Samarium neodymium direct dating of fluorite mineralization
Calcites from early- and late-stage mineralization form two distinct isochrons corresponding to 155.5±1.1 and 124.1±3.7 Ma, respectively.
The isochron ages suggest that Sb mineralization took place during the Late Jurassic–Early Cretaceous Period in the Xikuangshan district, consistent with previous geological observations and with independent isotope data.
The mid-Cretaceous age of ~111 Ma suggests the Albian/Aptian transition as the most likely period for large-scale fluid circulation during a regional extensional tectonic event, related to the opening of the North Atlantic ocean.
These calcite veins contain relatively high concentrations of rare earth elements with MREE-enriched patterns, and yield Sm-Nd isochron ages of 134 ± 3 Ma to 136 ± 3 Ma, with significant different initial ε values of − 12.9 and − 2.0, respectively.
Shuiyindong is one of the largest and highest grade, stratabound Carlin-type gold deposits in China.
It is hosted in Permian bioclastic limestone near the axis of an anticline.
Samarium–neodymium dating of calcites shows potential for determining ages of hydrothermal mineralization.
Sr of ~0.71245 suggest an upper crustal source of the hydrothermal system, in agreement with earlier work on fluid inclusions which indicated a basinal brine origin.