Geochemical Characteristics and Chemostratigraphic Analysis of Wufeng and Lower Longmaxi Shales, Southwest China

The demand for shale gas has propelled researchers to focus on precise and high-resolution stratigraphic divisions homogeneous shales, of which the late-Ordovician Wufeng (O3w) early-Silurian Longmaxi (S1l) formations in southwest China are two best candidates exploration China. However, systematic chemostratigraphic work these strata is still sparse, existing either lack representativeness terms proxies used or subjective during their division procedures. Thus, automatic process based multi an objective statistical technique was applied establish a quantitative, high-resolution, robust scheme lower shales. geochemical analysis unveils that Lower shales show prominent heterogeneities terrigenous inputs, redox conditions, paleoproductivity, enabling potential application chemostratigraphy strata. Based heterogeneities, been established, whole could be divided into 13 chemozones using constrained clustering analysis. not only comparable regional sequence but also more higher-resolution. high TOC content brittle minerals within chemozone C1 makes it most preferable layer development. This research gives testifies feasibility usage Chinese