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Geology topics

Keith Brindley Ketner

Publications and source records attributed to Keith Brindley Ketner.

At least 19 recordsLinked to original sources
USGS1998

The nature and timing of tectonism in the western facies terrane of Nevada and California; an outline of evidence and interpretations derived from geologic maps of key areas

Along the outer miogeocline of Nevada and Southern California, lower Paleozoic siliceous sediments and basalt flows, the western facies terrane emerged in Late Devonian time and were deeply eroded; but structural evidence that this event, the Antler Orogeny, involved intense folding and thrust faulting is notably scarce. Almost all the intense folding and thrust faulting of Proterozoic to Permian strata dates from the Jurassic to Eocene interval. If this tectonic history is valid, then the genesis of the Antler Orogeny is reduced to a question of vertical tectonics. Pre-Jurassic contraction involving subduction and collision with island arcs is not indicated or required, but the ultimate origin of Paleozoic tectonism remains unclear.

Professional Paper↗
USGS1998

An outline of tectonic, igneous, and metamorphic events in the Goshute-Toano Range between Silver Zone Pass and White Horse Pass, Elko County, Nevada; a history of superposed contractional and extensional deformation

Seven kinds of fault-bounded tracts are described. One of the tracts provides a good example of Mesozoic contractional folding and faulting; six exemplify various aspects of Miocene extensional faulting. Massive landslide deposits resulting from Tertiary faulting are described. Mesozoic intrusive rocks and extensive exposures of Miocene volcanic rocks are described and dated. The age ranges of stratigraphic units were based on numerous conodont collections, and ages of igneous rocks were determined by argon/argon and fission-track methods. The geologic complexity of the Goshute-Toano Range provides opportunities for many additional productive structural studies.

Professional Paper↗
USGS1983

Strata-bound, silver-bearing iron, lead, and zinc sulfide deposits in Silurian and Ordovician rocks of allochthonous terranes, Nevada and northern Mexico

Allochthonous terranes in northern Nevada contain strata-bound sulfide deposits at two horizons in Silurian and Ordovician siliceous sedimentary rocks. The most intensively mineralized horizon and most extensive deposit is at the base of the Silurian. Another less extensive deposit is in the lower Middle Ordovician. Spectrographic analyses of gossan from the basal Silurian horizon indicate anomalously high values of lead and zinc; and in about 40 percent of the samples, silver values are anomalously high. Suhsurface samples contain the primary minerals pyrite, galena, and sphalerite. The basal Silurian deposits are in thick-bedded chert that is overlain by micaceous siltstone. They are underlain by a thick-bedded black chert unit of Late Ordovician age. The basal Silurian gossan has been identified also in southwestern Nevada and in northern Mexico in stratigraphic sequences very similar to that of northern Nevada.

Open-File Report↗
USGS1979

Grain-size analyses of Ordovician sandstones from the Midwestern states

Certain Ordovician sandstones of the Midwestern States were investigated for the purpose of determining the range in size of constituent sand grains. Although many size analyses of the same formations have been reported in the literature, the methods of sample collection, preparation, and sieving were not uniform, and the results of the different studies therefore are not comparable. This investigation is intended to supply a uniform data base that will be useful for a variety of practical and scientific purposes. A total of 276 samples was collected from the St. Peter Sandstone and Everton, Oil Creek, McLish, and Tulip Creek Formations at the 29 locations shown on figure 1. At each location 4-14 samples were taken at about equal intervals from the base to the top of the sandstone exposure. Each sample of about 500 gm was obtained from a strati-graphic interval of no more than 10 cm. Each sample was air dried, and lumps were broken with a rubber pestle (some samples were case-hardened but none was firmly cemented). A representative fraction of 50 to 120 gm was separated by use of a sample splitter. This fraction was then weighed to the nearest .1 gm and agitated for 30 seconds in water in a kitchen blender. The process efficiently broke apart the remaining small lumps and freed the sand surfaces of clay and almost all of the iron oxide. The sample was then washed on a sieve having openings of .06 mm in order to remove clay and silt-size particles. The remaining sample, composed of clean loose sand, was then oven-dried. Each sample of dry sand was sieved for 10 minutes in a stack of 12 or more sieves on a mechanical shaker, and the size fractions were weighed to the nearest .1 gm. The weight of the discarded silt and clay fraction was determined by subtracting the weight of the sand from the weight of the unwashed sample. In the following tables, the figures at the left are diameters of sieve openings; samples, numbered on the top line, run from base of section (or exposure) to the top of the formation; figures in the body of the tables are grams of samples retained on the indicated sieves; bars in place of figures indicate unused sieves.

Arkansas, Illinois, Iowa, Minnesota, Missouri, Okl↗
USGS1979

Phosphatic Permian rocks of the Adobe Range, Nevada, and their environment of deposition

Permian sedimentary rocks in the Adobe range, northern Nevada, are phosphatic, and although the particles of phosphate are relatively more disseminated, they closely resemble the rocks of the Phosphoria Formation. In the northern Adobe Range, where the entire Permian sequence is approximately correlative with the Phosphoria Formation, it is 200 m thick and averages 1.7 percent P2O5 . In the southern Adobe Range, the Permian sequence is more than 1,700 m thick, and the upper half which is roughly correlative with the Phosphoria Formation averages more than 2 percent P2O5. Some thin beds in rocks of Permian age contain more than 20 percent P2O5. Phosphatic rocks of the Adobe Range were deposited in shallow water among islands in the western part of the epicontinental Phosphoria sea. The continental margin and the open ocean lay far to the west. At the same time, the Phosphoria Formation was being deposited in the eastern and central parts of the Phosphoria sea. Theories based on the work of Kasakov done in 1937 relating phosphate deposition directly to sites of upwelling oceanic waters are questioned. Nondeposition of diluent materials such as detritus and carbonate is probably of more importance in producing phosphate in economic concentrations than is geographic position with respect to upwelling waters.

Open-File Report↗