Early preservation of organic carbon in turbidites in small basins, the Azores analog for petroleum basins.

Abstract

As sandy turbidites in deep marine environments can store substantial amounts of organic carbon, they are vital sources of petroleum. With sufficient burial time and heat, turbidite organic matter can ultimately become valuable oil and gas sources. Turbidites can originate from sedimentary flows caused by slope failure. Oceanic volcanic islands, such as the Azores, where earthquakes and volcanic eruptions frequently generate submarine landslides, are useful locations to study how slope failure leads to the burial of organic carbon in nearby basins, in effect, providing a small-scale analog for larger source-to-sink systems. In this study, we combine information from geophysical data and geochemical analyses of sediment cores to better understand the dynamics of organic matter change in and around turbidites. Multibeam sonar data will be used to identify upper-slope landslide embayments around the islands, whereas high-resolution seismic reflection data will allow us to study the geometries of the turbidite basins. An extensive set of shallow sediment cores collected for tephra studies by Hansteen of GEOMAR (Germany) and earlier cores collected on RV Trident, archived at University of Rhode Island, will allow us to study how rapid transport of slope sediment and subsequent burial can potentially preserve organic carbon by changing sedimentary redox state. We are seeking funding to travel to Rhode Island to interpret log, sample the Trident cores, and do some organic carbon analyses. Photos of the cores have shown dark sandy layers likely to be volcanic sand turbidites.

AAPG Datapages/Search and Discovery Article #90351 © 2019 AAPG Foundation 2019 Grants-in-Aid Projects