Expedition gathers new data on crust beneath Mexican West Coast

Dañobeitia, Juanjo; Córdoba, Diego; Delgado-Argote, Luis Alberto; Michaud, François; Bartolomé, Rafael; Farran, Marcel-lí; Carbonell, Ramón; Núñez-Cornũ, F. J.

doi:10.1029/97eo00338

Cited by 25 publications

(17 citation statements)

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“…The strong sedimentation and shallow penetration did not allow imaging of magmatic products in other areas, except for some isolated submarine volcanoes. Lava bodies were interpreted from backscattering images, magnetic and seismic data for the upper Delfín basin and mainly along the Ballenas‐Salsipuedes channel [ Frías‐Camacho et al , 1999; Delgado‐Argote , 2000; Paz‐López et al , 2000; Paz‐López , 2000] using CORTES‐P96 cruise data [ Dañobeitia et al , 1997]. …”

Section: Introductionmentioning

confidence: 99%

Mode of extension and rifting history of upper Tiburón and upper Delfín basins, northern Gulf of California

González‐Fernández¹,

Dañobeitia²,

Delgado-Argote³

et al. 2005

J. Geophys. Res.

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[1] The crustal structure of the northern Gulf of California transtensional margin has been investigated by a 280-km-long NW-SE profile, including deep multichannel seismic reflection and densely sampled refraction/wide-angle reflection seismic information combined with gravity modeling. The seismic and gravity modeling constrains two thinned crustal areas, corresponding to the upper Delfín and the upper Tiburón basins. On both sides of the profile, toward the Baja California Peninsula and the Mexico mainland, a progressive thickening of the continental crust is observed. Our results indicate that the crustal thickness is 19 km below the coastline, and it decreases to 14 and 17 km below the upper Delfín and upper Tiburón basins, respectively. In the area between both basins, the crust thickens to 19.5 km. There are significant lateral thickness variations for the different levels of the crust. The interpreted structure is consistent with the existence of an aborted rift below the upper Tiburón basin. Prominent dipping reflections in the multichannel data under upper Tiburón basin and the ridge between upper Tiburón and upper Delfín basins can be explained as a mylonite like zone related to a detachment fault. This interpretation suggests that the structural evolution of upper Tiburón basin could be controlled by a major fault that cuts through the upper crust and merges into a zone of subhorizontal reflections in the lower crust. The mode and locus of extension have evolved from a core complex in upper Tiburón to a narrow rift mode in upper Delfín basin.

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Section: Introductionmentioning

confidence: 99%

Mode of extension and rifting history of upper Tiburón and upper Delfín basins, northern Gulf of California

González‐Fernández¹,

Dañobeitia²,

Delgado-Argote³

et al. 2005

J. Geophys. Res.

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“…EISSLER and MCNALLY (1984) and SINGH et al (1985) suggested a dip angle of 20°for the interface between the Rivera and North American Plates. NÚ Ñ EZ-CORNÚ and SÁ NCHEZ-MORA (1999), reported a dip angle of 12°as estimated from local seismicity data, and similar values were obtained from reflection-refraction studies carried out in the central and northern regions of the Jalisco coast (DAÑ OBEITIA et al, 1997). More controversial are the geometry of the interface and the relative motion between the Rivera and Cocos Plates.…”

Section: Tectonic Settingmentioning

confidence: 52%

Using an Enhanced Dataset for Reassessing the Source Region of the 2003 Armería, Mexico Earthquake

Núñez-Cornũ

Rutz-Lopez

Márquez-Ramírez

et al. 2010

Pure Appl. Geophys.

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Abstract-We present a fresh look at the source region of the 22 January 2003 M w 7.4 Armería earthquake, which occurred off the Pacific coast of the state of Colima, Mexico, near the town of Armería. The effects of this earthquake in the neighboring states of Colima and Jalisco were different and stronger than those of previous recent major earthquakes in the region. This earthquake and its aftershocks were recorded by two local telemetered seismograph networks (RESCO and RESJAL). From 22 January to 24 January 2003, no important seismicity was located on the plates interface, or within the Rivera Plate, and most epicenters were located west of the Armería River, which is the western border of the Colima Graben, and is located outside of the Colima Gap region. From 24 January to 31 January, the seismicity recorded by both networks showed a migration in depth, with an almost vertical offshore distribution between 4 and 24 km in depth. For this period, a sevenstation portable digital seismograph network, equipped with threecomponent seismometers, was deployed in the epicentral area to study the aftershock sequence in detail. With this denser network more than 200 M L [ 2.0 aftershocks were recorded. The aftershock foci were deeper than those recorded during the early period and most of them locate on a hypothetical 12°dipping interface between the Rivera and North American Plates. Composite focal mechanism solutions for the aftershocks located during both periods indicate a reverse fault character that changes with time. Analysis of the new dataset still indicates that the earthquake was a shallow intraplate event.

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“…There is also considerable relief on the Rivera plate seaward of the trench. Seismic velocity models based on the OBS data indicate a dip of 8-128 for the subducting oceanic plate [6], consistent with the initial dip of the Benioff zone further landward [10]. The top of oceanic basement may be traced for about 10 km beneath the accretionary wedge, and the Rivera plate is covered by about 1 km of sediments as it enters the subduction zone.…”

Section: Tectonic Settingmentioning

confidence: 79%

“…Close to continental margins, determination of the depth to this reflector allows average geothermal gradients between the seabed and the BSR to be measured over wide areas [5]. Here we estimate conductive heat flow through sediments overlying young oceanic crust subducted beneath the western margin of Mexico at 208N, based on observations of a strong and continuous BSR in multichannel seismic reflection (MCS) profiles acquired during the Crustal Offshore Research Transect by Extensive Seismic Profiling (CORTES) experiment [6].…”

Section: Introductionmentioning

confidence: 99%

Low heat flow from young oceanic lithosphere at the Middle America Trench off Mexico

Minshull

Bartolomé

Byrne

et al. 2005

Earth and Planetary Science Letters

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Seismic reflection profiles across the Middle America Trench at 208N show a high amplitude bottom simulating reflector interpreted as marking a phase transition between methane hydrate and free gas in the pore space of both accreted and trench sediments. We determine the depth of the hydrate-gas phase boundary in order to estimate the geothermal gradient and hence the heat flow beneath the trench and the frontal part of the accretionary wedge which overlies the downgoing plate. After correction for sedimentation, heat flow values in the trench and through the accretionary wedge are only about half of the values predicted by plate cooling models for the 10 Ma subducting lithosphere. There is no systematic correlation between heat flow in the accretionary wedge and distance from the trench. A comparison with heat flow predicted by a simple analytical model suggests that there is little shear heating from within or beneath the wedge, despite the high basal friction suggested by the large taper angle of the wedge. The geothermal gradient varies systematically along the margin and is negatively correlated with the frontal slope of the wedge. Some local peaks may be attributed to channelised fluid expulsion. D

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Expedition gathers new data on crust beneath Mexican West Coast

Cited by 25 publications

References 0 publications

Mode of extension and rifting history of upper Tiburón and upper Delfín basins, northern Gulf of California

Mode of extension and rifting history of upper Tiburón and upper Delfín basins, northern Gulf of California

Using an Enhanced Dataset for Reassessing the Source Region of the 2003 Armería, Mexico Earthquake

Low heat flow from young oceanic lithosphere at the Middle America Trench off Mexico

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