http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Basinal sandstone facies in the Delaware Mountain Group, west Texas and southeast New Mexico
The Delaware Mountain Group in the Delaware Basin of west Texas and southeast New Mexico consists of a thick sequence of late Permian clastics deposited in a deep-water, marine setting. The basinal facies and depositional environments of these sediments are interpreted from a detailed study of the uppermost part of this sequence, the pre-Lamar Bell Canyon sandstones. These sandstones were described from well cores and outcrops and analysed for texture and composition by petrographic techniques. The results show that three basic lithofacies are present: luxite, laminate, and arenite. These can be defined by textural and compositional features as well as sedimentary structures. The lutite lithofacies is a pelagic, carbonaceous, fissile shale. It is clay poor and contains varying amounts of silt and mica, and is interpreted to represent pelagic deposition during periods of local quiescence. Closely related to the lutite is the laminate lithofacies. It is laminated, coarse-grained siltstone (mean size 0.05 mm to 0.06 mm) with alternate laminae having concentrations of organic material, suggesting deposition from a suspension. It is often disturbed by Nereites trace fossils which indicate an abyssal environment. A finer, organic-poor laminate also occurs in limited amounts and is inferred to have been deposited from turbidity currents because of its close association with other turbidite features. The arenite lithofacies dominates linear submarine channel areas and is a feldspar-rich, quartz sandstone with a very fine texture (mean size of 0.065 mm to 0.95mm) and low matrix content..
Ph. D. in Geology Texas A & M University