Quaternary extrusion rates of the Cascade Range, northwestern United States and southern British Columbia

Journal Article · Sat Nov 10 00:00:00 EST 1990 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JB095iB12p19465· OSTI ID:5195786

Sherrod, D R; Smith, J G ^[1]

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1. Geological Survey, Menlo Park, CA (USA)

Quaternary (2-0 Ma) extrusion rates change significantly along the Cascade Range volcanic arc. The extrusion rate north of Mount Rainier is about 0.21 km{sup 3} km{sup {minus}1} m.y.{sup {minus}1}; the rate in southern Washington and northern Oregon south to Mount Hood is about 1.6 km{sup 3} km{sup {minus}1} m.y.{sup {minus}1}; in central Oregon the rate is 3-6 km{sup 3} km{sup {minus}1}; and in northern California, the rate is 3.2 km{sup 3} km{sup {minus}1} m.y.{sup {minus}1}. Eruption style also changes along the arc but at latitudes different from rate changes. At the ends of the arc, volcanism is focused at isolated intermediate to silicic composite volcanoes. The composite volcanoes represent {approximately}30% of the total volume of the arc. Mafic volcanic fields partly ring some composite volcanoes, especially in the south. In contrast, volcanism is diffused in the middle of the arc, where numerous overlapping mafic shields and a few composite volcanoes have built a broad ridge. Contrasting eruption style may signify diffuse versus focused heat sources or may reflect changes in permeability to ascending magma along the arc.

• OSTI ID: 5195786
• Journal Information: Journal of Geophysical Research; (United States), Vol. 95:B12; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
BRITISH COLUMBIA
VOLCANISM
CALIFORNIA
OREGON
WASHINGTON
AGE ESTIMATION
CASCADE MOUNTAINS
EXTRUSION
MAGMA
MAGMA SYSTEMS
MAPPING
PERMEABILITY
QUATERNARY PERIOD
VOLCANIC REGIONS
VOLCANOES
VOLUME
CANADA
CENOZOIC ERA
DEVELOPED COUNTRIES
FABRICATION
FEDERAL REGION IX
FEDERAL REGION X
GEOLOGIC AGES
GEOTHERMAL SYSTEMS
MATERIALS WORKING
MOUNTAINS
NORTH AMERICA
USA
580000* - Geosciences