⁸⁷Sr/⁸⁶Sr evidence from the epeiric Martin Ridge Basin for enhanced carbonate weathering during the Hirnantian.

ABSTRACT: A pronounced positive δ¹³C excursion in the Hirnantian Age has been documented globally, reflecting large perturbations of carbon cycling in the Late Ordovician oceans. Increased organic-carbon burial or enhanced carbonate weathering during glacioeustatic sea-level regression has been proposed to account for this anomalous C-isotope excursion. To test the two competing hypotheses, we measured ⁸⁷Sr/⁸⁶Sr and δ¹³C of carbonates from the Copenhagen Canyon section in Nevada, USA. Our data reveal two rapid negative ⁸⁷Sr/⁸⁶Sr shifts that coincide with two prominent positive δ¹³C excursions and glacial advances. Numerical model simulations suggest that enhanced weathering of carbonates driven by glacio-eustatically contro

SUBMITTER: Hu D 

PROVIDER: S-EPMC5595791 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature