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Research about Iowa

Source-linked reports with geographic coverage including Iowa.

At least 469 records · Page 26Linked to original sources
USGS1963

Preliminary interpretation of an aeromagnetic survey in north-central Iowa

Publication of Lyons' gravity map of the United States in 1950 focused attention on a spectacular geophysical feature now generally referred to as the "midcontinent gravity high." This feature, the largest gravity maximum in North America, was discovered and later detailed by geophysicists at the University of Wisconsin (Woollard, 1943, 1951) and Thiel (1956). Their work reveals an essentially continuous large positive gravity anomaly extending southwestward for 800 miles from Lake Superior to the Salina Basin in Kansas. The midcontinent gravity high reaches its maximum intensity in central Iowa where the Bouguer anomaly ranges from -100 to 60 milligals. In September-October 1961, the U. S. Geological Survey made a 5,000 square mile aeromagnetic survey in north-central Iowa in cooperation with the Iowa Geological Survey. Objectives of the investigation were to prepare and interpret a detailed aeromagnetic contour map for part of the midcontinent gravity high in Iowa. Analysis of the magnetic data could be expected to yield estimates of local thickness of the Paleozoic-Mesozoic sedimentary section and provide a basis for informed speculation about the character, configuration, and distribution of the Precambrian rocks. Such information would have obvious scientific and possible economic value in an area covered by glacial till and for which little deep subsurface knowledge was available. Interpretation of the Indiana aeromagnetic survey (Henderson and Zietz, 1958) had previously demonstrated that aeromagnetic data from the central stable region of North America would provide a significant amount of geologic information. The 5,000 square mile area surveyed in 1961 has been combined with a previously unpublished 600 square mile aeromagnetic survey made in 1953, centered on Manson, Pocahontas Co., Iowa. The combined area is shown as the patterned area in figure 1. The unpatterned area outlined on this same figure is the additional 10,000 square mile cooperative aeromagnetic survey made in the summer of 1962 to complete coverage of the midcontinent gravity high in Iowa. The primary purpose of this report is to make the 1953 and 1961 aeromagnetic data available to the public in advance of more formal publication. Only salient magnetic features are discussed in this preliminary presentation and in a second report on results obtained during the 1962 flying. A more complete interpretation of the entire aeromagnetic survey will be prepared.

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USGS1961

Geology and ground-water resources of Clayton County, Iowa

Clayton County includes 784 square miles in northeastern Iowa and in 1960 had a population of 21, 962. For the most part, the county is a dissected upland that is drained mainly by the southeastward flowing Turkey River and its principal tributary, the Volga River. The Turkey River empties into the Mississippi River, which flows southward along the eastern border of the county. The climate is humid continental, and the average annual precipitation is 33.01 inches. The economy of the county is based on farming and the raising of livestock. The natural resources of the county include soil, water, rock, sand, and timber.

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USGS1957

Geology and zinc-lead deposits in the Catfish Creek area, Dubuque County, Iowa

A detailed geologic study was begun in 1951 by the U.S. Geological Survey in cooperation with the Iowa Geological Survey to appraise the potentialities of the Iowa part of the Wisconsin-Illinois-Iowa zinc-lead district for (1) zinc ore in rock strata that contain pitch-and-flat zinc ore bodies elsewhere in the mining district and (2) joint-controlled lead and zinc ore like that mined extensively during the 19th century in Dubuque County, Iowa. This investigation is an outgrowth of a geologic study of the entire district, begun in 1942 by the U.S. Geological Survey.

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USGS1957

Drainage areas of Iowa streams

The drainage area of a stream at a specified location ordinarily may be defined as that area, measured in a horizontal plane, which is enclosed by a topographic divide such that direct surface runoff from precipitation would drain by gravity into the river basin above the specified point. One of the most important factors in the hydrologic computation for the design of structures on or over watercourses is the drainage area upstream from the point under consideration. Other hydrologic studies such as low-flow, flood-frequency analyses, rainfall-runoff correlations, stream density, and area-distance make use of this factor as a basic premise for computation. In order that the drainage-area information of the interior streams of Iowa be of uniform accuracy and available to all users of these data, this report has been compiled, and the drainage areas of all streams in excess of 5 square mies are listed. For the larger streams, drainage areas have been determined at numerous intermediate points. As a result of this report much basic background material has been compiled that will he useful in future hydrologic studies of drainage basin characteristics. This publication is limited to the presentation of the drainage-area data for the interior streams of the State. The methods of application of these data to the study of streamflow characteristics, and the design of related structures are properly the function of the design engineer and are not discussed herein.

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USGS1955

Geology and zinc-lead deposits in the Durango area, Dubuque County, Iowa

Geologic investigations were begun in Iowa to appraise; (1) the possible occurrence of zinc ore in strata that elsewhere in the Upper Mississippi Valley zinc-lead district have been the principal sites of zinc concentration; and (2) lead ore of the type known as "crevice deposits," which were mined so extensively during the 19th century in Dubuque County, Iowa, but have been mined very little since 1910.

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USGS1955

Geology and ground-water resources of Webster County, Iowa

Webster County, comprising an area of 718 square miles just northwest of the center of Iowa, had a population of 44,241 in 1950, with 25,115 in Fort Dodge, the principal city. Some 94.4 percent of the county is in farm land; corn is the principal crop and is used in the raising of hogs and cattle, an important occupation in this part of the country. Mineral products include gypsum, clay, coal, sand, gravel and limestone. The mean annual precipitation at Fort Dodge is 31.21 inches, of which more than 3 inches normally occurs during each of the months May, June, July, August, and September. The average number of growing days is 150. The warmest month generally is July; during December, January, and February the average temperature normally is below freezing. The upland area, comprising over 80 percent of the county, is mostly a gently undulating, slightly eroded glacial-drift plain. Morainal hills of low relief occur in the extreme southern and northern parts of the county. The Des Moines River flows through the county from north to south and, together with its tributaries, drains the entire county except the southwestern part, which is tributary to the Raccoon River. The Des Moines River has cut a deep, narrow valley about 90 feet below the upland in the northern part of the county and about 220 feet below the upland in the southern part. The tributary streams commonly have shallow valleys more than a few miles back from the Des Moines River. Glacial deposits of Pleistocene age, ranging in thickness from 50 feet in the north to 175 feet in the south, mantle the indurated rocks over all the upland area, but indurated rocks ranging in age from Mississippian to Cretaceous are exposed in places along the valleys of the Des Moines River and its tributaries.

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USGS1954

A new sphenopsid cone from Iowa

A new Pennsylvanian cone genus (Litostrobus iowensis, n. gen., n. sp.), apparently of sphenophyllalean affinity, is described on the basis of a coal-ball specimen from the Urbandale Mine, Urbandale, Iowa . The cone is small and extremely simple in organization. It consists of superposed whorls of twelve bracts each. The bases of the bracts are fused to form shallow cuplike discs. Six sporangia are produced in each whorl; they are erect, each terminating a short, thick, axillary pedicel. Small spores with highly distinctive ornamentation are present in the sporangia.Comparison with other previously described sphenopsid fructifications reveals morphological differences that warrant recognition of the Urbandale specimen as a new genus.

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USGS1953

Descriptive logs of exploratory holes drilled during 1952 by the U.S. Geological Survey in Dubuque County, Iowa

The exploratory holes were drilled as part of a larger geologic investigation, the objective of which is to determine in the Dubuque, Iowa, area the probable occurrence of zinc and lead ore stratigraphically lower than that which has been mined. The primary purpose of the drilling was to supply information required for geologic mapping in upland areas where bedrock exposures are sparse or absent. Where possible, the doles were located also on the extension of known mineralized trends. Seven holes aggregating 1,687 feet were drilled with cable tools. Descriptive logs, prepared by A. E. Flint and C. E. Brown frog binocular microscope study of cuttings that were recovered from the drilling, are accompanied by assay values of significant mineralized samples. Index maps show hole locations.

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USGS1944

Surface water resources of Iowa for the period October 1, 1940 to September 30, 1942

The State and Federal cooperative program for the systematic collection of stream-flow records in Iowa was initiated in L914, although a few records were obtained by special arrangements during an earlier period. Since the beginning of the cooperative program measurements of stage or discharge have been obtained at about 100 stations on Iowa streams and lakes for periods of various lengths. The longest records are those for the Mississippi River at Le Claire and Keokuk where authenticated data have been used to extend the record back to 1873 with decreasing accuracy for the earlier years. In addition to the records of daily stages or discharges, hundreds of measurements of a miscellaneous character also have been made at other points.

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USGS1942

Summaries of yearly and flood flow relating to Iowa streams 1873-1940

As a result of the need for basic data and the lack of a current and convenient summary concerning the surface-water resources of Iowa, a synoptic inventory has been prepared as a part of the present State-wide program which is made possible by State and Federal cooperative action. These hydrologic data are assembled in abbreviated form for the convenient* of the public and in order that a current State report containing stream-flow records under one cover will be more readily accessible for Iowa. This inventory is here presented in the form of a brief compilation report which summarizes results of stream-flow measurements relating to Iowa streams through out the years during which local. State and Federal agencies have cooperated in Iowa with the water resources branch of the United States Geological Survey. The principal basic data consist of concise summaries for gaging stations in Iowa and certain relevant locations adjacent thereto for which records for five or more complete years have been collected. These summaries include a comprehensive description and history of each station followed by a table giving in convenient form and for general use the figures of maximum and minimum daily dis charge and yearly mean discharge and runoff for the water and calendar years of record. In addition, approximately 300 miscellaneous discharge measurements, which have been made within the State of Iowa, am included in an original and convenient listing. A summary of maximum discharges at LIS places is also given together with other data pertinent to flood flow in Iowa.

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