Precambrian Basement Topography, and Fault-And-Fold Zones, Within the Cratonic Platform of the United States

THE MIDCONTINENT EXPOSED: PRECAMBRIAN BASEMENT TOPOGRAPHY, AND FAULT-AND-FOLD ZONES, WITHIN THE CRATONIC PLATFORM OF THE UNITED STATES

STEFANIE L. DOMROIS

THESIS

Submitted in partial fulfillment of the requirements for the degree of Master of Science in Geology in the Graduate College of the University of Illinois at Urbana-Champaign, 2013

Urbana, Illinois

Adviser:

Professor Stephen Marshak

ABSTRACT ______

The Midcontinent region of the United States is part of the cratonic platform of the North

American craton. This region is underlain by Precambrian basement formed dominantly during

Proterozoic accretionary orogenies. It was modified by Proterozoic anorogenic felsic magmatism and was cracked by several episodes of rifting. Subsequently, when North America was part of a supercontinent, the region underwent extensive Late Precambrian erosion and exhumation. Marine transgressions during the Phanerozoic buried the region with sequences

Phanerozoic sedimentary strata. The continent-wide contact between Precambrian crystalline rock and the overlying cover of Phanerozoic strata is known as the "Great Unconformity."

Though the cratonic platform has been relatively stable, tectonically, for over a billion years, it has been affected by epeirogenic movements that produced regional-scale basins, domes and arches. Also, faults within the region have been reactivated, displacing crustal blocks and warping overlying strata into monoclinal folds—these faults may be relicts of Proterozoic rifting.

How can this Phanerozoic tectonism be represented visually in a way that can provide a basis for interpreting new lithospheric features being revealed by EarthScope's USArray seismic network?

In the Appalachian and Cordilleran orogens, ground-surface topography provides insight into the character and distribution of tectonic activity, because topography is structurally controlled. This is not the case in the Midcontinent, a region of broad plains where surface topography does not reflect the structure beneath. Fortunately, the Great Unconformity makes an excellent marker horizon for mapping intracratonic structures.

In order to create an intuitive visual image of the basement topography and of fault-and- fold distribution in the cratonic platform of the United States, I constructed two maps of the

region using ArcGIS software. My study area extends from the Wasatch front on the west to the

Appalachian front on the east, and from the Ouachita front and Gulf coastal plain on the south to the southern edge of the Canadian Shield on the north. The first map portrays the top of the

Precambrian basement surface in shaded relief, and the second map portrays the distribution of major faults and folds within the region. Production of the maps required compiling and digitizing a variety of data, which was imported into ArcGIS and processed to produce a 3-D surface. The shaded-relief map provides new insight into the crustal architecture of the cratonic platform, by visually emphasizing that the region consists of distinct provinces: the Midcontinent

Sector (a broad area of low relief, locally broken by steep faults); the Rocky Mountain Sector

(with structural relief of up to 10 km, and relatively short distances between uplifts), the

Colorado Plateau Sector (a moderate-relief area containing fault-bounded crustal blocks), and the

Bordering Basins Sector (deep rift basins, linked at crustal bridges, and locally amplified by flexural loading). Overlaying the fault map and a map of earthquake epicenters over the shaded relief map emphasizes that seismicity is concentrated in the bordering basins, particularly where steep gradients in basement topography coincide with major faults.

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ACKNOWLEDGEMENTS ______

First of all, I would like to express my warmest gratitude to my adviser, Prof. Stephen

Marshak, for his guidance and support throughout the research, and for his editing of the manuscript. I would have never completed the ArcGIS maps without the expertise of Curt Abert at the Illinois State Geological Survey. Tim Larsen of the Illinois State Geological Survey also provided valuable criticism of my presentation and maps. Hersh Gilbert, Michael Hamburger,

Gary Pavlis, and the others from the EarthScope team helped to make my research possible, and

I extend my heartfelt thanks to them. Partial funding for this research was provided by NSF grant EAR 10-53551, through the EarthScope 'OIINK' project. Additional funding was provided by the College of Liberal Arts & Sciences of the University of Illinois.

My research would have never been completed without help from University of Illinois library staff, especially from Jenny Johnson and Jim Cotter from the Map and Geography

Library and Mary Schlembach and Lura Joseph from the Geology Department Library. I would also like to thank the following people for their help in providing me the necessary maps and literature for my research: Julie Chang (Oklahoma Geological Survey), Sigrid Clift (University of Texas Bureau of Economic Geology), Ray Anderson and Bob McKay (Iowa Geological

Survey), Tom Evans and Linda Deith (Wisconsin Geological and Natural History Survey), Ranie

Lynds (Wyoming State Geological Survey), Dale Bird (for the USGS basement maps), and others. I greatly appreciate the moral support and friendship with my two Structural Geology office mates: Stephanie Mager and Pragnyadipta (Deep) Sen, and the other graduate and undergraduate students at the University of Illinois. Lastly, I thank my parents and extended family, who always encourage me to achieve my goals in life.

TABLE OF CONTENTS

______

CHAPTER 1: Introduction…………………………………………………………………1

CHAPTER 2: Methodology……………………………………………………………….10

CHAPTER 3: Observations………………………………………………………………..55

CHAPTER 4: Discussion and Conclusions………………………………………………..65

REFERENCES …………………………………………………………………………….73

— CHAPTER 1 —

INTRODUCTION ______

1.1 Geology of the Cratonic Platform of the United States

The craton of North America includes the Canadian Shield, where Precambrian igneous and metamorphic rocks are exposed at the surface, and the cratonic platform, where Precambrian igneous and metamorphic rocks (basement) are buried beneath Phanerozoic sedimentary strata

(cover). The thickness of sedimentary strata range from 0 km (where basement is exposed) to over 7.5 km. North America’s cratonic platform extends from the Wasatch Front in the west to the Appalachian front in the east, and from the Ouachita front and Gulf coastal plain in the south to the southern edge of the Canadian Shield in the north (Fig. 1.1). Between the Wasatch front and the Rocky Mountain front, the cratonic platform has been uplifted and deformed by

Mesozoic and Cenozoic faulting and folding, and now comprises the Rocky Mountains (to the north) and the Colorado Plateau (to the south). East of the Rocky Mountain front, the cratonic platform forms a broad region of low relief, known as the Great Plains or the Midcontinent. The region outside of the cratonic platform includes the Appalachian, Ouachita, and Cordilleran orogens, and the Atlantic and Gulf coastal plains.

In the Midcontinent, the only exposure of Precambrian basement south of the Canadian

Shield occurs in the St. Francis Mountains of the Ozark Plateau in eastern Missouri, in the

Adirondack Dome of northeastern New York, and in isolated exposures of exhumed

Precambrian islands in Wisconsin and Minnesota. Surface exposures of the Phanerozoic cover, west of a longitude of about 97°W, consist dominantly of Mesozoic and Cenozoic strata. East of this longitude line, surface exposures consist of Paleozoic strata. Variations in thickness of

Phanerozoic strata define broad basins, domes, and arches; these structures formed by epeirogenic uplift and subsidence during the Paleozoic. The major intracratonic basins of the

Midcontinent are the Michigan basin, the Illinois basin, and the Williston basin. Locally, strata of the Midcontinent have been warped into monoclinal folds and/or have been cut by localized high-angle faults.

The basement of the North American craton assembled during the Proterozoic (Fig. 1.2).

According to the synthesis by Whitmeyer and Karlstrom (2007), the earliest stage of craton assembly involved growth of several Archean lithospheric blocks. These Archean nuclei sutured together during the Paleoproterozoic (2.0 to 1.8 Ga). Later in the Proterozoic, progressively younger terranes accreted to the outer edges of the Paleoproterozoic continent, forming two distinct accretionary orogenic belts that have a general northeast trend. The older of this, which fringes the Archean cratonic nucleus, is the Yavapai terrane, which was accreted between 1.71 and 1.69 Ga. The Mazatzal terrane accreted to the edge of the Yavapai between 1.65-1.60 Ga.

Subsequently, intracratonic magmatism between 1.5 and 1.3 Ga produced anorogenic granites and rhyolites; the region affected by this magmatism is known as the Granite-Rhyolite Province.

Rocks of the Llano-Grenville province attached to North America during the Grenville orogeny

(1.3 and 0.9 Ga). By the end of the Grenville orogeny, North America lay in the interior of a large supercontinent, Rodinia, which broke apart and reassembled as Pannotia. Pannotia survived until the end of the Precambrian, when it broke apart leaving Midcontinent North

America as part of Laurentia.

Rifting occurred at several times during the Precambrian, and produced distinct, narrow rift basins filled with sediments, and in some cases, volcanics. The largest rift is the 1.1 Ga

Midcontinent Rift System, consisting of one arm of which cuts NW from Kansas across Iowa to

Lake Superior, and another arm which cuts SE across Michigan. Other, younger rifts associated with the breakup of the late Precambrian supercontinent include the Oklahoma aulacogen, the

Reelfoot Rift and the Rome Trough (e.g., Whitmeyer and Karlstrom, 2007; Marshak et al.,

2003). Extensional tectonism led to widespread intrusion of dikes and normal faulting, even in areas outside of the particularly distinctive rifts.

While in the interior of the supercontinent, North America was emergent, and thus its surface was eroded and rocks that had been kilometers below the surface were exhumed. This erosion may have stripped away the fill of smaller rifts, though the associated basement- penetrating normal faults still remained. Though the craton of North America’s Midcontinent has been relatively tectonically stable and unmetamorphosed for the past 1 billion years, it has not been totally inactive. Rather, structures within it have undergone pulses of reactivation that are roughly coeval with Paleozoic orogenic events in the Appalachian/Ouachita orogens. During these events, domes and arches have gone up, basins have undergone subsidence pulses, and faults have been reactivated (Marshak and Paulsen, 1997). At the end of the Paleozoic, hot brines migrated though the sedimentary basins causing mineralization, anthracitization, and dolomitization (Bethke and Marshak, 1990).

1.2 Statement of Purpose

Topography can be used as a tool for identifying and characterizing tectonic features, for the geologic structures they yield can control the shape of landforms directly and/or can control erosion over time, so that the shapes of structures stand out in the landscape. Digital Elevation

Maps (DEMs) increasingly have been used to study landforms, for by using shading to simulate shadows cast by the Sun, they can convey a sense of the 3-D shape of the land surface. The

1:3,500,000-scale DEM map, Landforms of the Conterminous United States (Thelin and Pike,

1991) serves as an example. This map portrays topography in shaded relief by varying tints of gray. More recent versions of this map add colors (usually a palette ranging from green through tan, to white) to add visual information about relative elevation. A shaded-relief DEM can clearly show tectonically controlled textures of the terrain, if the map has sufficient resolution.

For example, on Thelin and Pike's map, the Valley and Ridge Province in the Northern

Appalachians stands out and its morphology allows interpretation of the wavelength and amplitude of the underlying folds and even inference of principle stress directions at the time the folds formed (Fig. 1.3). Similarly, the distribution and orientation of Laramide basement-cored uplifts in the United States can be delineated by the morphology of the Rocky Mountains, and the area and extension direction of Cenozoic rifting in the Cordillera is indicated by the topographic characteristics of the Basin and Range Province.

Geologic maps can provide additional perspective on continent-scale tectonic features.

For example, one can identify continental-interior basin or domes based on the bulls-eye pattern of stratigraphic units—in a dome, older units crop out in the center, whereas in a basin, younger units crop out in a center. The Tapestry of Time and Terrain map, published by the United States

Geological Survey in 2000, combines a DEM and the geologic map of King and Beikman (1974) to emphasize the relationships between bedrock distribution and landforms. Notably, however, in the Midcontinent, the landforms are largely independent of the distribution of geologic formations. Tectonic maps (e.g., P.B. King's 1969 Tectonic Map of North America, and W.

Muehlberger's 1992 Tectonic Map of North America) provide further insight grouping geologic map units according to their tectonic meaning and by including contours on the top of the

Precambrian, but these maps include many types of data that create a clutter that makes it hard, in some cases, to focus on basement data, and they do not show features in shaded relief.

Digital elevation maps, geologic maps, and existing tectonic maps do not provide a clear picture of tectonic movements across the Midcontinent. Specifically, DEMs of the Midcontinent display primarily plains, locally incised by Cenozoic drainage or covered by Cenozoic fans and glacial deposits, so intracratonic domes and basins, with few exceptions (e.g., the Ozark Plateau) do not control the details of landscape features. In other words, they do not provide insight into the aerial extent of upwarped or downwarped crust resulting from epeirogenic movements.

Similarly, while geologic and tectonic maps clearly outline epeirogenic structures and display the surface manifestation of faults in the Midcontinent, they do not provide direct insight into the magnitudes of differential vertical movements.

How, then, can the tectonic character of the Midcontinent be portrayed on a map to give a clear visual impression of differential movements, localization of deformation, and the role that

Precambrian tectonic features have played in controlling Phanerozoic structure? To address this question, I have developed two digital maps of the Midcontinent region that display the tectonic character of the Midcontinent visually. The first map is a shaded-relief map of the depth to the

Precambrian surface. The map was first produced as a 2-D image, but with additional processing it can be converted into a 3-D surface that provides an excellent visual tool for interpreting structures (both surface and subsurface). The second map shows the distribution of major faults and folds in the region. I provide examples of how my new maps can be merged with other digital data sets (e.g., distribution of seismicity; geophysical potential field; crustal and mantle tomography) to provide a basis for interpreting relationships among lithospheric features and to provide insight into how pre-existing crustal structures in the cratonic platform.

1.3 Strategy and Organization of this Thesis

In this thesis, I first present a brief outline of published maps that show the depth to the

Precambrian basement within the study area. I will then discuss the reasons why I chose the depth to the Great Unconformity (the Precambrian/cover contact) as a marker horizon for my maps. Following these two sections, I provide greater detail on the procedure of constructing my maps. In the procedure section, I outline how I acquired the data necessary for developing the maps, and then show how I constructed both the 2-D and 3-D versions of the shaded relief map.

Section 2.4 illustrates how I produced the map of faults and folds, and of other features discussed in this thesis.

My next chapter (Chapter 3) incorporates observations for both maps. I will first discuss visual observations based on examination of the shaded-relief map, and show how different tectonic domains of the Midcontinent can be delineated based on the morphology of the Great

Unconformity surface. Next, I provide observations on the different structures within the study area, and introduce the data spreadsheet that I developed for analyzing these structures.

Following this section, I discuss the dominant trends of Midcontinent structures. The final chapter (Chapter 4) provides the discussion and conclusions of this thesis, with a focus on the relationships among basement topography, structure, and seismicity.

Figure 1.1: Visual of the study area (area not in color), including the cratonic platform and the Colorado Plateau.

Figure 1.2: Precambrian tectonic assembly map of North America (Whitmeyer and Karlstrom 2007).

Figure 1.3: Digital Elevation Map of the United States, showing sample topographic provinces (Thelin and Pike, 1991).

— CHAPTER 2 —

METHODOLOGY ______

2.1 Previous Precambrian Basement Maps

The first step of my research involved determining what maps are already available that characterized Midcontinent tectonic features. There have been many attempts to portray the role of the Precambrian basement surface in influencing later Phanerozoic tectonics. Two of the earliest maps produced of the Precambrian basement are the 1:5,000,000-scale Basement Map of

North America, published by the American Association of Petroleum Geologists and the USGS in 1967, and the 1:2,500,000-scale Basement Rock Map of the United States by Bayley and

Muehlberger (1968). Both maps provide a generalized interpretation of the Precambrian basement surface. On the Basement Rock Map of the United States, the different Precambrian rock types are clearly emphasized, and while depth to the top of the Precambrian data are indicated by hard-to-see contour lines. Major faults that are expressed at the surface are also drawn and labeled in some cases, but major subsurface faults are not shown due to the lack of seismic-reflection data available at the time the map was produced.

The Generalized Tectonic Map of North America by King and Edmonston (1972) provides a very simplified contour map of the top-of-Precambrian surface. Major basins are clearly visible, but the map is generalized and doesn't offer any data that was not already shown by the Basement Rock Map of the United States. Muehlberger et al.'s (1992) Tectonic Map of

North America, published by the American Association of Petroleum Geologists, provides an update of the Basement Rock Map of the United States. Muehlberger et al.'s map (actually, a series of 4 plates) shows significantly more detail than earlier versions of tectonic maps of North

America. The contours on the Precambrian surface are better constrained as they utilize additional data from seismic-reflection profiles and new drilling data. The map not only shows more faults, but the depiction of the faults clearly shows how they offset the structural contours on the Precambrian surface. The colors and shades of colors used on the map also make the major basins stand out.

The Precambrian Basement Structure Map of the Continental United States by Sims et al. (2008) is one of the most current maps of major structures within the Precambrian basement.

This map uses an interpretation of magnetic anomaly maps to delineate major structures such as suture zones and large, continental-scale faults. Sims and others (2008) emphasizes that most of the major structures have been reactivated when stress fields within the region changed. The suture zones and other large faults within the region behave as zones of weakness within the

Precambrian basement. Sims et al.'s map does not, however, display contours on top of the

Precambrian basement.

Maps portraying one state, or several adjacent states, have been prepared for portions of the cratonic platform, and these reveal the local form of the Precambrian top surface in greater detail. Most of these maps are based on well data, though some also include evidence from seismic-reflection profiles. Faults shown on these maps are based on stratigraphic separations, vertical displacements of seismic reflectors, or Bouguer gravity or magnetic anomaly maps.

Examples of state-scale maps (maps showing contours on top of the Precambrian basement in one state) are the Configuration of the Top of Precambrian Rocks in Kansas by Cole (1978) and the Precambrian Structure Map of North Dakota by Heck (1988). In these two maps (and maps similar to these for other states), the contours and faults stop abruptly at the state boundaries.

Examples of regional basement-surface maps include the Precambrian Basement Map of the

Northern Midcontinent, USA by Sims (1990), and the Precambrian Basement Map of the Trans-

Hudson Orogen, USA by Sims et al. (1992). Both maps illustrate faults and contours on the

Precambrian top surface in detail but, like many state-scale maps, do not show the regional associations of the Precambrian surface across the Midcontinent, and do not cleanly link to maps of adjacent states. Notably, most state-scale maps are decades old, and have not been updated to a digital form.

2.2 Identifying a Marker Horizon

The top of the Precambrian surface is marked by a continent-wide unconformity—known as the Great Unconformity—that formed due to extensive erosion during the Late Precambrian, prior to the deposition of Paleozoic strata (Peters and Gaines, 2012). The Great Unconformity is exposed at the Earth’s surface in at many locations along the edges of basement-cored uplifts in the Rocky Mountains, as well as at the top of the inner gorge in the Grand Canyon and at the top of the gorge in Black Canyon of the Gunnison. In the Midcontinent, it is almost completely covered except at localities along the boundary between the Canadian Shield and the continental- interior platform in Minnesota and Wisconsin. South of the Canadian Shield, the unconformity is exposed at only a few localities, such as the Baraboo Syncline, in southern Wisconsin, and the

St. Francis Mountains in eastern Missouri. Elsewhere, the Great Unconformity exists tens of meters to more than several thousand meters below the Earth’s surface, and has been sampled only in drill holes.

The Great Unconformity is an excellent marker horizon for characterizing intracratonic tectonic features (basins, domes, and faults), for it exists everywhere in the Midcontinent, can be recognized definitively on seismic profiles and in drill cores, and has not been affected by

surface erosion since the Late Precambrian. Further, all geologists tend to interpret the surface in the same way, so there isn't uncertainty in correlating the surface across the Midcontinent— younger stratigraphic features, in contrast, may be interpreted differently by different authors.

The depth to the unconformity can also be referred to as "depth to basement" or "depth to the cover/basement contact," or "depth to the top of the Precambrian."

2.3 Data Acquisition for the Shaded Relief Map

Data for the shaded relief map was primarily acquired by a basic literature research on the internet and through on-line reference systems, such as GeoRef, available through the

University of Illinois Library. Maps showing structure contours on the Precambrian basement were mostly found as images on the internet through state geological survey websites. In some states, contour data representing the shape of the Precambrian surface were already available in downloadable packages. I called many state geological surveys directly to acquire information that was not available on the internet or through the library system. I also contacted libraries at other universities, as well as individuals on the faculty of other universities, throughout the country to try to obtain additional information. Maps that were not in a digital format were scanned on a large-format scanner at the Illinois State Geological Survey. However, a couple of maps were either in too poor condition to be scanned (meaning that the map had too many creases, or ripped easily) or only a small area needed to be scanned, so a smaller scanner was put into use. To obtain data in areas for which existing structural contour maps were not available, I used either drillhole data, which was added as point data to my data base, or point data extracted from published cross sections.

Cross sections were of particular use to constrain depth to basement along the southern and eastern borders of my map area, where the basement and its platformal cover were overlapped by thrust faults in the foreland of the Appalachian/Ouachita orogen. To obtain this data I pasted a scan of the cross section into Adobe Illustrator, and then set up a vertical scale, which I scrolled across the section, measuring depth to basement at regular intervals. I stopped data acquisition at the forelandward-most fault that thrust basement up over Phanerozoic cover. I also marked the location of points where basement-penetrating faults intersected the line of section. Finally, I plotted the strings of resulting point data on a map, hand-contoured the data, and then transferred the resulting map into the digital data base.

2.4 Production of the Shaded-Relief Map

I used ArcGIS, a software product produced by ESRI (www.esri.com), for creating the maps described in this thesis. This work was done under the supervision of Curt Abert, and utilized the facilities of the GIS laboratory of the Illinois State Geological Survey. ArcGIS can be used to geo-reference spatial data sets, and to draw the results in both 2-D (ArcMap) and 3-D

(ArcScene). A map showing the outline of the states within the conterminous United States provided serves as the "base map" on which I projected my depth-to-basement and structural trace data. The map projection of this base map is NAD 1983, UTM Zone 14N.

Use of Preexisting Digital Maps: The geological surveys of several states (Illinois,

Iowa, Missouri, Kentucky, South Dakota, Indiana, Nebraska, and Ohio) have prepared ArcGIS- based maps showing depth to basement for the entire state. (The Texas Bureau of Economic

Geology has produced a map for a portion of west Texas, but not for the whole state.) On such maps, the contour lines are shapes with each point on the line representing a geo-referenced

point; the data set representing this line is called a “shapefile.” I converted the shapefiles to the map projection mentioned above and added it as an overlay to the map (Fig. 2.1). Shapefiles for other areas, including small map areas represented in research publications and/or continent- scale maps, were also added where available.

Using Archival Non-Digital Maps: The majority of the maps that showed the depth to the Precambrian surface for the continental interior are available only as a raster image (bitmap) in the form of a JPEG, TIFF, or PDF file, or as a paper copy that needed to be scanned and turned into a digital raster image. Regardless of its origin, the raster image or "source map" was placed as an overlay into ArcMap and was georeferenced by distorting it so it registered as closely as possible to the base map's orientation and projection (Fig. 2.2a). Specific lines or points on the source map image that I used to align the image to the base map include state boundaries, county boundaries, and latitude or longitude lines.

Once the source map was aligned to the base map, I digitized the raster map by "hands-on digitizing," which involves tracing out contours on the computer by using the computer mouse

(Fig. 2.2b). I first created a new line shapefile and set the projection to the one I used for producing the maps. I added a contour field to the attribute table so that I could record the depth to the Precambrian that the line represented. I then overlaid the contour shapefile onto the georeferenced map and I started an edit session, in which I drew straight-line segments over the map image for each contour line. For curving lines, I increased the number of vertices, which are points at the end of each line segment, and the number of line segments, so that the drawn lines would closely follow the map’s curving contour lines. The above procedure was repeated numerous times for each source map. If lines were too close to resolve at the scale of the entire

study area, I queried a contour interval (usually 1000 ft. contour interval) so that individual contour lines can be visualized.

Unfortunately, my digitizing procedure introduces some error into the map compilation.

Part of this error comes from scanning (for the scanning lenses do not reproduce images exactly), part comes from stretching and distorting within ArcGIS to fit the source map to the base map

(for the process does not produce a perfect match across the entire area of the map, especially if the source map was not the same projection as the base map), and part comes from the process of tracing contour lines (since the inherent inaccuracy of hand motions means that the tracing is not exact). Also, contour maps, by their nature, are not unique solutions to point data. Effort was made to keep the amount of error to a minimum, and I estimate that tracings as it appears on the base map is no more than approximately 500 m off of the "true" tracing on the source map.

Use of Drill-Hole and Cross-Section Data: To constrain depth to basement in areas for which map data do not exist, I used drill-hole data and/or data extracted from cross sections. To use drill-hole data, I prepared a spread sheet in Microsoft Excel that contains latitude, longitude, and depth. This data can be entered directly to the ArcMap document, for ArcGIS software converts longitude and latitude into X (north-south) and Y (east-west) coordinates, respectively, and depth into a Z coordinate, which then becomes a shapefile that shows the wells or drill hole locations as points on the map. To extract depth data from cross sections, I scanned the cross section to produce a JPEG of the cross section, or obtained an existing JPEG image of the cross section. I exported the JPEG into Adobe Illustrator as a base layer. Then, I created a new layer on which I drew a horizontal sea-level reference line as an overlay, and created an accurate vertical (i.e., depth) scale. I then moved the scale along the sea-level reference line, and measured the depth to the basement/cover contact (the Great Unconformity) at regular intervals.

In places where the change in depth was rapid (e.g., at basement-penetrating faults), I added additional points for extra control. I then produced a map-view image showing the trace of the cross sections and the points of measurement along it. This trace was then geo-referenced onto the map document. Next, I extracted the latitude and longitude for each measured point along the cross section, and entered into a Microsoft Excel document, along with the depth to basement data for the point. The Excel document was then placed into the ArcMap document and subsequently made into a point shapefile. Once the depth points were visualized, I hand contoured the subsequent area, along with adding faults where needed, to produce the

Precambrian surface in that area.

The Trace of Precambrian Outcrop: To depict the trace of the basement/cover contact

(the Great Unconformity or the top of the crystalline Precambrian) where it intersects the ground surface, I produced a shapefile outlining areas where the Precambrian rocks are the bedrock at the Earth’s surface. Some of these areas include: Minnesota, Wisconsin, northern Michigan, northern New York (the Adirondack Mountains), the Blue Ridge and its along-strike equivalents

(the "Blue-Green-Long Axis") in the Appalachians, the basement of the basement-cored uplifts in the Rocky Mountain region, and the floors of deep canyons in the Colorado Plateau.

Elevation data, which was derived from a 30 arc-second DEM of North America produced by the

U.S. Geological Survey’s Center for Earth Resources Observation and Science, was downloaded from ArcGIS’ online data repository and exported directly into the ArcMap document. An

‘Extract by Mask’ tool was used to clip the elevation data to fill in the Precambrian outcrop shapefile. The clipped elevation data was then changed from raster data to point elevation data using tools in the ArcGIS toolbox. The resulting shapefile was then used to create the

Precambrian surface along with the other contour and point elevation data.

Data Compilation in ArcGIS: The shapefiles of the depth to the Precambrian surface contours and points were added to the ArcMap document to create a "primary data contour layer" for the entire study area. Most of the reference maps provided contours measured in feet, but some provided contours in meters. The contours provided in meters were converted to feet by multiplying the number of meters by 3.2808. I also checked to insure that all depths on the map represented depth below sea level, not depth below the ground surface. I accomplished this task by conducting a literature search on the source maps, identifying any additional texts provided by the author of the source map. For source maps with no additional information, I visually judged the source maps by the contours’ continuity with other surrounding data/source maps that had more precise information.

Due to inherent errors made during georeferencing, or due to errors on source maps themselves, contours did not all line up across state boundaries. The non-matching contours were adjusted by hand on the primary data contour layer so that the contours would be smooth lines, and would not give the false impression that faults exist at state borders. I also hand corrected places where contours appeared to cross one another, and hand-adjusted contours along or near faults, so that they were aligned as closely as possible to the faults. In the ArcMap document, the contours were actually ‘snapped’ to the fault lines (Fig. 2.3).

Transformation of the Contour Map into the Shaded-Relief Map: Production of the shaded-relief image of the Precambrian surface required two steps. First, I used the "Topo-to-

Raster" tool in the Spatial Analyst toolbox of ArcGIS to transform point and line shapefiles into a raster image on which variations in color represent depth. Initially, I created a colored topographic map with a cell size (the size of the area assigned a particular elevation) at the default setting of 2000 meters on a side. This setting did not produce a clear-enough image, so

subsequently, I used a cell size of 500 meters, which greatly enhanced the sharpness of the map

(Fig. 2.4). The map employed a stretched color scheme, ranging from light yellow to dark brown—lighter colors represent higher areas and the darker colors represent deeper areas. Thus, the tops of domes and arches are lighter colored, whereas the floors of basins are darker colored.

Second, I applied the "Hillshade tool" to the completed Topo-to-Raster image to create a shading affect giving the impression that if the surface of the Precambrian was lit by the Sun positioned at 315° at an angle of 45° above the horizon. Depth values were multiplied first by 0.3048 to adjust the measured units to meters, and then were multiplied by 10 to produce a vertical exaggeration of 10X. The Hillshade image was made 50% transparent and then was placed over the Topo-to-Raster color image, to create the digitally rendered shaded-relief map of the Great

Unconformity (Fig. 2.5). Areas of Precambrian outcrop were colored red, so that they stand out.

After producing several preliminary versions of the map, I produced the final version (Fig. 2.6).

To create the 3-D look of the map, the map was exported as a georeferenced TIFF image file. The image file was then placed into ArcScene, which transforms the map from a 2-D surface to a 3-D surface that can be viewed at any angle the viewer desires. The georeferenced map image was assigned the base heights of the Topo-to-Raster image to create the 3-D aspect of the map. To make variations in elevation stand out, the image was produced with a vertical exaggeration of 10X (Fig. 2.7).

2.5 Production of the Fault-and-Fold Map and Other Shapefile Maps

The second map that I produced is a map that shows the traces of major faults and folds in the Midcontinent. Obtaining data for this map proved to be a challenge, for structures in the

Midcontinent are not well exposed, and in many cases can only be inferred from subsurface data

(e.g., structure-contour maps of reference horizons), and literature about these structures is sparse. Nevertheless, I was able to find sufficient information by using preexisting maps and cross sections at a variety of scales, available in journals, USGS or state-survey publications and open-file reports, field guides, and theses. Data were difficult to correlate; however, because some source maps show entire regions, some show individual states, and some show only relatively small portions of states. Compilation problems also occurred because different data sources portray the structures at different levels of detail, structures mapped in one area were not necessarily mapped in adjacent areas, one map depicts a given structure as fault while another map of the same area depicts it as a fold or as a fault-fold pair, and existing portrayals of structures on maps do not all depict cross-cutting relationships correctly. Because of the nature of source data, the map that I have produced should not be viewed as having the same level of accuracy as a surface-geology map, but it can be used to help visualize the distribution and trend of structures.

To produce my ArcGIS map, I first created digital shapefiles of faults and folds by scanning and then digitizing the faults and folds. A separate shapefile was created for each structure. These were added directly to a base map, the same base map that I used for the shaded-relief map of basement topography (Fig. 2.8). Once all of the faults and folds were added to the map, I reviewed available descriptions of each structure, and then produced a summary description which was entered in a Microsoft Excel spreadsheet, which ended up being

21 pages long (Table 2.1). Examples of data collected include the age of the formation of the structure, the age of the last known activity along that structure, the sense of displacement on the structure, and references that describe the structure. Faults and folds that were found to not intersect at the Great Unconformity (based on the literature research) were removed from the

final shapefile. I determined which basement-involved structures to include in the study by examining how much data I collected from a detailed literature research on all of the faults and folds I could find references to. I classified the faults and folds by the amount of confidence I had that the structures existed based on this literature research, with a scale from 0 to 3, in which

0 indicates no confidence and no information available other than the drawn structure on the map and 3 indicates great confidence that the structure exists based on a large amount of data available. I also simplified some of the major structures, meaning that I removed the subsidiary faults and folds so that the structure lines appear relatively smooth at a page-size scale of the map. The updated Excel spreadsheet was attached to the final fault and fold shapefile (Fig. 2.9) to create a more detailed attribute table for the dataset (see Table 2.1).

Additional shapefiles were created to further analyze both the shaded-relief map and the fault- and-fold map. The shapefile labeled ‘Cordillera’ defines the foreland edge of the region that lies to the west of cratonic-platform crust. Thus, the trace of this line corresponds with the eastern edge of the Basin-and-Range Province, the region of crust that has undergone significant stretching and thinning in the Cenozoic, and had undergone stretching and thinning at the end of the Precambrian. The Ouachita orogen shapefile shows the foreland edge of the Ouachita fold- thrust belt in Oklahoma and Arkansas, the Appalachian shapefile shows the western edge of the

Appalachian fold-thrust belt, and the ‘Coastal Plain’ outlines the northern edge of the region that was submerged when sea level was high during the Cretaceous and early Cenozoic. The subsurface of the coastal plain was not included in my study, because it has undergone stretching and faulting due to Atlantic Ocean opening, so the region is not considered part of the continental-interior platform.

In general, the area of my study included only areas inboard of the Cordilleran, Ouachita,

Appalachian, and Coastal plain shapefiles (see Fig. 1.1). There are two exceptions to this rule, however. The first exception is the area beneath Mississippi Embayment, a region where coastal-plain sediments extend north, up the Mississippi Valley to the southern end of Illinois. I included this area because it has not undergone significant tectonic subsidence due to Atlantic

Ocean opening, even though it was buried by Cretaceous/Cenozoic sediment. By including the area beneath the Mississippi Embayment, my map can depict the important New Madrid Seismic zone, as well as the Oklahoma-Alabama transform fault. The second exception is the area of the

Appalachian foreland between the foreland edge of the Appalachian fold-thrust belt and the exposed basement thrust slices of the Blue-Green-Long Axis. I included this region because it encompasses the deeper portion of the Appalachian Basin as well as relict rifts, such as the

Montgomery Rift. Leaving these features out would give the false impression that basement gradually got shallower progressively from the western edge of the Appalachian basin up to the

Blue-Green-Long axis.

My map also includes several other shapefiles that can be useful for tectonic interpretation (Fig. 2.10). A shapefile labeled ‘Precambrian Outcrop’, as noted earlier, which outlines areas within the study area where Precambrian rocks exist at the Earth’s surface.

Another shapefile, called ‘Rift Zones’, indicates where the failed rift zones (e.g., aulacogens) that have filled with significant sediment and/or volcanics are located. I constructed this shapefile based on the literature search and the major rift bounding faults that I mapped. The final shapefile that I produced is labeled ‘Domes and Basins’, which outlines the borders of intracratonic domes, arches, and basins (Fig. 2.11). Data used to construct the Domes and

Basins shapefile comes from the literature research (especially the source maps).

Table 2.1: Attributes of Midcontinent Structural Features. ______

The table that follows was constructed in conjunction with the fault-and-fold map produced in this study. Information collected for the attribute table was collected between September 2011 and May 2013, and was entered into an Excel document for readability. The fields are filled according to the varying degrees of information available for each structure. The following title column descriptions will attempt to provide an explanation for the information entered into the attribute table:

• FID: The FID, or Feature Identification number is a distinctive number provided by ArcGIS for each line or structure on the map.

• Type of Feature: The Type of Feature column provides a choice of fourteen different types of structures that could be present in the Precambrian basement, including faults and folds.

• Structure Name: The Structure-name column indicates the recognized name of the structure, if one is available in the literature.

• Trend/Strike: This description provides a generalized map trend and measured strike (if available) of the structures.

• Dip/Plunge: This description provides a generalized or measured (if available) explanation of the vertical motion of the structure.

• Age formed: The Age formed column indicates a timing of when the structure began to experience movement or deformation (if available).

• Last Activity: The Last Activity column provides a timing of the last movement or deformation experienced by the structure (if available).

• Const.: The Const. (Constraint) column attempts to assign a number between 1 and 3 based on the level of confidence from the literature research that the structures are true on the map, with 1 being the lowest level of confidence and 3 being the highest level.

• Other: The Other column provides a more detailed description of the structure, regarding to the deformation history, type of structure, displacement measurements, and other important information.

• References: The References column includes the references used in the map layout and informative descriptions of the structures. The full citations for the references are provided in the references section at the end of this thesis.

Schmus etal 1989 etal Schmus

Schmus 1992, Van Van 1992, Schmus

Cannon 2007, Van Van 2007, Cannon

etal 2007, Schulz and and Schulz 2007, etal

Chandler etal 2007, Holm Holm 2007, etal Chandler

Chandler etal 2007 etal Chandler

Bickford etal 2006, 2006, etal Bickford

Craddock 1972 1972 Craddock

Gibbs etal 1984, 1984, etal Gibbs

Chandler etal 2007, 2007, etal Chandler

Bunker etal 1985, 1985, etal Bunker

Van Schmus 1992 Schmus Van

Bauer et al 2011 al et Bauer

1991

Southwick and Morey Morey and Southwick

and Morey 1972 1972 Morey and

Van Schmus 1992, Sims Sims 1992, Schmus Van

Sims 1972 Sims

Bauer et al 2011 al et Bauer

Sims 1972 Sims

Bauer et al 2011 2011 al et Bauer

Bauer et al 2011 al et Bauer

Bauer et al 2011 2011 al et Bauer

Sims 1972 Sims

Bauer et al 2011 2011 al et Bauer

Sims etal 1991 etal Sims

et al 2011, Sims 1972 , , 1972 Sims 2011, al et

Bunker etal 1985, Bauer Bauer 1985, etal Bunker

references

truncates main Penokean suture Penokean main truncates

N boundary of Yavapai orogen, orogen, Yavapai of Nboundary

thrust fault? thrust

deformation, reactivated as as reactivated deformation,

several periods of ductile ductile of periods several

fault

movement , reactivated as thrust thrust as reactivated , movement

SE, strike slip and dip slip slip dip and slip strike SE,

deflects Midcontinent Rift to the the to Rift Midcontinent deflects

parallels Douglas fault Douglas parallels

zone

correlation with Niagara fault fault Niagara with correlation

tectonic zone, possible age age possible zone, tectonic

southern part of Great Lakes Lakes Great of part southern

system

W part of Midcontinent Rift Rift Midcontinent of part W

shear zone shear

both dextral shear and ductile ductile and shear dextral both

movement

dominantly strike slip sense of of sense slip strike dominantly

motion motion

initially dominant strike slip slip strike dominant initially

lateral strike slip fault slip strike lateral

motion, reverse fault and right right and fault reverse motion,

initially dominant strike slip slip strike dominant initially

border

Quetico fault at Canadian Canadian at fault Quetico

Kawishiwi faults, merges with with merges faults, Kawishiwi

splits into Wolf Lake and North North and Lake Wolf into splits

other

const.

Ordovician

post Early Early post

last activity last

structure

Yavapai-age Yavapai-age

2600Ma

Precambrian

age formed age

up?

vertical, SE side side SE vertical,

or vertical or

steeply dipping dipping steeply

S side down, down, Sside

vertical?

or vertical or

steeply dipping dipping steeply

S side down, down, Sside

steep dip steep

dip/plunge

E-NE E-NE

E-NE

NW-SE

NNE-SSW

NE-SW

N70E

NE-SW

E-W

NW-SE

NE-SW

WNW-ESE

trend/strike

Spirit Lake tectonic zone tectonic Lake Spirit

zone

Yellow Medicine shear shear Medicine Yellow

Belle Plaine fault zone fault Plaine Belle

Pine fault Pine

Hinckley fault Hinckley

discontinuity

Malmo Structural Structural Malmo

Douglas fault Douglas

Camp Rivard fault Rivard Camp

Murray shear zone shear Murray

Mud Creek shear zone shear Creek Mud

Bear River fault River Bear

Rauch fault zone fault Rauch

fault

Rainy Lake-Seine River River Lake-Seine Rainy

Wolff Lake fault Lake Wolff

Haley fault Haley

Waasa fault Waasa

Burnside Lake fault Lake Burnside

Vermillion fault Vermillion

structure_name

shear zone shear

transfer fault transfer

thrust fault fault thrust

thrust fault thrust

high angle thrust fault thrust angle high

thrust fault fault thrust

fault

left lateral strike slip slip strike lateral left

shear zone shear

thrust fault thrust

reverse fault fault reverse

fault

left lateral strike slip slip strike lateral left

high angle fault angle high

fault fault

right lateral strike slip slip strike lateral right

type of feature of type

11 10

FID Table 2.1: Attribute table for the Midcontinent structures.

etal 1985 etal

Anderson 2006, Bunker Bunker 2006, Anderson

etal 1985 etal

Anderson 2006, Bunker Bunker 2006, Anderson

etal 1985 etal

Anderson 2006, Bunker Bunker 2006, Anderson

etal 1985 etal

Anderson 2006, Bunker Bunker 2006, Anderson

Wheeler 2000 Wheeler

etal 1985, Crone and and Crone 1985, etal

Anderson 2006, Bunker Bunker 2006, Anderson

etal 1999, Sims etal 1991 etal Sims 1999, etal

Blackstone 1993, Wicks Wicks 1993, Blackstone

McCormick 2010, 2010, McCormick

etal 1991 etal

McCormick 2010, Sims Sims 2010, McCormick

etal 1991 etal

McCormick 2010, Sims Sims 2010, McCormick

etal 1991 etal

Nichols etal 1989, Sims Sims 1989, etal Nichols

2000, McCormick 2010, 2010, McCormick 2000,

Crone and Wheeler Wheeler and Crone

etal 1991 etal

McCormick 2010, Sims Sims 2010, McCormick

Sims 1972 Sims

Bauer et al 2011 al et Bauer

Sims 1972 Sims

Van Schmus 1992 Schmus Van

Bauer et al 2011 al et Bauer

2007, Sims etal 1980 etal Sims 2007,

etal 1998, Holm etal etal Holm 1998, etal

Gibbs etal 1984, Holm Holm 1984, etal Gibbs

Chandler etal 2007, 2007, etal Chandler

2007, Sims etal 1980 etal Sims 2007,

etal 1998, Holm etal etal Holm 1998, etal

Gibbs etal 1984, Holm Holm 1984, etal Gibbs

Chandler etal 2007, 2007, etal Chandler

rift bounding fault bounding rift

repeated Phanerozoic activity, activity, Phanerozoic repeated

rift bounding fault bounding rift

repeated Phanerozoic activity, activity, Phanerozoic repeated

rift bounding fault bounding rift

repeated Phanerozoic activity, activity, Phanerozoic repeated

displacement displacement

zones, 70m vertical vertical 70m zones,

brittle cataclastic deformation deformation cataclastic brittle

orogen, monocline at surface at monocline orogen,

W boundary of Trans-Hudson Trans-Hudson of boundary W

displacement

orogen, 900ft vertical vertical 900ft orogen,

W boundary of Trans-Hudson Trans-Hudson of boundary W

tectonic zone tectonic

aligned with Great Lakes Lakes Great with aligned

several times several

wrench movement, reactivated reactivated movement, wrench

Canada

merges with Vermillion fault by by fault Vermillion with merges

normal and reverse sense reverse and normal

reactivated multiple times with with times multiple reactivated

major crustal boundary, boundary, crustal major

slip

movement with later reverse dip dip reverse later with movement

95m, dominantly dip slip slip dip dominantly 95m,

apparent vertical offset ~75- offset vertical apparent

Quaternary

late Cretaceous late

Cretaceous

Late Late

Archean

2600 Ma, late late Ma, 2600

Archean

2600 Ma, Late Late Ma, 2600

the S the

downthrown to to downthrown

the S the

downthrown to to downthrown

the S the

downthrown to to downthrown

the SE the

downthrown to to downthrown

the N the

downthrown to to downthrown

steep limb to the the to limb steep

varying dip, dip, varying

downthrown to to downthrown

N,N 55 dip

downthrown to to downthrown

dip

the NE, steep steep NE, the

downthrown to to downthrown

S and N Sand

NE-SW

E-W

NNE-SSW

NNW-SSE

NE-SW

mostly NE- mostly

NW-SE

NE-SW

WNW-ESE

E-W

ENE-WSW

NE-SW

E-NE

structural zone structural

Thurman-Redfield Thurman-Redfield

structural zone structural

Thurman-Redfield Thurman-Redfield

structural zone structural

Thurman-Redfield Thurman-Redfield

Fayette structural zone structural Fayette

Plum River fault zone fault River Plum

Fanny Peak monocline monocline Peak Fanny

Hartville-Rawhide fault/ fault/ Hartville-Rawhide

Cedar Creek fault Creek Cedar

Phillip fault Phillip

Pierre fault Pierre

Reservation fault Reservation

Quetico fault Quetico

Fourtown fault Fourtown

Middle River fault River Middle

Lancaster fault Lancaster

Argyle fault Argyle

Great Lakes tectonic zone tectonic Lakes Great

normal fault normal

fault

inferred basement basement inferred

normal fault normal

fault

right lateral strike slip slip strike lateral right

fault

inferred basement basement inferred

thrust fault thrust

fault

inferred basement basement inferred

fault

inferred basement basement inferred

thrust fault thrust

shear zone shear

19 18

Table 2.1 (cont’d)

Clendenin etal 1989 etal Clendenin

McCracken 1966, 1966, McCracken

Clendenin etal 1989 etal Clendenin

McCracken 1966, 1966, McCracken

1990, Nelson 1990 1990 Nelson 1990,

Buschback and Kolata Kolata and Buschback

Clendenin etal 1989, 1989, etal Clendenin

McCracken 1966, 1966, McCracken

2007 2007

2000, Schulz and Cannon Cannon and Schulz 2000,

etal 2007, Romano etal etal Romano 2007, etal

Cannon etal 1991, Holm Holm 1991, etal Cannon

1991

Southwick and Morey Morey and Southwick

Chandler etal 2007, 2007, etal Chandler

Cannon etal 1991, 1991, etal Cannon

Cannon 2007 Cannon

etal 2007, Schulz and and Schulz 2007, etal

Chandler etal 2007, Holm Holm 2007, etal Chandler

1990

Van Schmus 1992, Sims Sims 1992, Schmus Van

1992

Van Schmus 1992, Sims Sims 1992, Schmus Van

1990, Braschayko 2005 Braschayko 1990,

Bunker etal 1985, Sims Sims 1985, etal Bunker

1990

Bunker etal 1985, Sims Sims 1985, etal Bunker

Berendsen 1997 Berendsen

Baars and Watney 1991, 1991, Watney and Baars

VanSchmus 1992 1992 VanSchmus

Anderson 2006, 2006, Anderson

Anderson 2006 Anderson

Anderson 2006 2006 Anderson

Anderson 2006 Anderson

1990

Anderson 2006, Sims Sims 2006, Anderson

faults

reactivated as reverse/thrust reverse/thrust as reactivated

Sue's Branch fault segments, segments, fault Branch Sue's

made up of Sweetwater and and Sweetwater of up made

fault to form Palmer fault zone fault Palmer form to fault

merges with Simms Mountain Mountain Simms with merges

movement, transfer fault? transfer movement,

monocline, possible left lateral lateral left possible monocline,

both reverse and normal faults, faults, normal and reverse both

paleosuture

terrane, interpreted to be a a be to interpreted terrane,

Wausau terrane and Marshfield Marshfield and terrane Wausau

boundary between Pembine- between boundary

rocks to the S the to rocks

rocks to the N from arc-related arc-related N from the to rocks

separates Superior cratonic cratonic Superior separates

truncates main Penokean suture Penokean main truncates

N boundary of Yavapai orogen, orogen, Yavapai of Nboundary

system

S part of Midcontinent Rift Rift Midcontinent of Spart

sinuous trend sinuous

1000ft

displaces Precambrian by by Precambrian displaces

series of anastomosing faults anastomosing of series

vertical offset as much as 915m, 915m, as much as offset vertical

Rift system Rift

N boundary of Midcontinent Midcontinent of Nboundary

in Iowa in

within Midcontinent Rift system system Rift Midcontinent within

Ordovician

Post-

sylvanian

post-Penn-

Paleozoic

Early Cambrian Early

Late Proterozoic- Late

Early Cambrian Early

Late Proterozoic- Late

Early Cambrian Early

Late Proterozoic- Late

1860-1840Ma

1850 Ma Ma 1850

structure

Yavapai-age Yavapai-age

1.1 Ga 1.1

dip (70-80) to to (70-80) dip

the SW, steep steep SW, the

downthrown to to downthrown

the NW the

downthrown to to downthrown

to the N the to

steeply dipping dipping steeply

N side up, up, Nside

vertical

S dip, near near Sdip,

S side up, steep steep up, Sside

the E the

downthrown to to downthrown

the S the

downthrown to to downthrown

the SE the

downthrown to to downthrown

the N the

downthrown to to downthrown

the E the

downthrown to to downthrown

the NW the

downthrown to to downthrown

the SE the

downthrown to to downthrown

the NE the

downthrown to to downthrown

NW-SE

NE-SW

NW-SE

E-W

ENE

NE-SW

NW-SE

NNE-SSW

NE-SW

N-S

NE-SW

N-S

NW-SE

Ellington fault Ellington

Big River fault River Big

Ste. Genevieve fault zone fault Genevieve Ste.

Eau Pleine shear zone shear Pleine Eau

Niagara fault zone fault Niagara

Spirit Lake tectonic zone tectonic Lake Spirit

Lake Owen fault Owen Lake

Keweenaw fault Keweenaw

Waukesha fault Waukesha

Sandwich fault zone fault Sandwich

Humboldt fault zone fault Humboldt

zone

Northern Boundary fault fault Boundary Northern

102 fault zone fault 102

Perry-Hampton fault zone fault Perry-Hampton

Sheeder Prairie fault zone fault Prairie Sheeder

zone

Des Moines River fault fault River Moines Des

transfer fault transfer

normal fault normal

high angle fault angle high

shear zone shear

suture zone suture

shear zone shear

normal fault normal

fault

high angle normal normal angle high

normal fault normal

fault

left lateral strike slip slip strike lateral left

normal fault normal

fault

inferred basement basement inferred

normal fault normal

fault

inferred basement basement inferred

normal fault normal

36 35

Table 2.1 (cont’d)

Nelson 1990 Nelson

Kolata and Nelson 1997, 1997, Nelson and Kolata

1997

2000, Kolata and Nelson Nelson and Kolata 2000,

Crone and Wheeler Wheeler and Crone

1990, Nelson 1990 Nelson 1990,

Buschback and Kolata Kolata and Buschback

Kolata and Nelson 1997, 1997, Nelson and Kolata

2002, Nelson 1990 Nelson 2002,

Harrison and Schultz Schultz and Harrison

Kolata and Nelson 1997, 1997, Nelson and Kolata

Nelson 1990 1990 Nelson

Kolata and Nelson 1997, 1997, Nelson and Kolata

Nelson 1990 Nelson

Kolata and Nelson 1997, 1997, Nelson and Kolata

Kolata and Nelson 1997 Nelson and Kolata

and Wheeler 2000, 2000, Wheeler and

Bunker etal 1985, Crone Crone 1985, etal Bunker

Kolata 1990 Kolata

etal 1997, Buschback and and Buschback 1997, etal

Bunker etal 1985, Bear Bear 1985, etal Bunker

2002

Harrison and Schultz Schultz and Harrison

McCracken 1966, 1966, McCracken

1990

McCracken 1966, Sims Sims 1966, McCracken

Clendinin etal 1989 etal Clendinin

McCracken 1966 McCracken

Clendenin etal 1989 etal Clendenin

McCracken 1966, 1966, McCracken

Clendenin etal 1989 etal Clendenin

McCracken 1966, 1966, McCracken

least 1100m least

structures, max vertical uplift at at uplift vertical max structures,

braided high angle faults, flower flower faults, angle high braided

orogeny, normal in Cambrian in normal orogeny,

reverse fault during Alleghenian Alleghenian during fault reverse

NW boundary of Reelfoot Rift, Rift, Reelfoot of NWboundary

oblique movement oblique

normal, reverse, strike slip, and and slip, strike reverse, normal,

both major and minor faults with with faults minor and major both

Cap au Gres structure? Gres Capau

extends into MO, extension of of MO, extension into extends

anticline

basement involved for Salem Salem for involved basement

zone zone

NNE from Cottage Grove fault fault Grove Cottage from NNE

basement involved, extends extends involved, basement

strike slip and reverse motion reverse and slip strike

0.6km, lateral offsets 2-4km, 2-4km, offsets lateral 0.6km,

dip slip displacement at least least at displacement slip dip

Paleozoic

several periods of uplift during during uplift of periods several

monocline, en echelon pair echelon en monocline,

partnered with Cap au Gres Gres Cap au with partnered

and left lateral movement lateral left and

deformation, reverse, normal, normal, reverse, deformation,

50m zone of intense intense of zone 50m

left lateral strike slip movement movement slip strike lateral left

left lateral movement by ~15m by movement lateral left

movement

lateral, normal, and reverse reverse and normal, lateral,

form Palmer fault zone, left left zone, fault Palmer form

merges with Big River fault to to fault River Big with merges

sylvanian

post Penn- post

(<750Ka)

Quaternary Quaternary

Mid-Late Mid-Late

Penn-sylvanian

issippian/ Early Early issippian/

Late Miss- Late

Penn-sylvanian

(<15Ka)

Quaternary Quaternary

Late Late

Early Cambrian Early

Precambrian to to Precambrian

Late Late

Early Cambrian Early

Precambrian to to Precambrian

Late Late

Permian

sylvanian/ Early Early sylvanian/

Late Penn- Late

late Cambrian late

Early Mesozoic Early

Late Paleozoic- Late

Early Cambrian Early

Late Proterozoic- Late

Early Cambrian Early

Late Proterozoic- Late

Early Cambrian Early

Late Proterozoic- Late

dip to S to dip

master fault master

SW dipping dipping SW

gentle E limb E gentle

steep W limb, limb, W steep

steep W limb W steep

asymmetrical asymmetrical

side on the E the on side

dips to E, steep steep E, to dips

throw, N45W throw,

down to SW SW to down

the NE the

downthrown to to downthrown

the NE the

the SW, dip to to dip SW, the

downthrown to to downthrown

the N the

downthrown to to downthrown

the SW the

downthrown to to downthrown

>80 NE >80

NE, dip <20 to to <20 dip NE,

downthrown to to downthrown

NE-SW

E-W

N-NW

N-S

N-NE

NNW-SSE

NW-SE

E-W

NW-SE

system

Shawneetown fault fault Shawneetown

Rough Creek- Rough

Lusk Creek fault zone fault Creek Lusk

system

Cottage Grove fault fault Grove Cottage

Waterloo-Dupo anticline Waterloo-Dupo

Salem-Louden anticlines Salem-Louden

Du Quoin monocline Quoin Du

system

Wabash Valley fault fault Valley Wabash

La Salle anticlinal belt anticlinal Salle La

Lincoln fold Lincoln

Chesapeake fault Chesapeake

Black fault Black

Shannon County fault County Shannon

Palmer fault zone fault Palmer

zone

Bolivar-Mansfield fault fault Bolivar-Mansfield

Sims Mountain fault Mountain Sims

fault

high angle normal normal angle high

normal fault normal

fault

right lateral strike slip slip strike lateral right

anticline

monocline

fault

high angle normal normal angle high

anticline

normal fault normal

transfer fault transfer

normal fault normal

fault

left lateral strike slip slip strike lateral left

transfer fault transfer

52 51

Table 2.1 (cont’d)

2115 2012 2115

Perry 1989, NUREG- 1989, Perry

1986, Luza etal 1987, 1987, etal Luza 1986,

Ramelli and Slemmons Slemmons and Ramelli

Burchett etal 1985, 1985, etal Burchett

Crone and Wheeler 2000 Wheeler and Crone

1995

Drahovzal and Noger Noger and Drahovzal

1995

Drahovzal and Noger Noger and Drahovzal

2000

Noger 1995, Gao etal etal Gao 1995, Noger

2000, Drahovzal and and Drahovzal 2000,

Crone and Wheeler Wheeler and Crone

Baranoski 2002 Baranoski

Onasch and Kahle 1991 Kahle and Onasch

Bunker etal 1985, 1985, etal Bunker

1990

and Nelson 1997, Nelson Nelson 1997, Nelson and

Bunker etal 1985, Kolata Kolata 1985, etal Bunker

Bunker etal 1985 etal Bunker

Nelson 1990 Nelson

Kolata and Nelson 1997, 1997, Nelson and Kolata

Kolata 1990 Kolata

2000, Buschback and and Buschback 2000,

Crone and Wheeler Wheeler and Crone

McDowell 1986 McDowell

Nelson 1990 Nelson

Kolata and Nelson 1997, 1997, Nelson and Kolata

various movement directions movement various

Meers fault, and Cordell fault, fault, Cordell and fault, Meers

fault, Duncan-Criner fault, fault, Duncan-Criner fault,

comprised of Mountain View View Mountain of comprised

basement, part of Grenville front Grenville of part basement,

600m offset of Precambrian Precambrian of offset 600m

W boundary of Rome Trough, Trough, Rome of boundary W

Trough

marks S boundary of Rome Rome of S boundary marks

either reverse or normal motion normal or reverse either

component

450m offset, left lateral lateral left offset, 450m

N boundary of Rome Trough, Trough, Rome of Nboundary

Precambrian

subsurface, may reach reach may subsurface,

Precambrian

subsurface, may reach reach may subsurface,

and thrust faults thrust and

fans common, normal, reverse, reverse, normal, common, fans

propagation folds, and imbricate imbricate and folds, propagation

fault bend folds, fault fault folds, bend fault

common

antithetic normal fault splays splays fault normal antithetic

major displacement to the S the to displacement major

movement

strike slip, and oblique slip slip oblique and slip, strike

diatremes, normal, reverse, reverse, normal, diatremes,

Permian dikes, sills, and and sills, dikes, Permian

Creek Graben Creek

directly underlain by Rough Rough by underlain directly

lateral offset lateral

some reverse faulting and left left and faulting reverse some

en echelon, intertwining faults, faults, intertwining echelon, en

Quaternary

(1.6 Ma) (1.6

Quaternary Quaternary

present

Ordovician to to Ordovician

Late Late

sylvanian

Early Penn- Early

sylvanian

post Penn- post

to Cambrian to

Late Proterozoic Proterozoic Late

Early Mesozoic Early

Late Paleozoic- Late

30-40S-SW

down to E and and E to down

the NW the

downthrown to to downthrown

the SE the

downthrown to to downthrown

and NE and

25-80 in SW SW 25-80in

the NE the

downthrown to to downthrown

direction

varying dip dip varying

near vertical near

vertical

64W dip to to dip 64W

the SE the

downthrown to to downthrown

the SE the

downthrown to to downthrown

down

steep dip, N side N side dip, steep

65 or steeper or 65

high angle dip to to dip angle high

(N50W)

NW-SE

N-NE

SW to E-NE to SW

N-SNE- to

E-NE

NW-SE

NNW-SSE

NE-SW

E-W to E-SE E-SE to E-W

ENE-WSW

E-W

ENE-WSW

Wichita fault zone fault Wichita

front

Lexington fault/Grenville fault/Grenville Lexington

Rock Castle River fault River Castle Rock

system

Irvine-Paint Creek fault fault Creek Irvine-Paint

system

Kentucky River fault fault River Kentucky

Marion fault Marion

Outlet fault Outlet

Bowling Green fault Green Bowling

Mount Carmel fault Carmel Mount

Fortville fault Fortville

Royal Center fault Center Royal

Tabb fault system fault Tabb

complex

Fluorspar area fault fault area Fluorspar

Moorman syncline Moorman

Pennyrile fault system fault Pennyrile

high angle fault angle high

normal fault normal

high angle fault angle high

reverse fault reverse

fault

inferred basement basement inferred

fault

inferred basement basement inferred

high angle fault angle high

normal fault normal

high angle fault angle high

normal fault normal

fault

high angle normal normal angle high

syncline

fault

high angle normal normal angle high

67 66

Table 2.1 (cont’d)

2010

1987, Perry 1989, Cox Cox 1989, Perry 1987,

and Luza 1986, Luza etal etal Luza 1986, Luza and

Slemmons 1986, Crone Crone 1986, Slemmons

2000, Ramelli and and Ramelli 2000,

Crone and Wheeler Wheeler and Crone

1993

Blackstone 1993, Stone Stone 1993, Blackstone

Blackstone 1993 Blackstone

Crone and Wheeler 2000 Wheeler and Crone

1985, Sims etal 1991, 1991, etal Sims 1985,

Bergantino and Clark Clark and Bergantino

1985

Bergantino and Clark Clark and Bergantino

1985

Bergantino and Clark Clark and Bergantino

1985

Bergantino and Clark Clark and Bergantino

1997

1985, Woodward etal etal Woodward 1985,

Bergantino and Clark Clark and Bergantino

1985

Bergantino and Clark Clark and Bergantino

McCracken 1966 McCracken

2002, Nelson 1990 Nelson 2002,

Harrison and Schultz Schultz and Harrison

and Nelson 1997, 1997, Nelson and

McCracken 1966, Kolata Kolata 1966, McCracken

etal 1983 etal

Merriam 1963, Brown Brown 1963, Merriam

Robbins and Keller 1992, 1992, Keller and Robbins

Burchett etal 1985, 1985, etal Burchett

Oklahoma transform Oklahoma

possibly part of Alabama- of part possibly

lateral displacement of 12m, 12m, of displacement lateral

vertical displacement of 5m, 5m, of displacement vertical

S boundary of Bighorn basin Bighorn of Sboundary

mountains

E boundary of Bighorn Bighorn of boundary E

fault

orogen, either normal or reverse reverse or normal either orogen,

W boundary of Trans-Hudson Trans-Hudson of boundary W

displacement, subsurface fault subsurface displacement,

both normal and reverse reverse and normal both

associated faults, reverse faults reverse faults, associated

echelon pair, monocline with with monocline pair, echelon

partnered with Lincoln fold, en en fold, Lincoln with partnered

anticline

NE-SW to NW-SE, includes an an NW-SE, includes NE-SWto

abruptly changes direction from from direction changes abruptly

Quaternary

Quaternary Quaternary

Penn-sylvanian

issippian/ Early Early issippian/

Late Miss- Late

issippian

post Miss- post

Early Cambrian Early

Precambrian/ Precambrian/

Late Late

Proterozoic

Penn-sylvanian

issippian/ Early Early issippian/

Late Miss- Late

(55N,56NE)

moderate N dip N dip moderate

40SW), 40SW),

throw (30- throw

down to SW SW to down

upthrown to the the to upthrown

dips to S to dips

the S the

downthrown to to downthrown

the E the

downthrown to to downthrown

the ENE the

downthrown to to downthrown

overturned

steeply steeply

dips of 65 S to S 65 to of dips

the SW, max max SW, the

downthrow to to downthrow

dips to E and W and E to dips

64W

W-NW,N60-

E-W

NW-SE

NE-SW

NW-SE

WNW-ESE

W-E

NE-SW

E-W

NW-SE

N-S

NW-SE

SSW, N16E SSW,

N-S/NNE-

Meers fault Meers

zone

Medicine Lodge fault fault Lodge Medicine

thrust

Bighorn eastern boundary boundary eastern Bighorn

fault zone fault

Weldon/Brockton Froid Froid Weldon/Brockton

fault zone fault

Scapegoat-Bannatyne Scapegoat-Bannatyne

Fromberg fault zone fault Fromberg

Nye-Bowler fault zone fault Nye-Bowler

Cat Creek fault zone fault Creek Cat

Lake Basin fault zone fault Basin Lake

Seneca fault Seneca

Ritchey fault Ritchey

Proctor anticline Proctor

Leasburg fault Leasburg

Cuba fault Cuba

anticline

Kirksville-Mendota Kirksville-Mendota

Cap au Gres fault Gres Capau

Nemaha fault zone/uplift fault Nemaha

reverse fault reverse

thrust fault thrust

high angle fault angle high

normal fault normal

fault

left lateral strike slip slip strike lateral left

high angle fault angle high

anticline

high angle fault angle high

anticline

high angle fault angle high

high angle fault fault angle high

82 81

Table 2.1 (cont’d)

Blackstone 1993 Blackstone

1993

Stone 1993, Blackstone Blackstone 1993, Stone

Blackstone 1993 Blackstone

Yonkee and Mitra 1993 Mitra and Yonkee

Blackstone 1993, 1993, Blackstone

1980

Sims etal 2001, Tweto Tweto 2001, etal Sims

1996

Sims etal 2001, Hemborg Hemborg 2001, etal Sims

and Van Arsdale 1988 Arsdale Van and

2000, Perry 1989, Cox Cox 1989, Perry 2000,

Crone and Wheeler Wheeler and Crone

Crone and Wheeler 2000 Wheeler and Crone

Burchett etal 1985 etal Burchett

sinuous trend sinuous

dips in different directions, directions, different in dips

uplifts Gros Ventre Range Ventre Gros uplifts

boundary of Sevier orogeny Sevier of boundary

uplift

W boundary of Rock Springs Springs Rock of boundary W

uplift

uplifts S end of Sweetwater Sweetwater of S end uplifts

N of Sweetwater uplift Sweetwater Nof

thrusts up Wind River Range River Wind up thrusts

strike slip fault slip strike

mylonite zone, originated as as originated zone, mylonite

subsurface (inferred) subsurface

fault

displacement, began as normal normal as began displacement,

4.3km of left lateral lateral left of 4.3km

thrust belt thrust

terminates at Ouachita fold fold Ouachita at terminates

SE end of Meers Fault, Fault, Meers of end SE

pre-Quaternary

Precambrian

Nside

upthrown on the the on upthrown

W side W

upthrown on the the on upthrown

side

upthrown on NE NE on upthrown

side

upthrown on W W on upthrown

side

upthrown on E E on upthrown

side

upthrown on NE NE on upthrown

side

upthrown on N on upthrown

side

upthrown on SE SE on upthrown

side

upthrown on S on upthrown

side

upthrown on N on upthrown

side

upthrown on E E on upthrown

W side W

upthrown on the the on upthrown

NE side NE

upthrown on the the on upthrown

side

upthrown on SE SE on upthrown

side, dips 40NE dips side,

upthrown on NE NE on upthrown

vertical

downthrown to to downthrown

near vertical, vertical, near

throw

down to SW SW to down

NE-SW

NW-SE to NW-SEto

NW-SE

N-S

NW-SE

E-W

NE-SW

E-W

NNW-SSE

NNE-SSW

N-SNW- to

NW-SE

E-W to NE- to E-W

WNW-ESE

NW-SE to NW-SEto

NW-SE

NW(N45W)

NNE-SSW

thrusts/Owl Creek fault Creek thrusts/Owl

Washakie range range Washakie

Hogsback thrust fault thrust Hogsback

Owl Creek uplift Creek Owl

Oregon basin fault basin Oregon

Wind River thrust fault thrust River Wind

Gore fault Gore

Apishapa fault Apishapa

Washita Valley fault Valley Washita

Criner fault Criner

Wilzetta fault Wilzetta

thrust fault thrust

high angle fault angle high

high angle thrust fault thrust angle high

thrust fault thrust

high angle fault angle high

reverse fault reverse

normal fault normal

fault

inferred basement basement inferred

117

116

115

114

113

112

111

110

109

108

107

106

105

104

103

102

101 100

Table 2.1 (cont’d)

Woodward 1984 Woodward

Hemborg 1996 Hemborg

1994, Crone etal 2006 etal Crone 1994,

Kluth and Schaftenaar Schaftenaar and Kluth

Hemborg 1996 Hemborg

Woodward 1984 Woodward

Hemborg 1996 Hemborg

Blackstone 1993 Blackstone

Hemborg 1996 Hemborg

Blackstone 1993, 1993, Blackstone

Blackstone 1993 Blackstone

Hemborg 1996 Hemborg

Blackstone 1993, 1993, Blackstone

Blackstone 1993 Blackstone

Blackstone 1993 1993 Blackstone

Blackstone 1993 Blackstone

Cristo Range Cristo

marks E boundary of Sangre de de Sangre of boundary E marks

subsurface subsurface

mountians

to the W of Sangre de Cristo Cristo de Sangre of W the to

Uncompagre uplift Uncompagre

marks SW boundary of of boundary SW marks

within North Park basin Park North within

W boundary of front ranges front of boundary W

thrust

sinuous trend, inferred basement basement inferred trend, sinuous

south of Uinta uplift Uinta of south

mountains

marks N boundary of Uinta Uinta of N boundary marks

cuts through Rock Springs uplift Springs Rock through cuts

mountains

E boundary of Sierra Madre Madre Sierra of boundary E

N boundary of Laramie range Laramie of Nboundary

Range

marks E boundary of Front Front of boundary E marks

Sweetwater ranges Sweetwater

between Wind River and and River Wind between

range

uplifts W end of Sweetwater Sweetwater of end W uplifts

to the E of Beartooth mountains Beartooth of E the to

Quaternary

Late Late

the W the

downthrown to to downthrown

upthrown to the the to upthrown

60 to the W the to 60

the SW the

downthrown to to downthrown

upthrown to the the to upthrown

the W the

downthrown to to downthrown

varying dip varying

side

upthrown on E E on upthrown

upthrown to the the to upthrown

the S the

downthrown to to downthrown

side

upthrown on S on upthrown

Sside

downthrown on on downthrown

side

upthrown on N on upthrown

side

upthrown on S on upthrown

direction

varying dip dip varying

side

upthrown on S on upthrown

side

upthrown on E E on upthrown

W side W

upthrown on the the on upthrown

NE-SW to N- NE-SWto

N-S

NW-SE

N-S

NW-SE

N-SE-W to

NNW-SSE

N-SNW- to

NW-SE

E-W

S to E-W Sto

NW-SE to N- NW-SEto

NE-SW to E- NE-SWto

NE-SW

ENE-WSW

NW-SE

N-S

Sangre de Cristo fault Cristo de Sangre

normal fault normal

thrust fault thrust

fault

inferred basement basement inferred

fault

inferred basement basement inferred

normal fault normal

thrust fault thrust

normal fault normal

thrust fault thrust

normal fault normal

thrust fault thrust

normal fault normal

thrust fault thrust

138

137

136

135

134

133

132

131

130

129

128

127

126

125

124

123

122

121

120 119 118 Table 2.1 (cont’d)

Cole 1976 Cole

1997

Carlson 1970, Carlson Carlson 1970, Carlson

Sims etal 1991 etal Sims

Sims etal 1991 1991 etal Sims

Carlson 1970 Carlson

Woodward 1984 Woodward

Hemborg 1996 Hemborg

1994 1994

Lozinski 1994, May etal etal May 1994, Lozinski

Magnani etal 2004, 2004, etal Magnani

Campbell 1976 Campbell

Lozinski 1994, Slack and and Slack 1994, Lozinski

Lozinski 1994 Lozinski

1994

Salyards and Aldrich Aldrich and Salyards

and Keller 1994, 1994, Keller and

Baldridge 1994, Barrow Barrow 1994, Baldridge

Cather 1994, Lewis and and Lewis 1994, Cather

Aldrich 1986, Chapin and and Chapin 1986, Aldrich

part of Central Kansas Uplift Kansas Central of part

in NE in

S boundary of Midcontinent rift rift Midcontinent of Sboundary

Precambrian crustal boundary? crustal Precambrian

sinuous trend sinuous

part of Rio Grande Rift Grande Rio of part

subsurface (inferred) subsurface

boundary of Rio Grande Rift Grande Rio of boundary

right lateral component, E E component, lateral right

basin, numerous faults and folds and faults numerous basin,

W boundary of Albuquerque Albuquerque of boundary W

basin

W boundary of Albuquerque Albuquerque of boundary W

angle faults angle

anastomosing en echelon high high echelon en anastomosing

lateral oblique movement, movement, oblique lateral

major strike slip fault with left left with fault slip strike major

Cenozoic

Paleozoic?

Middle Middle

(1.65-1.60Ga)

Proterozoic Proterozoic

Precambrian

the SW the

downthrown to to downthrown

the W the

downthrown to to downthrown

the SW the

downthrown to to downthrown

the SW the

downthrown to to downthrown

the SW the

downthrown to to downthrown

the SE the

downthrown to to downthrown

the SE the

downthrown to to downthrown

the W the

downthrown to to downthrown

the E the

downthrown to to downthrown

upthrown to the the to upthrown

downthrown to to downthrown

S dip, Sdip,

downthrown to to downthrown

NW and SE NWand

downthrown to to downthrown

NW-SE

NNE-SSW

NW-SE

NE-SW

NW-SE

NE-SW

NW-SE

N-S

NNE-SSW

N-S

SSW

N-SNNE- to

N-S, NE to

Union fault Union

Chadron Arch Chadron

Manzano-Los Pinos uplift Pinos Manzano-Los

zone/Lucero uplift zone/Lucero

Rio Puerco fault fault Puerco Rio

Nacimiento uplift Nacimiento

Canoncito fault zone fault Canoncito

Pecos-Picuris fault/Tijeras- Pecos-Picuris

high angle fault angle high

normal fault normal

fault

right lateral strike slip slip strike lateral right

fault

right lateral strike slip slip strike lateral right

high angle fault angle high

anticline

normal fault normal

fault

inferred basement basement inferred

normal fault normal

thrust fault thrust

fault

inferred basement basement inferred

reverse fault reverse

high angle fault angle high

fault

inferred basement basement inferred

high angle fault fault angle high

157

156

155

154

153

152

151

150

149

148

147

146

145

144

143

142

141 140 139 Table 2.1 (cont’d)

Woodward 1984 Woodward

1992

Bergh and Karlstrom Karlstrom and Bergh

Woodward 1984 Woodward

Huntoon 1993 Huntoon

Woodward 1984 Woodward

Davis 1999 Davis

Woodward 1984 Woodward

Davis 1999 Davis

Sims 1990 Sims

2006

Campbell and Weber Weber and Campbell

2006, Ewing 1990 Ewing 2006,

Campbell and Weber Weber and Campbell

2006

Campbell and Weber Weber and Campbell

2006

Campbell and Weber Weber and Campbell

2006, Ewing 1990 Ewing 2006,

Campbell and Weber Weber and Campbell

Cole 1976 Cole

monocline

Precambrian fault under under fault Precambrian

max offset of 750m, reactivated reactivated 750m, of offset max

extends as a monocline to the N the to monocline a as extends

Miocene)

Basin and Range structure (Late (Late structure Range and Basin

normal fault? normal

reaches basement reaches

reaches Precambrian rocks Precambrian reaches

part of Central Kansas Uplift Kansas Central of part

Holocene

late Tertiary to to Tertiary late

active today active

Precambrian

steep side to the the to side steep

E dipping? E

steep side to the the to side steep

the W the

downthrown to to downthrown

the W the

downthrown to to downthrown

75W

steeply W steeply

the SE the

downthrown to to downthrown

the SW the

downthrown to to downthrown

the N the

downthrown to to downthrown

the SW the

downthrown to to downthrown

the E and W and E the

downthrown to to downthrown

the SW the

downthrown to to downthrown

the SW the

downthrown to to downthrown

the E the

downthrown to to downthrown

the SW the

downthrown to to downthrown

NE-SW to E- NE-SW to

N-S

NE-SW to E- NE-SW to

N-S

NE-SW

NW-SE

NNE-SSW

NE-SW

NW-SE

N-S

NW-SE

NNE-SSW

NW-SE

Shylock shear zone shear Shylock

East Kaibab monocline Kaibab East

San Rafael monocline Rafael San

Waterpocket fold Waterpocket

Pausaugunt fault Pausaugunt

Sevier fault Sevier

Hurricane fault Hurricane

Sulphur fault? Sulphur

zone

Central Oklahoma fault fault Oklahoma Central

Waurika Arch Waurika

monocline

shear zone shear

monocline

normal fault normal

fault

high angle normal normal angle high

normal fault fault normal

fault

inferred basement basement inferred

fault

inferred basement basement inferred

thrust fault thrust

fault

inferred basement basement inferred

high angle fault angle high

fault

inferred basement basement inferred

high angle fault angle high

178

177

176

175

174

173

172

171

170

169

168

167

166

165

164

163

162

161

160 159 158 Table 2.1 (cont’d)

Ewing 1990 Ewing

Rickard 1973 Rickard

1973

Jacobi 2002, Rickard Rickard 2002, Jacobi

1973

Jacobi 2002, Rickard Rickard 2002, Jacobi

Crone and Wheeler 2000 Wheeler and Crone

2002, Rickard 1973, 1973, Rickard 2002,

Fakundiny and Pomeroy Pomeroy and Fakundiny

Patchen etal 2006 etal Patchen

Baranoski 2002 Baranoski

Brannock 1993 Brannock

Baranoski 2002, 2002, Baranoski

Baranoski 2002 Baranoski

Saylor 1999 Saylor

displacement faults displacement

broad zone of small small of zone broad

Trough

N boundary of the Rome Rome the of Nboundary

normal fault? normal

structural discontinuity structural

Washington cross strike strike cross Washington

includes part of Pittsburg- of part includes

set of 3 en echelon faults echelon en 3 of set

N boundary of Rome Trough Rome of Nboundary

to Cambrian to

Late Proterozoic Proterozoic Late

the E the

downthrown to to downthrown

the S the

downthrown to to downthrown

direction

varying dip dip varying

the NE the

downthrown to to downthrown

the SW the

downthrown to to downthrown

the N the

downthrown to to downthrown

the SW the

downthrown to to downthrown

the S the

downthrown to to downthrown

the E the

downthrown to to downthrown

the E the

downthrown to to downthrown

the E the

downthrown to to downthrown

the E the

downthrown to to downthrown

the W the

downthrown to to downthrown

E and W and E

the SW the

downthrown to to downthrown

the S the

downthrown to to downthrown

the SW the

downthrown to to downthrown

the SW the

downthrown to to downthrown

N-S

E-W

N-SE-W to

NW-SE

E-W

NW-SE

NW-SE to E- NW-SEto

N-S

NE-SW to N- NE-SWto

NNE-SSW

N-S

NE-SW

NW-SE

E-W

WNW-ESE

NE-SW

Big Lake fault Lake Big

Hoffmans fault Hoffmans

Nosefault

Dolgerville fault Dolgerville

system

Clarendon-Linden fault fault Clarendon-Linden

Structural discontinuity Structural

Cambridge Cross Strike Strike Cross Cambridge

Starr fault system fault Starr

Highlandtown fault Highlandtown

Township fault zones fault Township

Akron-Suffield-Smith Akron-Suffield-Smith

normal fault normal

fault

inferred basement basement inferred

normal fault normal

fault

inferred basement basement inferred

fault

inferred basement basement inferred

normal fault normal

fault

inferred basement basement inferred

fault

inferred basement basement inferred

high angle fault angle high

normal fault normal

198

197

196

195

194

193

192

191

190

189

188

187

186

185

184

183

182

181 180 179 Table 2.1 (cont’d)

Ewing 1990 Ewing

Ewing 1990 1990 Ewing

Ewing 1990 Ewing

Ewing 1990 1990 Ewing

Ewing 1990 Ewing

normal fault? normal

the SW the

downthrown to to downthrown

the S the

downthrown to to downthrown

the N the

downthrown to to downthrown

the S the

downthrown to to downthrown

upthrown to the the to upthrown

the NE the

downthrown to to downthrown

the NE the

downthrown to to downthrown

the NE the

downthrown to to downthrown

direction

varying dip dip varying

the S the

downthrown to to downthrown

the N the

downthrown to to downthrown

the N the

downthrown to to downthrown

the SW the

downthrown to to downthrown

the NE the

downthrown to to downthrown

the NE the

downthrown to to downthrown

the NE the

downthrown to to downthrown

the NE the

downthrown to to downthrown

the W the

downthrown to to downthrown

the SW the

downthrown to to downthrown

direction

varying dip dip varying

the NE the

downthrown to to downthrown

the NE the

downthrown to to downthrown

NW-SE

E-W

NW-SE

E-W

NW-SE

E-W to NW- to E-W

N-S

NW-SE

Apache Mountain fault Mountain Apache

Huapache fault Huapache

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

thrust fault thrust

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

normal fault normal

thrust fault thrust

fault

inferred basement basement inferred

fault

inferred basement basement inferred

220

219

218

217

216

215

214

213

212

211

210

209

208

207

206

205

204

203

202

201 200 199 Table 2.1 (cont’d)

Sims 1992 Sims

Saylor 1999 Saylor

Patchen etal 2006 etal Patchen

2005

Thomas and Bayona Bayona and Thomas

Groshong etal 2010 etal Groshong

Csontos etal 2008 etal Csontos

Woodward 1984 Woodward

Ewing 1990 Ewing

fault intruded by narrow dike narrow by intruded fault

S boundary of Rome Trough Rome of Sboundary

part of Reelfoot Rift Reelfoot of part

central part of Reelfoot Rift Reelfoot of part central

SE boundary of Reelfoot Rift Reelfoot of boundary SE

NW boundary of Reelfoot Rift Reelfoot of NWboundary

Graben

cuts across Mississippi Valley Valley Mississippi across cuts

continuation of Waurika arch? Waurika of continuation

normal fault? normal

the SE the

downthrown to to downthrown

the SW the

downthrown to to downthrown

the SW the

downthrown to to downthrown

the SW the

downthrown to to downthrown

the NW the

downthrown to to downthrown

the SE the

downthrown to to downthrown

the SW the

downthrown to to downthrown

the SW the

downthrown to to downthrown

the SE the

downthrown to to downthrown

the SE the

downthrown to to downthrown

the SE the

downthrown to to downthrown

the SE the

downthrown to to downthrown

the SE the

downthrown to to downthrown

the SE the

downthrown to to downthrown

the W the

downthrown to to downthrown

the SE the

downthrown to to downthrown

the N the

downthrown to to downthrown

NE-SW

NW-SE

NE-SW

NW-SE

NE-SW

NW-SE

NNW-SSE

NE-SW

NW-SE

NE-SW

N-S

NE-SW

E-W to NW- to E-W

Monico fault Monico

White River fault zone fault River White

Reelfoot Fault Reelfoot

Lampasas arch Lampasas

Mason Graben Mason

Carta Valley fault zone fault Valley Carta

high angle fault angle high

normal fault normal

transfer fault transfer

normal fault normal

transfer fault transfer

high angle fault angle high

normal fault normal

fault

inferred basement basement inferred

normal fault normal

fault

right lateral strike slip slip strike lateral right

fault

inferred basement basement inferred

normal fault normal

fault

inferred basement basement inferred

normal fault normal

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

245

244

243

242

241

240

239

238

237

236

235

234

233

232

231

230

229

228

227

226

225

224

223 222 221 Table 2.1 (cont’d)

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

Huntoon 1993 Huntoon

Sims etal 1991 etal Sims

Sims 1992 Sims

Sims 1992, Sims 1989 Sims 1992, Sims

Birmingham Basement graben Basement Birmingham

NW boundary of the the of NWboundary

Birmingham Basement graben Basement Birmingham

NW boundary of the the of NWboundary

Basement graben Basement

SE boundary of the Birmingham Birmingham the of boundary SE

Basement graben Basement

transfer fault of the Birmingham Birmingham the of fault transfer

Basement graben Basement

transfer fault of the Birmingham Birmingham the of fault transfer

part of Marquette Iron Range Iron Marquette of part

intruded by narrow dike narrow by intruded

inferred to flatten at depth at flatten to inferred

by Mineral Lake fault Lake Mineral by

inferred to flatten at depth, offset offset depth, at flatten to inferred

component

later reversed, right lateral lateral right reversed, later

initiated as a normal fault and and fault normal a as initiated

Proterozoic

Early Early

Proterozoic

Early Early

Proterozoic

Early Early

Proterozoic

Early Early

Proterozoic

Middle Middle

upthrown to the the to upthrown

the S the

downthrown to to downthrown

the SE the

downthrown to to downthrown

dips 72 NW, 72 dips

the NW the

downthrown to to downthrown

the NW the

downthrown to to downthrown

NE-SW

NW-SE

N-S

NNE-SSW

NE-SW

E-W

NE-SW

E-W

NW-SE

E-W to NE- to E-W

WNW-ESE

NE-SW

basement fault basement

Anniston transverse transverse Anniston

basement fault basement

Rome transverse transverse Rome

Echo Cliffs monocline Cliffs Echo

South Range fault Range South

Bush Lake fault Lake Bush

Flambeau Flowage fault Flowage Flambeau

Mineral Lake fault Lake Mineral

Athens Shear zone Shear Athens

Jump River shear zone shear River Jump

Owen fault Owen

normal fault normal

fault

right lateral strike slip slip strike lateral right

fault

right lateral strike slip slip strike lateral right

monocline

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

right lateral strike slip slip strike lateral right

high angle fault angle high

high angle thrust fault thrust angle high

high angle fault angle high

high angle thrust fault thrust angle high

reverse fault fault reverse

shear zone shear

high angle fault angle high

266

265

264

263

262

261

260

259

258

257

256

255

254

253

252

251

250

249

248 247 246 Table 2.1 (cont’d)

Esch 2010 Esch

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

based on lineament map lineament on based

Basement graben Basement

W boundary of the Birmingham Birmingham the of boundary W

Basement graben Basement

W boundary of the Birmingham Birmingham the of boundary W

Basement graben Basement

E boundary of the Birmingham Birmingham the of boundary E

Basement graben Basement

SE boundary of the Birmingham Birmingham the of boundary SE

Birmingham Basement graben Basement Birmingham

NW boundary of the the of NW boundary

Basement graben Basement

transfer fault of the Birmingham Birmingham the of fault transfer

Basement graben Basement

transfer fault of the Birmingham Birmingham the of fault transfer

Basement graben Basement

W boundary of the Birmingham Birmingham the of boundary W

Basement graben Basement

E boundary of the Birmingham Birmingham the of boundary E

Basement graben Basement

transfer fault of the Birmingham Birmingham the of fault transfer

Birmingham Basement graben Basement Birmingham

NW boundary of the the of NW boundary

Basement graben Basement

SE boundary of the Birmingham Birmingham the of boundary SE

Basement graben Basement

SE boundary of the Birmingham Birmingham the of boundary SE

NW-SE

WNW-ESE

NE-SW

N-S

NE-SW

NW-SE

WNW-ESE

NNE-SSW

N-S

NW-SE

NE-SW

fault

inferred basement basement inferred

fault

inferred basement basement inferred

normal fault normal

transfer fault transfer

normal fault normal

fault

left lateral strike slip slip strike lateral left

normal fault normal

281

280

279

278

277

276

275

274

273

272

271

270

269 268 267 Table 2.1 (cont’d)

Esch 2010 Esch

based on lineament map lineament on based

N-S

NW-SE

N-S

NW-SE

N-S

E-W

NE-SW

E-W

NE-SW

NW-SE

NE-SW

NW-SE

NE-SW

E-W

NW-SE

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

303

302

301

300

299

298

297

296

295

294

293

292

291

290

289

288

287

286

285

284

283 282

Table 2.1 (cont’d)

Esch 2010 Esch

Bader 2008, 2009 2008, Bader

Esch 2010 Esch

based on lineament map lineament on based

part of Cheyenne belt? Cheyenne of part

based on lineament map lineament on based

Precambrian?

NE-SW

NW-SE

NE-SW

WNW-ESE

NW-SE

E-W

NW-SE

E-W

NW-SE

WNW-ESE

NW-SE

NE-SW

NW-SE

WNW-ESE

NW-SE

N-S

NW-SE

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

suture zone suture

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

325

324

323

322

321

320

319

318

317

316

315

314

313

312

311

310

309

308

307

306

305 304

Table 2.1 (cont’d)

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

Sims 1990 Sims

Wicks etal 1999 etal Wicks

1990

Buschback and Kolata Kolata and Buschback

1990

Buschback and Kolata Kolata and Buschback

1990

Buschback and Kolata Kolata and Buschback

Hickman 2011 Hickman

Bader 2008, 2009 2008, Bader

Esch 2010 Esch

Graben

part of Birmingham Basement Basement Birmingham of part

Graben

part of Birmingham Basement Basement Birmingham of part

Graben

part of Birmingham Basement Basement Birmingham of part

part of La Salle Anticlinal belt Anticlinal Salle La of part

subsurface

S part of Rome Trough, Trough, Rome of Spart

Grenville suture zone suture Grenville

Creek Graben Creek

S part of Rome Trough/ Rough Rough Trough/ Rome of Spart

Creek Graben Creek

N part of Rome Trough/ Rough Rough Trough/ Rome of Npart

Paleoproterozoic suture zone suture Paleoproterozoic

based on lineament map lineament on based

Precambrian

the N the

downthrown to to downthrown

the S the

downthrown to to downthrown

the N the

downthrown to to downthrown

the N the

downthrown to to downthrown

steep limb to the the to limb steep

NE-SW

N-S

NNW-SSE

NE-SW

N-S

ENE-WSW

WNW-ESE

NW-SE

N-S

NE-SW

structural zone structural

Northern Chickasaw Chickasaw Northern

Decorah structural zone structural Decorah

Eldora structural zone structural Eldora

Osborne structural zone structural Osborne

Black Hills monocline Hills Black

Cheyenne belt Cheyenne

normal fault normal

monocline

normal fault normal

suture zone suture

normal fault normal

suture zone suture

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

fault

inferred basement basement inferred

346

345

344

343

342

341

340

339

338

337

336

335

334

333

332

331

330

329

328 327 326 Table 2.1 (cont’d)

Arbenz 2008 Arbenz

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

2005

Thomas and Bayona Bayona and Thomas

Bayona etal 2003, 2003, etal Bayona

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

Graben

part of Birmingham Basement Basement Birmingham of part

Basement Graben Basement

W part of Birmingham Birmingham of part W

Basement Graben Basement

W part of Birmingham Birmingham of part W

Basement Graben Basement

W part of Birmingham Birmingham of part W

Graben

part of Birmingham Basement Basement Birmingham of part

Graben

part of Birmingham Basement Basement Birmingham of part

Graben

part of Birmingham Basement Basement Birmingham of part

Graben

part of Birmingham Basement Basement Birmingham of part

graben

S part of Birmingham basement basement Birmingham of Spart

Graben

part of Birmingham Basement Basement Birmingham of part

ENE-WSW

NE-SW

normal fault normal

362

361

360

359

358

357

356

355

354

353

352

351

350

349

348 347

Table 2.1 (cont’d)

Arbenz 2008 Arbenz

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

unknown

E-W

WNW-ESE

NNE-SSW

NE-SW

N-S

NE-SW

E-W

NE-SW

ENE-WSW

NE-SW

normal fault normal

transfer fault transfer

normal fault normal

transfer fault transfer

normal fault normal

384

383

382

381

380

379

378

377

376

375

374

373

372

371

370

369

368

367

366

365 364 363 Table 2.1 (cont’d)

Groshong etal 2010 etal Groshong

Thomas 2011 Thomas

Powell etal 1994 etal Powell

Arbenz 2008 Arbenz

inferred in Black Warrior Basin Warrior Black in inferred

American craton American

marks the S edge of the North North the of S edge the marks

small faults trending N and E N and trending faults small

inferred from seismicity, multiple multiple seismicity, from inferred

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

in Arkoma basin Arkoma in

interpreted using cross sections sections cross using interpreted

active today active

unknown

NW-SE

NE-SW

E-W

transform

Oklahoma-Alabama Oklahoma-Alabama

Zone

East Tennessee Seismic Seismic Tennessee East

normal fault normal

fault

inferred basement basement inferred

fault

inferred basement basement inferred

normal fault normal

392

391

390

389

388

387

386 385

Table 2.1 (cont’d)

Figure 2.1: Outline of the United States overlaid by existing digital contour data (in red), with a contour interval of 1000 ft.

Figure 2.2a: Georeferenced image of the Precambrian Structure Map of North Dakota (Heck 1988).

Figure 2.2b: Precambrian contours (in blue) drawn over the georeferenced Precambrian Structure Map of North Dakota, with contour interval of 1000 ft.

Figure 2.3: Outline of the United States showing depth to the Precambrian basement contours; contours in red are measured in feet and have a 1000 ft contour interval, and contours in blue are measured in meters and have no set contour interval.

Figure 2.4: Topo-to-Raster image of the Precambrian basement in the United States, with darker areas representing basins and lighter areas representing domes and arches.

Figure 2.5: Second version of the Precambrian surface map of the United States, with the Hillshade raster overlying Topo-to-Raster image (see Figure 2.4).

Figure 2.6: Final version of the shaded relief map of the Precambrian surface, with the following overlays: Cordillera, Appalachians, and Ouachitas in purple, coastal plain in yellow, and Precambrian outcrops in red.

Figure 2.7: A 3-D perspective of the Precambrian shaded relief of the Midcontinent. Basin in foreground is the Arkoma basin.

Figure 2.8: Overlay of all of the faults and folds collected in the study. Not all of the faults and folds reach the Precambrian.

Figure 2.9: The final fault and fold map, showing the major faults and folds known to interact with the Precambrian basement (in black).

Figure 2.10: United States outline map with overlays of ‘Precambrian Outcrops’ (in red) and ‘Rift Areas’ (in green): MCR=Midcontinent Rift system, OA=Oklahoma Aulacogen, RF= Reelfoot Rift, RCG=Rough Creek Graben, RT=Rome Trough, and BBG=Birmingham Basement graben.

Figure 2.11: United States outline map overlain by the ‘Domes and Basins’ shapefile: AB=Appalachian Basin, AnB=Anadarko Basin, ArB=Arkoma Basin, BWB=Black Warrior Basin, IB=Illinois Basin, MB=Michigan Basin and WB=Williston Basin.

— CHAPTER 3 —

OBSERVATIONS

______

3.1 Observations of the Shaded Relief Map

An initial examination of the shaded-relief map of the basement topography in the

Midcontinent reveals that the subsurface elevation the Great Unconformity varies significantly.

The central Midcontinent is a broad, low-relief surface, whereas the southern and eastern edges of the Midcontinent have substantial structural relief. For example, the elevation of the basement surface in the St. Francis Mountains in the Ozark Plateau is up to 500 m above sea level, whereas the same surface in the southern end of the Illinois Basin, 100 km to the east, is as much as 7 km below sea level. Thus, there is locally up to 7.5 km of structural relief on this surface in the

Midcontinent. Comparison of the Midcontinent to other sectors of the cratonic platform (namely, the Rocky Mountains and the Colorado Plateau) indicates that the Midcontinent does have a different character. In this chapter, I will discuss details of the shaded relief map, considering each of the four sectors of the map (the Rocky Mountains; the Colorado Plateau; the

Midcontinent region; and the ‘bordering basins’) separately (Fig. 3.1).

The Rocky Mountains Sector: The Precambrian basement underneath the Rocky

Mountains shows evidence of intense episodes of past tectonic activity. Many of the high, elongate (50 to 200 km long by 20 to 50 km wide) ranges are cored by Precambrian rocks brought up on reverse faults (e.g., Yonkee and Mitra, 1993), some of which are exposed at elevations of up to 4.4 km above sea level. Between the ranges are basins that are down to 6 km deep, creating extreme structure relief on the Great Unconformity over a relatively short

horizontal distance. In this region, the amplitude is high (about 10 km) and the wavelength, or distance between uplifts, is relatively short (80 to 200 km). Notably, trends of ranges and intervening basins occur in different orientations (north-south, west-east, and northwest- southeast). The intensity of deformation of the basement, as indicated by structural relief and relatively short distances between ranges, is greatest in Wyoming and Colorado, or the Laramide

Rocky Mountain province. The distance between Precambrian surface uplifts increases north of

Wyoming and south of Colorado.

The Colorado Plateau Sector: The Colorado Plateau of Arizona, Utah, New Mexico, and Colorado lies south and west of the Rocky Mountains. Precambrian topography of the

Plateau differs significantly from that of the Rocky Mountains in that the Plateau’s Precambrian surface displays relatively subdued structural relief, with gentler gradients of the surface. The region contains monoclinal folds related to subsurface fault reactivation (e.g., Huntoon 1993), but these are significantly smaller in amplitude (less than 1 km) than those of the Rocky

Mountains Province. The magnitude of structural relief appears to decrease progressively to the south, toward the Mogollon Highlands of central Arizona, but the lack of structural relief may be an artifact of lack of data.

The Midcontinent Sector: The basement surface in the interior of the Midcontinent region is relatively smooth. In general, transitions between high areas (arches and domes) and low areas (basins) occur relatively gradually, in that the distance between the centers of large intracratonic basins (e.g., the Williston, Michigan, and Illinois basins) are on the order of 500 to

1000 km. Also, intracratonic basins of the Midcontinent are relatively equant (i.e., circular to slightly elliptical) in comparison to elongate (very elliptical) basins of the Rocky Mountain province. Notably, the Williston and Michigan basins are spoon-shaped structures, and the slope

of the basin surface from the margin of the basin to the interior is very gradual (e.g., a vertical change of 3 km over a distance of 150 km for the Michigan Basin, in comparison to the Bighorn

Basin in which the basement depth changes by about 10 km over a horizontal distance of 80 km.

The basement topography map emphasizes that, of the intracratonic basins in the Midcontinent, the Illinois basin appears to be unique, in that its character changes from north to south—the northern portion of the basin is a broad, spoon-shaped depression, whereas the southern end is a relatively narrow fault-controlled rift (the Rough Creek graben).

Through most of the Midcontinent (e.g., in Michigan, Wisconsin, Iowa, North Dakota,

South Dakota, Indiana, Kansas, and Nebraska), the basement surface has low-relief, locally cut by steps that are associated with recognized major faults (Fig. 3.2). For example, the

Proterozoic-age (1.1 Ga) Midcontinent Rift system visibly extends from Minnesota to Kansas.

This feature, despite originating as an extension-related graben, now appears as a positive feature on the shaded-relief map because its bordering normal faults were inverted during the Paleozoic to become reverse faults that thrust Precambrian rocks up relative to bordering Paleozoic cover.

The Nemaha Ridge (or uplift) clearly appears as a fault-controlled step in the basement that, at its north end, intersects the Midcontinent rift. The Ozark Plateau appears on the shaded-relief map as a rectilinear feature whose northeast corner has been relatively uplifted. Another notable feature within the Midcontinent region is the Manson impact structure in central Iowa, which affected the Precambrian surface, producing a central peak in the center of a circular depression.

The ‘Bordering Basins’ Sector: The shaded relief map emphasizes that relatively narrow, elongate basins (400 km long by 100 km across) border the southern and eastern part of the Midcontinent region. In effect, these basins define a chain that outlines the Midcontinent

Sector. In order from southwest to northeast, they are: the Permian basin of the Texas/New

Mexico border, the Anadarko Basin of Oklahoma, the Arkoma Basin of the Oklahoma and

Arkansas, the Reelfoot Rift of eastern Arkansas and southeast Missouri, the Rough Creek

Graben of western Kentucky, and the Rome Trough, which extends from eastern Kentucky, across West Virginia and Pennsylvania. These basins are locally very deep (up to 7.5 to 10.5 km), and their borders are relatively steep (7 to 10 km of relief over a horizontal distance of 100 km). Published studies indicate that the basins are bordered by and/or incorporate normal faults, some of which have been inverted.

Along the foreland edge of the Appalachians, a second set of basins, parallel to the

Reelfoot Rift, has formed. This set includes the Birmingham Basement Graben of northern

Alabama (Thomas and Bayona 2005), and the interior portion of the Appalachian basin. The

Birmingham Basement Graben and the Reelfoot Rift together outline a crustal block spanning

Tennessee, and northern Alabama and Mississippi, that appears to have started separating from the Midcontinent Sector, but did not succeed. This block is bounded on the southwest by the

Oklahoma-Alabama transform (Thomas 2011). The Black Warrior Basin, which is a triangular- shaped basin in Mississippi and Alabama at the southeastern corner of this block, differs from the other ‘bordering basins’, in that its border has a relatively gentle gradient that slopes towards the Gulf of Mexico.

Notably, some of the bordering basins lie adjacent to uplifts where Precambrian rocks are locally exposed at the surface. Two examples of this occurring are the Ozark Plateau, which lies adjacent to the Illinois basin, and the Wichita-Arbuckle Mountains, which lies adjacent to the

Anadarko basin (see Figure 3.2). Also of note, some of the basins (e.g., the Arkoma and

Appalachian basins) lie adjacent to thrust belts, suggesting that some of their subsidence reflects

loading by the emplacement of thrust sheets. In other words, their great depth may reflect the superposition of thrust-related subsidence on prior rift-related subsidence.

3.2 Observations of Structures, Based on the Attribute Table and Fault/Fold Map

To provide constraints on the orientation and location of faults and folds in the cratonic platform, I collected data on the structures from the literature and compiled them into an attribute table, using an Excel spreadsheet (see Table 2.1). The level of detail concerning the structures varies significantly. Many of the structures exist in the subsurface, so direct measurements on fault dip, sense of slip and displacement amount is not available. In some cases, the dip-slip component can be estimated based on structure-contour maps, and in some cases, by study of seismic-reflection profiles.

I classified the structures, based on their character, into 14 types. Specifically, I refer to structures that are known only from subsurface data as "inferred basement faults", of which the type of structure or the sense of slip on that structure is not well known. I estimate approximately 20% to 30% of the structures involved both faulting and associated folding. If the fault has known normal-sense displacement, it is classified as a ‘normal fault’, and if it has known reverse-sense displacement, it is classified as a "reverse fault". Steep faults on which the sense of slip is not known are called simply ‘high-angle faults.’ I have also distinguished between left-lateral and right-lateral strike slip faults, suture zones, and shear zones. ‘Suture zones’ are structures that formed due to two or more Proterozoic terranes or crustal blocks colliding together.

A plot of fault traces on the map (see Fig. 2.9), indicates that Midcontinent faults and folds cluster, defining distinct fault-and-fold zones. The distribution of faulting that appears on

the map could reflect, to some extent, lack of data. But more likely, it indicates that the

Midcontinent consists of relatively intact blocks bounded by fault-and-fold zones. Fault length on the map varies. The longest faults are tens to hundreds of kilometers long, but some faults are only a few kilometers long.

I measured the map trends of the structures in order to determine if there are dominant trends of the structures in the Midcontinent, as had previously been suggested by previous authors (e.g., Marshak and Paulsen, 1997; Marshak et al., 2003). I then used the StereoNet8 software to produce four rose diagrams for each group of structures (Almendinger et.al. 2013,

Cardozo and Almendinger 2013). The first group of structures involves the categorized normal, reverse, thrust, high angle thrust, high angle normal, and high angle faults. This first rose diagram, shown in Figure 3.3, shows two dominant trends in the NE and ENE directions. There are also three notable trends that should be mentioned, which are in the NNE, NW, and WNW directions. The second group of structures involves the designated strike slip faults, transform faults, shear zones, and suture zones. Figure 3.4 reveals two dominant trends (NW and WNW), and two notable trends (NE and ENE). The third group of structures includes the folds identified in the study, involving anticlines, synclines, and monoclines. Two dominant trends that are visible in this fold group (shown in Fig. 3.5) are in the NNW and NNE directions. The final group of structures includes the ‘inferred basement faults’, which have two dominant trends in the NW and WNW directions and two notable trends in the NNE and NNW directions (Fig. 3.6).

Figure 3.1: Precambrian shaded relief map of the United States, with an overlay of the four domains described in Chapter 3: the Rocky Mountain Sector, the Colorado Plateau Sector, the Midcontinent Sector, and the Bordering Basins Sector.

Figure 3.2: Precambrian shaded relief map of the Midcontinent, with overlays of the Cordillera, Appalachians, and Ouachitas in purple, the coastal plain in yellow, and Precambrian outcrops in red. MIS=Manson Impact Structure, MRS=Midcontinent Rift System, NR=Nemaha Ridge, and WM=Wichita Mountains.

Figure 3.3: Half-Rose Diagram of the normal, reverse, high angle, and thrust faults, showing the dominant trends (NE and ENE trends) and the notable trends (WNW, NW, and NNE trends).

Figure 3.4: Half-Rose Diagram of the strike slip faults, transfer faults, suture zones, and shear zones, showing the dominant trends (NW and WNW trends) and the notable trends (NE and ENE trends).

Figure 3.5: Half-Rose Diagram of the folds (anticlines, synclines, and monoclines, showing dominant trends in the NNW and NNE directions.

Figure 3.6: Half-Rose Diagram of the inferred basement faults, showing dominant trends in the NW and WNW directions and notable trends in the NNW and NNE directions.

— CHAPTER 4 —

DISCUSSION AND CONCLUSIONS ______

4.1 General Statement

The shaded-relief map of the Great Unconformity (i.e., on the top of the Precambrian basement surface) provides a fresh image accentuating tectonic features and crustal character in the Midcontinent. While the features that it shows have been recognized for decades, the visualization emphasizes relationships that do not stand out so clearly in conventional depictions of the basement top surface. In particular, is emphasizes that:

• The Midcontinent Sector is, overall, a coherent crustal block. It is delineated on the west by

the Rocky Mountain front, and on the south and east by rift basins, some of which have been

pushed down to greater depth by subsequent thrust-loading. The pattern of rifting stands out

on the map, and supports the hypothesis that during the Proterozoic separation of Laurentia

from Pannotia, a set of failed rifts formed inboard of the ultimately successful rift.

• In the Midcontinent Sector, basement topography is not controlled by the position of

Proterozoic sutures. Specifically, comparison of the Whitmeyer and Karlstrom map (see Fig.

1.2) with the basement topography map shows that there is little if any correlation between the

major Precambrian province boundaries and basement topography. This implies that sutures,

whose development is accompanied by prograde metamorphism and associated

recrystallization, do not behave as long-lived weaknesses.

• Proterozoic rifts do influence basement topography in the Midcontinent Sector. This is evident

by the structural relief associated with the Midcontinent Rift, the Nemaha Ridge, and the major

basins bordering the Midcontinent block. Therefore, the normal faults generated by rifting do

remain as long-lived weaknesses as suggested by Marshak et al. (2003). The dilation during

normal faulting may provide access of water to mid-crustal rocks, leading to retrograde

metamorphism and the production of weak phyllosilicates (e.g., chlorite); these zones have

never annealed.

• The distance between sedimentary basins in the Midcontinent Sector and the gentle slope

gradients of basement leading into the basins contrasts markedly with that of the Rocky

Mountain Sector, but is not that different from the Colorado Plateau Sector. Clearly, the crust

of the Rocky Mountains region has behaved differently than other regions of cratonic platform

crust during convergent tectonism. Specifically, the Laramide shortening of the Rocky

Mountains Sector had significantly different consequences than the Alleghanian shortening of

the Midcontinent block. This either reflects the difference between the consequences of

shallow subduction and the consequences of continental collision, or a difference between the

character of the crust of the two regions prior to shortening.

• The Bordering Basins on the south and east of the Midcontinent Sector are discontinuous, in

that they are separated along strike by distinct crustal bridges of unrifted crust between them.

4.2 Implications of the Shaded-Relief Map to Interpreting Intraplate Seismicity

Using data collected from the U.S. Geological Survey, I constructed a shapefile showing the most recent earthquake epicenters (from January 1979 to April 2013) throughout the cratonic platform. To emphasize the spatial distribution of events, rather than the energy release by cumulative earthquakes in an area, all epicenters are shown by the same dot size. I overlaid the earthquake epicenter shapefile over the shaded relief map to see if any correlation exists between epicenter distribution and basement structure (Fig. 4.1). The map clearly shows that the vast

majority of events occur in the Bordering Basins Sector. Relatively few events occur in the

Midcontinent Sector. Those events that do occur in the Midcontinent Sector appear to be aligned in semi-distinct zones that generally do not coincide with known basement-penetrating faults.

The three areas with the greatest concentration of earthquake epicenters (i.e., areas with the most seismicity) are in central Oklahoma, in the New Madrid seismic zone/Reelfoot Rift area, and in the East Tennessee seismic zone. The central Oklahoma seismic zone coincides with several major faults (e.g., the Central Oklahoma fault zone and the Meers/Criner fault system). The Central Oklahoma fault zone, which trends north-south, appears to be the southern extension of the Nemaha uplift and delineates the steep gradient in basement topography at the western edge of a crustal bridge between the Arkoma and Anadarko basins. Both the Criner and

Meers faults trend northwest-southeast and lie in the deepest part of the Anadarko basin. The

New Madrid seismic zone in the Reelfoot Rift occurs in the eastern boundary of the western

Tennessee crustal block, and appears continuous with a line of seismicity that extends northeast to Lake Ontario. The zone also coincides with the steepest gradient in the slope of the basement surface. The difference in Precambrian topographic relief from the deepest part of the Illinois basin to the top of the Ozark Plateau is about 7.5 km. This is also the area where the Precambrian topography is very steep, although the faulting patterns are not well known. The East Tennessee seismic zone, in contrast, does not appear to correlate with a steep basement gradient. In fact, structure associated the East Tennessee seismic zone is relatively subtle; the zone follows the trend of the New York-Alabama Lineament (Powell et.al., 1994).

Notably, there are distinct gaps in seismicity within the Midcontinent region, even in places where there are faults. One example is the central part of the Arkoma basin, which is the region that lies between central Oklahoma and the New Madrid seismic zones. According to

cross-sections and maps of this region (Arbenz, 2008; Csontos et.al., 2008), an extensional fault system exists in the subsurface. Another example lies between the Rough Creek Graben and the

Rome Trough, in central Kentucky. This area is a crustal bridge between the two rift systems, and contains the Grenville suture. Using information from Hickman (2011), I have extended the rift-bounding faults to connect the two rift systems.

4.3 Implications of the Shaded Relief Map to Interpreting Crustal Inhomogeneities

Both gravity and magnetic anomaly maps provide insight into crustal differences within a region. The use of both of these maps can help to identify small-scale and large-scale structures, in the subsurface and at the land surface. Comparing the gravity and magnetic anomaly maps to the Precambrian basement shaded-relief map can enhance interpretation of where basement structures are located and possibly how they are derived. Gravity maps, in particular isostatic gravity maps, provide images of mass anomalies within the crust—where positive gravity anomalies occur, there is an excess in mass, and where negative gravity anomalies occur, there is a deficit in mass. Figure 4.2 compares the isostatic gravity map of the United States to the shaded-relief map of the basement top surface, and reveals clear correlations. For example, the

Midcontinent Rift System and the Meers/Criner faults appear as a strong positive anomaly relative to the surrounding area. Another example is the western part of the Arkoma basin, which is a strong negative anomaly in the isostatic gravity map.

Magnetic anomaly maps can highlight areas where rocks contain a relatively large or relatively small concentration of magnetic minerals. A comparison between the magnetic- anomaly map and the shaded-relief map of the basement top surface is shown in Figure 4.3.

One clear positive anomaly in the magnetic map is a portion of the Midcontinent Rift System

(from Minnesota through Iowa).

4.4 Conclusions

The construction in ArcGIS of a 3-D shaded relief map of the Great Unconformity, and of faults and folds, in the cratonic platform is challenging because the data necessary to produce these maps is not easily accessible, and occurs in a variety of different forms. The maps provide useful insight into architecture of regional-scale structures and suggest relationships among the

Precambrian basement topography, faulting, and seismicity. Specifically, the shaded-relief map emphasizes that the cratonic platform includes distinct sectors that differ from one another in terms of structural relief, gradients in the slope of the basement surface, and the wavelength of uplifts and basins. The map of fault-and-fold zones emphasizes that the structures are not randomly oriented, but concentrate in distinct sets. Comparison of the maps to the distribution of earthquake epicenters emphasizes that most seismicity of the cratonic platform east of the Rocky

Mountain front concentrates in the rift-controlled basins that lie along the southern and eastern margins of the low-relief Midcontinent sector.

Figure 4.1: Precambrian shaded relief map of the Midcontinent showing earthquake epicenters (red circles). ETSZ=East Tennessee Seismic Zone and NMSZ=New Madrid Seismic Zone.

Figure 4.2: Comparison of an Isostatic Gravity map (above) to the Precambrian shaded relief map (below).

Figure 4.3: Comparison of a magnetic map (above) to the Precambrian shaded relief map (below).

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