Past Event Summaries

Dr. Brian Atwater:


On Sunday March 27th, the Port Townsend Marine Science Center will sponsor what should be a very popular pair of presentations on earthquake and tsunami hazards of the Port Townsend region.  Our invited speakers are Brian Atwater, a geologist with the U.S. Geological Survey in Seattle and Ron Tognazzini, a retired civil engineer from Sequim. 


Port Townsend is subject to earthquakes and tsunamis from the Cascadia Subduction Zone and local faults such as the Seattle fault.  Compounding the hazard is unreinforced masonry buildings that make our downtown both charming and potentially hazardous.  If you have a business or residence near the coast, this presentation will show you what might happen during the run up from a large tsunami.  


Brian’s specialty is paleoseismology—the study of prehistoric earthquakes.  A member of the National Academy of Sciences, Brian helped identify Washington’s most recent giant (magnitude 9) earthquake and date it to January 26, 1700, over 100 years before Lewis and Clark arrived in the Pacific Northwest.  The clues include ghost forests on the Washington coast and written records of a puzzling orphan tsunami in Japan.  Brian has also worked in Chile, Japan, Puerto Rico, and Thailand, and he recently spent six months in Indonesia as a Fulbright scholar.  On March 27, Brian will begin with detective stories of Pacific Northwest earthquakes and tsunamis.   Then he’ll turn to eyewitness accounts of tsunamis in Indonesia, and of the public-safety lessons they provide.


Ron has applied his background in civil engineering to natural disaster preparedness and emergency response.  A long history of participation in Science Fairs led to his mentoring of Marley Iredale, a Sequim High School student who did research on Washington State’s best record of recurring tsunamis—a sequence of sand sheets from the past 2,500 years at Discovery Bay, near the Snug Harbor Restaurant.  This record applies equally well to Port Townsend, where such tsunami studies have yet to be attempted.  Marley’s study won her numerous awards, culminating in the best earth and planetary sciences presentation at the International Science and Engineering Fair in Reno in 2009.  She is now a freshman at Washington State University in Pullman, WA.  Marley is a fine example of what high-school students can do to make a difference through science research and field investigations.  On March 27, Ron will summarize her findings from the Discovery Bay site.


Bill Baccus:


“Glaciers of Olympic National Park”


On Saturday Dec. 5th, Bill Baccus will present an overview of the Glaciers of the Olympic National Park, where he has worked for 30 years.  As you may know, the winter of 2014-15 was one of extremely low snowfall in the Park, which has a direct impact of the glaciers. Is this a harbinger of the future?
 
Bill will introduce the glacial resources at Olympic National Park and discuss the methods used to inventory the park’s glaciers. These include the use of high-resolution aerial photograhy to delineate glacier perimeters and determine surface area, as well as the use of high-precision GPS to calculate changes in ice thickness. In addition, they have replicated historic photos (see sidebar) to provide a visual record of the dramatic changes that have occurred over the past century.
 
Recent monitoring work on two park glaciers includes a multiple-year study of glacier mass balance which helps us understand the response of glaciers to annual climate variations and provides a more accurate understanding of glacier contributions to Olympic Peninsula rivers.  Highlights of that study include the discovery that rates of retreat of Olympic glaciers were some of the highest in the Pacific Northwest and showed that there has been a loss of nearly a third of our small alpine glaciers, as well as major changes in both surface area and volume to larger glaciers.
 
Bill Baccus is a Physical Scientist with the National Park Service where he works on the North Coast and Cascades Network supporting their long-term monitoring program. He operates a network of climate stations within the park, studies winter snow pack, glaciers, and mountain lakes, and studies coastal ecosystems.



Dr. Scott Burns:


“Terroir in the Pacific Northwest: A Scientific Wine Tasting”


Port Townsend, WA—If you’ve ever wondered why wine tastes differently grown in one region over another, it may very well be due to the terroir (pronounced tair-wah)—a French term describing the geology, soils and climate of a region which influence a grape varietal’s quality and contributes to the personality of the wine.


On Saturday, Mary 8, from 3-5 p.m. at the USO Hall at Fort Worden State Park, the Port Townsend Marine Science Center (PTMSC) will be hosting Terroir in the Pacific Northwest: A Scientific Wine Tasting with Dr. Scott Burns.


“For many years, our geology study group has explored a variety of topics and this is one that will fascinate both scientists and wine aficionados alike,” said Anne Murphy, executive director for the PTMSC. “We’re pleased to welcome Scott Burns to Port Townsend.”


With his perspective as a professor of geology at Portland State University, Dr. Burns’ presentation and wine tasting will address the terroir of the Columbia and Willamette River valley appellations in Washington and Oregon respectively through the geology of each region, then compare and contrast two wines from each of those areas.


Dr. Burns has taught geology for nearly 35 years with a specialization in soils, geomorphology, and regional geology. Terroir is one of Scott’s many passions; his presentations are hugely popular with wine enthusiasts, cooks, and geologists.


Ralph Dawes: Assembling the Pacific Northwest


   Two hundred million years ago, the west coast was where Spokane is now. This was the edge of the craton—the old part of the continent. How did the rest of the Pacific Northwest come to be here and where did it come from?
The west coast became an active plate boundary when an oceanic plate started to subduct beneath it.  As the oceanic plate subducted, blocks of crust that it carried, such as island arcs or oceanic plateaus, were scraped off and added to the edge of the continent in a process known as accretion, thus building the Pacific Northwest we know it today.
   Accreted terranes have a different geologic history than the bodies of rock adjacent to them and are separated from their surroundings by major faults. The Crescent Formation of the Quimper Peninsula, for example, is part of a large accreted terrane that underlies much of the coastal Pacific Northwest. The Crescent Terrane originated as piles of basalt which erupted from the sea floor and in some places built broad oceanic islands. This basalt, along with oceanic sediment, was then shoved against and accreted to the continent. Deep thrust faults separate the Crescent Terrane from terranes that had accreted earlier to the Pacific Northwest. Subsequently, younger oceanic crust has been added seaward of the Crescent Terrane. Each piece of accreted crust is separated from the others by thrust faults, and the subduction zone continues to shift westward as younger terranes are added to the edge of the continent.
   The accreted terranes of the Pacific Northwest are a four-dimensional (in time as well as space) jigsaw puzzle that is still being assembled. Western North America was the main testing ground for the development of the accreted terrane concept. We will delve into the discovery that some Pacific Northwest terranes may have moved north more than a thousand miles along the edge of the continent. We will also discuss the current state of knowledge of accreted terranes in the Pacific Northwest, with the Olympic Peninsula representing the leading edge of the North American continent, where terrane accretion continues today.



Dr. Wendell Duffield:


Geologic Adventures at Kilauea Volcano, Hawaii


In 1969, as Neil Armstrong set foot on the moon, a young geologist known as Duff (aka Wendell Duffield) was preparing to set foot on a rocky landscape of another sort:  Kilauea Volcano, a growing shield volcano, on the island of Hawaii, where he would spend three years at the U.S. Geological Survey’s Hawaiian Volcano Observatory. Duff’s time at HVO encompassed everything from the scientific to the humorous to life threatening.

While he was at HVO, Kilauea erupted at three areas. Several times, 2,000-ft-tall lava fountains spewed from the east rift zone, at a site later named Mauna Ulu (Hawaiian: growing mountain). Elsewhere, so-called “curtains of fire” danced from long cracks on the floor of Kilauea’s summit caldera. And for only the fourth time in Hawaii’s historic record, lava emerged from a fissure along the southwest rift zone.

An unexpected “extra” for Duff was a large, sluggishly circulating lake of thinly-crusted-over molten lava that played out a miniature version of global plate tectonics — then a revolutionary and newly developing model of how Earth’s crust moves about. Duff’s movies and photos of the small-scale version of ‘plate’ motions quickly became a popular teaching aid in classrooms worldwide.

Meanwhile, during the brief moments between Duff’s observing and recording antics of the active volcano, his dog Cinda discovered a reticulated python hiding in the rainforest — in a state that proudly advertised a total lack of snakes other than at the Oahu zoo. This discovery was very unwelcome news for Hawaiian political officials.

Wendell “Duff” Duffield will describe these and other adventures at HVO in Kilauea.  Come and enjoy some hot times!


Wendy Gerstel: “Bluff Retreat—What to do about the Law of Averages”


Options for addressing coastal erosion and landslide hazards vary as much as do the combinations of bluff composition and the coastal processes acting on them. For this reason, owners, both private and public, of bluffs along Puget Sound need to consider site conditions and their geologic and geographic setting when deciding how or whether to take action to counter slope retreat. On Saturday, February 28th, Wendy Gerstel will offer insights into what must be considered for long-term adaptation to natural geologic processes and will provide a few site-specific examples of geotechnical investigations and how these relate to the broader context of unstable slopes around Puget Sound. She will discuss how and why to be clear on objectives and manage expectations for any actions taken. Wendy will touch on the rules, tools, and options that apply to living with geologic hazards associated with bluffs, and on gaining the necessary resilience we need to take on associated risks.

Wendy is a licensed Engineering Geologist and Hydrogeologist and owner and principal scientist of Qwg Applied Geology (http://qwgappliedgeology.com/),  a small woman-owned business she established in 2005. She has over 30 years of experience working with Federal, State, and local jurisdictions, Tribes, non-profit groups, and private landowners throughout the U.S. and extensively in the Pacific Northwest.  Since 1992 Wendy has provided coastal geologic, geomorphic, and hydrogeologic input to a range of research, mapping, mitigation, and restoration projects.  She obtained a B.Sc. in Geology from the University of New Hampshire in 1980 and her MSc. in Geology from Humboldt State University, California, in 1989.  In August of last year, Wendy was appointed to the Governor’s Joint SR 530 Landslide Commission charged to develop recommendations for improved state-wide landslide hazard preparedness and emergency response.


Wendy’s lecture will start at 4 pm on Saturday, February 28 at the Quimper Unitarian Universalist Fellowship, 2333 San Juan Avenue, Port Townsend.  The talk is free and open to the public, although a donation of $5 would be appreciated to defray expenses. For more information, visit our web site at www.quimpergeology.org.


Grant Heiken: Geology and Urban Sustainability, The View from Rome


From its time as the historic center of the Roman world, Rome has been continuously a political, religious, and administrative capital. Geologic and terrain factors assured its population growth and provided the conditions for survival of its culture in the ancient world. From lessons of urban development and prosperity, the Roman people developed a capacity to recognize and to manage the natural resources of the region. Modern Rome, born after the unification of Italy, was developed in a haphazard manner after WW II. Most residents have not been pleased with the results of rapid development, but have developed a strong awareness for a need to care for the city and to better manage its environment. There are new, detailed geologic maps of the city, programs for engineering and environmental geology, and cooperative work with archeologists—all within the city and regional governments. It is appropriate that the term urban geology has its origin in Urbs, which was the ancient name for the City of Rome. This work is based on his 2005 book The Seven Hills of Rome—A Geological Tour of the Eternal City” (G. Heiken, R. Funiciello, R., and D. DeRita, Princeton University Press, Princeton, 288 p).


After completing his Ph.D. at the University of California in Santa Barbara in 1972, Grant Heiken (heiken@whidbey.com) worked for NASA’s Apollo Program, as a geology instructor, and as a researcher on lunar surface processes. In 1975, he and his wife moved to the Los Alamos Scientific Laboratory in New Mexico, where he worked on geothermal exploration and development, volcanic hazard analysis, the uses of volcanic rocks, basic research on explosive volcanism, continental scientific drilling, and integrated urban science.  He has co-written or edited 11 books. He retired in 2003 and moved to Freeland on Whidbey Island, Washington, with his wife Jody, who is a scientific editor. Grant volunteers for several service organizations, is on the board of the Whidbey-Camano Land Trust and is on the Island County water-resources advisory committee.


Dr. Heiken’s lecture is 4 pm on Saturday, March 15, at the Quimper Unitarian Universalist Fellowship, 2333 San Juan Avenue, Port Townsend.  It is sponsored by the Jefferson Land Trust’s Geology Group and is free and open to the public, although a donation of $5 would be appreciated to defray expenses. For more information, contact Michael Machette (paleoseis@gmail.com) or visit our web site at www.quimpergeology.org.


Dan McShane:


The Hazel/Ozo Landslide: Geologic Background and Policy Implications


On March 22, 2014, at 10:37 a.m, a massive landslide struck a rural area of the Stillaguamish River Valley, killing 43 persons and displacing many more.  News of this catastrophe spread through the surrounding communities, some of which were cut off from outside help.  However surprising this may seem, the geology history of the area shows that is has a long history of hazardous behavior.


About 20,000 years ago, the advance of the Puget ice lobe into the Puget Sound area blocked the outlets of several rivers flowing out of the Cascade Range. Glacial-related sediments deposited within the Stillaguamish River Valley were later incised, initially by the combined flow of the Stillaguamish and Sauk Rivers and then by continued erosion of the North Fork Stillaguamish River. The erosion has left steep, high terraces of unconsolidated sediments along the valley walls, which have led to multiple deep-seated large landslides that have covered the North Fork Stillaguamish River Valley floor on multiple occasions. The catastrophic Hazel/Oso Landside is simply the latest valley-covering landslide in this long post-glacial history.


There are some unique geologic aspects of the Oso Landslide that will likely offer some valuable lessons regarding landslide risks and help inform policy regarding landslides. This talk will attempt to put the Hazel/Oso landslide in perspective with other landslide hazards in Washington State. While the Hazel/Oso Landslide may hold some technical and policy lessons, information on other landslide sites in Washington State will be presented, including some landslides in Jefferson County. Part of the presentation will discuss how landslide risks and public policy meet and various approaches to landslide hazard risk reduction.   


Dan McShane has a B.Sc. and M.Sc. in Geology from WWU in Bellingham. He has worked as a geologist and engineering geologist in Washington State since 1989 conducting geologic and geotechnical evaluations at a wide variety of geologic hazardous or potentially hazardous sites. Projects have included numerous forest practice application prescriptions, critical areas per Growth Management Act local regulations, evaluation of channel migration zones, debris flow and alluvial fan hazards, steep slope/landslide areas, shoreline sites and abandoned coal mine areas. Dan has also completed numerous mineral and aggregate resource assessments.  He is currently employed by the Stratum Group as an Engineering Geologist in Bellingham, WA. Dan writes a geology blog (http://washingtonlandscape.blogspot.com) that provided some early information about the Oso Landslide to the general public as well as geologists not familiar with the specific area.


Dr. Ian Miller:


Coastal Response to Dam Removals on the Elwha River:  Present and Future


Ian Miller of Washington Sea Grant (University of Washington) will present a lecture on “Coastal Response to Dam Removals on the Elwah River:  Present and Future” at 4 pm on Saturday, January 12 in Port Townsend.

For nearly a century, two dams on the Elwha River disrupted the flow of sediment from the Olympic Mountains to the Strait of San Juan de Fuca, contributing to the erosion of the Elwha River delta just west of Port Angeles and altering coastal habitat both to the east and west.  Removal of the dams was completed last fall, and now the river is free to flow in its natural course.  Already, salmon have returned to the river and are starting to spawn. Researchers from a variety of state and government agencies are tracking how the river’s ecosystem responds as millions of tons of sediment make their way north to the coast.  

Ian’s talk will provide a “status report” on how the coastal zone is responding to the removal of the dams and rapid erosion of the sediment impounded behind them.  

Based at Peninsula College, Dr. Miller focuses on research, education and outreach on natural coastal hazards on the Olympic Peninsula, including hazards due to climate change, tsunamis, and chronic erosion. He has a bachelor’s degree in marine ecology from Western Washington University and earned his doctorate in oceanography from the University of California—Santa Cruz in 2011.  


David Montgomery: Dirt—The Erosion of Civilizations

Dirt, soil, call it what you want—is the root of our existence, supporting our feet, our farms, our cities. Dr. David Montgomery, Professor of Geology at the University of Washington, will present an engaging lecture on the natural and cultural history of soil that sweeps from ancient civilizations to modern times.  In Dirt: The Erosion of Civilizations, he explores the compelling idea that we are—and have long been—using up Earth's soil. He makes the case that modern agricultural practices are now stripping the planet of its relatively thin skin of topsoil at such an alarming rate we should be looking at erosion and soil loss as a comprehensive threat on par with climate change. A rich mix of history, archaeology and geology, he traces the role of soil use and abuse in the history of Mesopotamia, Ancient Greece, the Roman Empire, China, European colonialism, Central America, and the American push westward. We see how soil has shaped us and we have shaped soil—as society after society has risen, prospered, and plowed through a natural endowment of fertile dirt.


However, with the recent rise of organic and no-till farming, Dr. Montgomery sees the hope for a new agricultural revolution that might help us avoid the fate of previous civilizations.  These subjects are especially relevant to Eastern Jefferson County and the Jefferson Land Trust (JLT), which is sponsoring the lecture.


David Montgomery was selected for a 2008 MacArthur Foundation Grant (popularly known as "genius awards") for his groundbreaking scientific contributions to understanding how landscapes form -- on Mars as well as here on Earth -- along with his ongoing effort to communicate the significance of these findings to the public.  His book DIRT won the Washington State Book Award in General Nonfiction, Washington Center for the Book at the Seattle Public Library.


Dr. Elizabeth Nesbitt: Burke Museum Seattle


Liz Nesbitt will take you on an adventure back to the end of the Cretaceous time period, when dinosaurs became extinct but mammals started to flourish. Among these were sea-going mammals that evolved into the whales we know today.

After the end-Cretaceous extinctions 66 million years ago, global climates remained warm and Earth was free of ice sheets. Hothouse climates generally persisted until about 35 million years ago, when the world was plunged into icehouse conditions. Ice sheets spread across high latitudes for the first time in 200 million years. With the extinction of all large dinosaurs and marine reptiles at the end-Cretaceous, mammals rapidly evolved to fill many vacated eco-spaces. A lineage of land mammals went into the sea over this time, and the group evolved rapidly into completely aquatic animals, resulting in a diversity of whale body types and feeding strategies. During the early Cenozoic Era (55 to 25 million years ago), significant swings in climate may have been one driver of whale evolution.

This will be a non-technical talk weaving together the early Cenozoic climates, whale evolution, and the fossil record for this time period that is preserved in western Washington.


Keith Norlin: Armchair Geology of Zion, Bryce & Grand Canyon National Parks


On Saturday May 14th, Geologist Keith Norlin will present a panoramic overview of some of America’s most magnificent landscapes.  We’ll take a virtual geology field trip to Zion, Bryce and Grand Canyon National Parks without getting boots dirty and just in time for vacation planning.  You can sit back, take in some amazing geologic history and leave your rock hammer at home, but be sure to bring your curiosity and questions.

 

Keith recently retired and moved to Port Townsend from the desert Southwest.  He was a geology instructor for Dixie State University in St. George, Utah, where he also led many geology excursions into the national parks for the Road Scholar program (www.roadscholar.org).  Keith is a graduate of the University of Wisconsin, where he obtained a BSc. in Geology.  He spent much of his career serving as a geophysicist for the U.S. Naval Oceanographic Office, worked as an engineer for Westinghouse Ocean Research Laboratory and mapped the outback as an exploration geologist in Australia. 

 

This one-hour illustrated geologic extravaganza will start at 4 pm at the Quimper Unitarian Universalist Fellowship, 2333 San Juan Avenue, Port Townsend. The talk, sponsored by the Jefferson Land Trust Geology Group, is free and open to the public, although a donation of $5 would be appreciated to defray expenses.


Dr. Ray Pestrong: Earth Art


   In his 2012 book, “The Sciences and the Arts,” Chemist Harold Cassidy draws parallels between the way artists and scientists view their worlds. He states that “there is no subject that is unfit for the probing insight of the artist, nor is there anything unsuitable for the scientist to examine.” The premise of Dr. Pestrong’s coming presentation is that Art is central to the Earth, both figuratively and literally. If you cover the first and last letters of the word “Earth”, there is “art”. This is a symbolic indication of how integral Art is to the Earth and how aspects of the Arts enhance our understanding of Earth Sciences.

   A 21st century paradigm is emerging in which the integration of different fields of knowledge is seen as a necessary goal. When connections are established among otherwise disparate bits of data, more universal theorems and deeper understanding result. Our speaker’s goals, in this context, are to show how aspects of the Arts may be used to generate interest and gain insights into how the Earth works and to demonstrate how logic is not restricted solely to the scientist and that intuition is not the sole realm of the artist.

   This hour-long program has been shown all across the United State to a broad spectrum of audiences. It was developed as a teaching tool for introductory geology courses, but its wide acceptance is an indication of the profound interest we have in the physical environment. Like the world it reflects, Earth Art is constantly changing as new relationships become apparent; as you’ll see, Earth Art comes in many forms.

   Ray Pestrong is an Emeritus Professor of Geology in the Department of Earth & Climate Sciences at San Francisco State University. For 44 years, he has taught geomorphology and engineering geology, as well as  numerous general education courses in introductory geology. He has written college texts and scientific articles and has produced geologic videos. For the past 22 years, Ray has led rafting trips on the Colorado River through the Grand Canyon. What he loves most is teaching and the exciting interactions possible through that venture.

The Jefferson Land Trust’s Geology Group is sponsoring Dr. Pestrong’s talk. His lecture will start at 4 pm on Saturday, January 10th, at the Quimper Unitarian Universalist Fellowship, 2333 San Juan Avenue, Port Townsend.  The talk is free and open to the public, although a donation of $5 would be appreciated to defray expenses. For more information, contact Michael Machette (paleoseis@gmail.com) or visit our web site at www.quimpergeology.org.


Dr. Pat Pringle: ANCIENT BURIED FORESTS

At 4 pm on Saturday, Feb. 12th, Patrick Pringle, Associate Professor of Earth Science at Centralia College will return to the Port Townsend Marine Science Center to present an intriguing lecture he’s titled "Ancient buried forests—Indicators of catastrophic geologic events".  These fossil and old forests are associated with tsunamis, debris flows and landslides, some as close at Crescent Lake south of Port Angeles.  Dr. Pringle is a highly regarded geologist who has studied throughout western Washington and is the author of roadside geology guides to Mount Rainier and Mount St. Helens.

Dr. Hugh Shipman

Bluffs and Beaches—Geology on the watery edge of Jefferson County

 

Puget Sound is best distinguished from other large American salt-water estuaries by the strong influence of the last glaciation.  This glacial legacy includes a steep, irregular coastline, an abundance of coarse-grained sediment, and a shoreline dominated by coastal bluffs.  These bluffs are erosional landforms, although the rate and character of this erosion varies greatly.  Most shoreline bluffs are subject to shallow landsliding, typically associated with heavy rainfall.  The coastal landscape also includes numerous deep-seated landslides, ancient features that can be reactivated by unusually wet conditions or perhaps by earthquakes.


Bluffs are a key component of a dynamic beach system that supports an incredible array of coastal landforms and environments, including spits and small estuaries.  This talk will draw on local examples to show how geologic processes have shaped the modern shoreline and how they continue to do so—sometimes with significant implications for people who live near the shore.  The talk will also include observations on how geology is becoming increasingly important to our thinking about how we protect Puget Sound’s shorelines.

 

Hugh Shipman has been a geologist with the Shorelands Program at the WA Department of Ecology since 1989.  His interests include coastal erosion, geologic hazards, and the environmental impacts of shoreline modifications and his work takes him to all corners of Puget Sound.  Hugh received his B.A. from Dartmouth College in 1981.  After a brief stint in the oil patch, he came to the UW where he received his M.S. in Geological Sciences in 1986.  Hugh grew up near the coast of Maine, but moved to the Puget Sound region in 1983.


Dr. Rowland Tabor:


Rocks and Rain in the Olympic Mountains


Ever hiked deep into the Olympic Mountains and wondered why they are so high, so steep and where they came from? Well, Dr. Rowland Tabor of the U.S. Geological Survey is ready to answer these and many more questions about the Olympic Mountains when he presents “Mapping a Tectonic--‐Plate Boundary: Rocks and Rain in the Olympic Backcountry.” Dr. Tabor, a leading scientist in the Northwest and author of the sentinel publication Geology of Olympic

National Park, will present his personal experiences from years of mapping in the Olympic Mountains, a detailed outline of their geology, the development of geologic ideas about their

formation, and briefly mention of some new work by others.  Along the west coast of North America, from Mexico to southern Canada, are mountain ranges of diverse character collectively called the Coast Ranges. The Olympic Mountains, at the extreme northwest corner of the conterminous United States, are a unique part of these ranges. Even though they are closely related in rock composition to the Coast Ranges of Oregon, they are separated from them by the broad lowland of the Chehalis River and are considerably higher and more rugged. They have some scenery in common with the Insular Ranges of Vancouver Island in Canada but are geologically quite different. To learn more about the geology of the region, or to take a virtual field trip, go to http://geomaps.wr.usgs.gov/parks/olym/index.html


Dr. Jeff Tepper:

Geology Lecture on Volcanic and Tectonic Origins of Tamanowas Rock


Dr. Jeff Tepper will deliver an illustrated geology lecture at the Tri-Area Community Center in Chimacum on Saturday, June 11, 2011, at 1 p.m. Following the one-hour talk, an optional field trip hike to the Tamanowas Rock Sanctuary will be conducted.


Tamanowas Rock, the prominent monolith visible among the trees just north of Chimacum High School, is a sacred place to the S’Klallum people. It is also a very unique geologic feature.  The rocks at this site were formed in an explosive volcanic eruption that occurred in the Eocene Period, 43 million years ago.  This time in the Pacific Northwest’s tectonic history followed a period of widespread rift-related volcanism on the Olympic Peninsula. It predated the beginning of subduction-related volcanism associated with the modern Cascade Range. 


Studies suggest Tamanowas Rock is an example of “slab window volcanism,” an unusual process that occurs when a sea floor spreading ridge enters a subduction zone.  The geology talk will review the evidence that a slab window existed here at the time of eruption, discuss how these rocks were dated, reconstruct what eruptions would have been like, and speculate on where the now-eroded volcanic center might have been located. 


By special arrangement with Jefferson Land Trust, the Tamanowas Rock Sanctuary will be open for a short hike (approximately one and a half hours round trip) to view the rock outcrop. Anyone interested in the hike should wear sturdy boots with traction soles, as the trail is steep and can be slippery. It is not ADA accessible.
 
Jeff Tepper is a Professor and Chair of the Geology Department at the University of Puget Sound.  He received his BA from Dartmouth College and his PhD from the University of Washington, where he studied the origins of granites in the North Cascades.  After teaching on the east coast for ten years, he joined the faculty at UPS in 2001.  Dr. Tepper’s research uses geochemistry to investigate geologic questions.  He and his students are currently studying the Eocene magmatic and tectonic history of the Pacific Northwest and the environmental history of the Puget Sound area as recorded in lake sediments.


Professor Tepper Radio Interview


Dr. David Tucker: Eruptive History and Hazards of the Mount Baker Volcanic Field


On a clear day in Port Townsend, you can’t help but notice Mount Baker to the northeast, just beyond Bellingham.  Just 60 miles away, this spectacular volcano lies restless, its history largely unknown until recently.

Geologic mapping coupled with geochemical and radiometric studies at Mount Baker over the past decade have moved the volcano's eruptive history from relative obscurity to among the best studied in the Cascades volcanic arc. The geologic history of the 3- to 4- million-year-old Mount Baker Volcanic Field is now well known for the past.  The ice-mantled cone of Mount Baker is but the youngest in a long series of eruptive centers, which includes two calderas (large eruptive cauldrons). The past 10,000 years (the Holocene) has seen a decrease in "constructional" lava flows. Conversely, "destructional" events, such as flank collapses that evolve into far more hazardous lahars are now recognized as the Holocene norm at Mount Baker.  Mount Baker’s historical record begins in 1843 and ironically is among the most obscure, despite eye-witnesses reports and newspaper accounts. The reasons for the famous “failed-eruption” of 1975 is the latest example of the historic puzzle; this event provided the backdrop to the modern age of volcano monitoring in the Cascade and Aleutian arcs.

This talk will present some of the eruptive history of the Mount Baker volcanic field, will discuss the newly recognized hazards associated with the modern glaciated cone, briefly describe some of the recent physical volcanology studies, include video from the hundreds of vigorous fumaroles in the active Sherman Crater, and introduce the Mount Baker Volcano Research Center.

Dave Tucker is a Research Associate in the Geology Department at Western Washington State University (Bellingham) and Director of the Mount Baker Volcanic Research Center, which is the nucleus for ongoing volcanic research at the mountain.  The talk will be part of the Center’s ongoing efforts to raise community awareness and financial support for more research and education on the Mount Baker volcanic field.  The event is free, but a $5 donation is suggested.  In his off time, Dave is writing Geology Underfoot in Western Washington, which will feature several dozen field trips to exciting geologic sites in our region.

 

Dr. Ray Wells:

Revolutionary tectonics in the Pacific Northwest—The role of rotating microplates and mega-blocks along the Cascadia convergent margin


On Saturday, Nov. 12, Ray Wells of the U.S. Geological Survey will present a lecture on the tectonics in the Pacific Northwest. Dr. Wells has been a research geologist for almost 30 years, concentrating on the use of field geology, magnetic rock properties (paleomagnetism), and GPS to solve large-scale problems in the Earth’s on-going structural evolution. Ray has produced a simple, hands-on block model of the Pacific Northwest, which he will demonstrate at the talk. Today, 165 of the models are used in classrooms around the Pacific Northwest.


Deformation and paleomagnetic rotations over the past 50 million years indicate that the Cascadia forearc is moving northward along the west coast and breaking up into large rotating blocks. Deformation occurs mostly around the margins of a large, relatively non-seismic Oregon coastal block, which is composed of thick oceanic crust. This 400-km-long block is moving slowly clockwise with respect to North America about a rotation pole in eastern Oregon, thus increasing convergence along its leading edge near Cape Blanco and creating an extensional volcanic arc on its trailing edge. Northward movement of the block breaks western Washington into smaller, seismically active blocks and compresses them against the Canadian Coast Mountains.  Movement of these blocks may be as much as 9 mm/yr, sufficient to produce damaging earthquakes in a broad deformation zone along block margins.


Recent GPS data show that clockwise rotation of Oregon continues today, but the rotations extend throughout the Pacific Northwest. Rotation rates from GPS studies are similar to older paleomagnetic rates.  Northward-moving Oregon is currently squeezing Washington against slower moving Canada:  this constriction has produced the Yakima fold and thrust belt and its analogs, like the Seattle fault, in the forearc.  Locally, right-lateral shear in the forearc is apparent in the GPS data, consistent with recently discovered right-lateral faults in the Portland area that may be seismically active. In a broad sense, the smaller, clockwise-rotating blocks of the Pacific Northwest appear to be caught like a giant ball bearing between the much larger Pacific and North American plates.


David Williams:

Stories in Stones: Urban Geology

Most people do not think of looking for geology from the sidewalks of a major city, but for the intrepid traveler any good rock can tell a fascinating story.  All one has to do is look at building stone in any downtown business district to find a range of rocks equal to any assembled by plate tectonics.  Furthermore, building stones provide the foundation for constructing stories about cultural as well as natural history.

Take Seattle as an example.  At the wonderful Art Deco Seattle Exchange building, you can find 3.54-billion year old gneiss, the oldest rock that most of us will ever see.  Just up the block is the Rainier Club and its 330-million year old stone menagerie of fossils called the Salem Limestone, the most commonly used building stone in America.  Or consider the Rainier Bank Building, partially covered in travertine, which comes from the same quarries that provided rock for the Colosseum in Rome.

David B. Williams is a freelance writer focused on the intersection of people and the natural world.  His books include Stories in Stone: Travels Through Urban Geology; The Seattle Street-Smart Naturalist: Field Notes from the City; and his latest, Cairns:  Messengers in Stone.  Williams also works at the Burke Museum and is a former National Parks ranger in Utah and Massachusetts.  He maintains the blog GeologyWriter.com from his home base in Seattle.




EVENTS