On the origin of high-pressure mafic granulite in the Eastern Himalayan Syntaxis: Implications for the tectonic evolution of the Himalayan orogen

Underthrusting and Pure Shear Mechanisms Dominate the Crustal Deformation Beneath the Core of the Eastern Himalayan Syntaxis as Inferred From High‐Resolution Receiver Function Imaging

“…Accordingly, we interpret the observed discontinuous intra‐crustal interface C to represent the top boundary of the underthrusting Indian lower crust (Figures 3 and 4). A supporting evidence for this interpretation is that the P‐T conditions of high‐pressure granulite from the EHS also indicate that the Indian continental crust underthrusted to at least 50–55 km depth (Zhang et al., 2022). Confined by the east‐dipping feature of this top interface, the Indian lower crust thins dramatically toward the east and finally disappears at the eastern edge of the HH.…”

Intraoceanic Subduction System Within the Neo‐Tethys: Evidence From Late Cretaceous Arc Magmatic Rocks of the Eastern Himalaya

“…The lower (southern) GHS unit is composed mainly of migmatitic amphibolite and orthogneiss and underwent upper amphibolite‐facies metamorphic and partial melting. Late Paleoproterozoic, Neoproterozoic, Early Paleozoic, and Early and Late Cretaceous protolith ages have been obtained from the orthogneisses and amphibolites of the GHS (Booth et al., 2004, 2009; Guo et al., 2008; Peng et al., 2018; Z. M. Zhang et al., 2008, 2012; Z. M. Zhang, Ding, Palin, et al., 2022).…”

“…These rocks consist of plagioclase, amphibole, biotite and quartz, with or without garnet (Figures 2c and 2d), indicating peak metamorphism of upper amphibolite‐ and granulite‐facies conditions. The garnet is replaced along its margins by a symplectitic corona consisting of fine‐grained amphibole, biotite, and plagioclase (Figure 2d), which is a typical texture formed during the exhumation of HP mafic granulites (Z. M. Zhang, Ding, Palin, et al., 2022). The studied rocks have the same deformation foliation, and metamorphic and migmatitic structure as the associated gneisses, schists and HP granulites of the upper GHS unit, indicating that all of the rocks experienced coherent Cenozoic deformation, metamorphism and anatexis during the subduction and exhumation of Indian continental crust.…”

“…The upper (northern) unit occurs as a NE‐SW striking belt within the northwestern part of the GHS and includes three tectonic slices that are separated by ductile shear zones or detachment and thrust faults (DF 1 and DF 2 ; Figures 1b and 1c). The upper GHS unit consists of gneiss, schist, amphibolite, marble, calc‐silicate rock and high‐pressure (HP) granulite and experienced an extended period of upper amphibolite‐facies to granulite‐facies metamorphism and partial melting from ∼50 to ∼3 Ma (Booth et al., 2004, 2009; L. Ding et al., 2001; Peng et al., 2018, 2022; Tian et al., 2016, 2020; Z. M. Zhang et al., 2012, 2015; Z. M. Zhang, Ding, Palin, et al., 2022). The lower (southern) GHS unit is composed mainly of migmatitic amphibolite and orthogneiss and underwent upper amphibolite‐facies metamorphic and partial melting.…”

Leucogranite Records Multiple Collisional Orogenies

“…Granite is a key component of the continental crust and is mainly formed at convergent continental margins in accretionary and collisional orogens (Sawyer et al., 2011; Zheng & Gao, 2021). Leucogranite, characterized by less than 5% of dark‐colored minerals (e.g., biotite), is a minor but widely distributed component of most orogens in Western Europe (e.g., Monecke et al., 2011), the North and South American Cordilleras (Atherton & Petford, 1993; Gaschnig et al., 2011), the Grenville Province (Chiarenzelli et al., 2017), and the Himalayas (Liu, Wang et al., 2020; Wu et al., 2020; Zhang et al., 2022). The late stage setting of leucogranites within the orogenic cycle makes leucogranite zircon an important time‐capsule into orogenic history extending from the inherited core to its zircon overgrowth, and potentially provides a complete record of multiple orogenic events.…”