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Full-Text Articles in Earth Sciences

Deposition, Diagenesis, And Porosity Development Of The Middle Devonian, Lucas Formation In The West Branch Oil Field, Ogemaw County, Michigan, Scott Gregory Park Dec 1987

Deposition, Diagenesis, And Porosity Development Of The Middle Devonian, Lucas Formation In The West Branch Oil Field, Ogemaw County, Michigan, Scott Gregory Park

Masters Theses

The Lucas Formation in the West Branch Oil Field contains over 1000 feet of carbonates and evaporites deposited in restricted marine environments. Deposition ranged from a tidal flat environment (Richfield Member) to subaqueous basin central type deposition (Iutzi and Horner Members).

Early diagenesis of the Lucas Formation carbonates included dolomitization and related porosity development in certain depositional facies where physiochemical conditions were favorable. Significant porosity and permeability reduction occurred during burial resulting from anhydrite, celestite, and halite cementation. Calcite pseudopar and microspar (a neomorphic product) also reduced porosity.

Hydrocarbon production from the Lucas Formation in the West Branch Field is …


Possible Role Of Petroliferous Materials In Sulfide Precipitation At The Frank R. Millikan Mine, Southeast Missouri, Clark Alan Niewendorp Aug 1987

Possible Role Of Petroliferous Materials In Sulfide Precipitation At The Frank R. Millikan Mine, Southeast Missouri, Clark Alan Niewendorp

Masters Theses

The Millikan Mine's ore body contains ubiquitous amounts of petroliferous materials occurring as blebs, coal-like pods and veinlets, and seeps coating mine stope walls. Emplacement of hydrocarbons into the ore occurred before the final episode of mineralization ceased, based on growth of dendritic galena in some coal-like bitumen and other paragenetic relationships. Growth of dendritic galena in a hydrocarbon substance suggests that hydrocarbons provided sulfur for galena mineralization by either abiogenetic reduction of sulfate or thermochemical evolution of organic sulfur. Texturally, it also suggests that the presence of hydrocarbons may have been responsible for some zones of rapid precipitate mineralization. …


A Thermodynamic Study Of The Zeolite Stilbite, David Adams Howell Aug 1987

A Thermodynamic Study Of The Zeolite Stilbite, David Adams Howell

Masters Theses

Stilbite is a calcium-rich zeolite found in low-grade metamorphic and hydrothermally altered environments. In this study, measurements of the enthalpy of formation at 298.15 K, heat capacity from 5 to 350 K, and enthalpy increments horn 350 to 500 K were performed on a specimen of stilbite characterized by electron microprobe analysis. The actual formula of the stilbite is: Ca1.019Na0.136K0.006Al2.180Si6.820O16 . 7.33H2O. Evaluation of the thermodynamic properties for stilbite at T = 298.15 K produced the following values: ΔrHOm(T)= -11034.6+6.6 kJ . mol …


Nitrate Pollution Of Ground Water In Glacial Sediments Underlying A Fertigated Site In Kalamazoo County, Michigan, Michael Wireman Aug 1987

Nitrate Pollution Of Ground Water In Glacial Sediments Underlying A Fertigated Site In Kalamazoo County, Michigan, Michael Wireman

Masters Theses

In the central part of Schoolcraft Township high yield corn crops are successfully grown on soils developed on permeable outwash deposits. The high yields are made possible with the utilization of modern irrigation techniques and regular application of nitrogen fertilizer.

Excess nitrogen which moves past the root zone is easily converted to nitrate and leached to the shallow ground water. Water quality data from 103 ground-water samples in the vicinity of a 160-acre corn field in Section 11 clearly indicate that nitrate concentrations in the ground water beneath the field and beneath the area immediately downgradient from the field are …


Structural Geology And Geothermal Investigation Of The White Sulphur Springs Area, Montana, William G. Gierke Apr 1987

Structural Geology And Geothermal Investigation Of The White Sulphur Springs Area, Montana, William G. Gierke

Masters Theses

Sevier thrusting in the White Sulphur Springs area was associated with left-lateral movement along the Lewis and Clark line . During Middle Miocene time, the Lewis and Clark line exhibited right-lateral movement, forming extensional features that either truncated Sevier structures or followed preexisting Sevier zones of weakness.

The Smith River Valley is a pull-apart basin that is filled with Tertiary volcanic ash and clay-rich sediments that are thermally nonconductive relative to surrounding rocks.

Hydrothermal activity in the area is associated with a structurally controlled circulation system accompanied by a high thermal gradient. Thermal discharge is constrained along the north-trending White …


The Effect Of Well Efficiency On In-Situ Permeability Test Results, Scott T. Dennis Apr 1987

The Effect Of Well Efficiency On In-Situ Permeability Test Results, Scott T. Dennis

Masters Theses

The purpose of this study was to determine what effect well efficiency has upon the results of in-situ permeability tests.

Several in-situ permeability tests were performed on wells during various stages of their development. The well efficiency was determined each time an in-situ test was performed. An accurate value of permeability was determined by performing local aquifer pumping tests. The accuracy of the results of the in-situ tests with respect to the aquifer pump test results were then compared to the efficiency of the well at the time of the test.

Test results showed that a linear relationship exists between …


Lithofacies Analysis Of The Lamotte Sandstone In South Central Missouri, Michael Gerard Kraenzle Jan 1987

Lithofacies Analysis Of The Lamotte Sandstone In South Central Missouri, Michael Gerard Kraenzle

Masters Theses

"Based on the analysis of thirty-one cores obtained from the Missouri Department of Natural Resources in Rolla, the upper Cambrian Lamotte Sandstone in South Central Missouri has been divided into six sedimentary facies ranging from alluvial fan and braided stream to open marine.

The Lamotte Sandstone is the basal Cambrian sandstone found throughout most of the state of Missouri. It directly overlies late Precambrian (1.4 to 1.5 billion year old) granites and metasediments. The Lamotte and overlying Bonneterre Formations are generally considered to have been deposited by a transgression which occurred during the Late Cambrian Period (Croixian Epoch).

The Lamotte …


A Petrographic Investigation Of The Rhythmically Bedded Upper Fayetteville Formation (Mississippian) In Northern Arkansas, Edith Ann Starbuck Jan 1987

A Petrographic Investigation Of The Rhythmically Bedded Upper Fayetteville Formation (Mississippian) In Northern Arkansas, Edith Ann Starbuck

Masters Theses

"The upper Mississippian Fayetteville Formation in northern Arkansas is primarily a calcareous black shale, but in some localities the upper one third to one half of the formation is made up of alternating black shales and limestones. Comparable lithologies have been suggested by some (Hallam, Ricken, Kent, and Sujkowski) to have been created by the diagenetic segregation of carbonate from calcareous shale.

Petrographic thin section analysis reveals that the lowest limestone beds of the rhythmic upper Fayetteville are made up almost entirely of microspar and all fossil material is recrystallized, even to the point of obliteration in some cases. The …


A Gravity And Magnetic Study Of The Crooked Creek Cryptoexplosion Structure, Crawford County, Missouri, Charles Edward Woodbury Jan 1987

A Gravity And Magnetic Study Of The Crooked Creek Cryptoexplosion Structure, Crawford County, Missouri, Charles Edward Woodbury

Masters Theses

"The pre-Pennsylvanian structure at Crooked Creek consists of a complex, vertically faulted ring of Cambrian and Ordovician sediments with a central uplifted core. The center of the structure is strongly deformed and contains shatter cones, brecciation, and other signs of extreme shock.

A magnetic low over the center of the structure suggests that igneous material was not involved in the formation of the structure, and this is corroborated by core analysis. Gravity data indicates several small gravity lows, possibly associated with areas of brecciation, circling the flanks of the structure. As in the magnetic data, there is no indication that …


A Paleoenvironmental Study Of The Salem Limestone In The Vicinity Of St. Louis, Missouri, Douglas J. Van Brunt Jan 1987

A Paleoenvironmental Study Of The Salem Limestone In The Vicinity Of St. Louis, Missouri, Douglas J. Van Brunt

Masters Theses

“The Salem Limestone (Meramecian) of Mississippian age in the vicinity of St. Louis, Missouri is composed of a variable sequence of limestones deposited in shallow waters adjacent to scattered positive elements. This unit varies in thickness from zero up to 160 feet.

A medium to coarse-grained calcarenite is the dominant rock-type of the thesis area and is most abundant in the central and southwest regions. Stratigraphic sections in the northern region are more dolomitic, increasingly brecciated, and contains numerous secondary features. The southeast region is thinly bedded and composed of greater amounts of micrite formed by algal activity or direct …


A Hydrogeologic Investigation Of The Balkema Wetland, Daniel V. Fronczek Dec 1986

A Hydrogeologic Investigation Of The Balkema Wetland, Daniel V. Fronczek

Masters Theses

The Balkema wetland, located In southwestern Kalamazoo County, Michigan, represents complex biological and hydrologic Interaction between surface water and a two-aquifer hydrologic system. Situated on the southeastern flank of the Kalamazoo moraine, the glacial geology of the area plays a key role in the understanding of the hydrogeologic function of the wetland. A two-aquifer system, an upper unconfined, and a lower confined, Interact In the vicin ity of the wetland where the c la y /till aqulclude dividing the two systems 1s absent. Various parameters, both hydrologic and geochemical, were measured In the study area, Including specific conductance values of …


A Structural Investigation Of A Basement-Involved Thrust System In Southern Sphinx Mountain Quadrangle (Madison Range) Southwestern Montana, Jeffrey Scott Brown Aug 1986

A Structural Investigation Of A Basement-Involved Thrust System In Southern Sphinx Mountain Quadrangle (Madison Range) Southwestern Montana, Jeffrey Scott Brown

Masters Theses

The Madison Range is the eastern limb of the Laramide Rocky Mountain foreland Madison-Gravelly Arch. The main segment of the Madison thrust system in the map area is the basement-involved Scarface thrust which dips westward, trends north-northwest, and places Archean rocks onto an overturned footwall of Cambrian through Cretaceous rocks. Foliation of Archean rocks in the footwall is folded with overlying sedimentary rocks.

The Shedhorn Mountain thrust splays from the Scarface thrust. It is exposed north and south of the Shedhorn Mountain anticline, but is blind beneath it. The Taylor fault, an east-dipping back thrust, is inferred to be associated …


Hydrodynamic Character Of The Dundee Limestone In The Central Michigan Basin, Ann Carol Little Aug 1986

Hydrodynamic Character Of The Dundee Limestone In The Central Michigan Basin, Ann Carol Little

Masters Theses

The Middle Devonian Dundee Limestone underlies most of the Lower Peninsula of Michigan. A potentiometric surface constructed of the formation, utilizing pressure data was compared to local and regional structure, permeability trends, specific gravity of the brines, oil accumulations, and surficial topography.

The data were distributed mainly in the central basin area, with information becoming more sparse around the basin margins. This created difficulties in the determination of the extent of control imparted by each of the factors, in flow direction. Surficial topography, on a regional scale, is likely the most influential of the controls, with the Dundee Limestone brines …


Stratigraphic And Sedimentologic Analysis Of The Middle Devonian Filer Sandstone, John Charles Rodwan Aug 1986

Stratigraphic And Sedimentologic Analysis Of The Middle Devonian Filer Sandstone, John Charles Rodwan

Masters Theses

The Filer Sandstone, a multistory assemblage o£ lenticular sand bodies, is a member of the Middle Devonian Amherstburg Formation of the Detroit River Group in the subsurface of the western and central portion of the Michigan Basin. It is distinguished from the reworked eolian and nearshore marine sand facies of the underlying Sylvania Sandstone by recognition of its barrier island facies relationships and stratigraphic position within enclosing carbonates unique to the Amherstburg Formation. Lithologically, the Filer ranges from a fine-grained, carbonate-cemented, supermature quartzarenite at its upper shoreface facies, to a texturally-inverted sandy carbonate at its lagoonal facies. Facies distribution was …


An Evaluation Of The Effectiveness Of Bentonite As A Soil Additive For The Cover Material On The Kl Avenue Sanitary Landfill, Kalamazoo, Michigan, Neal J. Carey Apr 1986

An Evaluation Of The Effectiveness Of Bentonite As A Soil Additive For The Cover Material On The Kl Avenue Sanitary Landfill, Kalamazoo, Michigan, Neal J. Carey

Masters Theses

A principle objective of using bentonite as a soil additive is to reduce the permeability of a cover material, thus, inhibiting the infiltration of surface waters at landfill sites.

Twenty-two cores of the KL landfill were taken to obtain in-situ soil columns for testing. Coefficients of permeability were calculated for each soil column using the falling-head permeameter. Mechanical and hydrometer analyses were used for the grain size analysis. The methylene-blue test was employed to determine the actual percentages of bentonite present in each soil column. X-ray diffraction work was done on the clay fraction of each soil column to verify …


Facies Development And Porosity Relationships In The Dundee Limestone Of Gladwin County, Michigan, Eric Lee Montgomery Apr 1986

Facies Development And Porosity Relationships In The Dundee Limestone Of Gladwin County, Michigan, Eric Lee Montgomery

Masters Theses

The Devonian of the Michigan Basin was a time of transgressive seas and extensive carbonate deposition including coral and stromatoporoid buildups. Deposited during the Middle Devonian, the Dundee Limestone represents deposition in subtidal, intertidal, and restricted environments. The Buckeye Oil Field, located in south-central Gladwin County, is a combined stratigraphic and structural carbonate trap which produces from a series of intertonguing patch reefs, fringing sand bodies, and "intertidal island" fenestral zones. The major reef building organisms include stromatoporoids, corals, calcareous algae, brachiopods, and crinoids, with the stromatoporoids providing the major framework. The patch reef facies is composed of massive stromatoporoid …


The Provenance Of The Jacobsville Formation Of The Upper Peninsula Of Michigan Through A Petrographic Study, David Walter Lindsay Apr 1986

The Provenance Of The Jacobsville Formation Of The Upper Peninsula Of Michigan Through A Petrographic Study, David Walter Lindsay

Masters Theses

The Upper Keweenawan Jacobsville Formation source areas were mixed source terranes with dominant terrane types changing regionally in relative abundances of sediment contribution. Dominant source terranes were older sediments, including a weathered soil zone, Upper Keweenawan Freda Sandstone and other recycled sandstones; plutonic Precambrian basement rocks;. Middle Keweenawan Portage Lake Volcanics; and the chlorite to staurolite grade metamorphic rocks and iron ranges of Michigan’s upper peninsula.

Depositional environments of the formation's four facies types range from fluvial to deltaic/lacustrine. Sediments were in transport for a short distance, resulting in grain freshness and angularity, moderate sorting and preservation of unstable sediments. …


Petrography, Diagenetic History, And Development Of Porosity In The Richfield Member Of The Lower Middle Devonian Lucas Formation, Northeast Isabella County, Central Michigan Basin, Kevin James Sullivan Apr 1986

Petrography, Diagenetic History, And Development Of Porosity In The Richfield Member Of The Lower Middle Devonian Lucas Formation, Northeast Isabella County, Central Michigan Basin, Kevin James Sullivan

Masters Theses

The Richfield Member of the lower Middle Devonian Lucas Formation is represented in the subsurface of northeast Isabella County, Michigan as a 180-foot-thick sequence of Interbedded limestone, dolomite and anhydrite. Richfield lithofacies within the study area reflect deposition in a complex patchwork mosaic of evaporative supratidal, in tertid al, shoal, and subtidal environments.

The present variations in Richfield porosities were caused almost entirely by post-depositlonal diagenetic changes. The carbonate units have undergone pervasive dolomltlzation of mud matrix, leaching of allochems, and extensive anhydrite void -fillin g . The best porosity developments are associated with partial to complete dolomitizatlon of the …


Geology Of The Escalante District, Iron County, Utah, James William Biehl Jan 1986

Geology Of The Escalante District, Iron County, Utah, James William Biehl

Masters Theses

"The Escalante Silver District, Iron County, Utah, occupies a group of low hills extending to the Escalante Desert from the Black Hills to the south. Tertiary volcanics serve as host rocks for silver bearing quartz veins. Five map units, with a total of 12 members are recognized. X-ray fluorescence and field mapping enabled differentiation of the units, while thin section analysis enabled characterization of the members. The map units formed in three episodes. The oldest is extrusive doming of distinctive older lava and breccia flows. The middle group is made up of tectontic breccias, sillar-like lava flows, and volcaniclastic sediments …


The Response Of The Kentucky River Drainage Basin To A Lowering Of Base Level Control, David B. Warwick Dec 1985

The Response Of The Kentucky River Drainage Basin To A Lowering Of Base Level Control, David B. Warwick

Masters Theses

The Kentucky River has responded to a lowering of base level control by: 1) deepening the course of its channel; 2) cutting off meanders as incision proceeded; 3) developing knickpoints on tributaries; 4) widening its valley; and 5) dissecting the upland surface.

Field work involved surveying streams to obtain profiles. Twenty streams covering 125 miles of river from Carrollton to Camp Nelson, Kentucky were surveyed. Knickpoints were defined from these profiles. Data from stream profiles showed knickpoint distances decreasing with increasing distance up river. Map work involved obtaining data for hypsometric curves. Hypsometric integrals were determined from these curves. Data …


Lithofacies And Geochemistry Of Interreef Carbonates, Middle Silurian, Michigan Basin, Eric N. Porcher Dec 1985

Lithofacies And Geochemistry Of Interreef Carbonates, Middle Silurian, Michigan Basin, Eric N. Porcher

Masters Theses

The Niagara Group of the Michigan Basin is composed of reef, interreef, and basinal carbonates. The Niagara Group interreef has herein been divided into several litho facies: algal-laminated dolomicrite, bioturbated dolomicrite, intraclastic dolomicrite, wispy-laminated dolomicrite, crinoidal micrite, and nodular micrite. These interreef carbonates show a shallowing upward sequence.

The geochemistry of the Niagara Group interreef was examined in an attempt to delineate any geochemical gradients with respect to reefs. The geochemistry of the inter reef was determined by Particle Induced X-Ray Emission (PIXE) analysis. No significant geochemical gradients were found to be associated with reefs. Reasons for this may include: …


The Use Of Electrical Resistivity To Delineate A Brine Contamination Plume In The Walker Oilfield, Kent County, Michigan, Kent E. Meisel Dec 1985

The Use Of Electrical Resistivity To Delineate A Brine Contamination Plume In The Walker Oilfield, Kent County, Michigan, Kent E. Meisel

Masters Theses

Contamination of groundwater with oil field brines was reported in the Walker Oil Field, Michigan. An electrical resistivity survey utilizing the Vertical Electrical Sounding method was conducted to test the method as an exploratory tool for delineating brine contamination in glacial deposits. The method was successful in defining the subsurface geology and delineating a shallow, confined aquifer, but the presence of extensive, conductive clays effectively masked the presence of brine contamination. The method was shown to be an effective exploratory tool for shallow investigations.


Subsurface Stratigrapy And Sedimentologic Control On The Productive Middle Devonian Age Richfield Member Of The Lucas Formation In The Michigan Basin, Sukru Nail Apak Aug 1985

Subsurface Stratigrapy And Sedimentologic Control On The Productive Middle Devonian Age Richfield Member Of The Lucas Formation In The Michigan Basin, Sukru Nail Apak

Masters Theses

The depositional system of the Middle Devonian Richfield Member of Lucas Formation in the Michigan Basin was delineated using well logs, cores, drillers' records, and the literature. The Richfield Member was deposited in Sabkha and lagoonal environments characterized by cycles of anhydrite, dolomite, and limestone. Seven significant productive dolomitic zones, interbedded with anhydrite and limestone can be correlated throughout the study area. These zones change laterally to anhydrite towards the west flank and to dense limestone towards the east flank of the basin. Post-depositional diagenetic history of the Richfield was established with the aid of scanning electron microscopy and electron …


A Seismic Study Of An Impact Feature In Cass County, Michigan, Mancheol Suh Aug 1985

A Seismic Study Of An Impact Feature In Cass County, Michigan, Mancheol Suh

Masters Theses

A geophysical investigation, including a seismic study, of the subsurface structure of the Calvin-28 oil field, Cass County, Michigan, indicates that the structure's origin may be related to an impact event. The structural closures in the time structure maps and drilling results both show a central uplift. The fault system in the Trempealeau Formation shows a structure similar to other proven astroblemes. Undisturbed layers just beneath the central uplift also provide evidence of an impact structure. The result of mathematical modeling of the central uplift under the assumption that the structure is an impact structure corresponds well with the drilling …


A Gravity Investigation Of Mountain Flank Thrusting And Normal Faulting, Madison And Tobacco Root Ranges, Montana, Stephen Thomas Wigger Aug 1985

A Gravity Investigation Of Mountain Flank Thrusting And Normal Faulting, Madison And Tobacco Root Ranges, Montana, Stephen Thomas Wigger

Masters Theses

Gravity modeling of west-dipping, Laramide mountain flank thrusts which involve Archean metamorphic rocks in the western Tobacco Root and northern Madison Ranges supports the idea that these thrusts are gently dipping.

The thrusts provided a favorable location for normal faulting during Neogene extension. The Neogene faults on the eastern portions of the Madison and Jefferson Basins are interpreted to be listric, and merge with the Laramide thrusts. Basin development occurred along a series of such faults, which dropped hanging wall blocks of the thrust sheets to progressively greater depths. The maximum depth of the Madison basin, near Ennis, was found …


Carbonate Facies Of The Kimmswick Limestone (Trenton/Galena) In Southwestern Illinois : Their Relations As Oil Reservoirs And Traps, Gregory A. Crews Jan 1985

Carbonate Facies Of The Kimmswick Limestone (Trenton/Galena) In Southwestern Illinois : Their Relations As Oil Reservoirs And Traps, Gregory A. Crews

Masters Theses

"Four potentially productive oil horizons have been identified in the Kimmswick Limestone (Trenton/Galena), Ordovician of southwestern Illinois. Four non-porous caprock zones and four porous horizons were identified and informally named after corresponding members of the Dunleith Formation (Illinois State Geological Survey classification). The porous horizons generally consist of coarse-grained, fossiliferous limestone, which is overlain by finer grained, spar-cemented, impermeable limestone.

In order of production potential, the horizons are the upper Moredock, lower Moredock, Beecher-St. James (lowermost stratigraphic unit), and New London (uppermost stratigraphic unit). Porosity in the upper Moredock horizon is relatively consistent throughout the study area, as determined by …


Hydrogeologic And Geochemical Factors Influencing The Impact Of A Chromium-Arsenic-Copper Wastewater Discharge On A Glacial Outwash Aquifer, Michael J. Gallagher Dec 1984

Hydrogeologic And Geochemical Factors Influencing The Impact Of A Chromium-Arsenic-Copper Wastewater Discharge On A Glacial Outwash Aquifer, Michael J. Gallagher

Masters Theses

A discharge of chromium-arsenic-copper laden wastewater occurred periodically from 1970 to 1980 at a wood preserving company located in southwestern Kalamazoo County, Michigan. As a result of this discharge, soils at the company site became contaminated with chromium, arsenic, and copper, and a local glacial outwash aquifer became contaminated with hexavalent chromium.

Soil samples collected from the discharge site were analyzed for clay-silt-sand-gravel content, organic matter, pH, clay mineralogy, and chromium, arsenic, copper, iron, and manganese content. Background soil samples were analyzed for most of the above catagories. Pearson r coefficients of correlation were calculated to determine the correlation of …


Uranium-Lead Zircon Ages And Crustal Contamination Of The Northeastern Idaho Batholith, James J. Dexter Dec 1984

Uranium-Lead Zircon Ages And Crustal Contamination Of The Northeastern Idaho Batholith, James J. Dexter

Masters Theses

The magmas which formed the northeastern Idaho batholith were contaminated with, or derived from, old crustal material as evidenced, from previous studies, by high whole-rock 87Sr/86Sr ratios, relatively high 207Pb/206Pb ages, and Archean to Proterozoic upper intercept ages for batholithic zircons.

The old zircon component has been identified in this study by separating zircons into fractions based on size and morphology. Pb/U isotopic ratios are distributed on a chord with a lower concordia intercept intrusive age of 73.6+6 m.y. Zircons from a batholithic sample located one kilometer inward from the contact were separated according …


The Depositional History Of The Point Pleasant Member Of The Cynthiana Formation In Northern Kentucky, Gary J. Stefaniak Dec 1984

The Depositional History Of The Point Pleasant Member Of The Cynthiana Formation In Northern Kentucky, Gary J. Stefaniak

Masters Theses

Bioclastic limestones, siltstones, and shales of the Point Pleasant Member were deposited in a shallow marine environment immediately below normal effective wave base. High-energy conditions produced by storms lowered the effective wave base and stirred the bottom sediments and redistributed them into bedforms. The different types of contacts, distribution of the faunal groups, and fabrics permit inferences regarding energy levels and assignment of samples to a mode of deposition. Vertical and lateral trends were then deduced. High-energy conditions are believed to have occurred during Early and Late Point Pleasant time, whereas, low-energy conditions prevailed during deposition of the middle Point …


Geology Of A Section Of The Northwest Tobacco Root Mountains, Madison County, Southwest Montana, Kiff James Samuelson Dec 1984

Geology Of A Section Of The Northwest Tobacco Root Mountains, Madison County, Southwest Montana, Kiff James Samuelson

Masters Theses

The northwest Tobacco Root Mountains are located on the boundary between two major tectonic provinces: the fold and thrust belt and the Rocky Mountain foreland. Deformation typical of the Rocky Mountain foreland is present in the form of two major northwest trending faults with associated folds. Paleozoic rocks were passively draped over at least one of the elevated Precambrian blocks. Foliation of the Precambrian rocks also appears to have been gently folded in the process.

Folds and thrusts occur within the Precambrian and Paleozoic rocks, on the westernmost flank of the range, appearing to follow the general trend of the …