Trace metal geochemistry of Bolivian carbonate rock formations - Patches of life during the Permian mass extinction

Trace metal (molybdenum, uranium, vanadium, zinc, and nickel) mass changes are used to investigate secular variations in oceanic redox conditions in the succession of Copacabana (Upper Pennsylvanian-Early Permian) and Chutani (Upper Permian) formations of the Titicaca sub-basin (western Bolivia). These trace metal mass variations display evidence of suboxic depositional conditions, with episodes of oxygenation in the shallow carbonate platform of the Titicaca Basin. These episodes are consistent with the unrestricted renewal of deep waters of the Late Pennsylvanian Midcontinent Sea via lateral advection of oxygen-deficient waters of the western tropical Panthalassic Ocean. Trace metals in the Chutani Formation also attest intermittent suboxic conditions with oxic periods being recorded. These results, compared to other Upper Permian sections worldwide, suggest the idea that shallower platforms had oxygen during the mass extinction events of that period.