Ghost Forest on the Oregon Coast. Photo by Jamie Hale for The Oregonian
Pat Pringle, Professor Emeritus of Earth Sciences at Centralia College, Washington will present an illustrated lecture on “Buried and Submerged Forests of the Pacific Northwest—Witnesses to Ancient Earthquakes, Landslides, and Volcanic Eruptions.”
How much we know about the Pacific Northwest’s post-Ice Age geologic events has grown rapidly in recent decades. The discovery and study of buried and submerged forests—victims of past catastrophes, has opened the door to new understanding. Testing techniques such as Carbon 14 wiggle matching and dendrochronology (tree-ring dating) now allow more precise dating of the geological past as well. These capabilities are revolutionizing our understanding of the history, behavior, and effects of past volcanic eruptions, regional earthquakes, major landslides, and (to a limited extent) regional climate history and fluctuations.
We will take a snapshot tour of some of the many locations of buried and submerged forests around Washington State and other Pacific Northwest locations to observe trees that were submerged by postglacial tectonic forces, or killed by a flow of hot volcanic fragments (pyroclastic surge) or buried in landslides, or drowned in lakes dammed by landslides. On our tour we’ll get a picture of the scale of some of the dramatic postglacial landscape changes, such as the episodic disturbances caused by volcanism- changes that the pre-Euro-American settlement peoples experienced and adapted to, and that early explorers, like Lewis and Clark, described vividly in their journals.
We’ll see how samples of “subfossil” trees are collected and prepared for tree ring analysis, and learn about what tree rings in these “time capsules” can tell us. Some of the scenic areas we will visit include the Washington Coast, the Olympic and Cascade Mountains, the Puget Lowland, and the Columbia Gorge, with a special focus on the Bonneville landslide, and Mount Rainier and Mount Hood volcanoes.
This event is sponsored by the Quimper Geological Society (QuimperGeology.org). Click here to view previously recorded events by Quimper Geological Society.