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Geology topics

Frederick S. Fisher

Publications and source records attributed to Frederick S. Fisher.

15 recordsLinked to original sources

Operational guidelines (version 1.0) for geological fieldwork in areas endemic for Coccidioidomycosis (Valley Fever)

Coccidioidomycosis (Valley Fever) is a disease caused by the inhalation of the arthroconidia (spores) of Coccidioides immitis, a fungus that lives in the soils of southwestern United States. Although large numbers of people are exposed to the arthroconidia and are consequently infected, very few individuals contract the more serious forms of the disease. Earth scientists working in field areas where Coccidioides immitis is endemic have an increased risk of becoming infected. Because field operations often disturb the upper surface of the ground, they may inhale large numbers of arthroconidia. This also increases their risk of developing more severe forms of the disease. Any other occupations or activities that create dusty conditions in endemic areas also have increased risk of infection. Risk management strategies can lower the incidence of infection and also reduce the numbers of arthroconidia inhaled thereby decreasing the chances of developing more serious disease. Dust control, by utilizing dust masks, and dust prevention, by limiting ground disturbing activities, are the primary weapons against infection. However, infection risk can also be lowered by conducting fields studies in the winter months; avoiding sites favorable for Coccidioides immitis growth; seeking prompt medical treatment if flu-like or respiratory illness occur during, or within a few weeks following, fieldwork; getting a coccidioidin skin test to determine susceptibility to the disease; and by educating all members of the field party about the possibilities and consequences of infection.

Open-File Report↗

Interpreting pan-concentrate analysis of stream sediments in geochemical exploration for gold

A study of methods of collecting and processing samples to determine whether or not gold is present in areas of moderate size was undertaken in the northwestern part of the San Juan Mountains, Colo. As part of this study, 57 samples of pan concentrates were taken from streams draining three types of areas: (1)'barren' areas, where gold mineralization might be geologically possible but no deposits are known, (2) slightly mineralized areas that contain only a few known veins and prospects and small mines, and (3) well-mineralized areas that contain numerous veins and some very productive mines. The concentrate samples were analyzed by the fire-assay-atomic-absorption method. Replicate analyses of large samples gave results consistent enough to permit placing considerable confidence in the results obtained for smaller samples on which only one analysis was made. For general field practice, it is necessary to pan only enough sand and gravel to yield about 15 grams of concentrate. The analytical r6sults are also quantitatively compatible with known geologic relations and indicate that a few samples from a stream are adequate to distinguish between 'barren' and mineralized areas and to determine the relative amount of gold in mineralized areas. In other areas of similar gold deposits, data of this type should help decide whether more intensive search for gold deposits is justified.

Circular↗

The return on the blueback salmon to the Columbia River

THE year 1941 was a crucial one for the blueback salmon of the Columbia River. During that year, one brood came closer to extinction than was realized by more than a few individuals. The immediate causes were not overfishing, hydroelectric power development, or irrigation—although these factors continued to exert their long-standing effects. The direct causes can be attributed to an “act of God” plus—in large measure--lack of knowledge concerning the basic principles of effective artificial propagation. With the security and assurance provided by subsequent developments, those concerned with the Columbia River blueback salmon may be interested in a brief recapitulation of events that transpired during the early 1940s. This particular piece of fishery history bears upon the problems of the immediate future on the Columbia River.

Oregon, Washington↗

Formalin for external protozoan parasites: A report on the prevention and control of Costia necatrix

The smallest and most destructive of the ectoparasitic protozoans infecting salmon and trout, Costia necatrix , has unfortunately been relegated to virtual obscurity during the past few years. Few references to this parasite can be found in the recent literature and, where such things are discussed, one seldom hears a mention of Costia necatrix . This apparent lack of interest in Costia certainly does not result from the infrequency of its appearances nor from any lack of pathogenicity on its part when it does occur. Preserved specimens of ailing trout an dsalmon submitted to the Seattle Pathology Laboratory for diagnosis have yielded very surprising indications concerning the frequency, intensity, and geographic distribution of Costiasis - surprising in that a parasite should be so widespread, so pathogenic, and yet so seldom mentioned. The answer undoubtedly lies in the fact that Costia , being small in size and usually sedentary in its habits, is being overlooked during parasitic examinations. Although Costia is not at all difficult to recognize, even well-trained workers unfamiliar with its appearance almost invariably pass it by.

Progressive Fish-Culturist↗