Whole-rock geochemistry and zircon O-Hf isotope compositions of ca. 2.35 Ga strongly peraluminous granites: Implications for increase in zircon δ18O values during the Paleoproterozoic
نویسندگان
چکیده
Zircon oxygen isotope ratios have been used to trace the incorporation of sedimentary rocks into magmas. The dramatic increase in maximum zircon δ 18 O values Paleoproterozoic observed global databases coincides with changes surface environments (e.g., rise subaerial and oxidative weathering), implying a connection between elevated these changes. 2.5 2.2 Ga, however, is relatively under-constrained owing limited available data this age range. To augment from critical time period understand potential causes for values, we report U-Pb ages zircon, as well as, whole-rock major element geochemistry strongly peraluminous granites (SPGs) southwestern margin Yangtze Block (China). Our geochronological demonstrate that SPGs crystallized at ∼2.35 Ga inherited 2428–2721 Ma are present granites, indicating source were deposited, subsequently metamorphosed, partially melted 2.43 2.35 Ga. Synmagmatic samples dated study ε Hf (t) −6.4 −0.9 high 7.6–9.9‰, above value Archean (∼7‰). These can be divided two groups based on geochemistry. Both Group 1 2 derived similar O, metapelitic source, but generated by dehydration melting hydrous melting, respectively. results fine-grained which had (as compared older rocks) 2.43–2.35 depositional interval high-δ sources studied here emergence continental crust sea level Great Oxidation Event. Supporting findings previous studies, contemporaneity our dataset Earth’s suggests potentially weathering contributed (at least partially) elevation rocks. Recycling magmas change magmatic earliest Paleoproterozoic. In addition, although focused single locality, suggest abrupt shift sets likely occurred Last, literature compilation suggested may also experienced stepwise Neoproterozoic Phanerozoic 12 14‰. coincidence increases oxygenation events atmospheric
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ژورنال
عنوان ژورنال: Geochimica et Cosmochimica Acta
سال: 2022
ISSN: ['1872-9533', '0016-7037']
DOI: https://doi.org/10.1016/j.gca.2022.06.029