page_title: Huangling Complex
section_title: Westward extrusion model
hierarchical_section_title: Huangling Complex / Formation of a dome-shaped Huangling massif / Westward extrusion model
caption_attribution_description: English: Convergence of Qinling-Tonbai-Dabie belt from the north and Xuefengshan-Jiuling belt from the south squeezed Huangling massif to escape to the west. The slip ratio is faster than 1, so the western flank is steeper than the eastern flank.
context_page_description: Huangling Complex represents a group of rock units appear in the middle of Yangtze Block in South China, distributed across Yixingshan, Zigui, Huangling and Yichang counties. The group of rock involves nonconformity that sedimentary rocks overlie the metamorphic basement. It is a 73-km long, asymmetrical dome-shaped anticline with axial plane orientating in north-south direction. It has a steeper west flank and a gentler east flank. Basically, there are three tectonic units from the anticline core to the rim, including Archean to Paleoproterozoic metamorphic basement, Neoproterozoic to Jurassic sedimentary rocks and Cretaceous fluvial deposit sedimentary cover. The northern part of the core is mainly tonalite-trondhjemite-gneiss and Cretaceous sedimentary rock, it is called the Archean Kongling Complex. The middle of the core is mainly the Neoproterozoic granitoid. The southern part of the core is the Neoproterozoic potassium granite. Two basins are situated on the western and eastern flanks of the core respectively, including the Zigui basin and Dangyang basin. Both basins are synforms while Zigui basin has a larger extent of folding.
context_section_description: During Lower Late Jurassic to Upper Cretaceous, the intracontinental belt, namely the Qinling-Tongbai-Dabie belt and Xuefengshan-Jiuling belt to the north and south of Huangling massif respectively thrust over it. They squeezed Huangling massif to the west. An asymmetric ramp anticline trending north-south with steeper western slope and gentler eastern slope was formed. Evidence of thrust deformation can be found in the northern and southern rim of the Huangling dome.
caption: Western Extrusion Model
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