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GEOREF RECORD

Geochemistry, petrogenesis, and tectonic implications of central High Cascade mafic platform lavas

Scott S. Hughes and Edward M. Taylor
Geochemistry, petrogenesis, and tectonic implications of central High Cascade mafic platform lavas
Geological Society of America Bulletin (August 1986) 97 (8): 1024-1036

Abstract

Petrographic and geochemical data allow the distinction of normal basalts (53 wt.% SiO (sub 2) ) from two types of basaltic andesites with associated high-silica basaltic andesites (53-62 wt.% SiO (sub 2) ) in the central High Cascades. All units yield fractionated REE and incompatible element-enriched patterns characteristic of continental tholeiitic magmas. The Mt Washington type basaltic andesites are distinguished from the North Sister ones by relatively higher total REE and other LIL element abundances. Based on trace-element signatures, separate magma sources are postulated for normal basalt and basaltic andesites with associated high-silica ones and models of their magma formation are proposed. Eruptions of near-primary basaltic andesite were catalysed by fluids which had been derived from a subducted slab. Basaltic andesites accompanied by locally evolved calc-alkaline silicic units, were interspersed with voluminous eruptions of basalt due to the juxtaposition of an extensional regime upon the older Cascade province.


ISSN: 0016-7606
EISSN: 1943-2674
Coden: BUGMAF
Serial Title: Geological Society of America Bulletin
Serial Volume: 97
Serial Issue: 8
Title: Geochemistry, petrogenesis, and tectonic implications of central High Cascade mafic platform lavas
Affiliation: Oreg. State Univ., Dep. Geol., Corvallis, OR, United States
Pages: 1024-1036
Published: 198608
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 38
Accession Number: 1986-061809
Categories: Geochemistry of rocks, soils, and sedimentsIgneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 7 tables, sketch map
N44°00'00" - N44°40'00", W122°04'60" - W121°25'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
Update Code: 1986
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