COUPLED SULFUR-SILICON ISOTOPES REVEAL SUPRACRUSTAL ORIGIN OF ARCHEAN CONTINENTS
Seminars
Semester 2
The genesis of Archean continental crust through partial melting of hydrous mafic protolith is widely acknowledged, yet the origin of the mafic protolith remains highly contentious. Silicon isotopes and quadruple sulfur isotopes serve as particularly powerful tools in this regard, as they directly trace the source nature of the felsic continent. Here, we integrate whole-rock silicon and sulfur isotopic data of Neoarchean granitoids from the North China Craton to constrain the origin and pathway of their protoliths. These granitoids exhibit non-zero Δ³³S (−0.06‰) and elevated δ³⁰Si (−0.09‰ to −0.05‰), requiring a supracrustal source. Global compilation shows that granitoids formed after 3800 Ma uniformly contain enriched δ³⁰Si and non-zero Δ³³S, implying that most, if not all Archean continental crusts were derived from partial melting of supracrustal sources rather than unaltered mafic cumulates.
For additional information, please contact Mr. Kun SHANG, kshang@connect.hku.hk.