Zircon saturation in terrestrial basaltic melts and its geological implications

Scratching the Surface: A Marine Sediment Provenance Record From the Continental Slope of Central Wilkes Land, East Antarctica

“…A third scenario that could explain the scarcity of Nuyina‐age detritus is an underrepresentation of mafic rock types in the detrital zircon record (Licht & Hemming, 2017; Shao et al., 2019). The Nuyina Province likely comprises juvenile mafic rocks similar to the Arubiddy Ophiolite Complex of the Madura Province (Figure 2b).…”

“…The Nuyina Province likely comprises juvenile mafic rocks similar to the Arubiddy Ophiolite Complex of the Madura Province (Figure 2b). Although detailed analysis of zircon grains revealed well-developed oscillatory growth zoning ( Figure 4) and trace element signatures typical of a felsic igneous source (Figures 6 and S2), this could be a biased record related to the high abundance of zircon in felsic rocks compared to the typically small amounts of zircon contained in mafic rocks (Licht & Hemming, 2017;Shao et al, 2019). Another bias in favor of felsic rock compositions may also be introduced by the different weathering rates of mafic and felsic rock types.…”

Geochronological and petrological constraints from the evolution in the Saxon Granulite Massif, Germany, on the Variscan continental collision orogeny

“…Ti‐in‐zircon thermometry indicating crystallization of the protolith zircon at a temperature near 1,000°C agrees with two‐pyroxene thermometry data recording magmatic crystallization of the MSU metabasites over the range 900–1,200°C, with higher estimates for the metagabbros than the metadolerites (Lünser, 1994). The zircon solubility models of Watson and Harrison (1983) and Shao, Xia, Ding, Cai, and Song (2019) when applied to MORB‐type rocks from the Variscan belt, including sample Steina1, predict zircon saturation temperatures (Table 3) clearly below the wet MORB solidus at appropriate pressure conditions (Vielzeuf & Schmidt, 2001). Hence, the models preclude that zircon can precipitate from melts equivalent to these rocks, contrary to the invariably inferred presence of magmatic zircon.…”

“…Watson and Harrison (1983) reported a strong decrease in zircon solubility with H 2 O content in melts with <2 wt% H 2 O. Shao et al. (2019) argued that not the solubility but the dissolution rate of zircon decreases in H 2 O‐deficient melts. Their solubility model considering also mafic melts predicts saturation concentrations of Zr that vary around those implied by Watson and Harrison’s (1983) model (Table 3).…”

“…Their solubility model considering also mafic melts predicts saturation concentrations of Zr that vary around those implied by Watson and Harrison’s (1983) model (Table 3). The slow Zr diffusion in H 2 O‐deficient melts and the high ability of mafic melts to dissolve inherited or entrained zircon (Shao et al., 2019; Watson & Harrison, 1983) may lead to local saturation in zircon, in particular, if the melt cools faster than the Zr diffusion allows localized high concentrations of Zr to homogenize. Mafic melts with bulk Zr concentrations far below the zircon saturation threshold could thus precipitate zircon.…”