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Geologic Publications for Mount Rainier

Roadside geology of Mount Rainier National Park and vicinity

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Author(s): Patrick T. Pringle

Document Type: Information Circular 107
Publisher: Washington State Department of Natural Resources, Division of Geology and Earth Resources
Published Year: 2008
Pages: 200
DOI Identifier:
ISBN Identifier:

Welcome to Mount Rainier National Park and the beautiful Cascade Range of south-central Washington. The legs in this road guide circumnavigate the majestic Mount Rainier volcano and cut across the southern Cascade Range from the Puget Lowland on the west, to the Columbia Basin on the east, following some of Washington State's Scenic Byways (see inside cover). Along the way, the geologically curious traveler can examine a wide variety of geologic features, including faulted and metamorphosed rocks older than the Cascade Range, as well as the faults, folds, and features of sedimentary and igneous rocks of the Cascades created before Mount Rainier was built. Roadcuts also reveal deposits of both continental and alpine glaciers, as well as the lavas and fragmental deposits of Mount Rainier.

Mount Rainier is an active volcano in our backyard that poses great potential risk to the increasing population in river valleys downstream. Because of this, Mount Rainier was designated a Decade Volcano by the International Association of Volcanology and Chemistry of the Earth's Interior in 1992, one of 16 volcanoes worldwide so recognized during the International Decade of Natural Disaster Reduction. The main goal of Decade Volcano studies at Mount Rainier has been to better understand the volcano in order to reduce the deaths and societal and economic disruption that could result from inevitable future volcanic events. However, another goal has been to find out whether we can live safely near it with lessened anxiety if we better comprehend and take seriously this great peak's volcanic history.

In this book, we will review the geologic history, processes, and hazards of Mount Rainier and learn about revealing new research on the volcano and the rocks and geologic structures nearby and underneath it. We will also inspect the geologic evidence for lahars, which are probably the most important hazardous geologic phenomenon at Mount Rainier. Deposits of more than 60 postglacial lahars have been identified in the strata of the valleys that drain the volcano. One of these ancient lahars, the Osceola Mudflow, is among the largest documented in the world. Along with later lahars and volcanic floods, the Osceola Mudflow radically changed the landscape downstream of the mountain.

This road guide describes and interprets the landscape and geologic features at diverse sites in Mount Rainier National Park and along highways that approach the park, including two that have been formally designated as Scenic Byways—State Route 410 and U.S. Highway 12. Primarily we will examine four aspects of Mount Rainier area geology: (1) the pre–Mount Rainier rocks and their history, (2) the glacial history and deposits of the area, (3) the history and activity of Mount Rainier volcano, and (4) the ongoing processes of erosion and landscape modification. We strongly recommend that this guide be used in conjunction with maps of Mount Rainier National Park available at visitor centers within the park and at certain stores outside the park.

View Report:
View Report [External Link]

Suggested Citations:
In Text Citation:
Pringle (2008) or (Pringle, 2008)

References Citation:
Pringle, P.T., 2008, Roadside geology of Mount Rainier National Park and vicinity: Information Circular 107, Washington State Department of Natural Resources, Division of Geology and Earth Resources, 200 p..