Generation of late Mesozoic felsic volcanic rocks in the Hailar Basin, northeastern China in response to overprinting of multiple tectonic regimes

Abstract

We performed zircon U–Pb age dating and geochemical analyses of late Mesozoic felsic volcanic rocks in the Hailar Basin, NE China, with the aim of eclucidating their emplacement ages, origin and geodynamic significance. The volcanic rocks consist of dacites, rhyolites and rhyolitic tuffs. Laser ablation–inductively coupled plasma–mass spectrometry zircon U–Pb dating results suggest that the rocks were erupted during the Late Jurassic–Early Cretaceous (161–117 Ma). They belong to the high-K calc-alkaline series and can be divided into two groups. Group I rocks are metaluminous to weakly peraluminous, contain low concentrations of heavy rare earth elements (HREEs) and high field strength elements (HFSEs), and have low zircon saturation temperatures (average 786 °C), all of which indicate an I-type affinity. In contrast, Group II rocks have higher HREE and HFSE concentrations and zircon saturation temperatures (average 918 °C), suggesting an A-type affinity. All the felsic volcanic rocks have positive εHf(t) values of 1.43–12.32 with two-stage model ages of 1110–401 Ma. Our data indicate that the I-type felsic volcanic rocks formed from magmas generated by partial melting of a dominantly juvenile mica-bearing K-rich basaltic lower crust, whereas the A-type felsic volcanic rocks originated from the partial melting of a dry mafic–intermediate middle–lower crust that was dehydrated but not melt depleted. Based on the present results and previous research, we propose that the Late Jurassic I- and A-type felsic volcanic rocks in the Hailar Basin were formed in a post-collisional environment related to break-off of the subducted oceanic slab of the Mongol–Okhotsk Ocean and the subsequent gravitational collapse of the orogenically-thickened crust after closure of the ocean. In contrast, the Early Cretaceous I- and A-type felsic volcanic rocks were erupted in an extensional setting related to rollback of the subducted Paleo-Pacific Plate.

A rift‐scale view at strain partitioning during multiphase rifting: Insights from the Hailar Basin, northeast Asia

“…The geodynamic origin of extension in the Hailar Basin and adjacent regions has been highly disputed, and two alternative models are generally invoked (Figure 8; Guo, 2018; Ji et al, 2019a, b, 2021; Li et al, 2014; Mao, 2020; Meng, 2003; Sun, 2016; Wang et al, 2015; Xu et al, 2013; Yang et al, 2015; Zhang et al, 2022). These competing models mainly include (a) the break‐off of the Mongol‐Okhotsk Oceanic slab (Guo, 2018; Mao, 2020; Meng, 2003; Yang et al, 2015); and (b) the rollback of the Paleo‐Pacific slab (Ji et al, 2019a, 2021; Li et al, 2014; Sun, 2016).…”

“…Some studies proposed a composite model and thought that the Mongol‐Okhotsk slab break‐off and Paleo‐Pacific slab rollback may have successively driven the evolution of the Hailar Basin (e.g. Ji et al, 2019b; Wang et al, 2015; Zhang et al, 2022). At present, limited work has been carried out with the aim to understand the variations of multiphase rifting and relevant controlling factors (e.g.…”

“…400 m (Liu, 2014). The stratigraphic ages are constrained by the combination of biostratigraphic data, zircon U–Pb dating of volcanic rocks and stratigraphic correlation with the Songliao Basin (Figure 2; Ji et al, 2019a, b, 2021; Li et al, 2010; Meng et al, 2003; Song et al, 2018; Wan et al, 2005; Wang et al, 2016; Zhu et al, 2020).…”

Geochemistry of the Laiyang Group from outcrops and Lingke-1 core on Lingshan Island, Shandong Province, Eastern China: implications for provenance, tectonic setting and palaeo-environment

“…The geochemical characteristics of sediments provide valuable information about their provenance (Wilson et al 1998;Verma & Armstrong-Altrin, 2013Armstrong-Altrin et al 2015bMadhavaraju, 2015;Wang et al 2015Wang et al , 2017aWang et al , b, c, 2018Wang et al , 2020Gholami et al 2017;Gao et al 2018;Zhang et al 2018;Ji et al 2019;Zeng et al 2019).…”