Fluid Flow, Thermal History, and Diagenesis of the Cambrian-Ordovician Arbuckle Group and Overlying Units in South-Central Kansas

Abstract

A diagenetic study of the Cambrian-Ordovician Arbuckle Group to the Middle Pennsylvanian Cherokee Group in south-central Kansas produced evidence of regional advective fluid flow and more localized fracture-controlled fluid flow affecting porosity. Late-stage megaquartz, baroque dolomite, and calcite produced high homogenization temperatures (86-144C), greater than can be explained by burial, necessitating hydrothermal fluids. Fluid inclusion salinities evolved from connate to those influenced by evaporites. Homogenization temperatures and 18O in baroque dolomite suggest warmer fluids stratigraphically shallower. The 87Sr/86Sr values indicate a regional advective aquifer during baroque dolomite precipitation, which may have been more locally controlled during calcite precipitation. Ouachita tectonism caused tectonically valved and gravity-driven fluid flow sourced from the Anadarko basin and possibly involved sandstone aquifers or basement. Mechanisms of ancient fluid flow appear to contrast with the modern system, which is separated internally by seal facies. The ancient aquifer system was vertically connected during migration of hydrothermal fluids.