Dissertations and Theses

Date of Award


Document Type



Earth and Atmospheric Sciences

First Advisor

Benjamin A. Black

Second Advisor

Steven B. Kidder

Third Advisor

Zhengrong Wang


carbonatite, LIP, δ13C


Large igneous province (LIP) eruptions have been linked in some cases to major perturbations of Earth’s carbon cycle. However, few observations directly constrain the isotopic composition of carbon released by LIP magmas because carbon isotopes fractionate during degassing, which hampers understanding of the relative roles of mantle versus crustal carbon reservoirs. Carbonatite magmatism associated with LIPs provides a unique window into the isotopic systematics of LIP carbon because the majority of carbon in carbonatites crystalizes rather than degassing. Here, we present new δ13C data for the Guli carbonatites in the Siberian Traps. In addition, we compile ~260 published measurements of δ13C from carbonatites related to the Deccan Traps and the Paraná-Etendeka. We find no evidence for magmas with carbon isotope ratios lighter than depleted mantle values of δ13C =−6±2‰ from any of these LIPs, though some carbonatites range to heavier δ13C ratios. We attribute relatively heavy δ13C ratios in some carbonatites to either slightly 13C-enriched domains in the mantle lithosphere or carbon isotope fractionation in deep, carbon-saturated LIP magma reservoirs. The absence of a light δ13C component in LIP magmas supports the view that lithospheric carbon reservoirs must be tapped during cases of LIP magmatism linked with negative carbon isotope excursions and mass extinctions.



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