VERTICAL GRAIN SIZE PROGRESSIONS AS AN AID IN INTERPRETING THE DEPOSITIONAL ENVIRONMENTS OF THE QUEEN CITY FORMATION (EOCENE), EAST TEXAS

[摘要] Vertical grain size progressions of sand deposits in the Queen City Formation (Eocene), East Texas, were studied to determine if unique textural trends characterize depositional environments. Results from this study indicate that certain groups of environments are more easily distinguished from other groups. Lower point bar, fluvial distributary channel, and distributary mouth bar deposits are more readily differentiated from distal bar, lower shoreface, and upper point bar deposits by the presence of a coarser mean grain size and mode, higher sand content, and more saltation modes with little suspension component. The overlap in grain size traits among many of the environments is attributed to the restricted grain size range of the formation, similarities in transport mechanisms among environments, and, to a lesser degree, diagenetic changes in the original grain size distributions. (Abstract shortened with permission of author.)

[发布机构] Rice University