Geochronology of early Mesozoic diabase units in southwestern China: metallogenic and tectonic implications

Abstract

Online supplementary material: Figures S1 and S2 Figure S1. Magma oxygen fugacity during the formation of Hawaiian ocean island basalt (OIB; Jackson et al. 2012), Neoproterozoic mafic rocks of the Yangtze Block (Zhou et al. 2006) and the Badu diabase samples analysed during this study.

Formation and Forward Propagation of the Indosinian Foreland Fold‐Thrust Belt and Nanpanjiang Foreland Basin in SW China

“…We interpret the NE-to NNE-verging thrusts and related fault-propagation anticlines in the middle and northern parts of the ST as D 1 2 deformation. The timing of D 1 2 deformation is constrained by U-Pb ages of diabase intrusions (Qiu et al, 2019;Yang et al, 2018) and our LA-ICP-MS results of detrital zircon. In the Baduwei area, early stage 249 Ma diabase is folded with the anticline and late stage 187 Ma diabase truncates the anticline (Qiu et al, 2019).…”

“…10.1029/2020TC006552 3 of 24 Qiu et al, 2019). LS = Lhasa Block, QD = Qaidam Block, QS = Qamdo-Simao Block, QT = Qiangtang Block, SG = Songpan Ganzi accretionary complex, WB = West Burma.…”

“…Late Permian to Early Jurassic mafic igneous rocks crop out sporadically in the Nanpanjiang Basin and have yielded zircon U-Pb ages of ∼259 Ma, ∼249 Ma, ∼213 Ma and ∼187 Ma (BGMRGX, 1985;Dong et al, 2013;Huang et al, 2013;Li et al, 2013;Liu et al, 2010;Qiu et al, 2019;Wu et al, 2019;Yang et al, 2018;M. F. Zhou, Zhao, et al, 2006).…”

“…A north-dipping back-thrust fault, cutting through the anticline and thrust sheets, form a pop-up structure. A 249 Ma diabase is folded by the anticline which is cut by a 187 Ma mafic dyke(Qiu et al, 2019).…”

The timing of brittle deformation: An example from the Cenozoic faults in the Youjiang fold‐thrust belt in southwestern China

“…The fold‐thrust belt is formed by collision of the Indochina and SCBs during the Triassic Indosinian Orogeny (Figure 1; e.g., Duan, Meng, Christie‐Blick, & Wu, 2018; Li et al, 2017; Li, Zhang, Dong, & Johnston, 2014; Qiu et al, 2014, 2015, 2016, 2017). Previous regional structural analyses reveal that the Youjiang fold‐thrust belt experienced at least three episodes of deformation, namely Triassic (Indosinian) top‐to‐north thrusting, Jurassic (Yanshanian) northeast‐directed thrusting, and Cenozoic extensional faulting (Li et al, 2017; Qiu et al, 2016, 2019). Previous studies documented Late Cretaceous to Cenozoic alkaline ultramafic dikes in the region and proposed the origin in an extensional setting (Chen et al, 2009; Liu et al, 2010; Xu et al, 2012; Yang et al, 2018), whereas the relevant extensional structures have not been well identified.…”