Constraints of multiple detachment layers on structural deformation patterns in the basin: insight from 3D geological structure model in the Puguang area, China

Author(s):  
hanyu huang ◽  
dengfa he ◽  
weikang zhang

<p>Based on outcrop investigations, 3D seismic interpretations, drilling data and results from physical simulation experiment, the structural deformation characteristics of the Puguang area in the Sichuan Basin were studied. Our results show that there are three main detachment layers at different depths in the Puguang area. The lower detachment layer, which is composed of middle Cambrian gypsum-salt rock, controlled the deep structural deformation system (∈<sub>2-3</sub>-S). The mudstone at the bottom of the Silurian acts as the central detachment layer, separated while influencing both the bottom and the central structural deformation system (S-T<sub>1</sub>j). The Triassic Jialingjiang Formation gypsum-salt rock forms the upper detachment layer, which mainly controls the shallow structural deformation system (T<sub>2</sub>l-K). Different structural deformation systems have different degrees of structural deformation and relatively independent deformation styles. The deformation degree of the deep structural deformation system is relatively high, faults of this system cut through the Cambrian to the Silurian strata, forming a series of low amplitude thrust anticline; the central structural deformation system, which is sandwiched by two gypsum-salt rock layers, mainly brittle ductile shear zone, is characterized by high dipping thrust faulted anticlines with relatively larger amplitudes; the deformation degree of the shallow structural deformation system is relatively low, with narrow detachment anticlines and wide synclines developed, while a series of small pop-up structures superimposing on the overlying Jurassic sequences, and asymmetric highs and steep anticlines formed in local areas. Balanced cross section and physical simulation experiments show that the Puguang area suffered from superimposed compressional deformations originated from two directions, northeast and southeast.They represent the compressive stresses transmitted from the Dabashan orogenic belt in the northern margin of the Sichuan Basin and the compressive stresses transmitted from the Xuefengshan orogenic belt in the eastern margin, respectively.In addition, the rheological properties and the thickness of the detachment layer have important influence on the structural style.</p>

2019 ◽  
Vol 132 (3-4) ◽  
pp. 668-686 ◽  
Author(s):  
Hanyu Huang ◽  
Dengfa He ◽  
Di Li ◽  
Yingqiang Li

Abstract The tectonic setting of the southwestern Sichuan foreland basin, China, changed rapidly during the Paleogene period, and records from this period may provide crucial information about the formation and tectonic processes that affected the Sichuan Basin. To constrain the provenance and to reconstruct the paleogeography of the Paleogene successions, we conducted a detailed analysis of the petrology, geochronology, and sedimentary facies of rocks from the southwestern Sichuan foreland basin. The detrital components of the three analyzed sandstone samples indicate moderately to highly mature sediment that was primarily derived from a recycled orogen provenance. Five major age populations were identified in the U-Pb age spectra: Neoarchean to Siderian (2524–2469 Ma and 2019–1703 Ma), Neoproterozoic (Tonian to Cryogenian, 946–653 Ma), Ordovician to Carboniferous (Katian to lower Pennsylvanian, 448–321 Ma), and Carboniferous to Triassic (306–201 Ma). Each of these age populations corresponds to one or several potential sources around the southwestern Sichuan foreland basin. A multidimensional scaling analysis indicated that the Paleogene zircons were mainly derived from recycled sediments of the Songpan-Ganzi terrane and the Sichuan Basin, with minor input from the Yidun terrane, Kangdian terrane, Qinling orogenic belt, and Jiangnan-Xuefeng orogenic belt. More specifically, the sediment supply from the Songpan-Ganzi terrane to the foreland basin decreased significantly from the Mingshan stage to the Lushan stage, and the Sichuan Basin simultaneously became the most important source area. In addition, there is a high correlation between the detrital zircon U-Pb age spectrum of the southwestern Sichuan Basin and that of the Xichang Basin, which may suggest that a wider and unified Paleo-Yangtze Basin existed during the Late Cretaceous-early Paleogene.


2018 ◽  
Vol 52 (5) ◽  
pp. 401-413 ◽  
Author(s):  
Chuanqing Zhu ◽  
Ming Xu ◽  
Nansheng Qiu ◽  
Shengbiao Hu

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Feng Zhang ◽  
Hai-Dong Yu ◽  
Can Xiong ◽  
Zhao-Ying Wei ◽  
Guang-Zhao Peng ◽  
...  

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