Sedimentology and stratigraphy of the Cenomanian Buda Limestone in central Texas, U.S.A.: Implications on regional and global depositional controls

Abstract

The Cenomanian Buda Limestone is a distinctive rock formation widely distributed in Texas and its neighboring regions. The extensive character and regional significance of this unit make the Buda Limestone a key stratigraphic datum in the Texas Gulf Coast Basin. Detailed sedimentologic and stratigraphic studies of this formation were mostly focused on the west Texas exposures. In central Texas, on the contrary, very few studies have been performed. Thus, the sedimentary environments and depositional dynamics in this region are still poorly understood. Moreover, the regional correlation between the central and west Texas lithostratigraphic members of this formation remains unknown. Here, based on a detailed sedimentologic and stratigraphic study of central Texas sections (Austin-Kingsbury-San Antonio transect), the Buda Limestone is interpreted as a shallow-subtidal, semi-restricted to nearly open marine (lagoonal) shelf deposit. This unit is subdivided into two members (comprising 4th-order sequences S1 and S2) laterally variable in the study area. Vertical and lateral facies changes in the Buda Limestone are interpreted to be a function of the dynamic interaction of an irregular topography with fluctuating sea levels, under possible eustatic control. The informal (central Texas) “lower Buda” member is laterally correlated with the Lechuguilla Member (lower Buda) and Red Light Member (middle Buda) of western Texas. The informal (central Texas) “upper Buda” member, on the other hand, corresponds to the Love Station Member (upper Buda) from west Texas.