Stratigraphy and Facies Analysis of the Dakota Sandstone, West-Central New Mexico

The term ‘Dakota sandstone’ is a problematic one for geologists studying the sedimentary fills of basins developed during the Cenomanian flooding of the Western Interior Seaway. Classically, the Dakota comprises the initial succession of sediment laid down during the genesis of this seaway, but these deposits exhibit such spatial variability that few commonalities can be drawn between them. In the chronostratigraphic or lithologic domain the term ‘Dakota’ means very little, encompassing rocks that were deposited throughout multiple ages and on either ends of the Western Interior of the present-day United States. Significant paleogeographic features isolate depositional systems of Cenomanian, leading to a high degree of spatial variation in cyclicity, depositional environment, and shoreline stacking within the different regions of the Dakota. In this thesis, collected field data is compared to several field studies on the Dakota present in available literature to highlight the need for a revision of where the term Dakota is applied, and how a single classification of the Dakota can only be applied to certain paleogeographic regions. The collection of field data was also used to advance the development of novel facies models, in particular the asymmetric delta model of Bhattacharya & Giosan (2003). This thesis, in addition to its synthesis of Dakota interpretations, proposes two asymmetric delta candidate sites for more detailed future study. Lastly, field data was collected in a region of the Dakota sandstone that has yet to have a sequence stratigraphic interpretation applied to it, functionally moving towards an update of outdated literature.