5 Council on Undergraduate Research—Undergraduate Research (Posters)

Monday, 23 May 2005
8:00 AM - 4:00 PM

PRIMARY AND SOFT-SEDIMENT STRUCTURES IN THE MIDDLE RED MEMBER OF THE MOENKOPI FORMATION

Paper number: 5-3
Program: THEME SESSIONS
Time: 8:00 AM – 4:00 PM

Authors

Abstract

The middle red member of the Moenkopi Formation (Lower Triassic) is well exposed along the road to the top of Hurricane Mesa, a few miles west of Zion National Park. The middle red member contains a variety of both primary sedimentary structures and soft-sediment deformation structures. Primary structures include: oscillation and current ripple marks, mud cracks (seen in both edge and plan view), cross beds, and a few fossils. Soft sediment deformation structures include: ball and pillow structures and numerous, well defined tepee structures. Tepee structures have tops that are both pointed and rounded and range in size from a few centimeters to a decimeter. The ridge–like character is well represented. These structures are particularly well developed in the more gypiferous layers. All of these structures, plus the general sedimentation sequence, are indicative of a sabkhas-peritidal environment.