DEPTH-GRADIENT ANALYSIS AND BIOTIC SUCCESSION IN THE COLONY CREEK CYCLE (LATE PENNSYLVANIAN) OF NORTH TEXAS. Conference Paper uri icon

abstract

  • The Colony Creek shale (Canyon Group) in north Texas contains a vertical succession of lithologies and biotas deposited during regression from deep water to shallow water and strandline deposition. Stratigraphic successions in the Colorado River valley and the Brazos River valley of the outcrop belt are similar, showing that regression was of regional extent. A thin layer of platy phosphatic black shale containing an ammonoid fauna occurs at the base of the Colony Creek and is diagnostic of deep-water deposition. This unit is similar to deposits of maximum transgression (stillstand) of many Pennsylvanian cycles. The overlying shoaling-upwards portions of the Colony Creek are characterized by upward increase in sand content, increasing numbers and thicknesses of sand beds, and culmination in a horizon of subaerial exposure.

author list (cited authors)

  • Kennedy, N. L., & Yancey, T. E

complete list of authors

  • Kennedy, NL||Yancey, TE

publication date

  • December 1985