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At least 73 records · Page 4Linked to original sources
USGS1963

Preliminary report on seismic-reflection studies of crustal structure in the western, central, and southern United States

During 1963 the U.S. Geological Survey, with the assistance of United ElectroDynamics, Inc., recorded five separate reversed seismic profiles. In addition to these profiles, the U.S. Geological Survey participated in a seismic-calibration program for the DRIBBLE experiment at Tatum Dome, Mississippi, a 20,000-pound shot near Dexter, Missouri, and in a cooperative seismic experiment in the Lake Superior region. This work is a continuation of the program started in 1961; however, the emphasis has shifted from a detailed study of the earth's crust in the western United States to a study of crustal structure in various geologic environments including the Wyoming thrust belt, Colorado Plateau, Central Lowlands, the Gulf Coastal Plain, and the southern part of the Canadian Shield. The U.S. Geological Survey has now completed reversed seismic-refraction profiles in nine different geologic provinces. These data present a promising indication that it may be possible to predict the crustal structure in unexplored areas by considering the regional geologic and physiographic environment. The following P n velocities have been determined: 8.2 km/sec in the Wyoming thrust belt, 7.9 km/sec in the Colorado Plateau, 8.1 km/sec in the Central Lowlands, and about 8.2 km/sec in the Gulf Coastal Plain. The data from the Lake Superior region have not yet been interpreted.

Arizona;Idaho;Mississippi;Missouri;Utah↗
USGS1964

Preliminary report on some factors affecting shotpoint efficiency

A study of first-arrival amplitudes from 6 water shotpoints and 7 drill-hole shotpoints in parts of central and western United States indicate a variation of over 100 to 1 between the best and poorest shotpoints. Water shotpoints are, in general, superior to drill-hole shotpoints; however, one drill-hole shotpoint produced higher signal amplitudes than more than half of the water shotpoints. Signal amplitudes from drill-hole shotpoints varied by a factor of over 20. Saturated clay shooting medium appears to be the best shooting medium. Amplitudes from water shotpoints varied by a factor of about 10. Signal amplitude increases, in general, with water depth for bottom shots.

Crustal Studies Technical Letter↗
USGS1875

Preliminary report upon a reconnaissance through southern and southeastern Nevada, made in 1869

By authority from headquarters Military Division of the Pacific, Lieut. George M. Wheeler, United States Engineers, will proceed with his civil assistants and three enlisted men to either Camps Halleck or Ruby, Nevada, and having been joined by Lieut. D.W. Lockwood, United States Engineers, now en route via Fort Churchill, will there organize a party, to consist of two-non-commissioned officers and twenty-three enlisted men, (cavalry, or infantry mounted,) such drivers, packers, and guides as may be required; equip them with the necessary, full, and complete outfit, as far as the resources of the posts will enable him so to do; after which he will proceed, via the White Pine district, to make a thorough and careful reconnaissance of the district of country to the south and east of White Pine, extending thereto from the White Pine or Grant district, of obtaining correct data for a military map of the country, and for the selection of the site or sites for such military post or posts to cover the mining country south and east of White Pine from hostile Indians, as may be required. Such explorations and examinations as may will be made in reference to the physical geography of the country, its resources in wood, water, agricultural or mineral productions. The character, habits, and numbers of Indian tribes, and their dispositions toward settlers and miners, will be subjects for investigations.

Nevada↗
USGS1900

Preliminary report on the Cape Nome gold region, Alaska

The following report is based on a few weeks' examination of the recently discovered Nome gold-mining region, made by us in October, 1899. We collected such topographic and geologic data of this important region as the climatic conditions would permit and our limited time would allow, the trip to Nome being a hurried utilization of a delay while waiting for a steamer for Seattle after the completion of the regular field work in the Yukon Basin.

Alaska↗
USGS1946

Preliminary report on the stratigraphy and structure of the Kurupa, Colville, and Oolamnagavik Rivers, Alaska

U. S. Geological Survey Party No. 4 covered the area between 68° 30' and 69° 08' N. latitude and between 154° and 155°20' W. longitude during the period May 18 to September 2. Traverses were confined mainly to the valleys of the Kurupa, Colville, and Oolamnagavik Rivers inasmuch as very little rock is exposed in the interstream areas. This report is limited to the Colville River valley area between the Kura and Killik Rivers, and to a stratigraphic section exposed. on the Kurupa 7-12 miles south of the Colville. A final report will be prepared by April 1, 1947, on the total area and will include discussions of the stratigraphy and structure of Upper Cretaceous formations A through D on the Oolamnagavik and Kurupa, the stratigraphy of Formation D on the Colville, and the Lower Cretaceous and Triassic rocks. Separation and identification of heavy minerals from the sandstones and conglomerates, binocular and petrographic microscope examinations of specimens, identification of megafossils, and separation and identification of microfossils, if any, will be undertaken. Detailed examination of all aerial photos will be made to trace out structures and formations in the adjacent areas to the east, north, and west. It seems probable that close correlation between this area, the Killik River area, and Maybe Creek area will be possible by extrapolating field and aerial photo data. It is possible also to trace structures and some formation westward from the Kurupa River.

Alaska↗
USGS1947

Preliminary report on stratigraphy and structure of the area of Kigalik and Awuna Rivers, Alaska

During the summer of. 1947, U. S. Geological Survey Party No. 2 made a reconnaissance survey of the area between Awuna River and the divide north of the Kigalik River. The westernmost observations were made along the Awuna anticline to longitude about 157°30' W. and along the Kigalik anticline to longitude about 156°55'W. The easternmost work was done along the Knife Blade Ridge anticline at a longitude of about 154°30'W. Not all of this area was traversed, but a general idea of the area studied may be had by noting the distribution of dip and strike symbols on Figure 1. Parts of this area had been previously visited by Smith 1/ in 1927 as a part of his traverse from Allakaket to the Arctic Coast. In the period from about July 10 to August 5 his party ascended the Awuna River and Birthday Creek, portaged over the Kigalik-Awuna divide at Birthday Pass, and descended the Kigalik River to its mouth. Various parties in the field season of 1946 worked in areas not far distant. Webber 2/ began his field work near the headwaters of the Meade River and measured a section across the Kigalik anticline about 25 miles beyond the westernmost observations made on that structure by Party No. 2. Work by Chapman and Thurrell 3/ along the Colville River parallels at a distance of three or four miles work by Party No. 2 in the vicinity of Knife Blade Ridge. The easternmost observations by Party No. 2 in the vicinity of Knife Blade Ridge are about 11 miles west of the area south of Maybe Creek mapped by Ray and Fischer.4/ Of the 1947 work of other field parties that of Thurrell 5/ along the Colville River is most closely related to this report. His thickness from the base of Zone A to his Trace No. 5 is included in Column 1 of Figure 3. Webber's work 6/ along the Ikpikpuk and Titaluk Rivers is also in a closely related area. Party No. 2 moved through this area by weasel, the weasels being used extensively on the daily traverses. The party assembled at Umiat late in May and was flown out to a lake about one mile west of the Ikpikpuk River at latitude 69°40' N. where the weasels and initial supplies had been previously cached. Early in June the party moved south into the area in which it was to begin work. For the next several weeks the party worked in the area north of the Kigalik River, moving westward along the divide north of that river. At this time considerable work was done south of the Kigalik River, west of longitude 154°40'W. No closure was detected along the Kigalik anticline. Shortly after the middle of July the party moved southwestward to the vicinity of the Awuna anticline where a westerly plunge had been suggested from the study of aerial photographs. The general route of the party from then on was eastward along the divide between the Awuna and Kigalik Rivers. Due to the need to reach a food cache further east very little data was gathered in the area between Birthday and Section Creeks. It was intended to work this area by one or two spike trips from the camp at the head of Section Creek. However, after constructing a cross-section from data gathered by the party along Section Creek and by Thurreli in the area between the Colville and Awuna Rivers it became apparent that the strata exposed along the axis of the Awuna anticline were stratigraphically below the base of Zone A. It thus appeared that there would be little point in attempting to gather additional data in the area between Birthday and Section Creeks. The party continued eastward, working along the south flank of the Kigalik anticline. On September 1, the party camped about one mile west of the summit of Knife Blade Ridge. Because of unfavorable weather at this time only a small amount of field work was accomplished in the next week. Enough data was gathered to give a general picture of the structure here, but the data on stratigraphy and structure is far from exhaustive. On September 9 the party moved eastward, camping that night about 3 miles northeast of :Wolf Creek, and arriving at Umiat on the afternoon of September 10. Aerial photographs were carried in the field and used to record the points at which observations were made. A considerable amount of data was recorded on the photographs. Approximate elevations were obtained, at first by aneroid barometers, and later by more sensitive airplane altimeters. Plane table and alidade were used in local traverses in the area north of the Kigalik River to obtain dips and strikes by the 'three-point method. Nearly all other dips and strikes recorded were measured by Brunton compass. Dips of 5° or less in the area south of the Kigalik River should, in general, be considered as dip components with only the approximate strike shown. These low dips were taken on bedding traces* where it was usually impossible to observe an accurate strike with the Brunton.

Alaska↗
USGS1947

Preliminary report on stratigraphy and structure of the area of the Colville River between Ninuluk and Prince Creeks, Alaska

Geological Survey Party 4 began studies at a point on the Colville River 18 miles downstream from the mouth of the Killik River on July 19. From this point the studies were continued along the Colville River to near the mouth of Prince Creek. The investigation was completed on September 1 and the party returned to Umiat. A traverse was made along the lower half of Prince Creek and along one of its northern tributaries between September 8 and September 15. Canvas boats were used for transportation along the Colville River and a weasel was used to traverse Prince Creek. The party was composed of four members: R. L. Detterman and D. E. Mathewson, geologists; J. L. Townley, surveyor; and Charles Segal, cook.

Alaska↗
USGS1947

Preliminary report on stratigraphy and structure of the area of the Colville River north of Umiat, Alaska

The stratigraphy and structure of the area of the Colville north of Umiat was studied by U. S. GeologicaI Survey Party No. 1 during the period of May 31 to July 19, 1947. The. party, consisting pf two geologists, a cook, and a "weasel" mechanic, left Umiat in two "weasels”. The weasels were used to transport the party and equipment from camp to camp, and also made it possible for the geologists to work as far as 15 to 20 miles out from a camp in one day. A ten-foot canvas-boat was carried along. During most of the month of June even the smaller tributaries to the Kogohokruk carried enough melt and run off water to make them navigable in the 10-foot boat. The party returned to Umiat on June 23, after traversing both the Kikiakrorak and the Kogohokruk Rivers, and several smaller tributaries to the Kogohokruk.

Alaska↗
USGS1947

Preliminary report on stratigraphy and structure of the Wolf Creek anticline, Alaska

In 1946 U. S. Geological Survey Party 2 was assigned the task of carrying out detailed structural and stratigraphic investigations in the area of Maybe Creek*. Field studies indicated the presence of a large anticlinal structure whose axis lies just south of Wolf Creek. Later structural data compiled from aerial photographic studies indicated that the anticline is a closed structure 8-9 miles long, and as much as 6 miles wide. The evidence for a closure on the east end of the structure appears very strong, but not enough evidence was obtained to prove closure on the west end. In 1947 U. S. Geological Survey Party 1 spent two weeks at Wolf Creek, mapping bedding traces on the west end of the structure with plane table and alidade, in an attempt to prove or disprove west closure on the anticline. Party 1, consisting of 3 geologists, cook, and a "weasel" mechanic, left Umiat on July 21, and returned on August 5. Two "weasels" were used for the transportation of the party and equipment, and were also used extensively in mapping the area.

Alaska↗