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Geology

Theses/Dissertations

2004

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Full-Text Articles in Physical Sciences and Mathematics

Origin Of The Central Kalamazoo River Valley, Southwestern Michigan, Usa, Andrew Kozlowski Dec 2004

Origin Of The Central Kalamazoo River Valley, Southwestern Michigan, Usa, Andrew Kozlowski

Dissertations

Chapter I

Introduction

Southern Michigan's geomorphology is a testament to the glacial processes that buried and sculpted the landscape during the last glaciation. Many glacial landforms in southwestern Michigan, including the Kalamazoo River Valley, provide evidence that aids in understanding the chronology, ice dynamics and glacial processes that occurred in Michigan during the last ice age.

As the climate began to warm about 20,000 yr B.P. (Larson and Schaetzl, 2001) the extensive Laurentide Ice Sheet began to recede from its maximum southern position reached during the Late Wisconsinan (Figure 1). It was at this point that modem surficial drainage systems …


The Glacial Geology Of Southern St. Joseph County, Michigan, Linda Nicks Dec 2004

The Glacial Geology Of Southern St. Joseph County, Michigan, Linda Nicks

Dissertations

The objective of the dissertation was to map the glacial geology in southern St. Joseph County, Michigan. The surficial geology was divided into three distinct land systems which are moraine, outwash and fan deposits. The Sturgis Moraine is the most prominent feature transecting the study area from east to west. The topography is further dissected by southwest-trending channels interpreted as tunnel channels.

Thick accumulations of sand and gravel in the study area indicate that glacial meltwater deposition played a dominant role in shaping the landscape. Based on the relative size of the channels and outwash deposits, the largest contribution from …


Slope Stability Analysis Of A Lake Michigan Coastal Bluff, Gregory Carlton Young Dec 2004

Slope Stability Analysis Of A Lake Michigan Coastal Bluff, Gregory Carlton Young

Masters Theses

Bluff failure along the Lake Michigan coast can be produced primarily by increased pore pressure from perched water tables above lacustrine clay deposits. To test this theory, a site in Allegan County, Michigan with alternating layers of sand, clay and glacial till was chosen for bluff failure monitoring. Historically, the site experiences sporadic massive failures as opposed to neighboring sites that show more regular and uniform displacements. Four pole and cable monitoring lines were measured bi-weekly from December 2001 to October 2003. Lake levels were low and no erosion of material at the base of the slope occurred. Slumps above …


Joint Size Estimation Using Joint Traces On Borehole Walls, Christopher James Heiny Dec 2004

Joint Size Estimation Using Joint Traces On Borehole Walls, Christopher James Heiny

Masters Theses

One approach to characterizing subsurface joint populations is to assume
surface joint patterns are representative of joints at depth. Yet, many times, either the analogous surface joints are unexposed, or absent because surface rocks did not experience the same deformation history. The alternative of direct subsurface characterization has been limited by joints not being resolvable in seismic data and borehole data not yielding fracture size. The present approach uses the subsurface geometry of joint/borehole intersections to estimate mean joint size (mean joint length and width) and aspect ratio (joint length to width ratio), and presents a new method for determining …


Pluton Zonation Unveiled By Gamma-Ray Spectrometry And Magnetic Susceptibility; A Case Study Of The Sheeprock Granite, Western, Utah, Paul D. Richardson Nov 2004

Pluton Zonation Unveiled By Gamma-Ray Spectrometry And Magnetic Susceptibility; A Case Study Of The Sheeprock Granite, Western, Utah, Paul D. Richardson

Theses and Dissertations

A radiometric survey of the zoned 21 Ma, A-type Sheeprock granite, western Utah, combined with measurements of magnetic susceptibility and field observations were analyzed using a geographic information system. The intrusion spans 25 square km and is roughly eliptical in shape with its long axis trending northwest. Concentration maps (composed of more than 500 survey stations) of eU, eTh, texture, magnetic susceptibility, color, and joint density help to constrain magmatic and post-magmatic processes related to its chemical and physical zonation. Uranium ranges from 3.9 to 26.9 ppm (mean 12.7) and thorium from 1.7 to 125.7 ppm (mean 45.5). Similarities in …


Hydrologic Variations Within Created And Natural Wetlands In Southeastern Virginia, Aaron Dyer Despres Oct 2004

Hydrologic Variations Within Created And Natural Wetlands In Southeastern Virginia, Aaron Dyer Despres

OES Theses and Dissertations

The hydrology of wetlands, particularly how wetland soils collect, store, and redistribute water strongly affects how wetland systems function. In created wetlands, construction processes and materials influence the hydrology and consequently, the potential for successful reestablishment of target vegetation communities. During .2002- 2004, the Virginia Department of Transportation constructed large mitigation wetlands on two different Quaternary aged surfaces with very similar hydrogeomorphic conditions. The Sandy Bottom Nature Park site (SBNP) located in Hampton, VA and rests on the sandy loam Tabb Formation while the Charles City Wetland site (CCW) lies on the older and clay-rich Shirley Formation. This study documents …


Anthropogenic Lead Deposition And Four National Parks In Poland As Determined By Lead Isotope Ratios, Shannon Simcoe Jul 2004

Anthropogenic Lead Deposition And Four National Parks In Poland As Determined By Lead Isotope Ratios, Shannon Simcoe

OES Theses and Dissertations

Polluted soils are recognized by having high concentrations of heavy metals, including Pb. Partitioning of metals in geochemical fractions, by sequential chemical extractions, may indicate whether a metal has been recently deposited in the soil. While concentration levels alone cannot distinguish between natural and anthropogenic Pb, studies have demonstrated that anthropogenic pollution is accurately recorded by specific Pb isotope signatures, which differ from natural Pb isotopes. The objective of this project was to use 206Pb/207Pb and 206Pb/204Pb isotope ratios to differentiate between the anthropogenic Pb input and the naturally occurring Pb in four national …


Platinum Group Element Mineralization In "Ballrooms" Of The J-M Reef Of The Stillwater Complex, Montana, Matthew P. Harper Jun 2004

Platinum Group Element Mineralization In "Ballrooms" Of The J-M Reef Of The Stillwater Complex, Montana, Matthew P. Harper

Theses and Dissertations

The J-M Reef of the Stillwater Complex, Montana (a large layered mafic intrusion), is one of the highest grade platinum group element (PGE) deposits known in the world, producing primarily palladium and platinum in a 3.4:1 ratio. "Ballrooms" of the Stillwater Complex are anomalously wide areas within or stratigraphically below the J-M Reef that host platinum group element mineralization. Ballrooms have two typical morphologies (type 1 and type 2); the first is an abrupt thickening of the mineralization that extends below the Reef Package and the second is a gentle widening of the Reef Package and associated reef mineralization to …


Structural Analysis Of Co2 Leakage Through The Salt Wash And Little Grand Wash Faults From Natural Reservoirs In The Colorado Plateau, Southeastern Utah, Anthony P. Williams May 2004

Structural Analysis Of Co2 Leakage Through The Salt Wash And Little Grand Wash Faults From Natural Reservoirs In The Colorado Plateau, Southeastern Utah, Anthony P. Williams

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Little Grand Wash fault and the Salt Wash Graben in the Colorado Plateau of southeastern Utah emit CO2 gas from abandoned drillholes, springs, and a hydrocarbon seep. Similar CO2-charged water has also been emitted in the past, as shown by large localized travertine deposits and veins along and near the fault traces. The faults cut natural CO2 reservoirs and provide an excellent analog for geologic CO2 sequestration. The faults cut a north-plunging anticline of rocks consisting of siltstones, shales, and sandstones from the Permian Cutler Formation through the Cretaceous Mancos Shale. The Little Grand …


Geochemistry Of Ground Water - Surface Water Interactions And Metals Loading Rates In The North Fork Of The American Fork River, Utah, From An Abandoned Silver/Lead Mine, Neil I. Burk May 2004

Geochemistry Of Ground Water - Surface Water Interactions And Metals Loading Rates In The North Fork Of The American Fork River, Utah, From An Abandoned Silver/Lead Mine, Neil I. Burk

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The aqueous geochemistry and hydrology of the North Fork of the American Fork River, its tributaries, and the ground water in the vicinity of the Pacific Mine site were investigated in order to determine what impact ground water entering the North Fork has on toxic metal loads in the river. Toxic metal contamination in the North Fork is great enough that brown and cutthroat trout have absorbed lead, cadmium, and arsenic in their tissues at concentrations that are hazardous to human health if consumed. Ground water that flows through the mine site flows directly through the mine tailings before entering …


Hydraulic Testing Of The Big Hole Fault, Northern San Rafael Swell, Utah, William M. Schieb May 2004

Hydraulic Testing Of The Big Hole Fault, Northern San Rafael Swell, Utah, William M. Schieb

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Six cross-hole packer tests were conducted at the Big Hole fault, a dip-slip normal fault in the northern San Rafael Swell of east-central Utah. Three tests were conducted at each of two locations along the fault, each location having a different total displacement. Water was injected in the footwall, hanging wall, and fault core and pressure changes were monitored in isolated intervals in the adjoining wells. Response curves were analyzed using the type curves developed by Hsieh and Neuman, and Theis, in order to evaluate the hydraulic properties of the fault and its associated damage zone.

The tests were not …


Chemical And Isotopic Investigation Of Groundwater In Eastern United Arab Emirates (Uae), Ahmed Ali Abdalla Murad Apr 2004

Chemical And Isotopic Investigation Of Groundwater In Eastern United Arab Emirates (Uae), Ahmed Ali Abdalla Murad

Dissertations

UAE is located at the southeast of Arabian Peninsula. Two main aquifers occupy the study area: the Eastern Gravel Plain and Ophiolite aquifer. Increasing salinity of groundwater and depletion of aquifers are a major concern in the UAE. Previous studies suggest that groundwater, particularly in the Eastern Gravel Plain aquifer, is affected by seawater intrusion and evaporation. Isotopes of oxygen, hydrogen, carbon and chlorine, and chemical analyses were used to investigate this problem in detail. Samples of groundwater from the Eastern Gravel Plain aquifer have R36Cl values in the range of 13.3 to 17.4 x10-15 while those …


Application Of Well Log Tomography To The Dundee And Rogers City Limestones, Michigan Basin, Usa, Mellisa A. Le M. Jan 2004

Application Of Well Log Tomography To The Dundee And Rogers City Limestones, Michigan Basin, Usa, Mellisa A. Le M.

Dissertations, Master's Theses and Master's Reports - Open

The Michigan Basin is located in the upper Midwest region of the United States and is centered geographically over the Lower Peninsula of Michigan. It is filled primarily with Paleozoic carbonates and clastics, overlying Precambrian basement rocks and covered by Pleistocene glacial drift. In Michigan, more than 46,000 wells have been drilled in the basin, many producing significant quantities of oil and gas since the 1920s in addition to providing a wealth of data for subsurface visualization.

Well log tomography, formerly log-curve amplitude slicing, is a visualization method recently developed at Michigan Technological University to correlate subsurface data by utilizing …


Hydrogeochemical Controls On Uranium In Aquifers Of The Jacobsville Sandstone, Heidi M. Sherman Jan 2004

Hydrogeochemical Controls On Uranium In Aquifers Of The Jacobsville Sandstone, Heidi M. Sherman

Dissertations, Master's Theses and Master's Reports - Open

The occurrence of elevated uranium (U) in sandstone aquifers was investigated in the Upper Peninsula of Michigan, focusing on aquifers of the Jacobsville Sandstone. The hydrogeochemical controls on groundwater U concentrations were characterized using a combination of water sampling and spectral gamma-ray logging of sandstone cliffs and residential water wells. 235U/238U isotope ratios were consistent with naturally occurring U. Approximately 25% of the 270 wells tested had U concentrations above the U.S. Environmental Protection Agency Maximum Contaminant Level (MCL) of 30 μg/L, with elevated U generally occurring in localized clusters. Water wells were logged to determine whether …


Complexity Of Devonian K-Bentonites In The Appalachian Foreland Basin: Geochemical And Physical Evidence Supporting Multi-Layered K-Bentonite Horizons, Lucas Benedict Jan 2004

Complexity Of Devonian K-Bentonites In The Appalachian Foreland Basin: Geochemical And Physical Evidence Supporting Multi-Layered K-Bentonite Horizons, Lucas Benedict

Geology Theses and Dissertations

Detailed analysis of Lower to Middle Devonian K-bentonites in the Appalachian Basin reveals physical and geochemical characteristics within supposed single eruptive event deposits that indicate a more complex depositional history is recorded in many of these volcanic beds. Variations in bedding showing multiple coarse and fine-grained layers within a K-bentonite layer can be seen in some Devonian K-bentonite beds. Microscopic irregularities show variations in the orientation of volcanic grains, and subtle phenocryst layers within a K-bentonite suggest changes in depositional environment where changing water and wave regimes rework and redeposit material on the sea floor. The presence of fossil layers …


Road Salt Application And Its Effects On Sodium And Chloride Ion Concentrations In An Urban Stream Patroon Creek, Albany, Ny, Elizabeth K. Erickson Jan 2004

Road Salt Application And Its Effects On Sodium And Chloride Ion Concentrations In An Urban Stream Patroon Creek, Albany, Ny, Elizabeth K. Erickson

Geology Theses and Dissertations

The application of road salt in an urban watershed leads to increased sodium and chloride concentrations in surface water and groundwater, which can adversely affect aquatic ecosystems, and may have consequences for soil cation exchange. This study focuses on the spatial and temporal variations in sodium and chloride concentrations in Patroon Creek, Albany County, New York, a tributary of the Hudson River. For two years, weekly surface water samples were gathered from 7 sites along Patroon Creek for major ion concentrations as measured by ion chromatography. Additionally, a USGS gage on Patroon Creek measures specific conductivity, water temperature, stage, and …


Stable Isotopic And Trace Metal Analyses Of Two Porites Lobata Colonies - Oahu, Hawaii: Implications For Past Seasonal Variation And Sea Surface Temperatures And Anthropogenic Effects On The Reef Environment, Jonathan Macdonald Jan 2004

Stable Isotopic And Trace Metal Analyses Of Two Porites Lobata Colonies - Oahu, Hawaii: Implications For Past Seasonal Variation And Sea Surface Temperatures And Anthropogenic Effects On The Reef Environment, Jonathan Macdonald

Geology Theses and Dissertations

Corals from the western and equatorial Pacific Ocean have been extensively studied for the purposes of generating paleoclimate reconstructions spanning the last several hundred years. However, in the central subtropical North Pacific, there are currently few published coral records extending beyond 10 to 20 years. The hermatypic coral species Porites lobata and Porites lutea have proven to be useful indicators of paleoclimate and past sea surface conditions at other locations. Here I have analyzed two Porites lobata coral cores collected from colonies from opposite sides of Oahu, Hawaii to assess their utility for developing multi-decadal length climatic reconstructions in this …


Structural Analysis Of The Gonic Formation In Berwick, Maine, Joseph F. Renda Jan 2004

Structural Analysis Of The Gonic Formation In Berwick, Maine, Joseph F. Renda

Geology Theses and Dissertations

RELATIONSHIP OF THE GONIC FORMATION AND NONSUCH RIVER FAULT TO THE NORUMBEGA FAULT ZONE IN BERWICK, MAINE
Located in southwestern Maine the Gonic Formation abuts the Nonesuch River Fault of the Norumbega Fault System. The rock types of the Gonic Fm. consist
predominantly of micaceous schist and lesser amounts of quartzite. Fieldwork suggests that the units have undergone transposition and thus appear to be
interlayered and pinch-out along strike. Granitoid rocks have also been observed and are interpreted as related to either the Lyman Pluton or White Mountain
Complex and serve as the backbone to the line of low-lying hills …


Microstructures And Deformation In Some Fault Rocks From The Mcconnell Thrust At Mount Yamnuska (Alberta): Implications For Fluid Flow And Faulting And Cycles Of Strain-Hardening And Softening, Lowell Miyagi Jan 2004

Microstructures And Deformation In Some Fault Rocks From The Mcconnell Thrust At Mount Yamnuska (Alberta): Implications For Fluid Flow And Faulting And Cycles Of Strain-Hardening And Softening, Lowell Miyagi

Honors Papers

Fault rocks from the McConnell thrust consist of limestone mylonite, carbonate and shale cataclasites, and deformed sandstones. The limestone mylonite in the hanging wall mayor may not show different levels of cataclastic overprint. Just below these hanging wall rocks is a zone of comminuted material. This zone contains cataclasites that are produced by the mixing of hanging wall and footwall materials. Underneath this unit are the shale cataclasites of the footwall and beneath this are deformed sandstones that become progressively less deformed further from the fault zone. Based on microstructural evidence these rocks show cycles of mesoscopically brittle and ductile …


Epibiont Guilds As Paleoecological Tools In Environmental Analysis: An Example From Modern And Ordovician Shell Substrates, Stacy M. Boore Jan 2004

Epibiont Guilds As Paleoecological Tools In Environmental Analysis: An Example From Modern And Ordovician Shell Substrates, Stacy M. Boore

Honors Papers

Paleocommunities of encrusting organisms exhibit characteristics that allow comparisons of modern and fossil systems and subsequent environmental analyses. Encrusting organisms attach to a substrate that is generally limited in area. Interactions between bionts and the host organism, and bionts and the environment, are preserved on epibiont encrusted fossils. Modern biont communities from known environments can be compared to fossil biont communities in order to determine the ancient environment experienced by that fossil. Using epibionts as a tool in paleo-environmental analyses employs the somewhat problematic idea that the present can be used as a key to the past. I suggest that …


Magnetic Susceptibility For The Paleocene-Eocene Boundary: Correlation Among Three Egyptian Sections, Kelli Willson Jan 2004

Magnetic Susceptibility For The Paleocene-Eocene Boundary: Correlation Among Three Egyptian Sections, Kelli Willson

Honors Theses

No abstract provided.


Assessing Anthropogenic And Natural Impacts On Ghost Crab ( Ocypode Quadrata) Populations At Cape Hatteras National Seashore, North Carolina, Cynthia B. Landry Jan 2004

Assessing Anthropogenic And Natural Impacts On Ghost Crab ( Ocypode Quadrata) Populations At Cape Hatteras National Seashore, North Carolina, Cynthia B. Landry

Dissertations, Theses, and Masters Projects

No abstract provided.


Geometric And Kinematic Evolution Of The Bessemer Transverse Zone, Alabama Alleghanian Thrust Belt, Margaret Colette Brewer Jan 2004

Geometric And Kinematic Evolution Of The Bessemer Transverse Zone, Alabama Alleghanian Thrust Belt, Margaret Colette Brewer

University of Kentucky Doctoral Dissertations

Transverse zones are important syn-kinematic components of thrust belt development. Various scales of data were utilized to develop three-dimensional geometric and kinematic models for the Bessemer transverse zone (BTZ) of the Alabama Alleghanian thrust belt.

Regional analysis of the BTZ began with the examination of geologic maps (1:250,000, 1:48,000, and 1:24,000 scales), seismic reflection profiles, well data, and previous stratigraphic research. All Paleozoic-age stratigraphic contacts, major thrust faults and associated folds, and various unnamed minor structures were compiled to create two strike-perpendicular, and five-strike parallel, cross sections transecting the extent of the BTZ at a scale of 1:100,000. The balanced …


Rugose Corals Of The Livingston Limestone Member, Bond Formation, Coles And Edgar County, Illinois, John Tobias Burke Jan 2004

Rugose Corals Of The Livingston Limestone Member, Bond Formation, Coles And Edgar County, Illinois, John Tobias Burke

Masters Theses

No abstract provided.


Sedimentological And Geochemical Characterization Of East Pond, Belgrade Lakes Watershed, Central Maine, Robin H. Nesbeda Jan 2004

Sedimentological And Geochemical Characterization Of East Pond, Belgrade Lakes Watershed, Central Maine, Robin H. Nesbeda

Honors Theses

The present study focuses on East Pond, the head of the lake-chain system. East Pond is roughly oval in shape with several coves along the margins; it has an average 3 depth of 4.5 m, a maximum depth of 7.3 m, and a total volume of 26.35 x 10 6 m . The lake is surrounded by North temperate hardwood forest and a marshy outlet to the other lakes exists in the northwest comer. East Pond has suffered severe yearly algal blooms during the late summer and into the fall since 1993. This project aims to develop a baseline for …


Compositional And Mineralogical Relationships Between Mafic Inclusions And Host Lavas As Key To Andesite Petrogenesis At Mount Hood Volcano, Oregon, Melinda Michelle Woods Jan 2004

Compositional And Mineralogical Relationships Between Mafic Inclusions And Host Lavas As Key To Andesite Petrogenesis At Mount Hood Volcano, Oregon, Melinda Michelle Woods

Dissertations and Theses

Throughout its eruptive history, Mount Hood has produced compositionally similar calc-alkaline andesite as lava flows and domes near the summit and basaltic andesitic flows from flank vents. Found within the andesite are slightly more mafic inclusions that are compositionally similar to the host andesite (or host lavas); no inclusions were found in the flank lavas. Host lavas and inclusions have the following mineral assemblage: plag + opx ± cpx ± amp + oxides. Flank lava mineralogy is similar to the inclusions and host lavas, but since they are more mafic they contain olivine instead of amphibole. Average silica content among …


Timing And Paleoclimatic Significance Of Latest Pleistocene And Holocene Cirque Glaciation In The Enchantment Lakes Basin, North Cascades, Wa, Eric L. (Eric Leland) Bilderback Jan 2004

Timing And Paleoclimatic Significance Of Latest Pleistocene And Holocene Cirque Glaciation In The Enchantment Lakes Basin, North Cascades, Wa, Eric L. (Eric Leland) Bilderback

WWU Graduate School Collection

The Enchantment Lakes Basin in the Alpine Lakes Wilderness, Washington, preserves two sets of moraines that record distinct post-Wisconsin maximum advances of cirque glaciers in the eastern North Cascades. Cores collected from five lakes adjacent to the moraines indicate that there were two Neoglacial advances, culminating with the Little Ice Age, and one slightly larger advance that ended coincident with the termination of the North Atlantic Younger Dryas event. The cores show no evidence for an early Holocene advance, in contrast to some other studies in the North Cascades, (e.g., Heine, 1998; Thomas, 1997; Thomas et al., 2000).

Upstream glacier …


The Paleomagnetism Of The Stewart’S Point And Anchor Bay Members Of The Point Arena Terrane, Northern California, Kirk Heim Jan 2004

The Paleomagnetism Of The Stewart’S Point And Anchor Bay Members Of The Point Arena Terrane, Northern California, Kirk Heim

WWU Graduate School Collection

Paleomagnetic investigation of Upper Cretaceous sedimentary strata of the Point Arena terrane has shown the rocks to be remagnetized. The study was initially intended to reconstruct the Cretaceous paleogeography of the Point Arena terrane and resolve conflicting translation estimates, but became one of remagnetization. Samples studied are from the Upper Cretaceous Stewart’s Point member and the Late Cretaceous Anchor Bay Member of the Gualala formation. Specimens surviving the remagnetization have a mean second-removed direction that indicates approximately 20 degrees vertical rotation from the expected direction of the Cretaceous magnetic field at the locality of the Point Arena terrane. The loss …


Modeling The Contributions Of Glacial Meltwater To Streamflow In Thunder Creek, North Cascades National Park, Washington, Jay W. (Jay William) Chennault Jan 2004

Modeling The Contributions Of Glacial Meltwater To Streamflow In Thunder Creek, North Cascades National Park, Washington, Jay W. (Jay William) Chennault

WWU Graduate School Collection

In regions where glaciers occur, like the North Cascades, glacial meltwater is a vital component of rivers and streams. Glacial meltwater can also be critical for hydroelectric and municipal purposes. A concern for water resources managers is that glaciers in the North Cascades have been shrinking. The glacier ice coverage of Thunder Creek watershed, the most heavily glaciated basin in the North Cascades, has dropped from approximately 22.5 % to 12.8 % since the Little Ice Age (LIA) maximum (ca. 1850). Glacial meltwater contributions to Thunder Creek are of interest because the creek serves as a tributary to Diablo Reservoir, …


The Extent Of The White Chuck Tuff, A High Temperature Pyroclastic Flow Deposit, Glacier Peak, Washington, Gerald T. Ladd Jan 2004

The Extent Of The White Chuck Tuff, A High Temperature Pyroclastic Flow Deposit, Glacier Peak, Washington, Gerald T. Ladd

WWU Graduate School Collection

The White Chuck Tuff, a massive deposit approximately 15 m thick, caps two terraces in the White Chuck River valley covering an area of approximately 5 km2 at the base of Glacier Peak, Washington. Three major post-glacial eruption cycles from Glacier Peak reportedly occurred approximately from 12,000 to 11,250 years ago (White Chuck Assemblage), from 5,500 to 5,100 years ago (Kennedy Creek Assemblage), and from 1,800 to 250 years ago (recent eruptions). West of Glacier Peak, pyroclastic and lahar deposits from all three episodes are found in drainages out to Puget Sound 100 km away. The White Chuck Tuff …