Earth Sciences Commons^™

A Small Look At The Big Picture: Linking Geopotential Height Anomalies To Paleofloods On The Snake River, Idaho And Oregon, Gwendolyn Bernitha Rhodes

All Master's Theses

A combined paleoflood and flood hydroclimatology study on the Snake River in Idaho and Oregon suggests a link between floods and patters of geopotential height anomalies over the North Pacific Ocean. Examination of the paleoflood record in two 4-m (12 ft) tall terraces along the Hells Canyon reach of the Snake River in Idaho and Oregon shows evidence of at least twenty-two late-Holocene extreme floods that occurred approximately 5,000 years. The ages of paleoflood deposits at these sites fall into two time periods, from 5130 ± 40 to 1960 ± 40 yr BP and from 320 ± 40 yr BP …

New Kinematic Models For Pacific‐North America Motion From 3 Ma To Present, Ii: Evidence For A “Baja California Shear Zone”, Timothy Dixon, Fred Farina, Charles Demets, Francisco Suarez-Vidal, John Fletcher, Bertha Marquez-Azua, M. Meghan Miller, Osvaldo Sanchez, Paul Umhoefer

All Faculty Scholarship for the College of the Sciences

We use new models for present‐day Pacific‐North America motion to evaluate the tectonics of offshore regions west of the Californias. Vandenburg in coastal Alta California moves at the Pacific plate velocity within uncertainties (∼1 mm/yr) after correcting for strain accumulation on the San Andreas and San Gregorio‐Hosgri faults with a model that includes a viscoelastic lower crust. Modeled and measured velocities at coastal sites in Baja California south of the Agua Blanca fault, a region that most previous models consider Pacific plate, differ by 3–8 mm/yr, with coastal sites moving slower that the Pacific plate. We interpret these discrepancies in …

Evolution Of The Kangmar Dome, Southern Tibet: Structural, Petrologic, And Thermochronologic Constraints, Jeffrey Lee, Bradley R. Hacker, William S. Dinklage, Yu Wang, Phillip Gans, Andrew Calvert, Jinglin Wan, Wenji Chen, Ann E. Blythe, William Mcclelland

All Faculty Scholarship for the College of the Sciences

Structural, thermobarometric, and thermochronologic investigations of the Kangmar Dome, southern Tibet, suggest that both extensional and contractional deformational histories are preserved within the dome. The dome is cored by an orthogneiss which is mantled by staurolite + kyanite zone metasedimentary rocks; metamorphic grade dies out up section and is defined by a series of concentric kyanite-in, staurolite-in, garnet-in, and chloritoid-in isograds. Three major deformational events, two older penetrative events and a younger doming event, are preserved. The oldest event, D1, resulted in approximately E-W trending tight to isoclinal folds of bedding with an associated moderately to steeply north dipping axial …

Present‐Day Motion Of The Sierra Nevada Block And Some Tectonic Implications For The Basin And Range Province, North American Cordillera, Timothy H. Dixon, M. Meghan Miller, Frederic Farina, Hongzhi Wang, Daniel Johnson

All Faculty Scholarship for the College of the Sciences

Global Positioning System (GPS) data from five sites on the stable interior of the Sierra Nevada block are inverted to describe its angular velocity relative to stable North America. The velocity data for the five sites fit the rigid block model with rms misfits of 0.3 mm/yr (north) and 0.8 mm/yr (east), smaller than independently estimated data uncertainty, indicating that the rigid block model is appropriate. The new Euler vector, 17.0°N, 137.3°W, rotation rate 0.28 degrees per million years, predicts that the block is translating to the northwest, nearly parallel to the plate motion direction, at 13–14 mm/yr, faster than …

Surficial Slip Distribution On The Central Emerson Fault During The June 28, 1992, Landers Earthquake, California, Sally F. Mcgill, Charles M. Rubin

All Faculty Scholarship for the College of the Sciences

We present the results of our mapping of a 5.6‐km length of the central Emerson fault that ruptured during the 1992 Landers earthquake in the southwestern Mojave Desert, California. The right‐lateral slip along this portion of the rupture varied from about 150 to 530 cm along the main rupture zone. In some locations a total of up to 110 cm of additional right‐lateral slip occurred on secondary faults up to 1.7 km away from the main rupture zone. Other secondary faults carried up to several tens of centimeters of left‐lateral or thrust displacement. The maximum net vertical displacement was 175 …

Precise Measurements Help Gauge Pacific Northwest's Earthquake Potential, M. Meghan Miller, Herb Dragert, Elliot Endo, Jeffrey T. Freymueller, Chris Goldfinger, Harvey M. Kelsey, Eugene D. Humphreys, Daniel J. Johnson, Robert Mccaffrey, John S. Oldow, Anthony Qamar, Charles M. Rubin

Geological Sciences Faculty Scholarship

Except for the recent rumblings of a few moderate earthquakes and the eruption of Mt. St. Helen's, all has been relatively quiet on the Pacific Northwestern front. The Cascades region in the Pacific Northwest, a sporadically active earthquake and volcanic zone, still has great seismic potential [Atwater, 1987], as comparisons with other subduction zones around the world have shown [Heaton and Kanamori, 1984]. Recent tsunami propagation models [Satake, 1996] and tree ring studies suggest that the last great Cascadia earthquake occurred in the winter of 1700 A.D. and had a magnitude of −8.9. The …

Factors Contributing To Landslide Activity In The Winter Of 1995-96, Clearwater County Near Orofino, Idaho, Aaron Paul Wisher

All Master's Theses

Significant landslide activity occurred in Clearwater County, Idaho in November 1995 and February-May 1996. Mass wasting in the study area consisted of debris slides and earthflows triggered by rain-on-snow weather events. It is important to determine what factors contribute to landsliding in this area so that reliable prediction can reduce the destruction of property. Through field observation and aerial photo analysis, the factors contributing to landslides were studied. The objectives included a study of the geology, soils, aspect, slope gradient, vegetation and slope position related to each slide. Also a goal was to assess the role of land use in …

Long Dormancy, Low Slip Rate, And Similar Slip‐Per‐Event For The Emerson Fault, Eastern California Shear Zone, Charles M. Rubin, Kerry Sieh

All Faculty Scholarship for the College of the Sciences

Excavations in a playa along the 1992 rupture of the Emerson fault reveal evidence of two paleoseismic events, with only one large prehistoric rupture in the past 15 millennia. Accelerator mass spectrometer radiocarbon ages of charcoal from playa sediments and from fault‐scarp colluvium directly beneath the playa beds indicate that the last large prehistoric slip event occurred about 9000 ka. Trench‐wall exposures revealed clear evidence of at least one pre‐9 ka rupture at the playa site. The event horizon of this earthquake is between two pedogenic carbonate layers that have radiocarbon ages of 14.8 ka and 24.1 ka, implying that …

The Geodetic Signature Of The M8.0 Oct. 9, 1995, Jalisco Subduction Earthquake, Timothy I. Melbourne, I. Carmichael, C. Demets, K. Hudnut, O. Sanchez, J. Stock, G. Suarez, F. Webb

Faculty Scholarship for the Cascadia Hazards Institute

The October, 1995 Mw 8.0 Jalisco subduction earthquake has provided a thorough geodetic observation of the coseismic subduction process. An 11 station regional GPS network located directly onshore of the rupture demonstrates consistent vertical subsidence verified by tide gauge data and southwest-directed extension, with measured displacements reaching 1 meter. Unusually shallow and non-uniform faulting is required to explain the displacements. We determine that up to 5 meters of slip occurred within the upper 15 km of the thrust fault zone and 2 meters possibly as shallow as 8 km, and that slip was likely distributed in two main patches. The …

Prolonged History Of Silicic Peralkaline Volcanism In The Eastern Pacific Ocean, Wendy A. Bohrson, Mary R. Reid, Anita L. Grunder, Matthew Heizler, T. Mark Harrison, Jeffrey Lee

All Faculty Scholarship for the College of the Sciences

Socorro Island, Mexico, is an alkaline and peralkaline volcanic island located in the eastern Pacific Ocean on a mid-ocean ridge spreading center that was abandoned at ∼3.5 Ma. Silicic peralkaline rocks comprise up to 80% of the surface of the island, rendering Socorro virtually unique in the Pacific Ocean. Precise, replicate ⁴⁰Ar/³⁹Ar ages of 21 peralkaline trachytes and rhyolites reveal a history of episodic volcanic activity from ∼540 to 370 ka that may have culminated with caldera formation; repose periods between these episodes may have had maximum duration of ∼30 kyr. After up to 200 kyr of …

Constraints On Present-Day Basin And Range Deformation From Space Geodesy, Jeffrey Lee, Timothy H. Dixon, Stefano Robaudo, Marith C. Reheis

All Faculty Scholarship for the College of the Sciences

We use new space geodetic data from very long baseline interferometry and satellite laser ranging combined with other geodetic and geologic data to study contemporary deformation in the Basin and Range province of the western United States. Northwest motion of the central Sierra Nevada block relative to stable North America, a measure of integrated Basin and Range deformation, is 12.1±1.2 mm/yr oriented N38°W±5° (one standard error), in agreement with previous geological estimates within uncertainties. This velocity reflects both east-west extension concentrated in the eastern Basin and Range and north-northwest directed right lateral shear concentrated in the western Basin and Range. …

Rapid Uplift And Rotation Of Mylonitic Rocks From Beneath A Detachment Fault: Insights From Potassium Feldspar 40ar/39ar Thermochronology, Northern Snake Range, Nevada, Jeffrey Lee

All Faculty Scholarship for the College of the Sciences

The thermal histories of mylonitic rocks from the footwall of the northern Snake Range decollement (NSRD), Nevada, were calculated using multiple diffusion domain analyses of potassium feldspar Arrhenius data and ⁴⁰Ar/³⁹Ar age spectra in order to characterize the cooling (exhumation) history of these mylonitic rocks and thereby constrain the origin and movement history of the NSRD. The calculated thermal histories, along with reported apatite fission track ages, indicate the three following episodes of rapid cooling (10–55°C/m.y.) related to extensional denudation: (1) middle Eocene (48–41 Ma), (2) late Oligocene (30–26 Ma), and (3) early Miocene (20–16 Ma). The …

Do Microplates In Subduction Zones Leave A Geological Record?, Jeffrey Lee, Joann M. Stock

All Faculty Scholarship for the College of the Sciences

Active microplate boundaries in ocean-continent subduction zones may induce deformation of the overlying plate and spatial or geochemical variations in the volcanic arc. We discuss two modern cases. The first is the South Gorda-Juan de Fuca plate boundary in the Cascadia subduction zone, where there is little or no effect on the overriding plate and the oceanic plate takes up much of the deformation. The second case is the Cocos-Rivera plate boundary in the Middle America trench, where the overlying Colima graben contains substantial deformation in a zone extending from the trench to the volcanic arc and the sub-duction-related volcanism …

An Outcome-Based Curriculum Design For Seventh Grade Earth Science, Jeffrey Scott Fields

All Graduate Projects

This project presents a curriculum design to be used for the seventh grade Earth Science course taught at Centerville School. The curriculum was created by modifying the district's student learning objectives into outcome-based objectives, lessons and units. This project was designed with the intent of enhancing the teaching of earth science and aiding other teachers in the district by giving them a possible model for their own curricula comparison and adoptions. The curriculum design was successful in meeting these intentions.

The Enhancement Of Earth Science Laboratories And Activities Through Inquiry, Discovery And Hands-On Methods, Diane Hinchliff Hesse

All Graduate Projects

The central objective of this project is to enhance the middle school eighthgrade Earth Science curriculum by developing or adapting existing laboratory activities to model hands-on, inquiry, and discovery learning methods. These laboratory activities are designed to encourage independent student-centered learning as opposed to teacher-centered and directed activities.

The project also explored the nature of the science laboratory as it exists in classrooms today and how it can be improved through an understanding of the nature and process of science.

Tertiary Coniferous Woods Of Western North America, George F. Beck

All Faculty Scholarship for the College of the Sciences

Almost four decades have elapsed since Platen (1908), the German paleobotanist, published his report upon the fossil woods of the western United States. Since then no over-all treatment of these materials has been attempted. although Platen overlooked the Pacific Northwest with its abundance of Tertiary petrified woods. The purpose of this paper is to bring knowledge of the western coniferous woods of the Tertiary up to date. In this effort the writer recognizes that much of this information has been accumulated incidentally in the study of the Russell Petrified Forest series of central Washington, and that it is not as …

Nyssa Woods Of The Pacific-Northwest Tertiary, George F. Beck

All Faculty Scholarship for the College of the Sciences

The nyssa gums are one of the modern genera of trees most certainly present among the petrified woods and forests of the Pacific Northwest. Almost every collection from the mid-Tertiary of this region contains a few specimens of typical tupelo or sour gum. These are fine-grained woods which to the unaided eye may be mistaken for conifers.

Ancient Maples Of The Central Washington Region, George F. Beck

All Faculty Scholarship for the College of the Sciences

When I began work on the petrified logs of the general Vantage area some 13 years ago, it became apparent at once that maple-like woods are commonplace in the main (Vantage) raft forest and slightly less abundant in two rooted units of the Yakima Canyon. So widely do these woods range throughout the structural variations found in modern maples that little success has attended the efforts to assign them to nominal species. The extremes can readily be established but few hints exist as to the boundaries between them.

Two Newly Discovered Conifers, George F. Beck

All Faculty Scholarship for the College of the Sciences

Two genera of coniferous wood, apparently not listed among the Tertiary woods of the western states, have been recognized in the Percy Train collections from Rainbow Ridge, northwestern Nevada. These two, Tsuga (hemlock) and Chamaecyparis (cedar) bring up to 14 the genera of coniferous wood more or less certainly identified from the period and area in question.

Status Of Tertiary Woods Of The Western States Representing The Juglandaceae, George F. Beck

All Faculty Scholarship for the College of the Sciences

For many years there has been uncertainty concerning the generic status of some fossil leaves belonging without question to the walnut family as a whole. A review of the woods of Juglandaceae as they have appeared in Tertiary horizons of the western states has suggested which genera are present, and in what proportions their leaves (or other remains) might be expected to appear.

Life History Of The Ginko Petrified Forest Or The Autobiography Of An Ancient Oak Tree, George F. Beck

Geological Sciences Faculty Scholarship

An account of a fossilized log at Ginkgo Tree State Park written by the man who discovered the fossil trees and established there were Ginkgo trees in North America in the distant past.

The booklet is written from the perspective of one of the fossilized trees, tracing the geologic forces that led to it becoming a fossil.

Additions To The Late Tertiary Floras Of The Pacific Northwest, George F. Beck

All Faculty Scholarship for the College of the Sciences

The purpose of this paper and those which will follow, is to present new types of flora found in several older leaf localities of the Pacific Northwest. A study will also be made of a number of new localities as yet not reported upon in the literature. The present paper refers to several new species found at the Bull Quarry, Ellensburg, and the Brickyard locality, Spokane, Washington. Both sites have been studied and reported upon in the past, as noted in attached bibliography.

Washington Petrified Forests-Ginkgo Exotic Forest, George F. Beck

All Faculty Scholarship for the College of the Sciences

Seven years ago we began our study of the Ginkgo Petrified Forest in Central Washington. This is in reality a series of forests occurring at various horizons in the Yakima ( and Wenas?) basalts throughout a vertical range of some 2,000 feet, and in a belt 150 miles long, and 50 miles wide, centering at Vantage on the Columbia River.

Determination Of Fossil Woods (Basswood In Ellensburg Formation), George F. Beck

All Faculty Scholarship for the College of the Sciences

From time to time isolated, rounded pebbles of petrified wood have been encountered in the Ellensburg gravels that overlie the Columbia Basalts in Central Washington. Recently a sufficient number of these specimens were collected to justify a study of the petrified woods of this above-named formation.

Determining Fossil Woods (Western Conifers), George F. Beck

All Faculty Scholarship for the College of the Sciences

In this paper we come to consider the problem of the coniferous woods. One cannot always recognize with certainty that a given wood is a conifer, yet in ninety percent of the specimens recognition is simple.

Remarkable West American Fossil, The Blue Lake Rhino, George F. Beck

All Faculty Scholarship for the College of the Sciences

Bidding for acceptance as fact, and for its place in the sun of fame and notoriety, we come now to the newly discovered fossil rhino animal mold of Blue Lake in Grand Coulee, central Washington. Not that fossil rhinos are rare or that their abundance in the Tertiary of America has waited until the present for revelation, is this fossil important. The feature in the Blue Lake rhino which taxes our credulity is the existence of the thing in what unquestionably must pass as once liquid basaltic lava. That anything organic could pass through the terrific heat and pressure of …

Determination Of Fossil Woods (Part V-Beech-Sycamore-Alder), George F. Beck

All Faculty Scholarship for the College of the Sciences

The group of woods considered in this paper are only superficially alike—no implication that they are closely related is intended. The beginner will almost certainly confuse the compound rays of these various woods with their annual rings.

Formations Of The Columbia Basin, Parade Of Extinct Mammals, George F. Beck

All Faculty Scholarship for the College of the Sciences

In this preliminary chart are shown the extinct mammals encountered as fossils in the various formations among and above the great Columbia Basalt series of the Pacific Northwest. A few shown as appearing in the Lake Vantage horizon of the basalts.

Determination Of Fossil Woods (Part Iv-Walnut-Hickory-Persimmon), George F. Beck

All Faculty Scholarship for the College of the Sciences

These three woods undoubtedly ranged over Western America in Tertiary and were well represented in the Ginkgo series of forest during Miocene. Fossil walnut wood is the more abundant of the three species, while hickory is not common.

Camels Of The Columbia Plateau, George F. Beck

All Faculty Scholarship for the College of the Sciences

However foreign they may seem to us the camels are one of our oldest American stocks. Our Western plains once supported large herds of them, humped and humpless, large and small, giraffe-necked and normal-necked. For some 35 million years, from Oligocene to the Pliocene, the camels were confined to North America and it was not until recently, geologically speaking that we shared the race with the Old World.