Development of Middle Triassic red-bed plays is commonly hampered by a lack of understanding of the stratigraphic relationships between reservoir sandstones. This inadequacy reflects poor palynological recoveries and a general deficiency in understanding the controls on palynological preservation. The sedimentology and palynology of Triassic red-bed facies, from the UK North Sea and onshore analogues, are studied to determine the sedimentary controls on palynological preservation and to investigate whether palynology is useful in these facies, where other stratigraphic techniques do not always provide unique solutions. The Skagerrak Formation (Quadrants 22, 29 and 30) typically comprises ephemeral channel and sheet-flood deposits in the north, but includes sediments deposited in perennially wet, alluvial plain and lacustrine settings in the south. Further north (Quadrant 210), the Cormorant Formation comprises dry alluvial deposits. Onshore, the Bromsgrove Sandstone Formation is characterised by ephemeral channel deposits that pass progressively upwards into tidally-influenced, fluvial and estuarine deposits; these are partly comparable with sediments in the Tarporley Siltstone Formation. Palynological analysis reveals that, in the absence of palynomorphs, palynodebris and absolute organic concentration can distinguish between preservational regimes, and thus environment. Palynological preservation demonstrates a correlation with facies deposited in perennially wet, alluvial plain, lacustrine and tidally influenced settings. Organic assemblages distinguish between members in the Bromsgrove Sandstone Formation, and can subdivide members on palaeoenvironmental criteria, which is of local value in correlation. Palynological assemblages are mostly lacking where ephemeral depositional processes were dominant. The assemblages demonstrate a close relationship with sedimentary facies, their associations, and sediment colour, but the oxidation potential of pore fluids, during and soon after deposition, is an overriding control on organic preservation. These relationships are all beneficial for targeting sediments for further palynological analysis.

No description available.

A depositional framework for the Mississippian (Chesterian) Pride Mountain Formation/Hartselle Sandstone clastic tongue and the lower Bangor Limestone carbonate ramp in the Black Warrior basin, Mississippi and Alabama, is constructed from approximately 250 geophysical well logs, 15 well cuttings descriptions, and outcrop data. The framework is based upon cross sections, isopach maps, and transgressive-regressive sequence stratigraphy. The Lowndes-Pickens synsedimentary fault block controlled sediment dispersal in during Pride Mountain/Hartselle deposition. The basin filled from the southwest, which pushed the depocenter northeastward during Hartselle deposition. The Hartselle sub-basin is composed of the Hartselle barrier-island and back-barrier deposits to the southwest, including the Pearce siltstone. The Pearce siltstone, a previously unidentified subsurface unit, was deposited in a restricted environment controlled by the Lowndes-Pickens block. The Pride Mountain, Hartselle, and lower Bangor succession contains one complete and one partial transgressive-regressive stratigraphic sequence. An exposure surface at the top of the Hartselle Sandstone and Monteagle Limestone is a maximum regressive surface. The upper part of the Bangor ramp is highly cyclic and grades from oolitic shoal deposits southwestward into a condensed section, the Neal black shale, at the toe of the ramp. The entire thickness of the lower Bangor is equivalent to the Neal shale.

No description available.

No description available.