Interpretation of gravity and magnetics north of Lake Superior.

by David G. Mackidd

Written in English
Published: Pages: 103 Downloads: 710
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Subjects:

  • Physics Theses

Edition Notes

Thesis (M.Sc), Dept. of Physics, University of Toronto

ContributionsWest, G. F. (supervisor)
The Physical Object
Pagination103 p.
Number of Pages103
ID Numbers
Open LibraryOL18763153M

MC North Atlantic Ocean: Bathymetry & Plate Tectonics Evolution; ; R.K. Perry et al. MC Seasonal Reconstructions of the Earth’s Surface at the Last Glacial Maximum; ; A. McIntyre et al. MC Great Lakes Region Gravity & Magnetic Map Sequence, Lake Superior Area; ; Norbert W. . Assess the utility of gravity and magnetic to map geology of interest. Assess the utility of gravity and magnetics for imaging the geologic target, and participate in design of new acquisition. Oversee and evaluate the interpretation process of gravity and magnetic data, both qualitative products and quantitative products. Instructor Biography. Prior to , the principal means of correlating MCR volcanic sequences in the Lake Superior region was by their magnetic polarity and apparent pole position of remnant magnetism. In the western Lake Superior basin, most volcanic rocks were correlated relative to a single magnetic polarity reversal from early reversed to late normal (Fig. 3).   On magnetic maps the Mid-Continent Gravity High shows up as parallel zones of abnormally high and low magnetic intensity. It is now widely thought to .

Seismic-reflection data from the GLIMPCE experiment in Lake Superior (Cannon et al., ; Behrendt et al., ) do not support the Lee and Keff model for the deep part of the central rift. As always with gravity and magnetic models, a number of possible models fit the data. Figure Modeling by Lee and Kerr (), using gravity only. Books on Lake Superior Agate Hunting & Rock Picking. Lake Superior's North Shore. Sparky's guide covers what north shore beaches to comb, a bit of history on the formation of the various rocks found on beaches, and helpful information and pictures on identifying beach rocks and minerals. These arms are identified using the large gravity and magnetic anomalies resulting from dense and highly magnetic igneous rocks. They are largely covered by younger sediments but outcrop near Lake Superior and along the St. Croix river (see picture above) and can be followed further south in drill cores. Bedrock geologic maps of northeastern, north-central, and western Minnesota and associated reports published by MGS. Jirsa, M.A., , Interflow sedimentary rocks in the Keweenawan North Shore Volcanic Group, northeastern Minnesota: MGS Report of Investigati 20 p.

Sexton, J.L., and Henson, H., Jr. () Interpretation of seismic reflection and gravity profile data in western Lake Superior: Canadian Journal of Earth Scien – Google Scholar Thomas, M.D., and Teskey, D.J. () An interpretation of gravity anomalies over the Midcontinent Rift, Lake Superior, constrained by GLIMPCE seismic. "Center of Gravity II," comprising 34 photographs, opens Saturday, April 5, and continues through May 17 at the Arboretum. Juhl will sign copies of his new "Center of Gravity" book on April 20 from a.m. to p.m. He will lead rock-balancing classes at the Arboretum on June 28 and Aug. 1. Introduction. The shallow, dense igneous rocks of North America's ‐Ga failed Midcontinent Rift (MCR) System create a striking magnetic anomaly and gravity high that demarcate the rift axis (Chase & Gilmer, ; Hinze et al., ; King & Zietz, ).The system consists of two arms that converge in the Lake Superior region—one extending southeast through Michigan and one extending. North and South Ranges and a syncline between the South Range and Bay Lake. A large magnitude negative gravity anomaly north of Mille Lacs is postulated to result from an intrusive mass extending to the erosion surface. Aero-magnetics are used to strengthen the gravity interpretation. The need is realized for additional regional gravity.

Interpretation of gravity and magnetics north of Lake Superior. by David G. Mackidd Download PDF EPUB FB2

Gravity and magnetic anomalies in Lake Superior are useful in tracing out the subsurface extent and geometry of igneous rocks of the Keweenawan Supergroup that crop out around the lake and on islands within the lake.

The data show that the Lake Superior structural basin generally is outlined by the shoreline of the by: The structure of western Lake Superior is studied by magnetic, gravity, and sub‐bottom profiling surveys. About miles of north‐south aeromagnetic tracks were flown, bottom gravity stations occupied, and miles of sub‐bottom profiles by: 1.

Geology and Tectonics of the Lake Superior Basin Author(s) Richard J. Wold; Richard J. Wold Geological evidence relating to interpretation of the Lake Superior Basin structure.

Author(s) Long-wavelength gravity and magnetic anomalies of the Lake Superior region. Author(s) V. Cited by: Download Citation | Aeromagnetic, Gravity, and Sub-Bottom Profiling Studies in Western Lake Superior: Steinhart/The Earth Beneath the Continents | The structure of western Lake Superior is studied.

Preface Acknowledgements List of symbols Part I. Introduction: 1. Introduction Part II. Gravity Exploration: 2. The gravity method 3. Gravity potential theory 4. Density of Earth materials 5. Gravity data acquisition 6. Gravity data processing 7. Gravity anomaly interpretation Part III.

Magnetic Exploration: 8. The magnetic method 9. Magnetic potential theory Integrated geophysical analysis provides an alternate interpretation of the northern margin of the North American Midcontinent Rift System, Central Lake Superior.

Grauch, Eric D. Anderson, Samuel J. Heller, Integrated interpretation of gravity, magnetic, seismic, and well data to image volcanic units for oil-gas exploration in the.

The seismic reflection interpretation in Lake Superior is based on the interpretation of Line C of the GLIMPCE program in Lake Superior (Cannon et al., ), and the section southeast of the lake across the Keweenaw fault is derived from seismic reflection and gravity.

PGS has an extensive library of gravity and magnetics datasets. These datasets can be either qualitatively interpreted to enhance the geological understanding in regions of sparse seismic data coverage (e.g.

2D only) or quantitatively analyzed to help with complex interpretation challenges. Interpretation of the 5-s reflection data constrained by surface geology, magnetics, and gravity modeling shows that volcanic rocks which cropout north of the Keweenaw fault dip northerly to depths of the order of 17 km.

South of the fault, volcanic rocks overlain by ̃2 km of clastic sedimentary rocks thin gradually to the south as they dip. • The acquisition, reduction, and interpretation of gravity and magnetic observations are very similar. *The expression potential field refers to a mathematical property of these types of force fields.

Both gravitational and the magnetic forces are known as conservative forces. This property relates to work being path independent. Detailed gravity surveys and combined geological-geophysical studies are being pursued, while new studies of heat flow, magnetics, and conductivity are under way or already complete.

We hope that these investigations will provide answers to some of the many questions still remaining about the structure of the Lake Superior area. Gravity and Magnetic Interpretation Interpretations of GravMag data are non-unique, meaning that sometimes a number of different geological models can fit the observed data.

With constraints from geological and other geophysical data types (e.g. seismic and well data), the interpretations can provide critical insights into the geometry of the. Integrated geophysical analysis provides an alternate interpretation of the northern margin of the North American Midcontinent Rift System, central Lake Superior Article in Interpretation June.

North America's Midcontinent Rift (MCR) and Grenville Front (GF) jointly record aspects of the complex history of the assembly of Rodinia. The ~ Ma MCR, remaining from a failed major rifting event, is exposed along Lake Superior and well defined by gravity, magnetic, and seismic data. Gravity and Magnetic Techniques for Geophysical Exploration Gravity and magnetic exploration techniques are both passive in that they exploit a naturally existing field of the Earth.

The measured quantity is the integrated effect of the subsurface. The gravity and magnetic fields are both irrotational vector fields described by potential. Magnetic and gravity interpretation Continued Page Anomalies in the northern part of the surveyed area Continued Old Man Lake gravity anomaly.____ _____ Paleozoic basement rocks north and south of these gravity lows.

The milligaI difference between the low- and high. Combined magnetic and gravity data are interpreted to Lake Superior region.

The area is mantled by Pleistocene glacial CoLLinwood township, just north of Lake Jenny in the southeastern part of the county--which was drilled in penetrated feet of blue. Interpretation In this we focus on various techniques used to interpret the magnetic data.

From an applied geoscientists standpoint, this is where most of the data integration and decision making steps are made. In some cases direct data interpretation can be used. New gravity and magnetic compilations and elevation-bathymetry models have been compiled for the Lake Superior region.

These data provide continuous sets of observations for geologic interpretations spanning political boundaries such as US States and the US-Canada border where bedrock geology is largely concealed beneath glacial deposits and surface water. ISBN: OCLC Number: Notes: 2 folded map in pocket.

Description: v, p.: ill. ; 29 cm. Contents: Preface --Introduction / Richard J. Wold and William J. Hinze --Geological evidence relating to interpretation of the Lake Superior Basin structure / Donald M. Davidson, Jr. --Status of the Keweenawan as a stratigraphic unit in the Lake Superior region / G.B.

Gravity & Magnetics CGG houses the most comprehensive, privately-owned, multi-client airborne, land and marine potential fields geophysical database in the world. The database incorporates approximat, line kilometers of aeromagnetic data, 1, line kilometers of marine gravity & magnetic data, and 2, stations of land.

Integrated Interpretation of Gravity, Magnetic & Seismic data for delineation of Basement Configuration in Sadiya Block, Upper Assam, India Fig. The interpreted NW-SE 2-D seismic line SC passing parallel to Gravity& Magnetic Profile L9.

basement structures. Where gravity and magnetics courses exist, too often they focus—with intimidatingly advanced mathematics—on the physics of potential fields at the expense of exploration applications, survey design and methods of geological interpretation.

Too many gravity and magnetics textbooks are also very mathematical (with a superb exception of. Synergistic interpretation of seismic reflection, gravity and magnetic anomaly, seismic refraction, rock physical properties, and geologic data has identified a great degree of structural heterogeneity of the MCR in Minnesota, Wisconsin, and western Lake Superior.

In the western Lake Superior region, the rift\u27s volcanic rocks are locally. Editor’s Note: The bottom of Lake Superior is paved with stones. However, many people have a hard time identifying what kinds of rocks they are looking Rock Picker’s Guide to Lake Superior’s North Shore by Mark Sparky Stensaas is a great tool for locating and classifying over 15 different rocks.

It also includes Lake Superior’s geological history, as well as beach profiles, tips. As the BBC’s Jonathan Amos reports, a new map does just was generated using data from the European Space Agency's Swarm mission, which is dedicated to studying Earth’s magnetic.

USGS Open-File Report Digital data grids for the magnetic anomaly map of North America. Airborne measurement of the earth's magnetic field over all of North America provides gridded data describing the magnetic anomaly caused by variations in earth materials and structure.

The Greenleaf Anomaly, A Significant Gravity Feature by Paul L. Lyons. Sinclair Oil and Gas Company The complete article is available as an Acrobat PDF file. Abstract. A gravity maximum anomaly, which attains a relief of almost milligals, Bouguer, traverses the Salina Basin of Kansas, extending southward into Oklahoma and northeastward into the Lake Superior area.

‘The geophysical applications of gravity and magnetic techniques have advanced a great deal in the twenty-first century. Thus, this rigorous book covering the physical basis, analysis, interpretation, and applications of these techniques is a timely and important contribution.

Gravity and magnetic maps compiled from published data additional gravity stations occupied as part of the present investigation were used in combination with geologic control from outcrops and drill holes as a guide in the location and later interpretation of the seismic profiles.

Magnetic and gravity study of Desert Mountain, Juab County, Utah. data --Magnetic intensity and gravity of Desert Mountain --Rock density and magnetic susceptibility --Analysis and interpretation of gravity data --Analysis and interpretation of magnetic data --Features of the magnetic maps Book\/a>, schema:CreativeWork\/a> ; \u00A0.Sexton, J.L.

and Henson, H. () Seismic reflection and gravity profile models of data from Lake Superior (Abs.): American Geophysical Union Spring Mtg, Google Scholar Teskey, D.J.

and Thomas, M.D. () Three-dimensional magnetic modelling of the Mid-Continent Rift - Central Lake Superior (abstr.).The Anomaly is located approximately four miles north of Isle Royal’s northern rocky shores, and a half mile south of the U.S./Canadian border.

According to Lake Superior bathymetric maps the feature appears to be submerged in approximately ft. of water.