Parasequence geometry and facies architecture in the upper Cretaceous Point Lookout Sandstone, Four Corners platform, southwestern Colorado
Danny R. Katzman and Robyn. Wright-Dunbar
In the Upper Cretaceous Point Lookout Sandstone in southwestern Colorado, the presence of distinctly different scales of transgressive deposits defines a hierarchy of high-frequency, nearshore-marine transgressive-regressive cycles. The two cycle scales, parasequences and parasequence sets, are delineated on the basis of thickness and lithologic characteristics of the transgressive deposits at inner-shelf and back-barrier positions. This observation is contrary to most previous work on cycles at this scale, which suggests that the stratigraphic record is composed of regressive strata with the transgressive portion of the cycle being represented only by a surface of erosion or nondeposition. Here, we recognize that both regressive and transgressive deposits are important components of the cycle stratigraphy.
- Katzman, Danny R.; Wright-Dunbar, Robyn., 1992, Parasequence geometry and facies architecture in the upper Cretaceous Point Lookout Sandstone, Four Corners platform, southwestern Colorado, in: San Juan Basin IV, Lucas, Spencer, G.; Kues, Barry S.; Williamson, Thomas E.; Hunt, Adrian P., New Mexico Geological Society, Guidebook, 43rd Field Conference, pp. 187-197.