A compilation of information and data on the Manson impact structure

A problem for the impact hypothesis for the Cretaceous-Tertiary (K-T) mass extinction is the apparent absence of an identifiable impact site. The Manson Impact Structure is a candidate because it is the largest recognized in the U.S.; it is relatively close to the largest and most abundant shocked quartz grains found at the K-T boundary; and its age is indistinguishable from that of the K-T boundary based on paleontological evidence, fission track dates, and preliminary Ar-40/Ar-39 measurements. The region of northwest central Iowa containing the Manson Impact Structure is covered by Quaternary glacial deposits underlain by Phanerozoic sedimentary rocks (mostly flat-lying carbonates) and Proterozoic red clastic, metamorphic, volcanic, and plutonic rocks. In a circular area about 22 miles (35 km) in diameter around Manson, Iowa, this normal sequence is absent or disturbed and near the center of the disturbed area granitic basement rocks have been uplifted some 20,000 ft (6000m). Attention was drawn to Manson initially by the unusual quality of the groundwater there. Within the structure three roughly concentric zones of rock associations have been identified: (1) displaced strata; (2) completely disrupted strata, and igneous and metamorphic rocks. Manson was established as an impact structure based on its circular shape, its central uplift, and the presence of shocked quartz within the granitic central uplift. A gravity survey identified locations of low-density brecciated rocks and high-density uplifted crystalline rocks, but the outer boundary of the structure could not be established. Aeromagnetic and ground magnetic surveys showed locations and depths of shallowly buried crystalline rock and the locations of faults. A refraction seismic survey identified the crystalline central uplift, determined that the average elevation of bedrock is 70 ft (20 m) higher outside the structure than within, and was used to map the bedrock topography within the structure. A connection between the Manson impact and the K-T boundary may be established or refuted through study of the impact energy, the impact time, and composition of host rock, possible impactors, and impact melts

Land-use in Iowa, 1976 : an explanation of the map

https://ir.uiowa.edu/igs_tis/1003/thumbnail.jp

Compilation of information and data on the Manson Impact Structure

A problem for the impact hypothesis for the Cretaceous-Tertiary (K-T) mass extinction is the apparent absence of an identifiable impact site. The Manson Impact Structure is a candidate because it is the largest recognized in the U.S.; it is relatively close to the largest and most abundant shocked quartz grains found at the K-T boundary; and its age is indistinguishable from that of the K-T boundary based on paleontological evidence, fission track dates, and preliminary Ar-40/Ar-39 measurements.by Jack B. Hartung and Raymond R. Anderson.Geology of Northwest Central Iowa -- Geology of the Manson Impact Structure -- Geophysical Studies of the Manson Impact Structure -- Ages of Samples from the Manson Impact Structure -- The Manson Impact Structure and the K-T Boundar

Geochemistry of Buried Midcontinent Rift Volcanic Rocks in Iowa: Data From Well Samples

We analyzed welt cores and cuttings from deep wells into Precambrian igneous rocks from five separate pacts of the buried Midcontinent Rife System in Iowa for major and trace elements. A total of 21 samples, 9 cores and 12 cuttings, were analyzed for trace elements by instrumental neutron activation analysis (INAA) and 11 of these, 9 cores and 2 cuttings, were analyzed for major elements by inductively coupled plasma (ICP) analysis

Bedrock Geology of Cedar County, Iowa Final Phase: Bedrock Geologic Map of Cedar County 1:100,000

https://ir.uiowa.edu/igs_ofm/1060/thumbnail.jp

Development of weight and cost estimates for lifting surfaces with active controls

Equations and methodology were developed for estimating the weight and cost incrementals due to active controls added to the wing and horizontal tail of a subsonic transport airplane. The methods are sufficiently generalized to be suitable for preliminary design. Supporting methodology and input specifications for the weight and cost equations are provided. The weight and cost equations are structured to be flexible in terms of the active control technology (ACT) flight control system specification. In order to present a self-contained package, methodology is also presented for generating ACT flight control system characteristics for the weight and cost equations. Use of the methodology is illustrated

Book Review: Iowa\u27s Geological Past: Three Billion Years of Change

Iowa\u27s Geological Past: Three Billion Years of Change. Wayne Anderson, 1998. University of Iowa Press, Iowa City IA. xii + 424 pages. ISBN 0-87745-639-9, ISBN 0-87745-640-2 (pbk.). Wayne Anderson, born in geode country in southeast Iowa, earned his Bachelors, Masters, and Ph.D. at the University of Iowa (writing a thesis and dissertation on Iowa geologic topics). He will complete a 37-year career teaching geology at the University of Northern Iowa with his retirement in the Spring of 2000. His research activities and the work of his students have added greatly to our understanding of the geology of eastern Iowa. In his many years of studying and teaching, Wayne has clearly developed a thorough understanding of the geology of the Iowa, and he has drawn on this wealth of information in his newest literary effort, to produce a very complete and accurate book on Iowa\u27s geologic history

Geology of the Precambrian Surface of Iowa and surrounding area

https://ir.uiowa.edu/igs_ofm/1048/thumbnail.jp

Book Review: Iowa\u27s Minerals: Their Occurrence, Origins, Industries, and Lore

Iowa\u27s Minerals: Their Occurrence, Origins, Industries, and Lore. Paul Garvin. 1998. University of Iowa Press, Iowa City IA. vii + 260 pages. ISBN 0-87745-626-7 hdbd., ISBN 0-87745-627-5 (pbk.). A mineral is defined as a naturally occurring, chemically homogeneous crystalline solid. Every mineral has a composition, structure, and characteristics that make it uniquely different from every other mineral. In his new book, Paul Garvin, Professor of Geology at Cornell College in Mount Vernon, Iowa, presents a uniquely different discussion of Iowa\u27s Minerals. While this book does contain the requisite discussions of mineral origins, chemistry, crystallography, and other descriptive information, Garvin enhances this information with tips for collecting minerals in Iowa, historical accounts of Iowa\u27s mineral industry, and a series of fascinating stories about Iowa minerals that will captivate readers from professional geologists to would-be rock hounds