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Articles 26701 - 26730 of 29719

Full-Text Articles in Physical Sciences and Mathematics

Plio-Pleistocene Stratigraphy And Tectonic Evolution Of The Northern Ohara Depression-Wakarara Range, North Island, New Zealand, Craig Fraser Erdman Jan 1990

Plio-Pleistocene Stratigraphy And Tectonic Evolution Of The Northern Ohara Depression-Wakarara Range, North Island, New Zealand, Craig Fraser Erdman

WWU Graduate School Collection

Development of the Ohara Depression and uplift of the Ruahine and Wakarara Ranges followed an increase of the convergence rate between the Pacific and Australian plates. The Ohara Depression is a trough of Plio-Pleistocene sediments that crops out between the Ruahine and Wakarara Ranges. Two episodes of uplift during the late Pliocene and Pleistocene are recorded in the geologic record. Initial uplift occurred in the late Pliocene followed by subsidence through the early Pleistocene. The greatest uplift occurred during the mid-Pleistocene, and is recorded by deposition of a 200-250 m-thick conglomerate unit. Although compressional structures are present within and to …


Strain And Volume Loss In A Second Order Buckle Fold, Central Appalachian Valley And Ridge, U.S.A., Michelle J. Markley Jan 1990

Strain And Volume Loss In A Second Order Buckle Fold, Central Appalachian Valley And Ridge, U.S.A., Michelle J. Markley

Honors Papers

Large scale thrusts and imbricates overlain by folded sedimentary strata characterize structure in the Valley and Ridge Province of the Central Appalachians. The Cambrian Waynesboro Formation is a decollement zone that detached an imbricated Cambro-Ordovician sequence from an unfaulted Pre-Cambrian basement. The Ordovician Martinsburg Shale is a second zone of major detachment that de-coupled the blind thrust system in the Cambro-Ordovician carbonates from the overlying orogenic wedge. Thus, the Central Valley and Ridge deformed during the late Paleozoic Alleghenian orogeny as a three tiered system consisting of the undeformed basement, the imbricated stiff layer, and the primarily folded cover layer. …


Analysis And Numerical Simulation Of The Ground Water System At The Bonneville Navigation Lock Site, Oregon, Dirk Baron Jan 1990

Analysis And Numerical Simulation Of The Ground Water System At The Bonneville Navigation Lock Site, Oregon, Dirk Baron

Dissertations and Theses

As part of the new navigation lock for Bonneville Dam a new water source for the Bonneville Fish Hatchery must be supplied. The hatchery is located on the Oregon side of the Columbia River downstream of the dam. It requires large quantities of water free from chemical and biological contamination. In addition, the water has to be in a narrow temperature range. Currently the fish hatchery receives its water from a well field that is located on the alluvial terrace downstream of Bonneville Dam. The well field lies in the proposed approach channel for the new lock and has to …


The Hydrogeologic Effects Of Fly Ash Utilization In Concrete At Coal Creek Station, Underwood, North Dakota, Terry R. Johnson Jan 1990

The Hydrogeologic Effects Of Fly Ash Utilization In Concrete At Coal Creek Station, Underwood, North Dakota, Terry R. Johnson

Theses and Dissertations

Coal Creek Station is a two-unit 1100 megawatt electrical power plant located in southern McLean county, North Dakota. Annually, 5 million tons (4.5 million metric tons) of lignite are burned at the plant producing 550,000 tons (500,000 metric tons) of fly ash. Approximately 80,000 tons (72,624 metric tons) of ash are sold as a cement replacement, while the remainder is disposed of in lined evaporation ponds. The present study investigates the environmental consequences of ash utilization as an alternative to disposal, The Electric Power Research Institute (EPRI) provided funding for this investigation which involves the installation of 5,288 cu yds …


Neogastropods (Melongenidae, Fasciolariidae, Turridae) From The Cannonball Formation (Paleocene: Thanetian), North Dakota And South Dakota, Brian E. Silfer Jan 1990

Neogastropods (Melongenidae, Fasciolariidae, Turridae) From The Cannonball Formation (Paleocene: Thanetian), North Dakota And South Dakota, Brian E. Silfer

Theses and Dissertations

The Cannonball Formation of Paleocene age is a shallow-marine, clastic sequence exposed primarily in southwest-central North Dakota and northwestern South Dakota. The formation is characterized by alternating, poorly consolidated, relatively thin sandstone and thick mudstone units. The Cannonball neogastropod families Melongenidae, Fasciolariidae, and Turridae contain 20 species assigned to 15 genera based on 334 individuals from 50 localities. Four genera, Alticollarum, Obtusicarina, Vitticoncha, and Ericksonia are new, whereas Serrifusus, Mesorhytis, Rhombopsis, and Deussenia are first reported occurrences from Tertiary strata. Marshallaria is newly reported from North America and likely from the Northern Hemisphere. Twelve species are additions to the Cannonball …


Depositional Environments And Sandstone Diagenesis In The Tyler Formation (Pennsylvanian), Western North Dakota, Larry R. Quandt Jan 1990

Depositional Environments And Sandstone Diagenesis In The Tyler Formation (Pennsylvanian), Western North Dakota, Larry R. Quandt

Theses and Dissertations

Thirty-three oil well cores were examined and approximately 3,100 oil well logs were used to determine the depositional environments of the Tyler Formation (Pennsylvanian) in northwestern North Dakota. Ninety sandstone thin-sections were described and twenty-nine sandstone samples were analyzed by scanning electron microscope/X-ray microanalysis techniques to characterize sandstone diagenesis.

The Tyler Formation in northwestern North Dakota is correlative with the lower unit of the Tyler Formation in southwestern North Dakota. The upper unit of the Tyler Formation in southwestern North Dakota is not present in northwestern North Dakota, contrary to previous workers suggestions. The Tyler Formation in northwestern North Dakota …


The Broom Creek Formation (Permian), In Southwestern North Dakota: Depositional Environments And Nitrogen Occurrence, Marvin E. Rygh Jan 1990

The Broom Creek Formation (Permian), In Southwestern North Dakota: Depositional Environments And Nitrogen Occurrence, Marvin E. Rygh

Theses and Dissertations

In North Dakota, the Broom Creek Formation (Wolfcampian> exists in the subsurface as the upper unit of the Minnelusa Group. The Broom Creek Formation consists of pink quartzarenite with some intervening dolostone beds. The identification of lithofacies, areal distribution, and stratigraphic relationships were determined from oil well logs, mainly the dual laterolog suite and the FDC-CNL log suite, and macroscopic and microscopic core analysis. were examined from four wells.

The major lithofacies identified are, 1) eolian Cores sandstone, 2) nearshore marine sandstone, and 3) marine carbonate. From the sandstone-dolostone distribution, marine predominance existed in the eastern part of the study …


Depositional Environments, Ichnology And Diagenesis Of The Upper Frobisher-Alida Beds Of The Elkhorn Ranch And Roughrider Fields Of Western North Dakota, Jeffrey R. Valvik Jan 1990

Depositional Environments, Ichnology And Diagenesis Of The Upper Frobisher-Alida Beds Of The Elkhorn Ranch And Roughrider Fields Of Western North Dakota, Jeffrey R. Valvik

Theses and Dissertations

The upper Frobisher-Alida interval of western North Dakota was studied in order to determine the depositional envirornnents, bioturbation features, and the diagenetic history of these carbonate and evaporite rocks.

Detailed examination resulted in the identification of six distinct lithotypes: 1) crinoid, coral packstone-wackestone (LT-1); 2) brachiopod, skeletal wackestone (LT-2); 3) skeletal, burrowed mudstone-wackestone; 4) intraclast, peloid packstone-grainstone; 5) peloid, intraclast, ostracode packstone-wackestone; 6) nodular and bedded anhydrite (LT-6). Lithofacies generally follow a depositional sequence of thick units of sublittoral carbonates, followed by a thin sequence of littoral carbonates, and culminating in a thick unit of sublittoral evaporites. Sublittoral rocks dominate …


Petrology And Provenance Of Miocene Sedimentary Rocks, Point Sur, California: Implications For Offset Along The San Gregorio-Hosgri Fault Zone, Mark Sutherland Dec 1989

Petrology And Provenance Of Miocene Sedimentary Rocks, Point Sur, California: Implications For Offset Along The San Gregorio-Hosgri Fault Zone, Mark Sutherland

Mark Sutherland

No abstract provided.


Geology Newsletter- 1989, Department Of Geology Dec 1989

Geology Newsletter- 1989, Department Of Geology

Geological and Environmental Sciences News

Vol.1, No. 14

  • Dear Alumni and Friends
  • Geology Development and Scholarship Donations
  • Faculty Briefs
  • News from the Support Staff
  • Geology Earth Science Club
  • Awards & Scholarships
  • 1989 Speakers Program


Regionalization Of Flood Data Using Probability Distributions And Their Parameters, Nageshwar Rao Bhaskar, Carol Alf O'Connor, Harold Andrew Myers, William Paul Puckett Dec 1989

Regionalization Of Flood Data Using Probability Distributions And Their Parameters, Nageshwar Rao Bhaskar, Carol Alf O'Connor, Harold Andrew Myers, William Paul Puckett

KWRRI Research Reports

The U. S. Geological survey recently used the method of residuals to delineate seven flood regions for the State of Kentucky. As an alternative approach, the FASTCLUS clustering procedure of the Statistical Analysis system (SAS) is used in this study to delineate five to six cluster regions in conjunction with statistical properties of the AMF series, like the coefficient of variation as estimated using method of L-moments, LCV, the parameters of the EVl and GEV flood frequency distributions, and the specific mean annual flood, QSP. For both cluster and USGS flood regions, regionalized flood frequency growth curves are developed and …


The Relation Of Radium-226 And 228 To The Groundwater Geochemistry Of Carbon, Sulfur, And Chlorine Near Michigan's Saginaw Bay, Ray Milejczak Dec 1989

The Relation Of Radium-226 And 228 To The Groundwater Geochemistry Of Carbon, Sulfur, And Chlorine Near Michigan's Saginaw Bay, Ray Milejczak

Masters Theses

The Michigan Department of Public Health (MDPH) sampled 149 residential wells producing from glacial drift and Saginaw Formation aquifers in Bay, Midland, Saginaw, and Tuscola counties in 1987. These wells were analyzed for 226Ra, 228Ra and general chemistry. Of the 149 samples, 50 exceeded the USEPA MCL of 5 pCi/L or greater for combined 226Ra + 228Ra activities. A geochemical model (WATEQF, Plummer et al., 1976) was used to determine activity coefficients, activities, ionic strength, and mineral saturation. The radium isotopes were statistically analyzed with respect to the chemical data from MDPH and the geochemical model …


Low- And High-Relief Leduc Formation Reefs: A Seismic Analysis, Neil Lennart Anderson, Robert James Sidford Brown, Ronald C. Hinds Nov 1989

Low- And High-Relief Leduc Formation Reefs: A Seismic Analysis, Neil Lennart Anderson, Robert James Sidford Brown, Ronald C. Hinds

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Leduc reefs have grown to widely varying heights and aereal extents along the Rimbey-Meadowbrook trend of central Alberta, resulting in significantly different seismic signatures. Three examples considered in this paper include two high-relief or full reefs from the Leduc-Woodbend field, an atoll and a pinnacle, each around 200 m in height but differing greatly in areal extent, about 100 km2 for the atoll and 1 km2 for the pinnacle. The third example, a low-relief or basalt reef from the Morinville field, is about 100 m high and 1 km2 in areal extent.

The Leduc-Woodbend and Morinville reefs …


Ua12/2/1 College Heights Herald, Vol. 65, No. 17, Wku Student Affairs Oct 1989

Ua12/2/1 College Heights Herald, Vol. 65, No. 17, Wku Student Affairs

WKU Administration Documents

WKU campus newspaper reporting campus, athletic and Bowling Green, Kentucky news. This issue contains articles:

  • White, Douglas. Sports Debate Shows Need for Closer Look
  • Bricking, Tanya. Conflicting Reports Argue the Costs of College Sports
  • Tsimekles, Diane. Earthquake Shakes Some on Campus – San Francisco
  • Bricking, Tanya. Sole Regent Nominee is Incumbent Eugene Evans
  • Applications for Japanese Program Due
  • World Rain Forest Week Events Planned
  • Graduates to Read Poetry on Campus Today
  • Kinslow, Gina. Baptist Student Union Sponsors Three-Day Revival
  • Turner, Karla. Bands, Tents Part of Homecoming
  • Professor to Speak with Senators – Joyce Rasdall
  • Department Head-Chair Discussion Needed
  • Chattin, John. …


A Revision Of The North American Papillose Allocreadiidae (Digenea) With Independent Cladistic Analyses Of Larval And Adult Forms, Janine N. Caira Oct 1989

A Revision Of The North American Papillose Allocreadiidae (Digenea) With Independent Cladistic Analyses Of Larval And Adult Forms, Janine N. Caira

Bulletin of the University of Nebraska State Museum

Adult specimens of all 19 North American species of papillose allocreadiids were examined. A description and figure is given for the adult of each species; details of the cirrus sacs are presented for most spesies for the first time. Descriptions were emended where necessary and judgments were made on synonymies. Scanning electron micrographs of the oral sucker of 10 species are presented as is a new key to the 19 species. A cladistic analysis was performed on the group based on adult characters. The analysis indicated that the group is monophyletic on the basis of the ventral papillae associated with …


Lithofacies Of The Pliocene Yorktown Formation In The Vicinity Of Kingsmill On The James River, Virginia, Michael David Lawless Oct 1989

Lithofacies Of The Pliocene Yorktown Formation In The Vicinity Of Kingsmill On The James River, Virginia, Michael David Lawless

OES Theses and Dissertations

The Yorktown Formation beds which crop out along the James River in southeastern Virginia near Kingsmill and Carter's Grove are lithologically described in order to compare them with the "typical" Yorktown beds upriver in the area of Fort Boykins, Rushmere, and Cobham Wharf. Thirty-four stratigraphic sections are constructed of the bluffs along the river. The Yorktown beds in the area of Kingsmill and Cobham Wharf are divided into ten lithofacies: the silty sand facies (B), the Chesapecten facies (C), the Glycymeris facies (D), the Chama facies (E), the glauconitic biofragmental sand facies (F), the laminated silty clay facies (G), the …


A Geophysical Study Of The Easternmost Piedmont: Brunswick County, Virginia, Mark A. Corbin Oct 1989

A Geophysical Study Of The Easternmost Piedmont: Brunswick County, Virginia, Mark A. Corbin

OES Theses and Dissertations

Gravity and magnetic models indicate that a steeply dipping, mylonitic shear zone recognized by reconnaissance mapping in the easternmost Piedmont of Brunswick County, Virginia is a listric fault. A pronounced 3 to 5 mgal Bouguer anomaly high is associated with the fault zone. A band of N10° trending aeromagnetic anomalies delineate the areal extent of the fault zone. The fault zone flattens eastward over a short distance to a depth of 15 kms where it joins a near horizontal surface that cuts across the region. This surface is herein interpreted to be a decollement. The fault zone of this study …


Groundwater Levels In Nebraska, 1988, Michael J. Ellis, Gregory V. Steele, Perry B. Wigley Oct 1989

Groundwater Levels In Nebraska, 1988, Michael J. Ellis, Gregory V. Steele, Perry B. Wigley

Conservation and Survey Division

No abstract provided.


Significant Bedrock Features Of The Maine Coast : Boothbay To Calais, Carol White, A. M. Hussey Ii Sep 1989

Significant Bedrock Features Of The Maine Coast : Boothbay To Calais, Carol White, A. M. Hussey Ii

Maine Collection

Significant Bedrock Features of the Maine Coast : Boothbay to Calais

Carol White and A.M.Hussey II

Planning Report # 85

A Report Prepared for the Maine Critical Areas Program, Maine State Planning Office, 184 State Street, Augusta, Maine 04333 (September 1989).

Contents: Introduction / Types of Significant Features / Description and Interpretation of Geologic Features / Overview of the Geology of Coastal Maine / Criteria for Significant Geological Localities / Inventory Methods / Area Descriptions / Site Descriptions / Conclusions and Recommendations / References


Wetland Study Of Southeastern Portage Township, Kalamazoo County, Michigan, Kevin M. Walsh Aug 1989

Wetland Study Of Southeastern Portage Township, Kalamazoo County, Michigan, Kevin M. Walsh

Masters Theses

Under the Clean Water Act, Congress passed legislation to maintain and restore the chemical, physical, and biological integrity of the water of the United States. The objective of this study is to determine if the wooded area located in Upjohn Company's Property in southeastern Portage Township, Portage, Michigan falls under the classification of a wetland.

This objective has been pursued through an examination of the hydrology of the area, the soil characteristics of the area, and the vegetation types and characteristics of the area. These parameters have been utilized following the guidelines outlined in the "Corps of Engineers Wetland Delineation …


Debris Slides And Flows On Anakeesta Ridge Within The Great Smoky Mountains National Park, Tennessee, U.S.A, Patrick T. Ryan Aug 1989

Debris Slides And Flows On Anakeesta Ridge Within The Great Smoky Mountains National Park, Tennessee, U.S.A, Patrick T. Ryan

Masters Theses

Debris slides and flows along Anakeesta Ridge in the GSMNP have been investigated utilizing dendrochronology, aerial photography, erosion stations, precipitation data and rockslope engineering techniques.

Based on the slides for which the specific dates of occurrence are known, the corresponding precipitation that was at least in part responsible for triggering the mass-wasting events varies from 1 .5 inches of rain per day to 4 inches of rain for a 6 hour period. Unfortunately, intensity records are not available to provide at what rate the precipitation was delivered. Based on TV A precipitation records it was determined that 1273 storms (1 …


Late-Holocene Earthflows Of The Willard Playa/Dune Complex, Estancia Valley, New Mexico: A Geomorphic Response To Climatic Change, Kurt A. Goebel Aug 1989

Late-Holocene Earthflows Of The Willard Playa/Dune Complex, Estancia Valley, New Mexico: A Geomorphic Response To Climatic Change, Kurt A. Goebel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Late-middle to late Holocene dune sediment that overlies Pleistocene lacustrine sediment marks the onset of xeric conditions in the Estancia Valley, central New Mexico. Incised into the underlying lacustrine sediments, the modern deflation basins are enclosed by parabolic dunes composed of clay and gypsum derived from the underlying sediment.

Located on the in-facing dune slopes of the deflation basins, the most striking geomorphic feature of this dune complex are numerous elongated scars. These relict scars document a geomorphically distinct earthflow event. Arroyos that cut into flow scars expose eolian earthflow sediment overlying lacustrine deposits. In the zone of depletion, erosional-flow …


Hillslope Processes On Late Quaternary Cinder Cones Of The Cima Volcanic Field, Eastern Mojave Desert, California, Claire Estelle Renault Jul 1989

Hillslope Processes On Late Quaternary Cinder Cones Of The Cima Volcanic Field, Eastern Mojave Desert, California, Claire Estelle Renault

Earth and Planetary Sciences ETDs

Four basaltic cinder cones of the cima volcanic field were studied in an attempt to understand the geomorphic and volcanic processes involved in the constructional and degradational evolution of late Quaternary cinder cones in an arid climate. Modern hillslope processes were mapped on cone slope and soil and subsurface stratigraphy were documented in the surrounding debris-apron deposits. In addition, morphometric parameters shown to be sensitive to cinder cone age (Dohrenwend et al., 1986) were measured on the four cinder cones to evaluate previous studies which estimated the relative or absolute age of cinder cones based only on morphologic changes in …


The Geomorphology And Surficial Geology Of The West Flank Of The Blue Ridge, Sherando Area, Virginia, Derek Weston Ryter Jul 1989

The Geomorphology And Surficial Geology Of The West Flank Of The Blue Ridge, Sherando Area, Virginia, Derek Weston Ryter

OES Theses and Dissertations

The west flank of the Blue Ridge near Sherando, Virginia (Augusta County) consists of many landforms including talus slopes, bedrock cliffs, boulder streams, colluvial slopes, residual knobs, and debris fans. The purpose of this study is to describe the geomorphic history of the area by understanding the spatial and temporal relationships between landforms on the hillslopes.

Boulder streams (maximum 30 m wide, 400 m long, 6.1 m thick) exhibit a gently dipping imbricated fabric and basal shear stresses of 0.1 to 0.4 bars.

Debris fans in Group L (lower) and Group U (upper) are distinguished by topographic position, degree of …


Geology In The Vicinity Of The City Of Fossil, Wheeler County, North-Central Oregon, Patrick W. Riseley Jun 1989

Geology In The Vicinity Of The City Of Fossil, Wheeler County, North-Central Oregon, Patrick W. Riseley

Loma Linda University Electronic Theses, Dissertations & Projects

The area of study is located on the north flank of the northeast-southwest trending Blue Mountains Anticlinorium in north-central Oregon. The primary geologic problems investigated were: 1) the age and stratigraphic position of leaf-bearing tufts mapped as Oligo-Miocene John Day Formation but surrounded by andesitic basalts of the Eo-Oligocene Clarno Formation, 2) the age of "olivine basalt" mapped as John Day Formation by some workers but referred to the Clarno Formation by others, and 3) the petroleum potential of the Fossil area.

To resolve these three problems I mapped a 25 square mile area surrounding Fossil at 1 :24,000 scale. …


Paleogeography And Paleoenvironments Of The Lower Unit, Fossil Butte Member, Eocene Green River Formation, Southwestern Wyoming, Roberto Enrique Biaggi Jun 1989

Paleogeography And Paleoenvironments Of The Lower Unit, Fossil Butte Member, Eocene Green River Formation, Southwestern Wyoming, Roberto Enrique Biaggi

Loma Linda University Electronic Theses, Dissertations & Projects

During Eocene time sediment accumulated in Fossil Lake, in what developed to be a small linear and structurally controlled basin. Fossil Lake was one of several lakes into which the Green River Formation was deposited in Wyoming, Utah and Colorado.

Detailed stratigraphic analysis of the Lower Unit of the Fossil Butte Member revealed a well developed lacustrine sequence south of Fossil Butte, and indicates four major depositional facies: (1) open lacustrine, (2) marginal lacustrine, (3) carbonate mudflat, and (4) marginal fluvio-deltaic. The open lacustrine facies is characterized by kerogen rich to kerogen poor finely laminated micrites , that consist mainly …


Taylor Instability In Ryholite Lava Flows, B. A. Baum, W. B. Krantz, Jonathan H. Fink, R. E. Dickinson May 1989

Taylor Instability In Ryholite Lava Flows, B. A. Baum, W. B. Krantz, Jonathan H. Fink, R. E. Dickinson

Geology Faculty Publications and Presentations

A refined Taylor instability model is developed to describe the surface morphology of rhyolite lava flows. The effect of the downslope flow of the lava on the structures resulting from the Taylor instability mechanism is considered. Squire's (1933) transformation is developed for this flow in order to extend the results to three-dimensional modes. This permits assessing why ridges thought to arise from the Taylor instability mechanism are preferentially oriented transverse to the direction of lava flow. Measured diapir and ridge spacings for the Little and Big Glass Mountain rhyolite flows in northern California are used in conjunction with the model …


Groundwater Flow Systems And Thermal Regimes Near Cooling Igneous Plutons: Influence Of Surface Topography, Mark U. Birch May 1989

Groundwater Flow Systems And Thermal Regimes Near Cooling Igneous Plutons: Influence Of Surface Topography, Mark U. Birch

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Previous studies of cooling igneous plutons did not consider the possible influence of sloping surface topography. Topographically-driven fluids in high relief terrain, however, are thought to interact with deep buoyancy-driven fluids to produce large lateral-flow systems up to 5 km long and 20 km long in silicic and andesitic volcanic terrain, respectively. In this study, a quantitative investigation of the interaction of topographically-driven and buoyancy-driven fluid flow is conducted through the use of a finite element numerical model to simulate the fluid flow and thermal regimes associated with a cooling igneous pluton in the presence of significant topographic relief. The …


Origin And Evolution Of Dolostone In The Middle Cambrian Langston Formation, Northern Utah, Mark C. Hall May 1989

Origin And Evolution Of Dolostone In The Middle Cambrian Langston Formation, Northern Utah, Mark C. Hall

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Six major generations of dolomite are present within the Cambrian Langston Formation in the Wellsville Mountains and Bear River Range of northern Utah. Identification of dolomite generations and delineation of their relative sequences are based on normal light petrography, cathodoluminescence, staining, chemistry, inferred burial history, and deformation features. The earliest stage is believed to be Middle to Late Cambrian in age. The presence of dolomite rhombs and dolomitized echinoid fragments and peloids suggests that this stage probably formed under sabkha reflux conditions. Extensive nonferroan, polymodal, nonplanar ("xenotopic") dolomite formed next under confined mixing zone conditions. A succeeding generation of pervasive …


The Geology And Structural Significance Of The Arch Mountain Area, Northern Black Mountains, Mohave County, Arizona, Edward Eschner May 1989

The Geology And Structural Significance Of The Arch Mountain Area, Northern Black Mountains, Mohave County, Arizona, Edward Eschner

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Arch Mountain area of northwestern Mohave County, Arizona, is typified by rocks that range from Precambrian to Quatemary in age. Arch mountain is a north-trending horst bounded on the west by the Petroglyph Wash graben and on the east by the Virgin Basin. A low-angle normal fault, herein named the Arch Mountain detachment fault, is exposed for 6 km along strike just below the ridge crest of Arch Mountain, and it is typified by a 2-20 cm thick zone of hematite-impregnated breccia and cataclasite. The detachment fault places an upper plate of Precambrian gneiss, Paleozoic quartzite, shale and dolomite, …