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Edwin K. Maughan

Publications and source records attributed to Edwin K. Maughan.

14 recordsLinked to original sources
USGS1980

Quantitative analysis versus semiquantitative optical emission spectrographic analysis of chromium, nickel, zinc, vanadium, and molybdenum in organic-rich Paleozoic marine strata, Western United States

Comparison of analytical results between the quantitative method and the semiquantitative six-step optical-emission spectrographic method commonly shows significantly lower values for the semiquantitative method. The lower values are most obvious for splits from the same samples of fine-grained organic-rich rocks where the concentrations of the metals chromium, nickel, zinc, vanadium, and molybdenum are greater than about 200 ppm (parts per million). Samples compared are Paleozoic marine rocks from the Western United States; they include the Permian Phosphoria Formation (Idaho, Montana, Utah, Wyoming), Mississippian Chainman Shale (Nevada and Utah), Mississippian Heath Formation (Montana), Mississippian Doughnut Formation (Utah), Devonian Woodruff Formation (Nevada), and Ordovician Vinini Formation (Nevada). The semiquantitative method consistently underestimates the concentration of the five metals studied by a factor of 1.7 to 2.7 and, thus, cannot be considered reliable for determining the concentration of metals in these rocks if the reported semiquantitative values exceed about 100 ppm. It is noteworthy that the most comprehensive analytical and statistical studies of metal concentrations in black shales of the United States have used the semiquantitative six-step optical-emission method of analysis.

Idaho, Montana, Nevada, Utah, Wyoming↗
USGS1978

Pennsylvanian (Upper Carboniferous) system of Wyoming

Pennsylvanian rocks in Wyoming comprise two stratigraphic sequences bounded by regional unconformities. Red mudstone and limestone characterize the strata in the lower sequence, and sandstone and dolomite characterize the strata in the upper sequence. Initial deposits of the lower sequence are-red mudstone probably of no older age than about middle Morrowan, except in the subsurface of southwestern Wyoming where early Morrowan strata may be present. The basal red mudstone lies unconformably upon Mississippian strata except in the vicinity of the ancestral Rocky Mountain Front Range where they lie upon Precambrian rocks. The red beds grade upward to interbedded limestone and mudstone of late Morrowan and early Atokan age; but the limestone strata are absent at many places because of beveling on a Middle Pennsylvanian erosional surface. Initial deposits of the upper sequence are heterogeneous and locally may be thinly bedded red, green, or varicolored mudstone, sandstone, or dolomite of late Atokan to early Des Moinesian age. Basal strata of the upper sequence lie unconformably upon lower Pennsylvanian strata at most places in Wyoming; but locally, where the lower Pennsylvanian strata are absent by erosion or possibly by nondeposition, the upper sequence lies upon Mississippian rocks. The upper sequence in central and northwestern Wyoming comprises mostly dolomite in the lower part but grades upward into mostly sandstone no younger than Des Moinesian. The upper sequence in eastern Wyoming comprises sandstone and dolomite about equally and also includes Upper Pennsylvanian strata as young as Virgilian. Upper Pennsylvanian strata also occur as part of the upper sequence in the thrust belt in western Wyoming. Pennsylvanian strata terminate upward at an erosional unconformity beneath Permian rocks everywhere in Wyoming.

Wyoming↗
USGS1975

Paleotectonic investigations of the Pennsylvanian System in the United States, Part I: Introduction and regional analyses of the Pennsylvanian System

The Pennsylvanian is the fourth geologic system to be analyzed and synthesized by geologists of the U.S. Geological Survey in the form of a paleotectonic study covering the conterminous United States. Earlier investigations were of the Jurassic, Triassic, and Permian Systems. Results were published as Miscellaneous Geologic Investigation Maps I-175, I-300, and I-450 and in Professional Paper 515. The objective of these investigations is to provide in graphic form the factual basis for recognition of tectonic events of each system on a countrywide scale. The maps in this publication depict rock thickness, generalized lithology, ancient geography, and other regional relations of the Pennsylvanian System. Method of preparation of the maps, the stratigraphic limits of the map units, and various stratigraphic and structural features and their probable tectonic significance are discussed. Pennsylvanian data were largely compiled between 1961 and 196 by 16 geologists, including the late Harold R. Wanless, who covered the five eastern regions and contributed to several of the special studies. The areas of responsibility of the cooperating geologists are indicated in figure 1. Work in Kansas was done by Gary F. Stewart, of the Kansas Geological Survey. Results of this investigation are presented in three units. Part I comprises an introduction and 17 chapters, each describing and discussing one of the regions in which the conterminous United States was divided for purposes of study and mapping. Part II is a synthesis of Pennsylvanian history to accompany interpretive maps of the five divisions of the Pennsylvanian System treated in this publication; it also includes a series of chapters on depositional environments, climatic conditions, and economic products of the system. The final section of part II is devoted to an index of localities and sources used in construction of the principal maps of this publication. Part III consists of the plates on which are presented the major maps and sections.

Professional Paper↗