Merensky-type platinum deposits and a reappraisal of magma chamber paradigms.

ABSTRACT: Most of the world's economically-viable platinum deposits occur as 'reefs' in layered intrusions - thin layers of silicate rocks that contain sulphides enriched in noble metals. There are two contrasting magmatic hypotheses for their formation. The first suggests accumulation through gravity-induced settling of crystals onto the magma chamber floor. The alternative argues for in situ crystallization, i.e. upward growth from the floor. Here we report on our discovery of the Merensky Reef in the Bushveld Complex that occurs on subvertical to overturned margins of depressions in a temporary chamber floor. Such relationships preclude crystal settling and demonstrate that the reef crystallized in situ. This finding indicates that platinum deposits can grow directly at the chamber floor, with im

SUBMITTER: Chistyakova S 

PROVIDER: S-EPMC6584556 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature