Geology Commons^™

Evolution Of The Naticid Gastropod Predator-Prey System: An Evaluation Of The Hypothesis Of Escalation, Patricia H. Kelley, Thor A. Hansen

Geology Faculty Publications

Previous work has suggested that escalation may have characterized the history of the naticid gastropod predator-prey system, based on apparent increases in drilling frequencies and the occurrence of antipredatory aptations among prey. We evaluate this hypothesis based on a comprehensive survey (over 40,000 specimens) of predation on molluscs from the Upper Cretaceous through lower Oligocene formations within the U.S. Gulf and Atlantic Coastal Plain. Patterns in drilling of both bivalve and gastropod prey are complex. Drilling frequencies were relatively low in the Cretaceous but increased sharply above the Cretaceous-Tertiary boundary, remaining high until the late Eocene. Following a significant decline …

Odp Leg 146 Examines Fluid Flow In Cascadia Margin, Bernard A. Housen

Geology Faculty Publications

For the better part of 2 decades, it has been known that dewatering of sediments accreted to or subducted beneath accretionary wedges is a fundamental aspect of the subduction-accretion process. Yet, evidence for fluid flow in modern accretionary wedges is largely secondary and based on the presence of geochemical and/or thermal anomalies [e.g., Vrolijk et al., 1991]; the analysis of seismic velocity as an indicator of porosity, which suggests a progressive loss of pore volume in a landward direction [e.g., Bray and Karig, 1985]; and the occurrence of secondary sediment microstructures characteristic of fluid movement [e.g., Maltman et …

Paleomagnetism And Tectonics Of The Crescent Formation, North Olympic Mountains, Washington, Andrew C. Warnock, Russ R. Burmester, David C. Engebretson

Geology Faculty Publications

A stable prefolding magnetization has been discovered in pillow basalts of the Eocene lower Crescent For­mation of the northem Olympic Mountains. The curved outcrop pattern of the Crescent Formation has been the target of several unsuccessful studies to test for oroclinal bending. The success of this study is due, in part, to the development of a small-diameter electric core drill for sampling the fractured rims of basalt pillows. Thermal demagnetization produced stable endpoints by 580°C in 12 of the 34 sites sampled (large within-site scatter was common in the remaining sites). Among the accepted sites, within-site scatter was small and …

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 …

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 …

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 …

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. …

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 …