Magnetic Anomalies and Fracture-Zone Trends in the Gulf of California

Larson, Peggy A.; Mudie, John D.; Larson, Roger L.

doi:10.1130/0016-7606(1972)83[3361:maafti]2.0.co;2

Cited by 55 publications

(29 citation statements)

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“…The North America-Pacific pole of rotation in northeast Canada at 48.8°N, 73.9°W [Minster and Jordan, 1978) implies that the Guaymas basin spreading rate does not differ significantly from that measured on the East Pacific Rise at the mouth of the Gulf of California, 3. 1-cm/yr half rate [Larson, 1972]. Therefore despite the lack of magnetic anomalies in the Guaymas basin, we can assume the spreading half rate there should be about 3 em/yr.…”

Section: The Guaymas Basinmentioning

confidence: 99%

“…However, two processes greatly complicate the determination of the heat flow anomaly in the Guaymas basin. First, the high sedimentation rate leads to an intrusive mode of crustal accretion with poorly developed magnetic anomalies [Larson, 1972;Moore, 1973;Klitgord eta/., 1974], so that crustal ages cannot be determined remotely. Second, since the spreading system is young and probably not yet fully developed, the thermal processes have probably not yet reached a stationary state, so the predictions of heat flow for a cooling plate may not be applicable.…”

Section: Lawver and Williamsmentioning

confidence: 99%

“…Some combination of strike slip faulting, crustal extension, and sea floor spreading has presumably occurred in the Guaymas basin for the last 4 m.y. that the East Pacific Rise has been actively spreading at the mouth of the Gulf [Larson, 1972]. Oceanic crust is indicated by a reversed seismic refraction station NW -SE across the Guaymas basin [Phillips, 1964].…”

Section: Lawver and Williamsmentioning

confidence: 99%

“…Extremely high sedimentation rates, both terrigenous and biogenic [van Andel, 1964;Calvert, 1966), combine with the oblique rifling geometry to prevent the development of many characteristics normally attributed to sea-floor-spreading systems. Thus elevated topography, rugged volcanic terrain, and identtfiable magnetic anomalies are absent at the spreading centers of the central Gulf of California [Larson, 1972;Moore, 1973). Sea floor spreading segments in this region are identifiable as a set of topographic basins connected by promment transform faults [Moore, 1973).…”

Section: Introductionmentioning

confidence: 99%

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Heat flow at the spreading centers of the Guaymas Basin, Gulf of California

Williams¹,

Becker²,

Lawver³

et al. 1979

J. Geophys. Res.

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Fifi~·four new heat ~ow measure~ents_in the central troughs of the Guaymas basin support the hypothesis that they are sues of active antrus1on In the northern trough a diStinct pattern of hydrothermal cooling is revealed, wuh ventang along the western boundary fault of the trough. In the southern trough an analogous pattern is apparently superimposed upon a conductive cooling anomaly associated with a recent central intrusion. The discharge of thermal waters occurs along the boundary faults and through other faults associated w1tb a possible horst block located in the north central floor of the southern trough. The heat flow patterns suggest that the intrusions are ep1sod1c and do not occur Simultaneously along the length ( 15-40 km) of a spreading segment. A review of all available beat flow measurementS ~or ~he G uaymas basin suggests that most of the recharge for a pervasive regional hydrothermal system is hm1ted to the central depress1ons, wuh perhaps some contribution from pore water. The discharge of thermal waters occurs predominantly in the central depressions and possibly along the boundary transform faults and fracture zones. The reg1ons of the basin more than a few kilometers an distance from the spreading a. xis, although presumably underlain by a hydrothermal system, are probably not the location of numerous vents or recharge zones.

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Section: The Guaymas Basinmentioning

confidence: 99%

Section: Lawver and Williamsmentioning

confidence: 99%

Section: Lawver and Williamsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Heat flow at the spreading centers of the Guaymas Basin, Gulf of California

Williams¹,

Becker²,

Lawver³

et al. 1979

J. Geophys. Res.

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“…Larson et al (1972) followed a suggestion of in suggesting that normal thermal remnant magnetism would not be acquired as readily in basaltic rocks intruded into sediment, in contrast to those extruded on the sea floor. Sharman (1976) suggested in addition that plate-edge jumps would further inhibit formation of correlatable oceanic magnetic anomalies.…”

Section: Structure Tectonics and Geophysicsmentioning

confidence: 99%

Guaymas Basin: Sites 477, 478, and 481

Curray¹,

Moore²

1982

Initial Reports of the Deep Sea Drilling Project

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Lower plate deformation at the Chile Triple Junction from the paleomagnetic record (45°30′S-46°S)

et al. 2015

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During the Chile Triple Junction (CTJ) cruise, geophysical surveys were conducted between 45°S and 48°S, in the region of the Chile Triple Junction (CTJ), where the Nazca and Antarctica Plates are subducting beneath the South American Plate. Near the CTJ, the South Chile Rise (SCR), which separates the Nazca and Antarctica lower plates, consists of three spreading segments trending~N160°, separated by a series of parallel fracture zones. The active spreading centers of the three segments consist of grabens with various widths and depths, bounded by steep fault scarps. We provide robust data showing that the SCR recorded remote and long-term effects of ridge subduction far from the subduction front. Magnetic profiles, multibeam bathymetric, and seismic data were acquired at intervals of 13 km along a N80°E direction across the SCR during the CTJ cruise of R/V L'Atalante. Deformation of the oceanic lithosphere includes (1) a segmentation of the spreading axes along strike, (2) some ridge jumps, and (3) local constriction and changes in trend of the fracture zone valleys. Off-axis volcanism is observed in places that may suggest a link with an abnormal stress field induced by ridge subduction. The tectonic and volcanic anomalies, which occurred in response to the subduction of the SCR1 axis, may be correlated with geochemical anomalies and slab fragmentation recognized by previous works.

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Magnetic Anomalies and Fracture-Zone Trends in the Gulf of California

Cited by 55 publications

References 0 publications

Heat flow at the spreading centers of the Guaymas Basin, Gulf of California

Heat flow at the spreading centers of the Guaymas Basin, Gulf of California

Guaymas Basin: Sites 477, 478, and 481

Lower plate deformation at the Chile Triple Junction from the paleomagnetic record (45°30′S-46°S)

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