Differential uplift on the northeast margin of Ordos Basin: Evidence from apatite fission track analysis

Apatite fission track analysis provides the opportunity for revealing differential uplift processes and uplift rate during the Mesozoic-Cenozoic on the northeast margin (Fugu-Wubao section of Jinxi flexural fold zone) of Ordos Basin, and offers new constraints and knowledge to the whole basin tectonic evolution history and the relationship between tectonic evolution and the coupling coexistence of multiple energy resources. The AFT age of different tectonic units and their different strata reveal that the uplift of Fugu-Xingxian area along the northern section of the study area was earlier during 86-56 Ma in the late Cretaceous and 44-37 Ma in Paleogene with the rate of speed being 24.5 m/Ma and 41.8 m/Ma. The uplift of Zijinshan area of the middle section of the study area was relatively late, and the key tectonic events took place at 68-56 Ma and 35 Ma during the late Cretaceous to middle-late Paleogene, with the rate of speed being 48.8m/Ma and 49.2 m/Ma respectively. The uplift of Linxian-Wubao area along the south section of the study area was during 35-21 Ma with the rate of speed being 73.9 m/Ma. Therefore, the north section uplifted early, the middle section uplifted relatively late, and the south section uplifted last. What is more, the overall tectonic activation period mainly happened late in Paleogene in Fugu-Wubao section of Jinxi flexural fold zone, and the tectonic uplift rate weakened gradually from the south to the north in the northeast of Ordos Basin. Additionally, the relationship analysis of the tectonic event and the mineralizing chronology revealed that the key structural events and moderate uplift speed controlled reservoir formation time or mineralization time of the coupling coexistence of multiple energy resources on the northeast margin of Ordos Basin, and show the collaborative and coupled relationship between the tectonic events and accumulations.