Geology topics

E. D. McKee

Publications and source records attributed to E. D. McKee.

4 recordsLinked to original sources

USGS1983

Eolian sand bodies of the world

This chapter examines the eolian sand bodies of the world. Analyses regarding grain size and sorting distribution at Great Sand Dunes indicate that the higher dunes contain much more fine-grained sand and much less medium-grained sand than do the lower dunes, and, in addition, they are definitely better sorted. Cross-stratification in eolian deposits is the product of several distinct processes of transport. These processes are saltation or ripple migration that include various amounts of surface creep, grainfall (a dropping of grains from sand in suspension), and avalanching either by mass movement or by grain flowage which involves the downhill rolling or sliding of discrete particles. Penecontemporaneous deformational structures including various types of faults and folds, flames, break aparts, and rotated blocks are sufficiently numerous in most eolian deposits to serve as useful tools in determining genesis. These structures are good indicators of the nature of the stress and therefore provide information on the part of a sand body involved. Sufficient observations have been recorded to establish that the lee side (or slipface) of most modern dunes stands at 30° or slightly more and that the length of the foresets developed on it may be 8 or 10 m and often much more. © 1983, Elsevier Science & Technology. All rights reserved.

Developments in Sedimentology↗

USGS1972

Pliocene uplift of the grand canyon region - time of drainage adjustment

Tertiary gravel deposits in ancient stream channels along the southern margin of the Colorado Plateaus of northern Arizona show by composition and structure that these deposits came from sources to the south and southwest at a time when central Arizona stood higher than the present Grand Canyon region. Three cobbles of basalt included in the gravel deposits have K-Ar ages of about 10.0 m.y., 12.2, and 12.4 m.y. showing that the major uplift of the plateau in northern Arizona had not taken place at that time. The present south-flowing drainage of the Verde River and neighboring streams resulted from final elevation of the northern Arizona region relative to central Arizona, and must have developed well before about 5 m.y. - the age of some basalts that flowed into the Verde Valley. Thus, the major relative uplift of the southern part of the Colorado Plateaus must have occurred within the 5 to 10 m.y. interval, or in early to middle Pliocene time. This time of uplift also was the time of major canyon erosion, including the cutting of Grand Canyon, within the Plateaus province. © 1972, The Geological Society of America, Inc.

Arizona↗

USGS1967

Devonian of the Southwestern United States

The structural framework that controlled Devonian deposition consisted of, from west to east: (1) a eugeosynclinal area in northern California and western Nevada; (2) a miogeosynclinal area in southeastern California, eastern Nevada, and western Utah; and (3) a cratonic area in Arizona, eastern Utah, Colorado, New Mexico, and western Texas, east of a northeast-trending hinge line (Wasatch line). The eugeosyncline contains a fragmentary record of Middle Devonian rocks at least 4,000 feet thick characterized by thin-bedded chert, siliceous mudstone, and some limestone and volcanic rocks. The original thickness, however, probably exceeded 6,000 feet and probably included Lower and Upper Devonian rocks. The miogeosyncline contains Lower, Middle, and Upper Devonian rocks as much as 6,000 feet thick characterized by thick units of dolomite and limestone and some local interbeds of sandstone. A transitional zone perhaps 50 miles wide separates the eugeosynclinal and miogeosynclinal facies. The craton contains mostly Upper Devonian rocks, generally less than 1,000 feet thick, characterized by dolomite and limestone and local interbeds of sandstone and mudstone. Widespread crustal movements occurred during Late Devonian time. The Antler orogeny in Nevada initiated a culm facies in the geosyncline. Eugeosynclinal and transitional rocks including those of Devonian age were uplifted to form the Antler orogenic belt, and then were thrust eastward over autochthonous miogeosynclinal rocks in latest Devonian or earliest Mississippian time. Folding and faulting, and subsequent erosion on local uplifts, produced clastic deposits of Late Devonian age in Utah and southwestern Colorado. Devonian rocks in many parts of the geosynclinal area have been moved since Devonian time by large-scale, generally eastward thrusting, oroflexural bending and strike-slip faulting. Four major subdivisions of the Devonian System and related rocks are treated separately: 1) Lower Devonian (Gedinnian, Siegenian, Emsian) and related Upper Silurian (Ludlovian) rocks. 2) Middle Devonian (Eifelian and Givetian) rocks. 3) Lower Upper Devonian (Frasnian, to I ) rocks. 4) Upper Upper Devonian (Famennian, to II-VI ) and related lowermost Mississippian (Tournaisian, cu I ) rocks.

Conference Paper↗

USGS1963

Origin of the Nubian and similar sandstones

The Nubian Sandstone and similar sandstone bodies exposed across much of northern Africa and adjoining parts of Asia are characteristically formed of clean sand that is conspicuously cross stratified throughout. Such sandstone, here called Nubian-type sandstone, ranges from Cambrian through Cretaceous in age and its genesis has been interpreted in many ways. Studies of its primary structures, and of the direction of sand transport, based on statistical measurements of foreset dip directions, have contributed new data on its genesis. By far the most common structure in Nubian-type sandstone is a medium-scale planar-type cross stratification in which sets of evenly dipping cross beds are bounded by essentially flat-lying top and bottom surfaces to form tabular bodies. Other less numerous but typical structures are large-scale, truncated-wedge cross strata, trough-type cross strata, intraformational recumbent folds, small-scale ripple laminae, and dipping sets of tabular-planar cross beds. An analysis of these structures suggests that in the typical Nubian Sandstone of Cretaceous age eolian deposits are not represented and normal marine types probably also are lacking; flood plain, pond or lagoon, and other continental and marginal environments are indicated. In the Carboniferous rocks of Sinai Peninsula some beach sandstone and possibly some eolian, in addition to the types described, form part of the sequence. Direction of sand transport, as determined from cross-bed dips, was northerly in the Cretaceous Nubian of Libya, Sudan, and Egypt; easterly in the Jurassic Adigrat of Ethiopia; westerly in the Carboniferous of Sinai; northwesterly in the early Paleozoic of Jordan.

Geologische Rundschau↗