Diagenesis and geochemistry of the Lower Permian Ingleside Formation, Owl Canyon area, Larimer County, Colorado
Date
2018
Authors
Issa, Ahmad, author
Sutton, Sally, advisor
Ridley, John, committee member
De Long, Susan, committee member
Journal Title
Journal ISSN
Volume Title
Abstract
The purpose of this study is to determine the diagenetic history and timing of hydrocarbon migration in the Lower Permian Ingleside Formation as revealed in the Ingleside roadcut at Owl Canyon area, Colorado. The studied exposure is divided into fourteen beds composed of quartz arenite sandstone, limestone, dolomite, or siltstone. Observations from outcrop and thin sections, including calcite veins, carbonate-hosted vugs, and carbonate cement, suggest carbonate mobility throughout the outcrop. Stylolites parallel to bedding may have formed by pressure solution related to compaction, and pressure solution of carbonates is one possible source of carbonate that could have precipitated in veins or as cement. The formation was affected by other diagenetic processes, in addition to compaction and carbonate cementation, including feldspar dissolution and alteration and several stages of cementation. Cements include hematite, calcite, dolomite, kaolinite, and quartz overgrowth cement. Hematite cement was determined to have precipitated very early. Poikilotopic carbonate cement was precipitated very early, but after the precipitation of the hematite cement. Blocky calcite and blocky dolomite cements, the most common cements within the formation, were precipitated after the hematite and poikilotopic cements. Kaolinite cement was probably precipitated in association with feldspar dissolution and alteration, or occurred with feldspar dissolution during modern weathering. Hydrocarbon migration probably occurred before the precipitation of the blocky carbonate cement. The relationship between S and MgO in some sandstone samples may indicate that Mg and S have been added by diagenetic fluids. Also, K2O correlates with Al2O3 probably because both elements are mainly in the same phases, clay minerals, micas, K-feldspar, or glauconite. This study of the Ingleside outcrop provides some information about the diagenesis, possible timing of possible hydrocarbon migration through the Ingleside Formation, and geochemical and mineralogical composition of the exposure, which was used to interpret the diagenetic history throughout the outcrop. Therefore, this study adds to understanding of hydrocarbon migration and the hydrocarbon pathways in this part of the Denver Basin.