Paleoproterozoic high-pressure metamorphism in the northern North China Craton and implications for the Nuna supercontinent.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 26388458.
- Also identified by DOI 10.1038/ncomms9344 and PMC identifier 4595726.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The connection between the North China Craton (NCC) and contiguous cratons is important for the configuration of the Nuna supercontinent. Here we document a new Paleoproterozoic high-pressure (HP) complex dominated by garnet websterite on the northern margin of the NCC. The peak metamorphism of the garnet websterite was after ∼1.90 Ga when it was subducted to eclogite facies at ∼2.4 GPa, then exhumed back to granulite facies at ∼0.9 GPa before ∼1.82 Ga. The rock associations with their structural relationships and geochemical affinities are comparable to those of supra-subduction zone ophiolites, and supported by subduction-related signatures of gabbros and basalts. We propose that a ∼1.90 Ga oceanic fragment was subducted and exhumed into an accretionary complex along the northern margin of the NCC. Presence of the coeval Sharyzhalgai complex with comparable HP garnet websterites in the southern Siberian active margin favours juxtaposition against the NCC in the Paleoproterozoic.