Geologic Map of the Park Reservoir Quadrangle, Sheridan County, Wyoming

2020 ◽  
Vol 57 (4) ◽  
pp. 375-388
Author(s):  
Ryan Bessen ◽  
Jennifer Gifford ◽  
Zack Ledbetter ◽  
Sean McGuire ◽  
Kyle True ◽  
...  
Keyword(s):  
Structural Features ◽  
Geologic Mapping ◽  
Rock Types ◽  
Basement Rocks ◽  
Geologic Maps ◽  
Geologic Map ◽  
Tear Fault ◽  
Mapping Techniques ◽  
Wyoming Province ◽  
Bighorn Mountains

This project involved the construction of a detailed geologic map of the Park Reservoir, Wyoming 7.5-Minute Quadrangle (Scale 1:24,000). The Quadrangle occurs entirely in the Bighorn National Forest, which is a popular recreation site for thousands of people each year. This research advances the scientific understanding of the geology of the Bighorn Mountains and the Archean geology of the Wyoming Province. Traditional geologic mapping techniques were used in concert with isotopic age determinations. Our goal was to further subdivide the various phases of the 2.8–3.0 Ga Archean rocks based on their rock types, age, and structural features. This research supports the broader efforts of the Wyoming State Geological Survey to complete 1:24,000 scale geologic maps of the state. The northern part of the Bighorn Mountains is composed of the Bighorn batholith, a composite complex of intrusive bodies that were emplaced between 2.96–2.87 Ga. Our mapping of the Park Reservoir Quadrangle has revealed the presence of five different Archean quartzofeldspathic units, two sets of amphibolite and diabase dikes, a small occurrence of the Cambrian Flathead Sandstone, two Quaternary tills, and Quaternary alluvium. The Archean rock units range in age from ca. 2.96–2.75 Ga, the oldest of which are the most ancient rocks yet reported in the Bighorn batholith. All the Archean rocks have subtle but apparent planar fabric elements, which are variable in orientation and are interpreted to represent magmatic flow during emplacement. The Granite Ridge tear fault, which is the northern boundary of the Piney Creek thrust block, is mapped into the Archean core as a mylonite zone. This relationship indicates that the bounding faults of the Piney Creek thrust block were controlled by weak zones within the Precambrian basement rocks.

scholarly journals Application of airborne radiometric method in geologic mapping of Malufashi area and Environs, Northwestern Nigeria

2020 ◽  
Vol 8 (2) ◽  
pp. 179
Author(s):  
Ibe Stephen Onyejiuwaka ◽  
Nwokeabia Charity Nkiru
Keyword(s):  
Gold Mineralization ◽  
Value Added ◽  
Geologic Mapping ◽  
Radioactive Elements ◽  
Rock Types ◽  
Reconnaissance Survey ◽  
Airborne Geophysics ◽  
Geologic Map ◽  
Hydrothermal Alteration Zones ◽  
Radiometric Data

In this study, the airborne radiometric data over Masufashi Area of Katsina State and Environs, Northwestern Nigeria were acquired, processed and gridded to generate the concentration maps of percentage Potassium, equivalent Thorium and equivalent Uranium in order to carry out the geologic mapping of the area. Additionally, the abundance ratios, U/Th, U/K and Th/K and the ternary images of the three radioactive elements were produced. The images obtained from the radiometric data showed that the study area comprises five major rock types, based on their variation in the concentration of the three radioactive elements. The actual extent, boundary and distribution of the rock units within the study area were defined; hydrothermal alteration zones were mapped. The altered zones were noted to be associated with mineralization in the quartzite rich schist formation. The interpretation also proved valuable in demarcating some rock types with different properties. The delineated geology and hydrothermally altered zones led to the identification of nine zones with the potentials of gold mineralization. The delineated structures aided the design of the geologic map of the study area. This research showed the value added by airborne geophysics in geologic mapping and recommends the analysis of airborne data as a major phase during reconnaissance survey, prior to geologic mapping.  

THE NATIONAL GEOLOGIC MAP DATABASE -- A RESOURCE FOR GEOLOGIC MAPPING

2016 ◽  
Author(s):  
David R. Soller ◽  
◽  
Nancy R. Stamm ◽  
Robert C. Wardwell ◽  
Christopher P. Garrity
Keyword(s):  
Geologic Mapping ◽  
Geologic Map

Surface and subsurface structural study of the Wadi El Rayan area, Southwest Fayoum, Egypt

1983 ◽  
Vol 120 (1) ◽  
pp. 59-66
Author(s):  
M. M. Youssef ◽  
H. M. El Khashab
Keyword(s):  
Structural Study ◽  
Middle Eocene ◽  
Structural Features ◽  
Aerial Photographs ◽  
Field Observations ◽  
Geologic Map

SummaryThe surface geologic map of the Wadi El Rayan area, based on the study of aerial photographs and field observations, is correlated with seismic structural two-way time maps for the basement, the top of Cenomanian and the base of Tertiary horizons. Major structural features comprise a northeasterly faulted plunging anticlinal stretch traversing the NW-SE Wadi El Rayan depression. Three sets (ENE-WSW, NW-SE and NE-SW) of faults dissect the area. Folding movement was still active at least to the end of Middle Eocene epoch. ENE-WSW faults affecting the basement, and traced in higher levels, have the same trend as the fold axes. It is thus possible that compressional features appearing on the surface and subsurface horizons are in part due to thrusting in deeper levels that took place parallel to folding.

scholarly journals An experimental aeromagnetic survey in the Volturno valley area (South-Eastern Latium)

1998 ◽  
Vol 41 (3) ◽  
Author(s):  
M. Chiappini ◽  
F. Ferraccioli ◽  
V. Bosi ◽  
E. Bozzo ◽  
G. Caneva ◽  
...  
Keyword(s):  
Structural Features ◽  
Tectonic Activity ◽  
Aeromagnetic Survey ◽  
Magnetic Image ◽  
Geologic Map ◽  
Anomaly Map ◽  
Area North ◽  
Valley Area ◽  
Shaded Relief ◽  
Extensional Setting

A helicopter-borne experimental aeromagnetic survey, covering an area of 200 km2, was performed in the Volturno valley area north of the Roccamonfina volcano and south of Venafro in November 1994. Although severe logistical, instrumental and meteorological conditions significantly reduced the planned coverage, the processed magnetic image still shows a remarkable improvement in the description of the geological and structural features of the area in comparison with previous regional aeromagnetic data. A multi-directional shaded relief anomaly map displays two moderately positive NW magnetic bands associated with lavas, pyroclastics and dykes of the Roccamonfina volcanic district together with N-S, NNE-SSW and NE-SW lineations. A comparative magnetic-geologic map allows correlation with known Pleistocene faults and reveals the existence, especially in the area between Sesto Campano and Presenzano, of a larger presence of high susceptibility dykes than seen in the outcrop, which is dominated by non-magnetic carbonatic rocks. We interpret the curvilinear and intricate pattern of magnetic lineaments as suggestive of an extensional setting along the main NW structures with previous strike slip components and of tectonic activity along a N-S fabric; the latter has no superficial evidence and has also been used for magma upwelling. Overall, this local scale investigation shows both the utility and the need for further efforts in high resolution aeromagnetics in Italy both for geological and environmental purposes similar to those successfully carried out in many other countries throughout the world.

Archean geochronological framework of the Bighorn Mountains, Wyoming

2006 ◽  
Vol 43 (10) ◽  
pp. 1399-1418 ◽  
Author(s):  
Carol D Frost ◽  
C Mark Fanning
Keyword(s):  
Ion Microprobe ◽  
Entire Area ◽  
Wind River Range ◽  
Gneiss Complex ◽  
Granitic Intrusion ◽  
Northern Portion ◽  
Tonalitic Gneiss ◽  
Archean Crust ◽  
Wyoming Province ◽  
Bighorn Mountains

The Bighorn Mountains of the central Wyoming Province expose a large tract of Archean crust that has been tectonically inactive and at relatively high crustal levels since ~2.7 Ga. Seven sensitive high-resolution ion microprobe (SHRIMP) U–Pb zircon and titanite age determinations on samples of the main lithologic units provide a geochronological framework for the evolution of this area. The oldest, precisely dated magmatic event occurred at 2950 ± 5 Ma, when diorite to granite dykes and sills intruded an older gneiss complex exposed in the central and southern Bighorn Mountains. Rocks as old as 3.25 Ga may be present in this gneissic basement, as indicated by the oldest dates obtained on areas of zircon grains that are interpreted as inherited cores. A tonalitic gneiss was intruded into the gneiss complex at 2886 ± 5 Ma. Deformation of the central and southern gneisses preceded the intrusion of the Bighorn batholith, a tonalitic to granitic intrusion that occupies the northern portion of the uplift. This composite batholith was intruded over the period 2.86–2.84 Ga. Ca. 3.0–2.8 Ga crust is also present in the Beartooth Mountains, the Washakie block of the northeastern Wind River Range, the Owl Creek Mountains, and the northern Granite Mountains, but late Archean deformation and plutonism has obscured much of the earlier history in the southern portion of this area. The entire area, referred to as the Beartooth–Bighorn Magmatic Zone, has been undeformed since 2.6 Ga. Proterozoic extension was focused in those parts of the Wyoming Province outside of this domain.

Determination of the characteristics of crystalline rocks by field experiments: a review

1986 ◽  
Vol 319 (1545) ◽  
pp. 139-156 ◽  
Keyword(s):  
Radioactive Waste ◽  
Field Experiments ◽  
The United States ◽  
Crystalline Rocks ◽  
Granitic Rocks ◽  
Rock Types ◽  
Basement Rocks ◽  
Deep Boreholes ◽  
High Level ◽  
Underground Research Laboratory

Crystalline rocks, particularly granitic rocks and basalts, are one of the principal rock types under consideration as a potential host rock for a high-level radioactive waste repository. Permeability in such rocks is related to discontinuities of various scales, and the quantification and prediction of groundwater flow within both the fractures and the intact rock between the fractures is the major goal of field experiments. The Canadian Underground Research Laboratory is unique in that the hydrogeological conditions within a large volume of rock surrounding the experimental shaft are being monitored before, during and after excavation and the results compared with model predictions. In Switzerland twelve deep boreholes are being drilled to over 1000 m to investigate crystalline basement rocks beneath a cover of sediments. The Stripa Mine in Sweden has hosted a major experimental programme including heater tests to stimulate the thermal effect of radioactive waste and hydrogeological tests at various scales down to individual fractures. The United States of America, the United Kingdom, France and Finland have also embarked on major experimental programmes. Continuing research is needed, with an emphasis on field experiments and research in underground rooms, to provide the data on which detailed risk assessments can be based.

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