Organic Sulfur Markers as Proxies of Depositional Paleoeenvironments Related to Recôncavo and Amazon Basins, Brazil.

This study employed organic sulfur markers (S-markers) associated with geochemistry parameters to evaluate the paleoenvironment of different depositional settings in 24 samples collected in vertical sections of outcrops of the Candeias and Barreirinha Formations in Recôncavo and Amazon basins, respectively. A total of twenty-one S-markers from benzothiophene (BT), dibenzothiophene (DBT), and benzonaphtothiophenes (BNT) classes were optimized and quantified by gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS). S-markers efficiently evaluated and differentiated the depositional paleoenvironment in the source rocks based on the individual compound, in cross-validation with saturated biomarkers, and associated with parameters such as total organic carbon (TOC) and Rock-Eval pyrolysis.

An Integrated Assessment of Different Depositional Paleoenvironment Using Nitrogen Markers and Biomarkers after Chromatographic Methods Optimization.

In this study, chromatographic methods were first optimized to ensure the robustness of the identification and quantification of nitrogen markers and biomarkers. Then, the optimal conditions were applied to 14 crude oil samples deposited in distinct paleoenvironments from Brazil, Venezuela, and Colombia to perform an integrated geochemical assessment. Analytical standards, certified reference material, and retention indices were used to confirm the identification of biomarkers and N-markers.