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Synthesis of crustal seismic structure and implications for the concept of a slab gap beneath Coastal California

International Geology Review

By:
, ,
DOI: 10.1080/00206819909465142

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Abstract

Compilation of seismic transects across the central and northern California Coast Ranges provides evidence for the widespread tectonic emplacement beneath the margin of a slab of partially subducted oceanic lithosphere. The oceanic crust of this lithosphere can be traced landward from the former convergent margin (fossil trench), beneath the Coast Ranges, to at least as far east as the Coast Range/Great Valley boundary. Comparison of measured shear and compressional wave velocities in the middle crust beneath the Hayward fault with laboratory measurements suggests that the middle crust is a diabase (oceanic crust). Both of these observations are consistent with recent models of the high heat flow and age progression of Neogene volcanism along the Coast Ranges based on tectonic emplacement (stalling) of young, hot oceanic lithosphere beneath the margin, but appear to contradict the major predictions of the slab-gap or asthenospheric-window model. Finally, the Neogene volcanism and major strike-slip faults in the Coast Ranges occur within the thickest regions (>14 km thick) of the forearc, suggesting that the locations of Cenozoic volcanism and faulting along the margin are structurally controlled by the forearc thickness rather than being determined by the location of a broad slab gap.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Synthesis of crustal seismic structure and implications for the concept of a slab gap beneath Coastal California
Series title:
International Geology Review
DOI:
10.1080/00206819909465142
Volume
41
Issue:
3
Year Published:
1999
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
263
Last page:
274
Number of Pages:
12