Hot, shallow mantle melting under the Cascades volcanic arc

Citation
Lte. Tanton et al., Hot, shallow mantle melting under the Cascades volcanic arc, GEOLOGY, 29(7), 2001, pp. 631-634
Citations number
19
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Earth Sciences
Journal title
GEOLOGY
ISSN journal
0091-7613 → ACNP
Volume
29
Issue
7
Year of publication
2001
Pages
631 - 634
Database
ISI
SICI code
0091-7613(200107)29:7<631:HSMMUT>2.0.ZU;2-K
Abstract
Melting occurs at progressively greater depths and higher temperatures from west to east across the Cascades volcanic are in northern California, as d emonstrated by compositional variations observed in high-alumina olivine th oleiites. The lavas studied erupted from seven vents defining a 75-km-long, east-west transect across the are, from near Mount Shasta to east of Medic ine Lake volcano. The increase in melting depth across the are parallels mo deled 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 similar to 36 km at the western end of the trans ect 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.