Organic geochemical characteristics of the late Eocene–early Oligocene submarine fans and shelf deposits on Lemnos Island, NE Greece

Abstract

The Paleogene deep-sea clastic and shelf deposits on Lemnos Island, NE Greece were studied regarding their organic geochemical characteristics. This study suggests that the above rocks can be designated as source rocks that have some moderate to fair potential for gaseous hydrocarbons. Studied sediments have been deposited in a forearc basin, with the outer arc ridge as a major sediment source. During late Eocene–early Oligocene Lemnos was the site of accumulation of submarine fans that underlay shelf deposits, with tectonic activity being responsible for the upward shallowing of the depositional environment. Areas of turbidites have been seen in parts of a sand-rich submarine fan, on the base of the slope to basin floor environment. On these rocks the Rock-Eval 6 pyrolysis method was performed to evaluate their hydrocarbon potential. Kerogens of both environments and subenvironments are of Type III and Type IV. Both submarine fans present considerable TOC content, but the ‘basin floor’ fan is the most enriched sub-environment. Shelf is presented in an immature oil stage, whereas both ‘slope’ and ‘basin floor’ fans are in the immature/mature oil stage.