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Environments of northwestern North America before the last glacial maximum
No abstract available.
Evaluation of LANDSAT-1 image applications to geologic mapping, structural analysis and mineral resource inventory of South America with special emphasis on the Andes Mountain region: Type III final report for period January 1973 to July 1974
The author has identified the following significant results. The discovery of copper mineralization along a lineament mapped in Area 7 (La Paz) has lent credence to the use of LANDSAT 1 data as a basic step in mineral exploration. In Area 9 (Copiapo Region), a number of lineaments were found to be associated with the largest copper deposits of the region. In Area 12 (Magallanes), the identification of what is believed to be a tertiary basin from LANDSAT 1 data has resulted in a new area for petroleum exploration. Band 7 images, as black and white transparencies, were found to be the most useful for geologic interpretation in both tropical vegetated areas and desert regions. Color composites made by the diazochrome process, chromaline process, and from color additive viewers provided additional information. Mosaics of LANDSAT 1 data covering 4 x 6 degrees of latitude and longitude compiled at the 1:1,000,000 scale were found to be an ideal size and format for most users.
Evaluation of LANDSAT-2 (ERTS) images applied to geologic structures and mineral resources of South America: Type II progress report for period March 14, 1975-June 30, 1975
The author has identified the following significant results. Work with the Image 100 clearly demonstrates that radiance values of LANDSAT data can be used for correlation of geologic formations across international boundaries. The Totora Formation of the Corocoro Group of Tertiary age was traced from known outcrops near Tiahuanaco, Bolivia, along the south side of Lake Titicaca westward into Peru where the same rocks are considered to be Cretaceous in age. This inconsistency suggests: (1) that a review of this formation is needed by joint geological surveys of both countries to determine similarities, differences, and the true age; (2) that recognition of the extension of the copper-bearing Totora Formation of Bolivia into Peru may provide Peru with a new target for exploration. Equal radiance maps made by use of the Image 100 system show as many as eight different units within salar deposits (salt flats) of the Bolivian Altiplano. Standard film processed images show them as nearly uniform areas of white because of lack of dynamic range in film products. The Image 100 system, therefore, appears to be of great assistance in subdividing the salt flats on the basis of moisture distribution, surface roughness, and distribution of windblown materials. Field work is needed to determine these relationships to mineral composition and distribution. Images representing seasonal changes should also improve the accuracy of such maps. Radiance values of alteration zones related to the occurrence of porphyry copper ores were measured at the San Juan del Abra deposit of northern Chile using the Image 100 system. The extent to which these same values may be used to detect similar alteration zones in other areas has not yet been tested.
Evaluation of LANDSAT-2 (ERTS) images applied to geologic structures and mineral resources of South America: Type II progress report for period June 30, 1975-June 30, 1976
The author has identified the following significant results. The Salar of Coposa is located in northern Chile along the frontier with Bolivia. The surface was divided into six general classes of materials. Analysis of LANDSAT image 1243-14001 by use of interactive multispectral computer (Image 100) enabled accurate repetition of these general classes based on reflectance. The Salar of Uyuni is the largest of the South American evaporite deposits. Using image 1243-13595, and parallel piped computer classification of reflectance units, the Salar was divided into nine classes ranging from deep to shallow water, water over salt, salt saturated with water, and several classes of dry salt.
Enhydra and Enhydriodon from the Pacific Coast of North America
Two lineages of the "crab-eating" otter Erihydriodon , from the Old World Miocene and Pliocene, are suggested by the fossil record. One appears to lead to the late Pliocene Enhydriodon sivalensis from Villafranchian-equivalent beds in India and can be characterized by the presence of a parastyle on P 4 and by the location of the protocone of this tooth, which is located as far lingually as is the hypocone. In the other lineage no parastyle is developed on P 4 , the anteroposterior length of the carnassial blade is progressively reduced while the transverse width is increased, and the protocone of P 4 remains in its primitive position anterolateral to the hypocone. The second lineage, insofar as it is known, seems to lead toward the living sea otter Enhydra , particularly so because of the evolutionary direction shown by two species of Enhydriodon from the late Miocene and late Pliocene of California.
Comparison of the deep crustal structure and seismicity of North America with the Indian subcontinent
No abstract available.
Diatoms of North America: Nomenclatural transfers within the Bacillariophyceae 1
No abstract available.
Amphibian and reptile conservation in the United States of America
Wildlife stewardship is of utmost importance in the United States, where management for sustainable natural resources is extended to native species including amphibians and reptiles. The U.S. wildlife conservation framework is a nested system of authorities regulating species and habitats, science-based management and policy decisions, and adaptive management as new knowledge is applied to improve outcomes of population- and habitat-management actions. Yet the approach has evolved through time, from single-species management of game species to the conservation of entire ecosystems and the biodiversity they support. Today, the mismatch of conservation ideals with conservation capacity puts nongame species like amphibians and reptiles in the crosshairs for losses due to insufficient resources to address growing numbers of threats. Despite these challenges, optimism prevails, as the management and conservation of U.S. herpetofauna is an increasing priority of the public, with considerable investment into habitat restoration, species-specific threat mitigation, research, public outreach, and education. Herein, we outline key elements of U.S. herpetological conservation efficacy: (1) a web of legal authorities governing the management of U.S. herpetofauna and their habitats; (2) a network of people and organizations that work toward filling priority knowledge gaps by conducting scientific research and that are actively engaged in the science-management interface for species-to-ecosystem level conservation decision-making, and (3) a learning framework of adaptive management within the legal landscape (“lawscape”) and for improving effectiveness of conservation actions. Lastly, the human dimension of species conservation in the U.S. is emerging, where bottom-up local efforts are having success in addition to state- and regional-scale approaches. We propose U.S. herpetological conservation priorities under three themes: threats, research, and human dimensions (people). Together these multifaceted efforts are contributing to advances in the maintenance of U.S. amphibian and reptile diversity. The success of these efforts is notable and could be viewed as a model system, where lessons learned may apply elsewhere.
Development of a regional clearinghouse for the dissemination of integrated information on natural hazards in Central America
No abstract available.
Pleistocene porcupine (Erethizontidae) records in arid southwestern North America and comparisons with the modern distribution of Erethizon dorsatum in southern California and Arizona
he North American porcupine ( Erethizon dorsatum ) is widely distributed throughout many ecosystems on the continent from northern Mexico to the Arctic Ocean, except for the southeastern portion of the United States. Habitats include the arid Desert Southwest region where modern records are generally sparse. The paleogeographic range in the Desert Southwest is not unlike the modern distribution of Erethizon , with some exceptions. Although there are early Pleistocene records of Erethizon for southern California, no late Pleistocene records (Rancholabrean North American Land Mammal Age [NALMA]) are known for Imperial, Inyo, Riverside, or San Bernardino Counties in southern California or in Mexico. This is surprising given late-Pleistocene records in Arizona, Nevada, and New Mexico and modern records from southern California and Mexico. Pleistocene habitats for porcupines were similar to those occupied today, just at different elevations due to differing climates. Modern preferred habitats in the Desert Southwest include conifer-clad high-elevation areas and associated pinyon pine / juniper belts, and occasionally riparian corridors in desert environments. The overall rarity of porcupines today in arid parts of the Desert Southwest is likely due to the combination of increasing aridity in the region during the Holocene, past persecution by humans, and increasing predator populations.
Sea lampreys in the Great Lakes of North America
The movement of sea lampreys into the upper Great Lakes (Superior, Michigan, and Huron) initiated a series of biological changes which have extended beyond the fish directly attacked by the parasite. The threat posed by the sea lamprey was not generally recognized until it was well established in all the lakes and had seriously affected the fisheries in Lakes Huron and Michigan. As the sea lamprey increased primarily at the expense of the valuable lake trout stocks and to a lesser degree other fish species, the need for research and concerted action became clear to the commercial fishery industry and fishery investigators of the United States and Canada.
Behavioral research on captive endangered fishes of North America
Abstract not supplied at this time
1997-1998 butterfly monitoring at Homestead National Monument of America
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The northern pintail in North America: the problem and prescription for recovery
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Stream macroinvertebrate biomonitoring report for Homestead National Monument of America, 1989-1999: status report
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