Belknap

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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 44.285°N
  • 121.841°W

  • 2095 m
    6872 ft

  • 322060
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

The Global Volcanism Program has no activity reports for Belknap.

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The Global Volcanism Program has no Bulletin Reports available for Belknap.

The Belknap Crater area near McKenzie Pass, north of the Three Sisters volcanoes in the central Oregon Cascades, was the source of one of the largest concentrations of youthful volcanism in the Cascade Range. The basaltic to basaltic-andesite Belknap shield volcano, topped by the Belknap Crater pyroclastic cone and the Little Belknap shield volcano immediately to the east, have produced widespread late-Holocene lava flows on all sides that form an impressive panorama of youthful volcanism in the McKenzie Pass area, much of which took place between about 3000 and 1500 years ago. Late-stage eruptions from the NE base of Belknap crater produced lava flows that traveled 15 km west into the McKenzie River valley. The narrow McKenzie Pass highway provides seasonal access across the barren lava fields with spectacular views toward Mt. Jefferson and the Three Sisters.

Summary of Holocene eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
0480 (?) Unknown Confirmed 2 Radiocarbon (corrected) Belknap Crater
0800 BCE ± 300 years Unknown Confirmed 2 Radiocarbon (corrected) South Belknap and Twin Craters
1030 BCE ± 300 years Unknown Confirmed 0 Radiocarbon (corrected) Little Belknap

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.


Synonyms

Mckenzie Highway Lava Field

Cones

Feature Name Feature Type Elevation Latitude Longitude
Innaccesible Cones Pyroclastic cone 1484 m 44° 18' 0" N 121° 55' 0" W
Little Belknap Shield volcano 1922 m 44° 17' 0" N 121° 49' 0" W
South Belknap Pyroclastic cone 1787 m 44° 16' 0" N 121° 51' 0" W
Twin Craters Pyroclastic cone 1611 m 44° 15' 0" N 121° 53' 0" W
The broad Belknap shield volcano at the left, viewed from Sand Mountain volcano to its NW, with the Three Sisters volcanoes in the background, is one of the youngest volcanoes in the central Oregon Cascades. The latest dated lava flow from Belknap volcano traveled 15 km west to the McKenzie River, beyond the right margin of this photo, from a vent on the NE side of Belknap about 1500 years ago.

Photo by Lee Siebert, 1981 (Smithsonian Institution).
Little Belknap shield volcano, seen here from the side of Belknap volcano on the west with Black Crater in the background, was formed about 2900 years ago. Lava flows from Little Belknap, buttressed against the higher Belknap volcano on the west, spread primarily to the east.

Photo by Lee Siebert, 1982 (Smithsonian Institution).
The McKenzie Pass area in the central Oregon Cascades contains one of the largest concentrations of youthful volcanism in the United States. Belknap shield volcano, seen here from Black Crater to the SE, is capped by a snow-covered pyroclastic cone. Lava flows from Belknap and the smaller Little Belknap shield volcano in front of it cover nearly 100 sq km. Most of the largely unvegetated flows were erupted between about 2900 and 1500 years ago.

Photo by Lee Siebert, 1995 (Smithsonian Institution).
Little Belknap (upper left) is an example of a small shield volcano in a continental margin setting. Little Belknap was constructed on the east flank of Belknap volcano and spread fresh-looking lava flows over the McKenzie Pass area of the central Oregon Cascades about 2900 years ago. Collapsed lava tubes that fed the flows diverge radially away from the summit. The summit pinnacle of Mount Washington appears at the right beyond the Little Belknap lava apron.

Photo by Lee Siebert, 1995 (Smithsonian Institution).
Lava flows from Little Belknap shield volcano in the central Cascade Range of Oregon on the right skyline diverge around a "kipuka," a forested island of pre-eruption terrain in the center of the photo. "Kipuka" is a Hawaiian term for older land surrounded by lava flows. In some cases the surface of the kipuka may be lower than the adjacent lava.

Photo by Lee Siebert, 1995 (Smithsonian Institution).
The young lava flow in the foreground, with snow-capped Mount Jefferson in the background, was erupted about 2600-2900 years ago from Yapoah cinder cone on the north flank of North Sister volcano. Lava flows in the middle of the photo originated from Little Belknap shield volcano, part of one of the largest concentrations of youthful volcanism in the continental United States: the McKenzie Pass area of the central Oregon Cascade Range.

Photo by Lee Siebert, 1995 (Smithsonian Institution).
Lava flows in the foreground originated about 1505 years ago from the breached South Belknap cinder cone below the skyline at the left center. South Belknap cinder cone lies below Belknap Crater, a pyroclastic cone capping the Belknap shield volcano. The low peak on the right skyline is Little Belknap, a small shield volcano constructed on the east flank of the Belknap shield volcano. Largely unvegetated lava flows cover nearly 100 sq km in the McKenzie Pass area.

Photo by Lee Siebert, 1995 (Smithsonian Institution).
The South Belknap cinder cone on the middle left skyline was constructed on the SW flank of Belknap shield volcano (upper right) about 2600 years ago during an eruption that produced lava flows that traveled to the south. The foreground lava flows originated from Belknap volcano.

Photo by Lee Siebert, 1995 (Smithsonian Institution).

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title.

Green J, Short N M, 1971. Volcanic Landforms and Surface Features: a Photographic Atlas and Glossary. New York: Springer-Verlag, 519 p.

Hildreth W E, 2007. Quaternary magmatism in the Cascades--geologic perpectives. U S Geol Surv Prof Pap, 1744: 1-125.

IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior..

Peterson N V, Groh E A, 1963. Recent volcanic landforms in central Oregon. Ore Bin, 25: 1-15.

Peterson N V, Groh E A, 1966. Lunar Geological Field Conference guidebook. Oregon Dept Geol Min Ind, 51 p.

Sherrod D R, Taylor E M, Ferns M L, Scott W E, Conrey R M, Smith G A, 2004. Geologic map of the Bend 30- x 60-minute quadrangle, central Oregon. U S Geol Surv Map , I-2683, 1:100,000 scale and 48 p text.

Taylor E M, 1965. Recent volcanism between Three Fingered Jack and North Sister Oregon Cascade Range. Ore Bin, 27: 121-148.

Taylor E M, 1968. Roadside geology, Santiam and McKenzie Pass Highways, Oregon. Oregon Dept Geol Min Ind Bull, 62: 3-34.

Wood C A, Kienle J (eds), 1990. Volcanoes of North America. Cambridge, England: Cambridge Univ Press, 354 p.

Volcano Types

Shield(s)
Pyroclastic cone(s)

Tectonic Setting

Subduction zone
Continental crust (> 25 km)

Rock Types

Major
Andesite / Basaltic Andesite
Basalt / Picro-Basalt

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
0
0
6,518
362,091

Affiliated Databases

Large Eruptions of Belknap Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).
WOVOdat WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.
EarthChem EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).
Smithsonian Collections Search the Smithsonian's NMNH Department of Mineral Sciences collections database. Go to the "Search Rocks and Ores" tab and use the Volcano Name drop-down to find samples.