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Hot, shallow mantle melting under the Cascades volcanic arc

Geology

By:
, ,
DOI: 10.1130/0091-7613(2001)​029<0631:HSMMUT>​2.0.CO;2

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Abstract

Melting occurs at progressively greater depths and higher temperatures from west to east across the Cascades volcanic arc in northern California, as demonstrated by compositional variations observed in high-alumina olivine tholeiites. The lavas studied erupted from seven vents defining a 75-km-long, east-west transect across the arc, from near Mount Shasta to east of Medicine Lake volcano. The increase in melting depth across the arc parallels modeled isotherms in the mantle wedge and does not parallel the inferred dip of the slab. The depth of mantle melting at which the high-alumina olivine tholeiites were created is ∼36 km at the western end of the transect and 66 km at the eastern end. The very high temperatures of dry melting so close to the crust indicate a transitory condition of the mantle.

Geospatial Extents

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Hot, shallow mantle melting under the Cascades volcanic arc
Series title:
Geology
DOI:
10.1130/0091-7613(2001)​029<0631:HSMMUT>​2.0.CO;2
Volume
29
Issue:
7
Year Published:
2001
Language:
English
Publisher:
Geological Society of America
Description:
4 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
631
Last page:
634
Number of Pages:
4
Country:
United States
State:
California;Oregon
Other Geospatial:
Cascades