Formation of the Cenozoic Ailao Shan mid-crustal tectonic discontinuity: Role of Oligo-Miocene stratified sub-horizontal middle to lower crustal flow in the southeastern Tibetan Plateau

Correlation among the Ailaoshan–Song Ma–Song Chay orogenic belts and implications for the evolution of the eastern Paleo-Tethys Ocean

“…9), consistent with the results of the field and microscopic observations. Our Ailaoshan results are consistent with the EBSD result of Fan et al (2022).…”

Thermal and Physical Properties of Barrovian Metamorphic Sequence Rocks in the Ailao Shan‐Red River Shear Zone, and Implications for Crustal Channel Flow

“…Cooling age discrepancies across the shear zone are closely associated with higher grade metamorphic rocks that have been differentially exhumed, thus forming an inverted BMS (Harrison et al., 1996). Many mechanisms have been proposed to explain this inverted metamorphic sequence, including shear heating (Leloup et al., 1999), emplacement of a hot overlying thrust sheet (Gilley et al., 2003), folding of pre‐existing isograds followed by juxtaposition by normal faulting (Chen et al., 2018), and differential displacement along shear zones (Fan et al., 2021). In other crustal‐scale shear zones on worldwide, the differential unroofing of high‐ P granulite‐facies compared to greenschist‐facies rocks has been documented, such as the Coimbra–Cordoba shear zone in Spain (Pereira et al., 2010), the Tauá and Senador Pompeu shear zone in northeast Brazil (Ávila et al., 2020, 2023), the Legs Lake shear zone in Canadian shield (Mahan et al., 2003), and in Fiordland, western New Zealand (Klepeis et al., 2007).…”

“…First, the metasedimentary rocks display an inverted BMS profile, with metamorphic grades spanning from the chlorite zone to the second-sillimanite zone (Harrison et al, 1992(Harrison et al, , 1996Ji et al, 2020;Liu et al, 2013). Second, adjacent to the southwest boundary fault, the micaschists are tectonically emplaced above older granites or Paleozoic phyllites/slates via a high-angle thrust (Leloup et al, 1995;Fan et al, 2021;Zhang et al, 2017a; Figure 2a). Third, as first identified in this study, a high-P granulite belt outcrops adjacent to the Red River Fault.…”

“…Furthermore, lateral ductile flow can produce a horizontal micaceous fabric in metapelitic units and induce pronounced radial anisotropy (Huang et al., 2007). These features are prominent in the upper levels of the BMS units in these shear zones, making them ideal samples to study such deformational phenomena (Fan et al., 2021). Many BMS units in shear zones in Southeast Tibet have experienced extensive recrystallization and syn‐shear magmatic intrusion, which has overprinted pre‐deformational metamorphic records (Gilley et al., 2003; Leloup & Kienast, 1993).…”