Physical Sciences and Mathematics Commons^™

Paleomagnetic Evidence Of Vertical Axis Block Rotations From The Mesozoic Of Northern Chile, Paul D. Riley, Myrl E. Beck Jr., Russ R. Burmester, Constantino Mpodozis, Alfredo Garcia

Geology Faculty Publications

We present paleomagnetic results for three Mesozoic formations from northern Chile: La Ternera Formation (Upper Triassic), Quebrada Monardes Formation (Upper Jurassic); Cerrillos Formation (Upper Cretaceous). Results from the Cerrillos are divided into eastern (Cuesta El Gao (CEG)) and western (Elisa De Bordo (EBD)) localities. Most specimens from La Ternera volcanic and sedimentary rocks are mag­netically stable, as shown by alternating field and thermal demagnetization. More complicated but still reliable results were obtained from Quebrada Monardes red beds. Normal and reverse polarities are present in both units; means of both populations are antiparallel at 95% confi­dence. The Quebrada Monardes Formation also …

The Planet, 1993, Volume 23, Issue 03, T. R. Morris, Huxley College Of The Environment, Western Washington University

The Planet

No abstract provided.

Lake Whatcom Monitoring Project 1991/1992 Report, Robin A. Matthews, Geoffrey B. Matthews

Lake Whatcom Annual Reports

This report is part of an on-going series of annual reports and special project reports that document the Lake Whatcom monitoring program.

This work is conducted by the Institute for Watershed Studies and other departments at Western Washington University. The major objective of this program is to provide long-term baseline water quality monitoring in Lake Whatcom and selected tributaries. Each section contains brief explanations about the water quality data, along with discussions of patterns observed in Lake Whatcom.

The Planet, 1993, Volume 23, Issue 02, T. R. Morris, Huxley College Of The Environment, Western Washington University

The Planet

No abstract provided.

Structure And Metamorphism Of The Magic Mountain – Johannesburg Mountain Area, North Cascades, Washington, Bernard E. Dougan

WWU Graduate School Collection

The orogenic history of the Cascades Crystalline Core is addressed in the study of a small, central region that straddles the Entiat fault on the southwest flank of the Skagit Gneiss. This region contains an arc-derived terrane with a preserved stratigraphy of volcanic, clastic and pelitic petrofacies of the Cascade River unit on a basement of sub-arc plutonics, the Marblemount Meta-Quartz Diorite. The Magic Mountain Gneiss, derived from the Marblemount arc, is inferred to have formed as a sub-volcanic sill-like pluton that intruded the protolith of the Cascade River unit In contact with the Cascade River unit is the Napeequa …

Net Shore-Drift Of San Juan County And Parts Of Jefferson, Island And Snohomish Counties, Washington, James W. Johannessen

WWU Graduate School Collection

Net shore-drift directions, representing the long-term, net result of littoral sediment transport on both the beachface and in nearshore waters, were determined in San Juan County, eastern Jefferson County, and southern Island and Snohomish Counties, Washington. Studies employing similar methods have been conducted in the state for the Washington State Department of Ecology, to update coastal drift information provided to area planners. This project completes net shore-drift mapping of the entire marine coast of Washington State. The Puget Lowland experiences prevailing and predominant southerly winds, but is also subjected to locally variable winds. The irregular coast of the islands and …

Channel Changes And Flood Frequency On The Upper Main Stem Of The Nooksack River, Whatcom County, Washington, Roger G. Bertschi

WWU Graduate School Collection

This study focuses on three aspects of the hydrology of the lower Nooksack River that are of interest in understanding flooding processes and for planning: (1) a comparison of changes in channel locations and cross-sections at several points along the Nooksack, (2) the determination of distribution of surface sediment in exposed bars and banks, and (3) an estimation of flood frequencies by the Gumbel and Log Pearson methods. These aspects give a useful depiction of recent flooding and channel activity.

The Nooksack River channel has remained within a defined thalweg zone from 1906 to 1991, the period of map record. …

Hydrogeochemical Interactions In A Subalpine Watershed, Mount Baker National Recreation Area, Washington, Joann Michele Holloway

WWU Graduate School Collection

The Upper Bagley watershed was monitored from April to November, 1992. The watershed is described as a series of chemically distinct subsystems: 1) the snowpack, 2) soil solutions, and 3) surface water. The hydrogeochemical interactions between these subsystems were investigated in the Upper Bagley watershed. Chemical analyses of these fluids were used to identify how soil solutions vary from water derived from the snowpack and what impact soil solutions have on surface-water chemistry.

Water-ice interactions alter the snowpack chemistry, enriching the melt in calcium, magnesium, sodium, chloride, and sulfate that accumulate at the surface of ice crystals. The melt from …

Life Histories In An Epifaunal Community: Coupling Of Adult And Larval Processes, Brian L. Bingham

Environmental Sciences Faculty and Staff Publications

Marine invertebrates growing epifaunally on red mangrove (Rhizophora mangle) prop roots in the Indian River, Florida, USA, were studied in a small mangrove island (Jim Island) through which a number of channels had been cut. Roots hanging down into the water supported diverse epifaunal communities including sponges, oysters, barnacles, bryozoans, and ascidians. To determine what factors control species' population dynamics and contribute to the high degree of spatial heterogeneity characteristic of communities in this unique habitat, two hypotheses were tested: (1) Distributions of species on the roots are controlled by differential growth and mortality due to physical features; and (2) …

The Planet, 1992, Volume 22, Issue 01, T. R. Morris, Huxley College Of The Environment, Western Washington University

The Planet

No abstract provided.

A Rifted Margin Origin For The Crescent Basalts And Related Rocks In The Northern Coast Range Volcanic Province, Washington And British-Columbia, Randall Scott Babcock, Russ R. Burmester, David C. Engebretson, A. C. Warnock, K. P. Clark

Geology Faculty Publications

The remarkable early to middle Eocene volcanic sequence of the Crescent Formation exposed on the Olympic Peninsula consists predominantly of tholeiitic to minor transitional alkaline basalts with sparse sedimentary interbeds. A composite section measured in the vicinity of the Dosewallips River includes 8.4 km of pillowed to massive submarine basalts overlain by 7.8 km of subaerial flows. An upper limit of about 48 Ma on the age of the Crescent basalts is indicated by faunal assemblages in sediments interbedded with the uppermost flows in the sequence and a circa 50 Ma ⁴⁰Ar/³⁹Ar age on a leucogabbro from …

The Planet, 1992, Volume 21, Issue 03, Peter Donaldson, Associated Students Environmental Center, Western Washington University

The Planet

No abstract provided.

The Planet, 1992, Volume 21, Issue 02, Peter Donaldson, Associated Students Environmental Center, Western Washington University

The Planet

No abstract provided.

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 …

The Sedimentology, Petrology, And Tectonic Significance Of The Middle Eocene Flattery Breccia, Lyre Formation, Northwestern Olympic Peninsula, Washington, Alice Benkovich Shilhanek

WWU Graduate School Collection

The Flattery breccia, an informally designated unit within the middle Eocene Lyre Formation, consists of sedimentary breccia and conglomerate exposed at Cape Flattery, located at the northwestern point of the Olympic Peninsula, Washington. The Flattery breccia was deposited during the late Narizian, approximately 44 to 42 Ma.

The boulder- through sand-size detritus of the Flattery breccia and western Lyre Formation, which changes in texture along strike, were deposited by sediment- gravity flows, such as surging high-density turbidity currents and sandy debris flows. Interfingering alluvial fan-deltas, interfingering lobes of coarse detritus on a submarine fan, or resedimented wedges of coarse-grained detritus …

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 …

Late Pleistocene Deglaciation History At Point Partridge, Central Whidbey Island, Washington, Cynthia A. Carlstad

WWU Graduate School Collection

The study area contains a record of deglaciation events that has not been recognized elsewhere in the Puget Lowland. This record includes both subaerial outwash and glaciomarine deposition. The geologic history of the study area during recession of the Vashon ice sheet is marked by the following events:

1. Deposition of a kame delta complex from grounded ice probably located in Penn Cove and west of Point Partridge. This delta complex was built into marine water with a sea-level at approximately 55 meters. Eventually, ice drained by the outwash streams stagnated in the Point Partridge kettle region.
2. Isostatic rebound of the …

Metamorphism And Plutonism Of The Mt. Buckindy – Snowking Region, North Cascades, Washington, Steve M. (Steven Milton) Fluke

WWU Graduate School Collection

The focus of this study is on the metamorphism, plutonism, and structures of the Mt. Buckindy-Snowking region of the North Cascades crystalline core.

In a 15 by 30 km region in the northwest portion of the crystalline core, Cretaceous plutons in a northwest-southeast belt intrude rocks of the Napeequa unit. Metamorphic grade in the country rock ranges from lower greenschist facies in the northwest to amphibolite facies in the southeast. Thermobarometry applied to the equilibrium assemblages garnet-biotite-muscovite-plagioclase and garnet-homblende- plagioclase defines orogen-normal isobars varying from less than 4 Kb in the northwest to over 9 Kb in the south.

Plutons …

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 …

Petrology And Structure Of The Eldorado Peak Area, North Cascades, Washington, Dan (Daniel Phelan) Mcshane

WWU Graduate School Collection

In this thesis the problem of the timing and mechanism of orogeny in the Skagit Gneiss of the North Cascades, Washington, is addressed by investigating plutonism and metamorphism in the vicinity of Eldorado Peak.

The primary finding of this project is that the 88-90 Ma Eldorado pluton was intruded, not faulted, into the Cascade River Schist and Skagit Gneiss. Intrusion is indicated by cross-cutting of foliations in country rock by the pluton, apophyses of Eldorado pluton in the country rock, and xenoliths of local country rock in the pluton. Detailed mapping shows that the Eldorado pluton does not cross-cut younger …

The Planet, 1991, Volume 21, Issue 01, Peter Donaldson, Associated Students Environmental Center, Western Washington University

The Planet

No abstract provided.

Metamorphic Evidence For Tilt Of The Spuzzum Pluton – Diminished Basis For The Baja British-Columbia Concept, E. H. Brown, Russ R. Burmester

Geology Faculty Publications

To address the question of tilt versus translation as the mechanism responsible for discordance between paleomagnetic directions of Cretaceous plutons in the British Columbia Coast Plutonic Complex and the North American reference direction, metamorphic pressures around the margin of the Spuzzum pluton have been determined. Pressures are derived from microprobe analyses and evaluation of exchange equilibria in the assemblage garnet-biotite-plagioclase-aluminum silicate-quartz. Samples studied come from eight localities in the contact aureole around the pluton and encompass the area of a previous paleomagnetic study. The analyzed samples are coarse grained and exhibit textural features indicative of equilibrium crystallization following emplacement of …

Paleomagnetism Of The Patagonian Plateau Basalts, Southern Chile And Argentina, Robert F. Butler, Francisco Herve, Francisco Munizaga, Myrl E. Beck Jr., Russ R. Burmester, Eduardo S. Oviedo

Geology Faculty Publications

A total of 505 paleomagnetic samples were collected from 65 sites (volcanic flows) of the Patagonian plateau basalts at four locations in southem Chile and Argentina. K/Ar analyses indicate that 38 flows from two locations form a Late Cretaceous group (64-79 Ma), while the remaining 27 flows are Eocene in age (42-56 Ma). Progressive demagnetization indicates that a characteristic remanent magnetization (ChRM) has been successfully isolated from 59 flows. Rock-magnetic prop­erties and analysis of ChRM directions within and between sites allow the secure inference that the ChRM is a thermoremanent magnetization acquired during original cooling. The Eocene flows yield 15 …

The Planet, 1991, Volume 20, Issue 03, Michael J. Lehnert, Associated Students Environmental Center, Western Washington University

The Planet

No abstract provided.

The Planet, 1991, Winter, Michael J. Lehnert, Associated Students Environmental Center, Western Washington University

The Planet

No abstract provided.

Sediment Budget For The Grouse Creek Basin, Humboldt County, California, Mary A. Raines

WWU Graduate School Collection

A sediment budget constructed for the Grouse Creek basin in northern California provides information on the sources and timing of sediment production to aid land managers in understanding the effects of logging impacts in a sensitive watershed. The sediment budget yields a sediment production rate of 1,750 t/km²/yr for a 29-year period. This rate is among the highest for such disturbed forested basins in the Pacific Northwest. Approximately 40 percent of the Grouse Creek basin, which is bisected by regional structural features that have created zones of weak and altered rock, has been logged in the last 35 …

Fabric Study And Structural History Of Deformed Plutonic And Metamorphic Rocks In The Holden Area, North Cascades, Washington, Gary K. Hurban

WWU Graduate School Collection

The Holden area, in the Crystalline Core of the North Cascades, contains deformed and undeformed plutons ranging from Triassic to Eocene in age.

Two deformational styles have been identified in the Holden area. Contractional deformation is indicated by steeply-plunging, down-dip, mineral and stretching lineations in the syn-tectonic Seven Fingered Jack pluton (estimated midLate Cretaceous), and in the pre-tectonic Dumbell Mountain pluton (220 Ma), associated with apparent flattened fabrics. Strike-slip shear deformation is represented by gently-plunging to subhorizontal, strike-parallel mineral and stretching lineations, which are commonly associated with constricted fabrics. These fabrics occur prominently in the Dumbell Mountain pluton, and crosscut …

The Planet, 1990, Fall, Michael J. Lehnert, Huxley College Of The Environment, Western Washington University

The Planet

No abstract provided.

The Planet, 1990, Spring, Sara Olason, Associated Students Environmental Center, Western Washington University

The Planet

No abstract provided.

The Planet, 1990, Winter, Sara Olason, Associated Students Environmental Center, Western Washington University

The Planet

No abstract provided.