DINNER RESERVATIONS: @ $30.00 for NWGS members; $35 for non-members. Send check to GINNY AGNEW 935 PINE STREET, EDMONDS, WA 98020. Telephone 425 776 6151.  Ginny’s email address is agnewv@msn.com.  Payment of $30 ($35 for non-members) or $10 for students in good standing at a college or university, must be received by the Thursday preceding the meeting.   LATE REGISTRANTS pay $40.

PEOPLE WHO CHOOSE NOT TO EAT WITH US ARE WELCOME TO ATTEND THE MEETING, BUT WE ASK A VOLUNTARY CONTRIBUTION OF $5 PER PERSON TO HELP DEFRAY THE MEETING ROOM EXPENSE.

NWGS BOARD MEETING 4:30 PM at TALARIS CONFERENCE CENTER.  ALL are welcome! 

Back to Top

UPCOMING SPEAKERS:
10/13/9
11/10/9
12/8/9

Back to Top

PREVIOUS MEETINGS:

May 12, 2009 MEETING
SPEAKER: Jody Bourgeois (University of Washington) Does Kamchatka Belong to North America?

APRIL 14, 2009 MEETING
SPEAKER: Tim Walsh (WA/DNR Geology) Tsunami Hazards
Washington is a founding member of the National Tsunami Hazard Mitigation Program (NTHMP) and has contributed significantly to its progress. The program has substantially improved the warning systems, created a new forecast model, produced tsunami hazard maps for most of the potentially affected shorelines in Washington, and produced engineering guidance for earthquake and tsunami resistant structures for vertical evacuation from tsunamis. A pilot project is planned for a tsunami-resistant school in Westport. We have designed evacuation plans for at-risk communities, and, most recently, have begun producing earthquake-induced ground failure analyses for tsunami inundation zones to guide effective evacuation and mitigation planning. Recent maps in this series cover Grays Harbor and the Long Beach Peninsula, and will next focus on Ocean Shores.

MARCH 10, 2009 MEETING
Don Swanson (USGS, HVO), Kilauea, an Explosive, Not Milquetoast, Volcano!  Kilauea is justly known for its colorful lava flows and spectacular lava fountains. But there is another, darker, side to Kilauea’s volcanic activity. Kilauea is an explosive volcano. It explodes about as often as does Mount St. Helens and many other volcanoes considered to be explosive. The explosions at Kilauea may not necessarily produce as much tephra, but they can be powerful, lethal, and hazardous to air traffic as well as to people near the vent. The designation of Kilauea as an explosive volcano may surprise some readers, but it would have been nothing special to people living in the 16th-18th centuries, when explosions probably took place every few decades or, at times, more often. Pele is prone to temper tantrums, probably a reflection of her explosive nature. Since Europeans arrived on the island, however, Kilauea has been in a relatively quiet, effusive, period. Its frequent eruptions of lava flows lull the public, and many volcanologists as well, into thinking that Kilauea is a milquetoast volcano. Such a reputation is unjustified.

FEBRUARY 10, 2009 MEETING
SPEAKER: Josh Banfield (University of Washington), Mars: Mineralogy, Morphology, and More! Joshua Bandfield is a Research Assistant Professor in the Department of Earth and Space Sciences at the University of Washington.  He received a B.S. in Geological Sciences from UC Santa Barbara in 1996 and Ph.D. in Geology from Arizona State University in 2000.  He has
actively participated in several spacecraft missions, including the Mars Global Surveyor, 2001 Mars Odyssey, Mars Exploration Rovers, Mars Reconnaissance Orbiter, and Lunar Reconnaissance Orbiter.

Data returned from spacecraft over the past decade have revealed a Mars with a diverse and dynamic history.  Fluvial and other landforms, such as valley networks, outflow channels, and layered terrains were identified in the 1970's, but the extent of the influence of water on the surface has been greatly expanded using high-resolution imagery. Mineralogical and elemental measurements have revealed the presence of
phyllosilicates, hydrated silica, hematite and goethite, sulfates, carbonates, zeolites, and possibly chlorides.  In addition to this diverse aqueous history, there is some indication that Mars may also have a range of igneous compositions, including limited exposures of highly differentiated felsic rocks.  These and other observations are beginning to characterize a complex planet that can not be defined by simplistic categorizations.

JANUARY 13, 2009 MEETING
SPEAKER: Tom Bush (Pierce College) Breccias, Breccias Everywhere, But Where is the Gold?

OCTOBER 14, 2008 MEETING
SPEAKER: Jon Reidel (North Cascade National Park), Shrinking Glaciers in the North Cascades. Joint meeting with PSAMS.
Drainage patterns established in the Tertiary in the North Cascades were reorganized to accommodate southern drainage of Cordilleran Ice Sheet meltwater. Repeated continental glaciation rendered the Skagit an interconnected valley, with meltwater routes opening it to the Fraser and Okanogan watersheds, and linking it to a drainage system around the east margin of the Puget lobe of the ice sheet.
Alpine glaciers from two major tributaries blocked Skagit valley during the late Wisconsin Evans Creek stade, creating glacial lakes Concrete and Skymo. Organic material from lake sediments provides the first radiometric constraint on the beginning of the Evans Creek stade in the Cascades about 25,040 14C yr BP. Sediments and macrofossils at the Cedar Grove section define two advances of Baker alpine glaciers during this stade, separated by warmer and wetter climate at 20,310 14C yr BP. During colder parts of the Evans Creek stade macrofossils indicate treeline was as much as 1200 ± 150 m lower than present, which corresponds to a mean July temperature depression of approximately 7 ± 1°C. Glacier equilibrium line altitudes (ELA) during the cold periods were depressed 730-970 m below the modern glaciation threshold.
Skagit valley alpine glaciers advanced several times to positions 5-10 km below valley heads between 12, 200 and 9,975 14C yr BP. ELA depression during these advances vary from 340 ± 100 m to 590 ±75 m, with greater depression in maritime western tributaries. Skagit ELA depression values are about 200 m less than reported for the southern North Cascades during the Sumas stade. The effect of the Cordilleran Ice Sheet on precipitation likely caused ELAs to be higher in the Skagit valley than in the southern North Cascades.

DECEMBER 11, 2007 MEETING

SPEAKER:  Dr. Tom Bush, Pierce College.  "Step Aside Darwin: Geology Rules in the Galapagos Islands."  The Galapagos Islands are well known among biologists as well as the general public for their unique biological communities consisting of numerous indigenous and endemic species, including the 13 species of "Darwin's finches". These unique islands are also well known among geologists as an archipelago of volcanic islands produced as a hot spot manifestation of the Galapagos mantle plume. From an "Earth systems" perspective, where the Earth's primary components, the geosphere, biosphere, atmosphere, and hydrosphere interact and influence each other, numerous large- and small-scale examples of geospheric controls on the the development and distribution of life in the Galapagos Islands have occurred.

 

NOVEMBER 13, 2007 MEETING

SPEAKER: Dr. Tom Pratt, USGS/UW Oceanography, Update of- and Findings on- the East End of the Seattle Fault.  Tom devoted 7 minutes to provide information equivalent to ”a college degree in geophysics” to prepare us to understand the seismic sections on which his interpretations are based.  Kink bands indicate a bend in a fault. Kink bands, fault propagation folds, breakthrough faults, growth triangles, bedding plane shear & deformation fronts are useful clues to tectonic structures.  The deformation front of the Seattle Fault marks the southern end of the Seattle Basin.  South of the deformation front, the strata dip steeply in contrast to the flat-lying beds in the Basin to the north.  His interpretation of the data indicates a fault propagation fold above the Seattle Fault.  The strata south of the fold crest (Newport Hills) dip southward about 70 degrees.  There is an occasional back thrust.  The Vasa Park Fault dips southward, with older rock thrust over the soil.  It is thought to be a splay of the main fault, which is at a deeper level.  Since Miocene strata have not been removed, it is thought that Vasa Park fault motion was 500 meters or less.  Estimated motion on the main Seattle Fault is 8 to 10 km., with about 2 km. movement on the back fault.  Very good data from a profile done in the 1970’s is only recently being analyzed.  The data indicate a main fault dipping 45 degrees south, with a splay cutting to the surface.  This configuration seems to prevail across the Puget Lowland.  To the south, the Tacoma Fault dips northward.  Beneath eastern Tacoma, it breaks into several splays.  Wave-cut platforms in Hood Canal & Henderson Bay stop abruptly to the south.  A prominent  2 meter fold scarp, detectable only on LIDAR images, marks a kink band from a growth fault active in the Quaternary.  A large magnetic anomaly north of the fold is imputed to volcanics.  South of the fold, the anomalous unit is deeply buried.  About 2 generations of earthquakes are recorded in the sediments.

MAY 8, 2007 MEETING
SPEAKER: Dr. Rowland Tabor, USGS, Living the High Life in the North Cascades.  We were honored to have ROWLAND TABOR speak to us about “LIVING THE HIGH LIFE IN THE NORTH CASCADES.” Rowland began his 35-year career with the USGS in 1952 on a project with Cater & Crowder, mapping the Holden Quadrangle. The goal was to find more copper there. Transportation of supplies & equipment was provided by Ray Courtney, a long-time horse-packer from Stehekin. Rowland;s role was to hike in front of the party, felling trees to clear a path. Helicopter use began in 1960 & Rowland experienced a lot of “one-skid” landings. Rowland expressed major indebtedness to Ralph Haugerud for his part in that mapping project. Early on they recognized three major crustal blocks & the Ross Lake Fault. The North Cascades is comprised of Pre-Tertiary terranes dating from 400 Ma to 100 Ma. Orogeny occurred in the lower Cretaceous-Early Tertiary interval. Eocene transtension gave rise to pull-apart basins. Uplift, erosion, & glaciation shaped the magnificent landscape. Peter Misch established the basic framework of the Northwest Cascade System, including rocks offset on the Straight Creek. Rowland gave a comprehensive review of the geologist history of that system, which consists of volcanic “arcs stacked on arcs,” with major thrust faults, extensional fault, magmatism, thermal metamorphism, uplift & major glaciation. He noted that meltwater from the glaciers had a more profound effect on that landscape than did glacial ice. This included a major outburst flood into the Skagit River drainage. Rowland’s work has enlightened not only the geologic community, but the general public & mountain climbers as well. Quite a few people brought their treasured copies of the book by Tabor & Crowder, “ROUTES & ROCKS IN THE NORTH CASCADES” to be autographed.