PAIRED ORGANIC AND CARBONATE CARBON ISOTOPE CHEMOSTRATIGRAPHY OF THE MULDE EXCURSION FROM THE ALTAJME CORE, GOTLAND, SWEDEN

A mass extinction event and perturbation to the global carbon cycle, known as the Mulde Event, took place during the late Wenlock Epoch of the Silurian Period. The Mulde positive carbon isotope excursion is recorded in the rock record by two positive excursions. Previous low-resolution studies indicated that the onset and end of the Mulde Excursion are not precisely synchronous between carbonate and organic carbon. The purpose of this study is to evaluate the synchronicity of the organic and carbonate carbon records during the Mulde Excursion at extremely high resolution.

In order to test the synchronicity, a core (Altajme) from the Swedish island of Gotland was drilled that contains more than 180 meters of late Wenlock strata. For this project, 311 total organic carbon samples were taken 60 centimeters apart. These new organic carbon samples are compared with greater than 500 carbonate carbon isotope samples from the same core to demonstrate small scale variations in the onset and end of the Mulde positive carbon isotope excursion at the highest resolution ever produced for this interval globally.