Geologic Framework for the National Assessment of Carbon Dioxide Storage Resources?Williston Basin, Central Montana Basins, and Montana Thrust Belt Study Areas.

摘要

This three-part report contains the geologic framework for three adjacent study areas, including the Williston Basin, multiple Central Montana basins, and the Montana Thrust Belt (MTB) (fig. 1). Although these study areas are in close proximity and are included in a combined geologic framework report, the basins were formed and filled under different circumstances, and each is investigated and assessed separately, when amenable.The Williston Basin study area is situated in the northern Great Plains and extends into North Dakota, South Dakota, Montana and Canada. It is a relatively large structural and sedimentary intracratonic basin, with Cambrian through Tertiary formations, and has no topographic depression. The Central Montana Basins study area contains many of the same Cambrian through Tertiary age formations found in the sedimentary basins east of the northern Rocky Mountain Cordillera. This wide study area encompasses numerous smaller basins and structural uplifts. The MTB study area occupies the mostly mountainous terrain of western Montana, and borders Canada and Idaho. The MTB comprises the Cordilleran Thrust Belt located within the State of Montana, includes Paleozoic to Tertiary age sedimentary units, and consists of numerous thrust sheets and intrusive bodies (Perry, 1995).As in previous chapters of the Geologic Framework for the National Assessment of Carbon Dioxide Storage Resources series, geologists describe their investigation of the study areas and their work on unique storage assessments units (SAUs), when amenable. Furthermore, to preserve a consistent format across report chapters, these individual SAU descriptions are treated as top-level sections. Lastly, each of the three study areas requires a separate introduction to develop the geologic assessment framework, as in prior chapters of this series.