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Asymmetric deep crustal structure across the Juan de Fuca Ridge

K. M. M. Rohr, B. Milkereit and C. J. Yorath
Asymmetric deep crustal structure across the Juan de Fuca Ridge
Geology (Boulder) (June 1988) 16 (6): 533-537


A multichannel line was shot across the Endeavour segment of the Juan de Fuca Ridge. Careful processing of 25 km of the line centered about the rise axis shows that young crustal structure is asymmetric. An intermittent reflector from the top 1 km of crust follows topography on both the Pacific and the Juan de Fuca plates. It could be either the pillow basalt-diabase dike contact or a metamorphic front within the pillow basalts. A reflection exists 2-3 km below the rift-valley floor; diffractions from its edges indicate that the rift valley's velocity structure is markedly different from the structure of the flanks. The deep crustal structure is highly asymmetric. Moho exists within 4 km of the rift valley on the Pacific plate, in contrast to the Juan de Fuca plate, which shows a reflector at intermediate depths dipping away from the rise to reach Moho depth 12 km from the rift valley. This reflector's origin is enigmatic; we speculate that the thermal history and structure of the two plates differ because of local differences in mantle structure caused by either ridge migration or a melting anomaly.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 16
Serial Issue: 6
Title: Asymmetric deep crustal structure across the Juan de Fuca Ridge
Affiliation: Geol. Surv. Can., Pac. Geosci. Cent., Sidney, BC, Canada
Pages: 533-537
Published: 198806
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 30
Accession Number: 1988-044695
Categories: Solid-earth geophysicsApplied geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
N44°00'00" - N52°00'00", W135°00'00" - W125°00'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 1988
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