f Chemostratigraphic correlation of cretaceous cansona formation outcrops and implications on the interpretation of its depositional environment

In the southern Colombian Caribbean coast (Sinú-San Jacinto Basins) a significant potential for hydrocarbon generation has been identified. This potential is also confirmed by the occurrences of oil and gas seepage on the surface. Previous research has suggested these manifestations, both liquid and gaseous to be correlated with source rocks of Cretaceous and Tertiary age. The absence of oil-rock correlations, the immaturity and the type of kerogen from the Tertiary rocks proposed as potential source rocks, have redirected the attention to the detailed study of the Cretaceous Cansona Formation. 460 rock samples collected from outcrops of the Cansona Formation in six different localities were characterized using basic geochemical techniques (Total organic carbon (TOC), RockEval pyrolysis VI) , Mass spectrometry with inductively coupled plasma (ICP-MS, macro elements and trace elements) and total sulfur (LECO sulfur analyzer carbon). These data were analyzed using statistical techniques and cluster dendrograms for the definition of quimiofacies. The results allowed the definition of six quimiofacies which are described in compositional and parametric terms. These facies were determined by the type of organic matter and the paleo environmental conditions of deposit. These chemo facies are positively correlated with organofacies described in previous works. The chemofacies 1 is associated with the best inputs of organic matter and higher contents of the elements S, V, Ni and Co. The Co/Ni ratio shows that the organic matter is predominantly of marine origin and the parameter V/Ni indicates that this organic matter was deposited under anoxic to disoxic conditions.