The Upper Smackover Formation (Jurassic) of the Paup Spur-Mandeville Fields, Miller County, Arkansas – a Study of Upward-Shoaling Carbonate Sand Deposition
Maryann M. Mc Graw, 1984. "The Upper Smackover Formation (Jurassic) of the Paup Spur-Mandeville Fields, Miller County, Arkansas – a Study of Upward-Shoaling Carbonate Sand Deposition", Carbonate Sands-A Core Workshop, Paul M. Harris
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Cores of the Upper Smackover Formation from Paup Spur-Mandeville Fields, Miller County, Arkansas, reveal shallow subtidal to intertidal lithofacies and a general vertical sequence suggesting decreasing water depth through time. The uppermost portion of the lower Smackover is a laminated pelsparite with shaly partings, interpreted as a low-energy-subtidal deposit. Overlying subtidal deposits of the upper Smackover consist of laterally adjacent cross-bedded and burrowed pelsparite-pelmicrite as well as laminated to burrowed silty pelsparite with shaly partings, representing current-sorted coarser material and some reworking in protected areas. These sediments are capped by intertidal algal biolithite and pelsparite or cross-bedded oosparite. The geometry of the Smackover carbonate sand body present in the area is the result of bottom topography and current-wave direction. The highest-energy facies are aligned southwest-northeast, perpendicular to the long axis of a prominent embayment and partly surrounding pre-Smackover structural highs.
Several phases of diagenesis occurred during the post-depositional history of the upper Smackover in Paup Spur-Mandeville Fields: (1) sea-floor, (2) near-surface meteoric with an important dissolution event and (3) burial. Most original interparticle porosity is now cement filled. Porosity distribution coincides mainly with facies and grain types, because secondary porosity is determined by the original mineralogy of the grains.
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Carbonate Sands-A Core Workshop
Carbonate sands, both skeletal and non-skeletal, have been studied by geologists as intensely as carbonate buildups. The underlying reason for the studies is the importance of those sands as significant hydrocarbon reservoirs. This core workshop is intended to provide a “hands on” look at the subsurface geologic record of carbonate sands with emphasis on lithofacies, stratigraphy of the sands and surrounding deposits, geometry of the sand deposits, diagenesis and porosity evolution, and wireline log data.