Kenilworth Member, Upper Cretaceous, Book Cliffs,eastern Utah

The Book Cliffs of eastern Utah contain some of thebest exposures to shallow marine strata in the world. The cliffs extend almost continuously for 300 kmfrom Helper, Utah to Grand Junction in Colorado. Along these cliffs are numerous canyons which haveprovided researchers with an excellent threedimensional image of the geology that has beenexposed. Within these strata two clastic wedges havebeen identified: the Star Point Formation and theBlackhawk Formation. The Blackhawk Formation containssix members, of which the Kenilworth Member is thefocus of this work. Through a petrographic study, itwas noted that moving down-dip on the shoreface thegrain size decreased as well as the quartz content.These trends support the expected transition from asand-rich shoreface environment to a mud-rich shelfenvironment. The shelf bodies are anomalous sand-richlenses or lobate bodies completely encased in shelfmudstones. The origin of these bodies is still underdebate but petrographically these bodies are similarto the lower attached shoreface sandstones andsupport both the detached shoreface hypothesis andsubaqueous channels hypothesis proposed by Pattison(2006).