoutala section. AFT thermal history modeling from the former shows a rapid cooling episode occurred at ~18–11 Ma, which is interpreted as marking the onset of intensive exhumation in the southern Qilian Shan. Within the Huaitoutala section, detrital grain up‐section shows progressively decreasing peak AFT ages followed by an age increase from midsection, implying that a sediment‐recycling event occurred at approximately 7 ± 2 Ma. Together with a shift in paleocurrent directions, this change marks the onset of Late Miocene deformation of the northern Qaidam Basin. Combined with previous studies on the deformation time of the Qilian Shan, our findings suggest that both the northern and southern Qilian Shan region grew outward synchronously in opposite directions during the Neogene. This resulted in the formation of a flower structure, which had an important impact on the deformation pattern of north Tibet. The synchronous outward expansion may have been triggered by the removal of mantle beneath north Tibet.