Geochronology and geochemistry of the Carboniferous felsic rocks in the central Great Xing'an Range, NE China: Implications for the amalgamation history of Xing'an and Songliao–Xilinhot blocks

Abstract

The tectonic evolutionary history between the Xing'an Block (XB) and Songliao-Xilinhot Block (SXB) has been hotly debated. Here, we present precise geochronological ages and whole-rock geochemical data in the central Great Xing'an Range for the Carboniferous felsic rocks to reveal this tectonic history, as the petrogenesis of these rocks were closely related to tectonic activity between the XB and SXB. The age data with detailed geochemical analyses indicate three important stages of magmatism: early Carboniferous, early Late Carboniferous, and middle Late Carboniferous. The early Carboniferous granodiorites formed from the partial melting of metavolcanic rocks at mantle depths and show I-type features. The early Late Carboniferous monzogranites were generated by the partial melting of metagreywackes at middle to lower crustal depths, and they are S-type granites. The middle Late Carboniferous rhyolites formed from the partial melting of a thinned lower crust, and they display A-type characteristics. The data reveal three tectonic evolutionary stages between the XB and SXB during the Carboniferous era: from early Carboniferous subduction to early Late Carboniferous syn-collision, and to middle Late Carboniferous post-collisional extension. The accretionary mechanism of each stage featured horizontal accretion above subduction zones, amalgamation of different blocks, and vertical accretion fed by deep mantle materials, respectively.

Late Devonian to early Carboniferous magmatism in the western Songliao–Xilinhot block, Northeast China: Implications for eastward subduction of the Nenjiang oceanic lithosphere

“…However, the sedimentary record in Jalaid Banner and adjacent areas of the western SXB from the Late Devonian to early Carboniferous is poorly known, and further research is needed to establish a more detailed and accurate record. Following the amalgamation of the XAC and SXB (Liu et al, 2017, 2019; Ma et al, a), sedimentation occurred in the central Great Xing'an Range, with deposition of the Baoligaomiao and Gegenaobao formations during the late Carboniferous and of the Dashizhai, Zhesi, and Linxi formations during the Permian. A ductile shear zone has been identified in western Jalaid Banner (Qin et al, ), as revealed by mylonitization in Late Devonian and early Carboniferous granites (Figure ).…”

“…The evolution of convergence between the XAC and the SXB is closely associated with the history of narrowing and closure of the Nenjiang Ocean (NJO, the paleo‐oceanic basin between the XAC and the SXB; Liu et al, 2017; Ma et al, a; Xiao et al, ). Previous studies have typically regarded the NJO as a northern branch of the Paleo‐Asian Ocean (e.g., Liu et al, 2017; Zhou et al, ).…”

“…However, a recent regional geological survey (Qin et al, ) has identified a series of late Palaeozoic subduction‐related magmatic events in the western SXB that imply eastward subduction of the NJO slab. Therefore, a bidirectional subduction model between the XAC and SXB has been proposed (e.g., Liu et al, 2019; Ma et al, a; this study). However, investigation of the eastward subduction has been limited (e.g., Liu et al, 2019; Ma et al, a), meaning that the timing, evolution, and style of this subduction remain uncertain.…”

“…Therefore, a bidirectional subduction model between the XAC and SXB has been proposed (e.g., Liu et al, 2019; Ma et al, a; this study). However, investigation of the eastward subduction has been limited (e.g., Liu et al, 2019; Ma et al, a), meaning that the timing, evolution, and style of this subduction remain uncertain.…”

Preface: Tectonics of China

“…There is lack of ophiolitic rocks along the boundary between the Xing'an Block and Songliao Block, which has raised long‐time arguments for the location and timing of the boundary (Y. Liu et al, ; Y. Ma et al, ; B. Xu & Xu, ). Shi et al () report several A‐type granites along the boundary in the Yili area in the northern Great Xing'an Range.…”