Geology topics

R.E. Grant

Publications and source records attributed to R.E. Grant.

5 recordsLinked to original sources

USGS2000

Guadalupian studies in West Texas

Murchison established the Permian System in the Ural Mountains of Russia in 1841. The first North American Permian fossils were discovered by Hall (1856) about 15 years later. The fossils, which were collected in New York State, were initially described as Carboniferous (Hall, 1856) but were subsequently recognized as Permian by Girty (1902). Benjamin F. Shumard (1858), however, was the first to place an unequivocal Permian designation on some North American fossils, which has been collected by his brother George G. Shumard from the Guadalupe Mountains in Texas. A half a century passed before Girty (1908) made known an extensive Guadalupian fauna, although his field work in Texas and his study of this fauna already lead him to propose a Guadalupian "period" (Girty, 1902). Girty's suggestion was accepted only when it was formalized as the Guadalupe Series by Adams et al. (1939). The "Guadalupian fauna" was based upon fossils that Girty collected in 1901 on an expedition headed by Robert T. Hill, a revered figure in Texas geology.

Smithsonian Contributions to Earth Sciences↗

USGS2000

Guidebook to the Gaudalupian symposium

Compared to the Guadalupe Mountains of Texas and New Mexico the depositional environments of the Permian strata of the Glass Mountains (and adjacent Del Norte Mountains) are less well known. In general, the Guadalupian facies in the the Glass and Del Norte mountains changes from predominantly carbonate facies in the northeast to thicker clastic facies in the southwest. Philip B. Kind (1931) originally considered this trend to reflect an uplifted clastic source to the southwest, with carbonate facies developing away from the source area. Ross (1986) interpreted the eastern portion of the Road Canyon and Word formations to consist the shelf, shelf-edge bioherm, and reef facies, and the southwest area to consist of deeper water siliceous shale, clastic limestone, and basinal sandstone facies. Probably the best known controversy in the Glass Mountains involves the depositional environment of the Skinner Ranch Formation (Leonardian according to Ross, 1986; Wolfcampian according to Cooper and Grant, 1972) at its type section on Leonard Mountain. Cooper and Grant (1964) identified in situ patch reefs at the base of the section, which were subsequently interpreted as displaced limestone blocks deposited in a slope environment (Rogers, 1972; Cys and Mazzullo, 1978; Ross, 1986). Later Flores, McMillan, and Watters (1977) interpreted the same units as subtidal and intertidal deposits. The Skinner Ranch Formation illustrates the complexities involved in interpreting the paleogeography of the Glass Mountains. If the Sinner Ranch contains displaced blocks, some eroded from older units, it explains the occurrence of Wolfcampian fossils in the Skinner Ranch (Ross, 1986).The slop facies interpretation also is used to place the shelf edge at that time between Skinner Ranch outcrops at Leonard Mountain and the lagoonal, backreef deposits of the Hess Formation to the east, although most of the actual shelf edge is not preserved (Ross, 1987:30). Similar conflicting interpretations exist in younger rocks in the western facies of the Leonardian Guadalupian to the southwest in the Del Norte Mountains. Ross (1986, 1987) considered the western facies of the Road Canyon and Word formations to be basinal shales and turbidites. Wardlaw et al. (1990) and Rohr et al. (1987) have interpreted this area to be shallow intertidal to lagoonal environments adjacent to an uplifted area to the south. The type section of the Road Canyon Formation is also a subject of disagreement and will be discusses in more detail later.

Texas↗

USGS2000

Geology and depositional environments of the Guadalupian rocks of the northern Del Norte Mountains, West Texas

The Guadalupian rocks of the northern Del Norte Mountains were deposited in a foreland basin between land of the Marathon orogen and a carbonate shoal established on the geanticline separating the foreland basin from the Delaware basin. Deposition was alternately influenced by coarse clastic input from the orogen and carbonate shoal, which interrupted shallow basinal siltstone depletion. Relatively deeper-water deposition is characterized by carbonate input from the shoal, and relatively shallow-water deposition is characterized by sandstone input from the orogen. Deposition was in five general transgressive-regressive packages that include (1) the Road Canyon Formation and the first siltstone member and first sandstone member of the Word Formation, (2) the second siltstone member, Appel Ranch Member, and limy sandy siltstone member of the Word Formation, (3) the Vidrio Formation, (4) the lower and part of the middle members of the Altuda Formation, and (5) part of the middle and upper members of the Altuda Formation.

Texas↗

USGS1968

Structural adaptation in two Permian brachiopod genera, Salt Range, West Pakistan

Silicified shells with spines preserved allow analysis of spine distribution as a specific character in the genus Marginifera Waagen and confirm validity of Waagen's (1884) six species. The animal lived with the ventral valve down, the adult shell partly buried, but many spines grew above the substrate prior to burial. Pseudopunctae are interpreted as seats of ciliate papillae or elongate setal follicles, as adaptation to partial burial in soft substrate. Auricular chambers, marginal ridges, and endospines provided effective protection against ingression of coarse or harmful particles. Productus opuntia Waagen is assigned to Echinauris Muir-Wood & Cooper; its habitat and adaptations are interpreted as similar to those of Marginifera. The stratigraphic position of the bed containing the late Permian guide ammonoid Cyclolobus proves to be lower than hitherto thought, thus extending the ammonoid's range. A Guadalupe age for the Chhidru formation is suggested.

West Pakistan↗

USGS1966

A Permian productoid brachiopod: Life history

Spine arrangements on silicified specimens of Waagenoconcha abichi (Waagen) from the Khisor Range of West Pakistan suggest that the juvenile shell attached itself to a foreign object, and that the adult shell lay on its ventral valve in the substrate, anchored and stabilized by a dense corona of long slender spines around the ventral visceral disc.

Khisor Range↗