Li S.,Sun Yat Sen University |
Li S.,Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resource Exploration |
Wang Y.,Sun Yat Sen University |
Wang Y.,Guangdong Provincial Key Laboratory of Geological Processes and Mineral Resource Exploration |
And 8 more authors.
Geotectonica et Metallogenia | Year: 2015
The South Taihang Mountains, tectonically located in the center of the North China Craton, was a stable tectonic zone during Paleoproterozoic and Early Mesozoic, but significantly reactivated since Late Triassic. It is an ideal area for better understanding of the mountain uplifting and unroofing during the Mesozoic lithospheric thinning of the North China Craton. This paper presents the results of our field investigations, apatite fission track dating, track length analysis and tectonothermal modeling of the Paleoproterozoic gneisses and Cretaceous diorite samples. The apatite fission track apparent ages of our samples range from 32 Ma to 75 Ma, significant younger than their corresponding ages of formation. The lengths of the fission tracks for each sample show a broad and unimodal pattern with the peak value of 11 μm. In combination with thermal simulation results and other geological observations, it is inferred that at least 3 km thick superficial materials of the South Taihang Mountains have been unroofed since the Late Cretaceous. The uplift of the mountains initiated before 100 Ma. Similar to the Weibei uplift of the Ordos basin, two episodic uplifts of the Taihang Mountains occurred at about 50-40 Ma and 10 Ma to present. The apatite fission track data also indicate that the uplift-cooling event of the South Taihang Mountains took place earlier in the north than in the south. Such an unroofing and uplift-cooling pattern temporally couples with the form of the Beitai planation surface and the rapid depression in the eastern North China (e.g. Bohaiwan basin). Our data provide important constraints on the shallow-level processes in response to the lithospheric thinning of the North China Craton. ©, 2015, Science Press. All right reserved.