Dual mixing for the formation of Neoproterozoic granitic intrusions within the composite Jiuling batholith, South China

Ephemeral Magma Reservoirs During the Incremental Growth of the Neoproterozoic Jiuling Composite Batholith in South China

“…The existence of inherited zircon cores may affect the shape of the zircon CSD, especially in granitoids. Moreover, a mixture of different magmatic batches is likely to be a common feature of granitic batholith formation (Wang & Wang, 2021). Igneous zircon that crystallized from earlier batches of melt might be partially dissolved in later batches, which would also influence the final CSD pattern.…”

“…The inter‐sample diversity in zircon oxygen isotopes indicates mixing of different batches of melts, which played an important role in the formation of the Neoproterozoic Jiuling batholith (Wang & Wang, 2021). In the CSD distribution, mixing of two magmas with non‐collinear straight CSDs will produce a concave‐up curved CSD (Figure S6 in the Supporting Information S1; Higgins, 1996; Higgins & Roberge, 2007).…”

“…830 and ca . 810 Ma (e.g., Rong et al., 2018; Sun et al., 2017; Wang & Wang, 2021; Wang, Zhou, et al., 2013, 2014; Zhao et al., 2013). The mean ages of individual intrusions vary from the oldest (Meiling) unit at ca .…”

“…The geochronological difference observed for individual intrusions has been interpreted to reflect incremental accumulation of different magmatic batches. The geochemical variations (e.g., whole‐rock major‐ and trace‐element contents, whole‐rock Nd isotopes, and zircon Hf and O isotopes) in all of these intrusions require multiple contributions of diverse melts to their parental magma bodies (Wang & Wang, 2021).…”

“…The common occurrence of accessory zircon in magmatic rocks, together with its refractory physical and chemical nature and low elemental volume diffusivities (Cherniak, 2010), makes it a potential tool for estimating the lifetimes of magma reservoirs, in particular for Precambrian igneous suites. The Jiuling composite batholith is one of the largest (>4,000 km 2 ; BGMRJX, 1984) Neoproterozoic granitic batholiths in South China and has been investigated thoroughly by whole‐rock geochemistry, geochronology, and in situ zircon Hf–O isotopes (e.g., Rong et al., 2018; Sun et al., 2017; Wang & Wang, 2021; Wang, Zhou, et al., 2013). In this paper, we report a study of zircon CSDs and oxygen isotopes for four intrusions in the Neoproterozoic Jiuling composite batholith.…”