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The AAPG/Datapages Combined Publications Database
Five distinct facies are recognized in Queen City exposures between the Trinity River valley and Louisiana boundary. These facies (fluvial, deltaic, tidal flat, barrier, and tidal delta) display distinctive suites of physical and biogenic structures, with substantial differences in paleocurrent pattern.
Fluvial influx was mainly from the northwest, possibly with minor contributions from the Sabine uplift on the east. A marginal alluvial plain was transected by sandy braided streams and sinuous mixed-load channels. Very small, high-constructive shoal-water deltas and crevasse subdeltas developed mainly along the northwestern embayment margin, prograding rapidly across the shallow shelf. Barriers may have originated as destructive components of delta abandonment or as contemporaneous strike-fed features marginal to the main delta complex in the west. In either event, barriers are poorly preserved, possibly because of transgressive ravinement, but more likely because they were never developed on a major scale. Flood-tidal deltas formed at the mouths of microtidal estuaries. Like some mo ern analogs, they are significantly larger than comparable mesotidal features. They also exhibit features reflecting storm processes. Extensive back-barrier or bay-margin intertidal and subtidal flats and shoals reflect the interplay of tidal and wave-generated processes, leaving a characteristic record of variable physical energy and flow patterns.
Regional depositional patterns were largely controlled by (1) location of the east Texas embayment with respect to the major deltaic depocenter, resulting in an eastward decrease in sediment supply; (2) configuration of the broadly funnel-shaped embayment which may have augmented tidal range; and (3) transition from overall progradational character, with local transgressions, to a major marine transgression that culminated in shelf sedimentation of the overlying Weches Formation.
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