DISTRIBUTION AND MAPPING OF THE CRETACEOUS TEPEE BUTTES OF THE WESTERN INTERIOR SEAWAY
A total of 106 buttes were studied in more detail at two sites ~32 km south of Colorado Springs, CO and ~5 km north east of Boone, CO. Six separate lithofacies were identified in outcrops of the Tepee Buttes and mapped at the meter scale: (I) vuggy facies, abundant vugs with thick cement rinds and coarse calcite spar and few fossils; (II) articulated clam facies, mostly articulated lucinids with some vugs; (III) muddy clam facies, lucinid clams in micrite; (IV) limestone concretion facies; (V) micrite facies; and (VI) microbialite facies, little to no fossil material with little to no early cement rinds around voids. Previous studies of the Tepee Buttes described a concentric arrangement of facies within each butte that ringed an inner, central vent pipe. Results of this study found that the facies showed distinct bedding patterns, suggesting vertical stacking of facies, rather than concentric arrangement.
The lithofacies on 106 separate buttes were mapped using differential GPS receivers. Preliminary analysis shows that a majority of the buttes (39%) are dominated by facies II, while only 16% are dominated by facies III. Facies I and VI each dominated 22% of the buttes mapped (facies VI and V had little mappable outcrop). If the buttes had a concentric arrangement of facies around a vent core, the same facies would be expected at the top and center of each butte. Our results show the presence of different facies at the center tops of different buttes. Therefore, these seep carbonates probably accumulated as vertical stacks of rapidly cemented carbonate that may or may not have had significant relief above the sea floor.