Category: National geology

2025-04-12 Dan Muhs – Tectonic Uplift in the Pacific Northwest

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The Lecture
Subduction-related late Quaternary tectonic uplift and sea-level change in the Pacific NW and around the Pacific Rim

This was a Zoom-only lecture.

Quimper Geological Society welcomed Dan Muhs, an emeritus USGS geologist. He provided marine terraces as evidence of tectonic uplift along the Pacific Ocean plate.

In 1979, Seiya Uyeda and Hiroo Kanamori introduced a tectonic model with two end members of a subduction-boundary continuum: the “Chilean” type (shallow dip of the subducting plate, great thrust events, compression, and uplift of the overriding plate) and the “Mariana” type (steep dip of the subducting plate, no great thrust events, tension, and little or no uplift). The concept has been used to explain variable rates of Quaternary uplift around the Pacific Rim, and the paper has been cited over a thousand times since its publication in the Journal of Geophysical Research.  We now have a sufficient number of dated late Quaternary marine terraces from around the Pacific Rim to test the veracity of this model. In this presentation, well-dated emergent shorelines of the Pacific Rim was explored, from South America, North America, the Aleutians, Japan, and the Marianas.

About the Speaker

Dan Muhs is an emeritus scientist with the U.S. Geological Survey. He earned B.A. and M.S. degrees from the University of Illinois and a Ph.D. from the University of Colorado. He was a research geologist with the USGS from 1985 until his retirement in 2022.  Despite his retirement, Dan remains an active researcher, lecturer, and writer.

Dan’s interests are in the fields of coastal and eolian geomorphology, Quaternary stratigraphy, soil genesis, and paleoclimatology. Most of his work has been in the US (Alaska, western US, and Great Plains), but he has also worked in Canada, Mexico, Caribbean, Spain, and western Pacific. Over the course of his career he has authored more than 150 scientific papers on a diverse range of subjects focused on the Quaternary period, including the origins and history of loess and dune fields, paleozoogeography of marine fossil invertebrates, tests of glacial isostatic adjustment models, and sea-level histories and tectonic uplift rates deduced from emergent marine terraces. Dan has received numerous awards and recognition, including the Geological Society of America Kirk Bryan Award.

2023-10-14 John Oldow – Subducted terrane exposed on Fidalgo Island

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Fidalgo Ophiolite Revisited: A chaotic assemblage of ophiolitic blocks deposited in a matrix of mudstone, sandstone, and basalt flows overlain by deep-water turbidites derived from a volcanic arc – John S. Oldow, Whidbey Island

The Lecture

It has long been thought that an intact ophiolite had accreted to North America and was preserved on Fidalgo Island in the San Juan Islands, just north of Port Townsend. (An ophiolite is a slab of oceanic crust and underlying mantle rock.) These ophiolitic rocks are on spectacular display along the coast of Fidalgo Island, including in Deception Pass State Park, the most-visited state park in Washington. This body of oceanic crust was interpreted to have subsequently been the site of an oceanic island arc, a chain of volcanoes, with parts of the island arc’s volcanic rock also accreted. Mount Erie, the highest point on Fidalgo Island, is underlain by a body of granite that represents a magma chamber beneath one of the volcanoes. It is easy to see why Fidalgo Island has long been a major attraction for people interested in exploring complex geology.

Recently, Dr. John Oldow and his Ph.D. student David Katapody reexamined and reinterpreted the geology of Fidalgo Island and adjacent islands. Here blocks of various parts of the subduction complex and volcanic arc were deposited as sedimentary mélange composed of debris flows and rock falls carried into a basin containing mudstone, sandstone, and basalt flows. The deep basin was ultimately filled and overlapped by deep marine clastic rocks derived exclusively from the adjacent island-arc complex. The mélange and overlap succession were subsequently subducted to high pressure – low temperature conditions before being returned to the surface and imbricated along the North American Cordillera. Their work rewrites the geology of the area and calls for revising how the accreted terranes of the area have been mapped and named. The work of Oldow and Katapody is a fresh, eye-opening look at the rocks of the San Juan Islands and how they formed.

The Speaker

John Oldow received his BS degree in geology from the University of Washington in 1972 and his Ph.D. in geology from Northwestern University in 1978. He taught geological sciences with a specialty in structure and tectonics for 40 years: at Rice University for 17 years, at the University of Idaho for 13, years and at the University of Texas Dallas for 10 years before he retired from academia in 2018. He returned home to the Pacific Northwest and lives on northern Whidbey Island. He is still active in research projects in the western Great Basin, northern Alaska and northwestern Canada, and the San Juan Islands of Washington State. He continues to consult for mineral and petroleum exploration companies and holds a position as a Research Associate at Western Washington University.

2023-05-13 Vince Matthews — Global Scramble for Natural Resources

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Vince Matthews, former director of the Colorado Geological Survey and now a consulting geologist in Wisconsin, spoke on the Global Scramble for Natural Resources. This was a ZOOM broadcast Saturday, May 13, 2023.

The Lecture

During the 1990s, the world’s most populous nations—China and India–were unleashed from Communist and Socialist regimes, respectively. The first decade of the 21st Century saw China’s GDP grow at more than 10 percent per year and India’s at 7-9 percent. Both are drastically increasing their use of all natural resources. Although they have resources of their own, they are insufficient to meet their internal demand.

Because the world’s mineral and energy resources are being strained to supply these exploding economies, the price of nearly every natural-resource commodity dramatically escalated beginning in 2003. Not only did the price of commodities increase, but the competition to simply obtain a share of these natural resources became intense. From cement, to petroleum, to fertilizer, to strategic metals; the scramble for a piece of the worldwide commodities pie is in a state the world has never known. The U.S. is being, and will be, significantly affected by this new world disorder.

As America looks increasingly to alternative energy sources, we face an increase in imports to achieve our goals.  Many of the current alternative energy technologies use a variety of imported mineral commodities, especially “rare earths.” The country’s increasing vulnerabilities to foreign sources of strategic mineral commodities were slow to be recognized.

The Speaker

Dr. Vince Matthews received B.S. and M.S. degrees in geology from the University of Georgia and a Ph.D. from the University of California, Santa Cruz. He was awarded “Outstanding Alumnus” recognition from both institutions. His career includes holding executive positions with four natural resource companies and teaching at eight institutions of higher education, two of them tenured positions.

About ten years ago Vince retired as Director of the Colorado Geological Survey. In retirement, he has served as Interim Executive Director of the National Mining Hall of Fame and Museum, served on the Special Scientific Committee on the Health Effects of Unconventional Oil and Gas Development in the Appalachian Basin, presented Zoom talks on a variety of topics to geological societies and universities, led field trips in the Rocky Mountains, completed the manuscript for a book entitled, Land of Ice: Jaunts into Colorado’s Glacial Landscape, and was recruited to teach “Earth Resources and Sustainability” at the University of Wisconsin-Eau Claire last fall semester.