Geochemistry of the Albian to Upper Maastrichtian formations of the K1 oil well (East of the Côte d’Ivoire offshore basin): Depositional environment and implication of provenance

Abstract

The studies were carried out on 93 samples of cuttings from the K1 oil well. These samples were processed using the Fluorescence Spectrometer (XRF) method. Chemical analyses contributed to the determination of depositional environments and origin of the sediments. Albian sediments deposited in an environment proximal to the continental characterize the MS1 mega-sequence. In contrast, the MS2 mega-sequence (Cenomanian to Maastrichtian) was deposited in a shallow to deep marine environment marked by a decrease in detrital flow. The ratio Ti/Y, with values below 0.017 in the MS1, means that the sediment source of the mega-sequence MS1would therefore be richer in phosphates, with a contribution from mafic volcanic rocks (rich in illite, iron and magnesium). In contrast to MS1, MS2 is characterized by ratio Ti/Y values above 0.017. This decrease in Yttrium content in this mega-sequence is consistent with Th/Al values below 1.588. This would suggest a richer source of titanium oxides, which could be rutile, sphene or anatase.