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NPS Geodiversity Atlas—Fort Vancouver National Historic Site, Washington and Oregon

Geodiversity refers to the full variety of natural geologic (rocks, minerals, sediments, fossils, landforms, and physical processes) and soil resources and processes that occur in the park. A product of the Geologic Resources Inventory, the NPS Geodiversity Atlas delivers information in support of education, Geoconservation, and integrated management of living (biotic) and non-living (abiotic) components of the ecosystem.

cover of gri report with photo of a sunset and a barn
In-depth geologic information is contained in the baseline inventory products of the Geologic Resources Inventory, see table below.

Introduction

Fort Vancouver National Historical Site consists of two park units located on the north bank of the Columbia River (Fort Vancouver Unit) and along the Willamette River (McLoughlin House Unit) in Clackamas County, Oregon and Clark County, Washington. Originally authorized as a national monument on June 19, 1948, the park unit was re-designated a national historic site on June 30, 1961. Fort Vancouver National Historical Site encompasses approximately 84 hectares (207 acres) and preserves significant resources of American history related to emigration over the Oregon Trail, the military history at Vancouver Barracks, and the aviation history at Pearson Air Museum. Fort Vancouver served as the western headquarters of the Hudson’s Bay Company’s fur trade empire and supply depot west of the Rocky Mountains. The McLoughlin house preserves the home of Dr. John McLoughlin, commonly referred to as “the Father of Oregon” because of the assistance he provided to migrating American homesteaders. The historical site protects historic structures and an extensive collection of American Indian, fur trade, and U.S. Army material which encompasses archeological artifacts, historic objects, and archival documents. These nationally significant resources directly contributed to the establishment of Fort Vancouver National Historical Site and showcase global trade networks, technological evolution, and cultural engagement over the past two centuries.

Geologic Setting

Fort Vancouver National Historic Site lies within the Portland Basin, a rhomboid-shaped depression that began forming during the Miocene ~20 Ma (mega-annum, million years ago) due to the subduction of the Juan de Fuca Plate beneath the North American Plate. The geology of Fort Vancouver and the surrounding region reflects four main geologic episodes: (1) the development of the Portland Basin, (2) the eruption of vast quantities of Columbia River Basalt lavas, (3) the evolution of the Columbia River, and (4) the influence of catastrophic ice age floods on the current landscape. The thick layers of rock and sediment that fill the Portland Basin record geologic processes that include voluminous flood basalts resulting from mantle upwelling, regionally and locally derived sediment and volcanic debris, earthquakes, subsidence, rivers and lake sediments, and catastrophic flood deposits. The bedrock geology of the McLoughlin House Unit consists solely of Miocene-age Wanapum Basalt of the Columbia River Basalt Group, while the Fort Vancouver Unit has underlying geology of younger Pleistocene-age Missoula flood deposits and Holocene alluvium of the Columbia River floodplain.

Regional Geology

Fort Vancouver National Historic Site is a part of the Puget Trough Section of the Pacific Border Physiographic Province and shares its geologic history and some characteristic geologic formations with a region that extends well beyond park boundaries.

Maps and Reports

geologic map of the park cropped thumbnail view
In-depth geologic information is contained in the baseline inventory products of the Geologic Resources Inventory, see table below.
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The Geologic Resources Inventory produces digital geologic maps and reports for more than 270 natural resource parks. The products listed below are currently available for this park, check back often for updates as many maps, reports, and posters are still in progress.
  • Scoping summaries are records of scoping meetings where NPS staff and local geologists determined the park’s geologic mapping plan and what content should be included in the report.
  • Digital geologic maps include files for viewing in GIS software, a guide to using the data, and a document with ancillary map information. Newer products also include data viewable in Google Earth and online map services.
  • Reports use the maps to discuss the park’s setting and significance, notable geologic features and processes, geologic resource management issues, and geologic history.
  • Posters are a static view of the GIS data in PDF format. Newer posters include aerial imagery or shaded relief and other park information. They are also included with the reports.
  • Projects list basic information about the program and all products available for a park.

Source: Data Store Saved Search 2865. To search for additional information, visit the Data Store.

NPS Soil Resources Inventory project has been completed for Fort Vancouver National Historic Site and can be found on the NPS Data Store.

Source: Data Store Saved Search 2934. To search for additional information, visit the Data Store.

Geology Image Gallery

archaeologists working on a shallow excavation
Archaeologists working on a shallow excavation at Fort Vancouver National Historic Site.

Related Links

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Fort Vancouver National Historic Site

National Park Service Geodiversity Atlas

The servicewide Geodiversity Atlas provides information on geoheritage and geodiversity resources and values within the National Park System. This information supports science-based geoconservation and interpretation in the NPS, as well as STEM education in schools, museums, and field camps. The NPS Geologic Resources Division and many parks work with National and International geoconservation communities to ensure that NPS abiotic resources are managed using the highest standards and best practices available.

For more information on the NPS Geodiversity Atlas, contact us.

Fort Vancouver National Historic Site

Last updated: November 30, 2023