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Theses/Dissertations

Geology

1992

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Articles 1 - 30 of 42

Full-Text Articles in Physical Sciences and Mathematics

Use Of Geology And Petrophysics In The Characterization Of St. Peter Sandstone Reservoirs, Rusli Bin Adam Dec 1992

Use Of Geology And Petrophysics In The Characterization Of St. Peter Sandstone Reservoirs, Rusli Bin Adam

Masters Theses

Core samples and petrophysical data from three reservoir intervals within the Middle Ordovician St. Peter Sandstone in the Michigan basin were utilized to assess the reservoir performance. Each reservoir interval coincides with major sedimentary facies which are in gradational contact with one another vertically and laterally throughout the basin. Reservoirs in the lower portions of the formation (reservoir type 1) are dominated by meso-intercrystalline porosity. This predominantly quartz cemented reservoir rock type is characterized by low porosity with high permeability, moderate pore apertures, and moderate irreducible water saturation. Reservoirs at the top of the formation (reservoir type 3) are dominated …


A Study Of Ground-Water Quality In A Priority Agricultural And Livestock Watershed, Cass County, Michigan, Matthew Alan Stuk Dec 1992

A Study Of Ground-Water Quality In A Priority Agricultural And Livestock Watershed, Cass County, Michigan, Matthew Alan Stuk

Masters Theses

A study of ground-water contamination in a shallow, sandy, glacial drift aquifer was performed in a watershed dominated by swine feedlots and crop fields in Cass County, Michigan. Monitoring wells were installed and sampled to study the flow pattern, chemistry, and contamination of ground water.

Results of chemical analyses show contamination from fertilizers and other soil-applied chemicals as well as the infiltration of breakdown products from pig waste. Shallow wells in impacted areas show potassium and nitrate from the breakdown of fertilizers, calcium from field application of lime, and additional nitrate from pig waste. Elevated calcium, potassium, and nitrate concentrations …


Gully Evolution In The Upper Delaware River Basin Northeastern Kansas, Iona L. Meyer Nov 1992

Gully Evolution In The Upper Delaware River Basin Northeastern Kansas, Iona L. Meyer

Student Work

A small gully network developed across a pasture in the Dissected Till Plain of northeastern Kansas was monitored for one year to assess gully evolution in non-loessial materials. The objectives of this investigation were to identify stable and unstable drainage elements within the gully network; identify zones of net erosion and deposition; estimate the volume of sediment removed or deposited during the monitoring period; determine rates of headcut advancement; determine processes that advance and widen gullies, and to determine the historic development of the gully network.

Portions of the gully network were measured after every rain event exceeding 1.5 cm …


Fluid Inclusion Studies Of The Morefield Pegmatite Amelia County, Virginia, John Richard Smerekanicz Oct 1992

Fluid Inclusion Studies Of The Morefield Pegmatite Amelia County, Virginia, John Richard Smerekanicz

OES Theses and Dissertations

The Morefield Pegmatite is a planar, nearly vertical body situated in Grenville age gneisses and schists in the southeast Piedmont of Virginia. It consists of a mineralogically simple albite-quartz outer zone and a texturally and mineralogically complex inner zone of microcline-topaz-quartz, with trace amounts of rare-element minerals. Fluid inclusions in samples of quartz, topaz, beryl, spessartite and albite that span the length, width and depth of both zones can be classified by chemical composition into two main groups: H2O-rich solutions and CO2- H2O -rich fluids. The H2O -rich inclusions consist of H …


Ground Water Investigation Of The Petersburg Granite In Chesterfield County, Virginia, Michael W. Bennett Oct 1992

Ground Water Investigation Of The Petersburg Granite In Chesterfield County, Virginia, Michael W. Bennett

OES Theses and Dissertations

Yields of new water wells in areas underlain by the Petersburg Granite in Chesterfield County, Virginia should improve if procedures for site selection and well construction follow the new guidelines proposed. These guidelines integrate analyses of aerial photo linears and drainage patterns, survey of bedrock joints and shallow geophysical properties and techniques using several statistical methods.

Throughout the study area, fracture traces form in nearly the same orientation as bedrock fractures. The dominant N-S and E-W trending bedrock joints also corresponded to aerial photo linears of similar orientation.

Across one large fracture zone, both gamma-ray and electrical resistivity surveys reveal …


Late Proterozoic Rifting Of Laurentia: Source And Deposition Of Conglomerate Units Of The Grandfather Mountain Formation, North Carolina Blue Ridge, Michael J. Neton Aug 1992

Late Proterozoic Rifting Of Laurentia: Source And Deposition Of Conglomerate Units Of The Grandfather Mountain Formation, North Carolina Blue Ridge, Michael J. Neton

Masters Theses

Crustal extension and initiation of rifting of Laurentia during the Late Proterozoic resulted in formation of a northeast-trending system of discontinuous to continuous, half-graben basins situated cratonward of the Iapetus Ocean spreading ridge. Thick accumulations of sandstone, siltstone, bimodal volcanic rocks, conglomerate, diamictite, and minor limestone were deposited largely in response to rifting and relief formation on the basin margins.

The Grandfather Mountain Formation contains five stratigraphically and compositionally distinct conglomerate/diamictite units and one pebbly sandstone unit which cap coarsening-upward, basin-fill sequences. The progradational sequences average 1300 m thick and are composed of a succession of volcanic flows (basalt/rhyolite) and/or …


Depositional Environments And Paleoecology Of The Lower Ordovician Pogonip Group, Opd Unit, Arrow Canyon Range, Clark County, Nevada, Jeffrey K. Donovan Aug 1992

Depositional Environments And Paleoecology Of The Lower Ordovician Pogonip Group, Opd Unit, Arrow Canyon Range, Clark County, Nevada, Jeffrey K. Donovan

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Opd Unit of the Pogonip Group is a slope-forming carbonate sequence that crops out in the Arrow Canyon Range 75 miles north of Las Vegas, Nevada. It is composed mainly of grainstones, packstones, and intraformational conglomerates and also contains Calathium-bearing bioherms composed dominantly of wackestones. These rocks were deposited in a shallow-water, high-energy, subtidal, tropical marine environment. Nuia and Nuia-crinoid shoals developed on this shallow ramp and the area was frequently disturbed by storms.

Calathium-dominated carbonate mudmounds emerged on the Nuia and Nuia-crinoid shoals. Although Calathium dominated the mounds on a macroscopic scale, the mounds …


Senior Theses: Department Of Physical Sciences, Patrick M. Higgins, Timothy Howard, Leah Carol Ross May 1992

Senior Theses: Department Of Physical Sciences, Patrick M. Higgins, Timothy Howard, Leah Carol Ross

Morehead State Theses and Dissertations

1992 Senior Theses from the Department of Physical Science at Morehead State University.

The Abundance, Diversity, and Stratigraphy of the Upper Crab Orchard Formation, Lewis County, Kentucky by Patrick M. Higgins.

The Modification of Flemion for Use in a Solid Electrolyte Battery by Timothy Howard.

Simple Analog Computers by Leah Carol Ross.


The Paleoecology And Geomorphology Of Holocene Deposits Of The Southern Malad River, Box Elder County, Utah, Ann Schaffer Elder May 1992

The Paleoecology And Geomorphology Of Holocene Deposits Of The Southern Malad River, Box Elder County, Utah, Ann Schaffer Elder

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Widespread Lake Bonneville sediments have been modified by river aggradation and degradation associated with Holocene fluctuations in the Great Salt Lake. Exposures of exceptionally abundant and well-preserved molluscan deposits in the Bear River Valley, Utah, allow detailed paleoenvironmental reconstruction of Holocene environments. The exposed basal unit consists of largely unfossiliferous deltaic silts and clays deposited during Lake Bonneville time (roughly 11,000 - 13,000 yr B. P.). An unconformity representing at least 2000 yr separates the deltaic material from overlying highly fossiliferous stream sands. Eight species of molluscs, comprising a single community, occupied this low energy stream environment at 7690 ± …


Sedimentology And Community Structure Of Reefs Of The Yucatan Peninsula, Mexico, Matthew J. Novak May 1992

Sedimentology And Community Structure Of Reefs Of The Yucatan Peninsula, Mexico, Matthew J. Novak

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Holocene carbonate sediments from Mexican reefs in the Caribbean and Gulf of Mexico display variations in constituent composition, texture and mineralogy which are related to their locations on the reefs. Samples were collected at barrier reef environments at Akumal and Chemuyil, on the northeast coast of the Yucatan Peninsula; at the oceanic atoll of Chinchorro, off the southeast coast of the peninsula; and at the shelf atoll of Alacranes, in the Gulf of Mexico. Samples were collected through a depth range of 0-40 m, which encompasses back reef, shallow fore reef, and deeper fore reef environments.

Constituent-particle analysis of reef …


Spatial And Temporal Variations Of The Pilot Valley Playa Interpreted From Remotely Sensed Images, Llyn Doremus May 1992

Spatial And Temporal Variations Of The Pilot Valley Playa Interpreted From Remotely Sensed Images, Llyn Doremus

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In the Basin and Range Province, the geologic regime of the Pilot Valley, linear trending block faults have isolated many valleys both topographically and hydrologically. Discharge from these arid, closed basins occurs only as evaporation. Minerals dissolved in discharging fluid are precipitated at the valley floor as the liquid evaporates. The resulting salt flats and high density brines are known as playas.

The Pilot Valley Playa surface was sampled concurrently with the recording of a Thematic Mapper remotely sensed image to define the surface conditions that correspond to image data. An association was found between the band 7 (infrared wavelength …


Quaternary Geology And Neotectonics Of Southern Star Valley And The Southwest Flank Of The Salt River Range, Western Wyoming, Gregory A. Warren May 1992

Quaternary Geology And Neotectonics Of Southern Star Valley And The Southwest Flank Of The Salt River Range, Western Wyoming, Gregory A. Warren

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Southern Star Valley is a structural and physiographic basin bounded on the east by the southern Star Valley fault, an active normal fault associated with Basin and Range extension. The southern Star Valley fault separates southern Star Valley from the Salt River Range and forms a dramatic north-south trending topographic escarpment. Statistical analysis of relative-age dating (RD) parameters taken from glacial deposits in the Salt River Range defined distinctive age groups for the deposits, and comparison of RD data allowed correlations with late Pleistocene and Holocene glacial deposits elsewhere in the Rocky Mountains. However, the sedimentary lithologies in the glacial …


Calcite Cementation Of Pleistocene Glacial Deposits In Southwest Michigan, Robert Lee Tolliver Apr 1992

Calcite Cementation Of Pleistocene Glacial Deposits In Southwest Michigan, Robert Lee Tolliver

Masters Theses

No abstract provided.


Hydrogeologic Characterization Of A Multi-Aquifer System At Station 11 In Kalamazoo, Michigan, Linda G. Jones Apr 1992

Hydrogeologic Characterization Of A Multi-Aquifer System At Station 11 In Kalamazoo, Michigan, Linda G. Jones

Masters Theses

The purpose of this study was to determine the hydraulic connection between the upper and lower confined glacial drift aquifers. The results of this study are based primarily upon the geologic profiles, a comparison of the head differences within each aquifer, potentiometric surfaces and different lag times for precipitation to reach each aquifer.

Results of the aquifer test showed that the upper confining layer pinches out in the western part of the well field. This area also provided significant recharge to the well field during the aquifer test. Data collected during the aquifer test and the increases in water levels …


The Application Of A Statistical Trend Analysis Program To Ground-Water Quality Monitoring Data From Eight Western Michigan Solid Waste Landfills, Amy Decosta Lachance Apr 1992

The Application Of A Statistical Trend Analysis Program To Ground-Water Quality Monitoring Data From Eight Western Michigan Solid Waste Landfills, Amy Decosta Lachance

Masters Theses

A statistical analysis and interpretation of ground-water chemistry data from eight landfills in Western Michigan was performed. Data were collected over approximately the past ten years, pursuant to the requirements of Michigan's Solid Waste Management Act. A statistical regression model was used to reduce the data to identifiable trends and estimated magnitudes. These results were analyzed with respect to each landfill's characteristics and hydrogeological setting. Comparisons were made concerning the landfills' relative potential for environmental harm. Also, the effectiveness and applicability of this model to the analysis of ground-water monitoring data was assessed.

It was concluded that this analysis and …


Evaluation Of Late Mesozoic And Cenozoic Tectonism: Atlantic Inner Coastal Plain Margin Near Richmond, Virginia, Andrew A. Gremos Apr 1992

Evaluation Of Late Mesozoic And Cenozoic Tectonism: Atlantic Inner Coastal Plain Margin Near Richmond, Virginia, Andrew A. Gremos

OES Theses and Dissertations

A combined geologic, geophysical, and geomorphic analysis of the Virginia Inner Coastal Plain margin near Richmond was conducted to investigate the presence of basement structures and to evaluate their influence on the overlying sedimentary package and present-day landscape. Basement structures identified included north-northeast and northwest oriented faults that appear to bound and transect a north-northeast trending early Mesozoic basin or basins and other pre-existing zones of weakness. Observed offsets are propagated upward through the pre-Miocene strata in the form of reverse faults and flexuring. Fracture sets measured in the Petersburg Granite and overlying Coastal Plain units, stream drainage lines, and …


Relation Of Groundwater Fluoride Concentrations To Sediment Mineralogy, Potomac Formation (Cretaceous), Southeastern Virginia, Paul Anthony Maciuika Apr 1992

Relation Of Groundwater Fluoride Concentrations To Sediment Mineralogy, Potomac Formation (Cretaceous), Southeastern Virginia, Paul Anthony Maciuika

OES Theses and Dissertations

Thirty-seven Early cretaceous sediment samples of the Potomac Formation were obtained from four cores to determine if fluoride bearing minerals are responsible for elevated fluoride concentrations in Potomac Formation groundwaters of southeastern Virginia. Investigative methods included total sediment fluoride and particle size analysis, semiquantitative mineralogical analysis (achieved by X-Ray Diffraction) and statistical methods (cluster, canonical and regression analysis). The sediments showed wide variation in textures, ranging from clean sands and gravels to silty clays. Sediment mineralogies were dependent on the prevailing size fraction, with quartz and feldspar dominating the sand and silt fractions, muscovite primarily being found in the silt …


Thermal-Mechanical Response To An Intruding Magma Chamber, Christoph Arz Jan 1992

Thermal-Mechanical Response To An Intruding Magma Chamber, Christoph Arz

Geology Theses and Dissertations

The thermal-mechanical response of rock at shallow to medium depth beneath the earth's surface has been modeled as a magma body ascends toward it. The overall stress field is calculated by considering the country rock as a viscous fluid, a thermal-elastic material, or as an elasto-plastic material that fractures when its strength is overcome.
The stress field within and around a spherical magma body surrounded by a homogeneous, Newtonian fluid has been evaluated and can be used at deeper levels in the earth's crust where the viscosity of the country rock is relatively low. With decreasing depth wall rock material …


The Origin Of Metalliferous Argillites In The Shoal Arm Formation Of North-Central Newfoundland, Volker Brüchert Jan 1992

The Origin Of Metalliferous Argillites In The Shoal Arm Formation Of North-Central Newfoundland, Volker Brüchert

Geology Theses and Dissertations

The Middle Ordovician Shoal Arm Formation, which is located in the central volcanic belt of north-central Newfoundland, is a tripartite assemblage of hematitic argillites, grey cherts, and black shales directly underlying a flysch sequence. The hematitic argillites are enriched in Fe, Mn, Ni, Pb, and Co. Factor analysis and principal component analysis indicate the presence of a hydrothermal component, presumably derived from hydrothermal activity in the coeval Lawrence Head volcanics. Unusual, (?) calcareous Mn-Fe-oxide nodules are present in the top parts of turbidites in the hematitic argillites. Electron microprobe analysis of a color transition from a red to a green …


A Kinematic Study Of The Summit Valley Plutonic Complex, Klamath Mountains, California, Nancy E. Griesau Jan 1992

A Kinematic Study Of The Summit Valley Plutonic Complex, Klamath Mountains, California, Nancy E. Griesau

Geology Theses and Dissertations

The Summit Valley plutonic complex (SVPC) is a multi-phase intrusive body of Late Jurassic age. Crystallization age for a zircon of 150±1 Ma and a cooling age for a hornblende of 144±1 Ma indicate a protracted period of high temperature. The SVPC is irregularly shaped, covers <15 km2, and is believed to be in the western limb of a post-Nevadan syncline, with an easterly dip estimated at about 45°. The SVPC penetrated the Orleans Fault and intruded and contact metamorphosed the upper and lower plates of the thrust. The Orleans Fault is a major tectonic boundary separating the Western Paleozoic …


The Geology Of The Vermont Valley And The Western Flank Of The Green Mountains Between Dorset Mountain And Wallingford, Vermont, Rolf Herrmann Jan 1992

The Geology Of The Vermont Valley And The Western Flank Of The Green Mountains Between Dorset Mountain And Wallingford, Vermont, Rolf Herrmann

Geology Theses and Dissertations

The carbonate sequence of the Vermont Valley has been generally believed to lie on the east limb of a major unfaulted syncline ("Middlebury Synclinorium"), and the exposed Precambrian basement and overlying cover rocks of the Green Mountain massif on the west limb of the adjacent major unfaulted anticline ("Green Mountain Anticlinorium"). Except for the Basal Thrust of the Taconic Allochthon, all faults shown on previous maps die out north of Dorset Mountain.
In contrast, detailed mapping for this thesis in the Vermont Valley and the western flank of the Green Mountain massif has revealed several major north/south trending thrust faults, …


Paleoenvironmental Analysis Of Three Subfossil Coleopteran Faunas From The Toklat River Drainage, Central Alaska, Lisa L. Churchill Jan 1992

Paleoenvironmental Analysis Of Three Subfossil Coleopteran Faunas From The Toklat River Drainage, Central Alaska, Lisa L. Churchill

Senior Scholar Papers

Three sediment samples were collected from exposures along the Tok lat River. Central Alaska and analyzed for subfossil Coleopteran remains. Two samples arc Holocene in age (650 ± b.p .. and submodem) and the other is believed to be laic Pleistocene in age, based on stratigraphic interpretations. The Pleistocene fauna was representative of a tundra environment adjacent to a fluvial system. The older Holocene sample was indicative of a point bar deposit wi rh sl ightly moister conditions. although rhe occurrence of several tundra species was also noted. These tundra species were evidently able to make the transition from their …


The Paleontology And Paleoenvironments Of The Kanawha Black Flint Member And Related Facies, Kanawha Formation (Middle Pennsylvanian), Northwest Boone County And Vicinity, West Virginia, Matthew B. Watson Jan 1992

The Paleontology And Paleoenvironments Of The Kanawha Black Flint Member And Related Facies, Kanawha Formation (Middle Pennsylvanian), Northwest Boone County And Vicinity, West Virginia, Matthew B. Watson

Theses, Dissertations and Capstones

The Kanawha Black Flint member of the Kanawha Formation was deposited in a shallow marine coastal setting with low sand supply and low wave energy. The Kanawha Black Flint member and adjacent coal zones are divisible into five sedimentary facies based on lithology, body and trace fossils and sedimentary structures. Coastal swamps and lakes are represented by thinly laminated carbonaceous shales and coals containing rooted seat rocks and crevasse sandstones with root traces and vertical Calamites trunks.

The offshore facies consists of a gray laminated sideritic shale. Phosphatic and calcareous brachiopods and shallow burrowing bivalves predominate in the offshore assemblage. …


The Stratigraphy And Sedimentology Of The Sentinel Butte Formation (Paleocene) In South-Central Williams County, North Dakota, Wesley D. Peck Jan 1992

The Stratigraphy And Sedimentology Of The Sentinel Butte Formation (Paleocene) In South-Central Williams County, North Dakota, Wesley D. Peck

Theses and Dissertations

Approximately 163 meters (535 feet) of the Paleocene Sentinel Butte Formation crop out in southcentral Williams county, North Dakota. To determine their mode of deposition and stratigraphic position within the formation, twelve stratigraphic sections were measured. These strata were deposited in alternating fluvial and lacustrine environments as determined by sedimentary structures, lithology, lithologic sequences, and fossil occurrences. A fining upward trend in grain size of the tabular sandstones, and the identification of epsilon cross-stratification in the tabular sandstones support a fluvial origin for some of the strata. The strongest evidence for the interpretation of lacustrine deposition is the presence of …


Denitrification In The Elk Valley Aquifer, Northeastern North Dakota, Gale G. Mayer Jan 1992

Denitrification In The Elk Valley Aquifer, Northeastern North Dakota, Gale G. Mayer

Theses and Dissertations

Biological denitrification controls nitrate distribution in the Elk Valley aquifer, which underlies approximately 725 square kilometres of northeastern North Dakota and provides drinking water for farms and rural communities in the area. Increased irrigation has raised concerns over potential contamination from agricultural practices. The purpose of this study was to establish the role of biological denitrification in minimizing concentration and distribution of nitrate and to determine the effect irrigation practices have on groundwater flow and nitrate distribution in the saturated zone.

The aquifer is unconfined and consists of up to 20 metres of glacial outwash and deltaic shale-rich sand deposits. …


Effect Of Sinkholes On Soil Moisture And Ground Water Recharge At An Abandoned Underground Coal Mine Near Wilton, North Dakota, Michael M. Sonderman Jan 1992

Effect Of Sinkholes On Soil Moisture And Ground Water Recharge At An Abandoned Underground Coal Mine Near Wilton, North Dakota, Michael M. Sonderman

Theses and Dissertations

Subsidence at abandoned underground mines in south-central and southwest North Dakota has produced numerous sinkholes. Previous studies in the Northern Great Plains have suggested depression-focused recharge may be a significant ground water recharge mechanism in this region. Thus, sinkholes may increase soil moisture and ground water recharge. Current reclamation practices include filling sinkholes with non-topsoil fill material. However, the benefits of increases in soil moisture and ground water supplies may outweigh the benefits of expensive reclamation. The purpose of this study was to determine whether soil moisture and, hence, the potential for ground water recharge, was greater in sinkholes than …


Stratigraphy And Structure Of The Southeast Part Of The Portland Basin, Oregon, Kenneth E. Lite Jr. Jan 1992

Stratigraphy And Structure Of The Southeast Part Of The Portland Basin, Oregon, Kenneth E. Lite Jr.

Dissertations and Theses

The southeast part of the Portland Basin has been previously described by other investigators. However, little detailed information existed on the depositional relationships between the units, the various sedimentary fades, or the origin of many of the units.


A Geographical Analysis Of Aquaculture Sites In Puget Sound, Dennis R. Gillespie Jan 1992

A Geographical Analysis Of Aquaculture Sites In Puget Sound, Dennis R. Gillespie

WWU Graduate School Collection

Attempts to promote aquaculture in Puget Sound waters have met with heated debate over the physical and environmental impacts such siting would produce. These are concerns that aquaculturists contend are nothing more than smoke screens used to conceal the only issues that matter to their opponents — aesthetic appearance and the potential threat to property values.

This essay examines the issues concerning aquaculture in the region. First the history of aquaculture in the Sound from the turn of the century through to the present is addressed. Highlighted are the problems of stewardship and the challenges faced by the industry in …


Paleomagnetism And Tectonics Of The Crescent Formation Northern Olympic Mountains, Washington, Andrew C. (Andrew Clyde) Warnock Jan 1992

Paleomagnetism And Tectonics Of The Crescent Formation Northern Olympic Mountains, Washington, Andrew C. (Andrew Clyde) Warnock

WWU Graduate School Collection

Use of a small-diameter core drill has allowed the paleomagnetic sampling of the rims of fractured pillow basalts of the lower Crescent Formation in the northern Olympic Mountains. The pillows selected have spherical or oblate morphologies which typically develop on horizontal or mildly-dipping surfaces. Pillow keel structures and sedimentary interbeds were used to obtain bedding attitudes and top directions for use in structural corrections. All specimens were subjected to progressive thermal demagnetization. After removal of a low blocking-temperature recent overprint, stable endpoints were reached by 580°C in 11 of the 33 sites sampled (large within-site scatter was commonly observed in …


Regional Significance Of The Tonga Formation, North Cascades, Washington, Kathleen (Kathleen Maura) Duggan Jan 1992

Regional Significance Of The Tonga Formation, North Cascades, Washington, Kathleen (Kathleen Maura) Duggan

WWU Graduate School Collection

The Tonga Formation of the North Cascades, Washington, is spatially situated between rocks of the crystalline core and those of the Northwest Cascades System. Its affinity to one or the other, or both, of these flanking units has been uncertain but is of importance to orogenic models for the region.

The Tonga Formation consists of weakly-deformed bedded feldspathic graywackes and shale metamorphosed at chlorite to staurolite grade. Comparison of protolith lithologic assemblage and Rb/Sr isotopic signature in addition to plutonic, metamorphic, and deformational histories suggests that the Tonga Formation is correlative with the Chiwaukum Schist and is not equivalent to …