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Wide-Angle Seismic Imaging of Two Modes of Crustal Accretion in Mature Atlantic Ocean Crust

Davy, R. G.; Collier, J. S.; Henstock, T. J.; Rietbrock, A.; Goes, S.; Blundy, J.; Harmon, N.; Rychert, C.; Macpherson, C. G.; Van Hunen, J.; Kendall, M.; Wilkinson, J.; Davidson, J.; Wilson, M.; Cooper, G.; Maunder, B.; Bie, L.; Hicks, S.; Allen, R.; Chichester, B.; ... mehr

We present a high‐resolution 2‐D P‐wave velocity model from a 225‐km‐long active seismic profile, collected over ~60–75 Ma central Atlantic crust. The profile crosses five ridge segments separated by a transform and three nontransform offsets. All ridge discontinuities share similar primary characteristics, independent of the offset. We identify two types of crustal segment. The first displays a classic two‐layer velocity structure with a high gradient Layer 2 (~0.9 s$^{−1}$) above a lower gradient Layer 3 (0.2 s$^{−1}$). Here, PmP coincides with the 7.5 km s$^{−1}$ contour, and velocity increases to >7.8 km s$^{−1}$ within 1 km below. We interpret these segments as magmatically robust, with PmP representing a petrological boundary between crust and mantle. The second has a reduced contrast in velocity gradient between the upper and lower crust and PmP shallower than the 7.5 km s$^{−1}$ contour. We interpret these segments as tectonically dominated, with PmP representing a serpentinized (alteration) front. While velocity‐depth profiles fit within previous envelopes for slow‐spreading crust, our results suggest that such generalizations give a misleading impression of uniformity. ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000122144
Veröffentlicht am 11.08.2020
DOI: 10.1029/2019JB019100
Zitationen: 2
Zitationen: 4
Cover der Publikation
Zugehörige Institution(en) am KIT Geophysikalisches Institut (GPI)
KIT-Zentrum Klima und Umwelt (ZKU)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 0148-0227, 2156-2202, 2169-9313, 2169-9356
KITopen-ID: 1000122144
Erschienen in Journal of geophysical research / Solid earth
Verlag Wiley
Band 125
Heft 6
Nachgewiesen in Dimensions
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