Mesozoic Tectonic Evolution in the Kurgovat‐Vanch Complex, NW Pamir

Abstract

Unraveling different episodes of deformation in regions that have a polyphase tectonic history is important in understanding the evolution of many orogens. Over the past several decades, growing geologic evidence of significant Mesozoic crustal shortening and thickening in the Tibetan-Pamir orogen has documented the importance that Mesozoic orogeny played in forming the vast Tibetan-Pamir Plateau (e.g.,

Was cratonic Asia deeply subducted beneath the Pamir? Evidence from P–T conditions and tectonic affinities of Cenozoic Pamir crustal xenoliths

“…Large uncertainties in interpretations of the xenolith origins are in part due to previous gaps in the understanding of the tectonic evolution of the Pamir. However, over the past decade, larger datasets of detrital and igneous zircon U–Pb ages and Sr–Nd isotopes in the region (Aminov et al, 2017; Chapman, Scoggin, et al, 2018; Jiang et al, 2013; Li, Robinson, Gadoev, & Oimuhammadzoda, 2020; Robinson et al, 2012; Schwab et al, 2004; Villarreal et al, 2020; Worthington et al, 2017) and an improved understanding of Pamir regional tectonics (e.g., Angiolini et al, 2013; Chapman, Robinson, et al, 2018; He et al, 2019; Imrecke et al, 2019; Kufner et al, 2016; Li, Robinson, Gadoev, & Oimuhammadzoda, 2020; Li et al, 2022; Robinson, 2015; Rutte, Ratschbacher, Schneider, et al, 2017; Schneider et al, 2019; Schurr et al, 2014; Sobel et al, 2013; Soret et al, 2019; Stübner et al, 2013) provide a critical framework to unravel where the xenoliths came from.…”

“…The earliest phase of Phanerozoic arc magmatism at c .480–405 Ma is recorded in the Western Kunlun terrane at the southeastern corner of the Pamir (e.g., Schwab et al, 2004). Late Palaeozoic oceanic arc magmatism at c .330 Ma is found in the Darvaz and Oytag terranes related to the northward subduction of the Variscan Ocean and assembly of Palaeo‐Asia (Jiang et al, 2008; Li et al, 2022; Rembe et al, 2021; Schwab et al, 2004). Late Triassic–Early Jurassic arc magmatism from c .230 to 200 Ma is widespread in the Northern Pamir Karakul‐Mazar and Kunlun terranes related to the northward subduction of Palaeotethyan Ocean (Chapman, Scoggin, et al, 2018; Robinson, 2015; Schwab et al, 2004).…”

“…Cessation of arc magma at c .90 Ma was coeval with the initial closure of the Shyok oceanic basin at c .92–85 Ma (Sharma, 1987; Boneman et al, 2015) shifting the Neotethyan oceanic subduction zone south of the Kohistan‐Ladakh arc. Subsequently, a period of Late Cretaceous juvenile magmatism at c .75–70 Ma is recorded in the Central Pamir terrane and Rushan‐Pshart arc (Chapman, Scoggin, et al, 2018), interpreted to result from retro‐arc extension related to Neotethyan slab‐rollback postdating the Early Cretaceous arc magmatism and retro‐arc crustal shortening (Chapman, Scoggin, et al, 2018; Li et al, 2022).…”

“…The Pamir is characterized by a thickened crust of $70 km (Schneider et al, 2019) interpreted to be primarily the result of the Cenozoic collision and subsequent underthrusting of the Indian plate to the south (Chapman et al, 2017;Chapman, Robinson, et al, 2018;Hacker et al, 2017;Shaffer et al, 2017). Further, although upper crustal shortening appears to be largely pre-Cenozoic (Chapman, Robinson, et al, 2018;Imrecke et al, 2019;Li et al, 2022;Robinson, 2015;Robinson et al, 2004Robinson et al, , 2007Robinson et al, , 2012, $90 km of Cenozoic internal shortening has been proposed within the Central Pamir and along the Rushan-Pshart suture zone (Rutte, Ratschbacher, Schneider, et al, 2017), which contributed to the Cenozoic crustal thickening along the Central Pamir (Hacker et al, 2017;Li, Robinson, Lapen, et al, 2020;Rutte, Ratschbacher, Schneider, et al, 2017).…”

Late Miocene to present synchronous extension and contraction in the eastern Pamir: Insights from inversion of thermochronologic data across the southern Muztaghata dome

“…1A), formed due to the late Paleozoic-early Mesozoic accretion of the Kunlun, Karakul-Mazar, central Pamir, and southern Pamir terranes (Fig. 1B; Burtman and Molnar, 1993;Burtman, 2010;Robinson et al, 2004Robinson et al, , 2012Robinson, 2015;Angiolini et al, 2013;Villarreal et al, 2020;Chen et al, 2021;Li et al, 2022;Rembe et al, 2022) and the late Mesozoic-Cenozoic intracontinental deformation caused by northward subduction of the Neo-Tethys oceanic slab and subsequent collision of the Indian and Asian plates (Burtman and Molnar, 1993;Sobel and Dumitru, 1997;Robinson et al, 2004;Cowgill, 2010;Bershaw et al, 2012;Sobel et al, 2011Sobel et al, , 2013Cao et al, 2013a;Robinson, 2015;Rutte et al, 2017aRutte et al, , 2017bChapman et al, 2018;Worthington et al, 2020;Cai et al, 2021;Li et al, 2022;Villarreal et al, 2023). In this convergent setting, igneous and medium-to high-grade (575-830 °C/6-22 kbar) metamorphic rocks were initially exhumed in the early Miocene in the Pamir interior in a series of gneiss domes that formed by detachment faulting associated with ∼N-S extension (Fig.…”