Heat flow and bending-related faulting at subduction trenches: Case studies offshore of Nicaragua and Central Chile

Grevemeyer, Ingo; Kaul, Norbert E; Díaz-Naveas, Juan; Villinger, Heinrich; Ranero, César R.; Reichert, Christian

doi:10.1016/j.epsl.2005.04.048

Cited by 105 publications

(108 citation statements)

References 35 publications

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“…The bending of the Cocos plate preferentially induces the reactivation of faults and fractures, creating a horst and graben structure . Vertical axis is kilometers below sea level, vertical exaggeration is 100 times (AUBOUIN et al, 1982;GREVEMEYER et al, 2005;RUFF, 1989). The faulting of the lithosphere allows water to penetrate into the young warm slab and alter the density.…”

Section: Hydrothermal Alterationmentioning

confidence: 99%

An Evaluation of Proposed Mechanisms of Slab Flattening in Central Mexico

Skinner

Clayton

2010

Pure Appl. Geophys.

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Abstract-Central Mexico is the site of an enigmatic zone of flat subduction. The general geometry of the subducting slab has been known for some time and is characterized by a horizontal zone bounded on either side by two moderately dipping sections. We systematically evaluate proposed hypotheses for shallow subduction in Mexico based on the spatial and temporal evidence, and we find no simple or obvious explanation for the shallow subduction in Mexico. We are unable to locate an oceanic lithosphere impactor, or the conjugate of an impactor, that is most often called upon to explain shallow subduction zones as in South America, Japan, and Laramide deformation in the US. The only bathymetric feature that is of the right age and in the correct position on the conjugate plate is a set of unnamed seamounts that are too small to have a significant effect on the buoyancy of the slab. The only candidate that we cannot dismiss is a change in the dynamics of subduction through a change in wedge viscosity, possibly caused by water brought in by the slab.

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Section: Hydrothermal Alterationmentioning

confidence: 99%

An Evaluation of Proposed Mechanisms of Slab Flattening in Central Mexico

Skinner

Clayton

2010

Pure Appl. Geophys.

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“…There, measured heat flow is lower than expected, suggesting that the crust is perhaps cooled by hydrothermal circulation through newly opened fault zones (Grevemeyer et al, 2005). However, these heat-flow values could also be explained by efficient hydrothermal circulation through permeable seamounts and basaltic outcrops (Fisher et al, 2003).…”

Section: Geophysical Properties Of a Hydrated Subducting Upper Mantlementioning

confidence: 66%

Evolution of oceanic margins : rifting in the Gulf of California and sediment diapirism and mantle hydration during subduction

Miller¹

2013

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This thesis investigates three processes that control the evolution of oceanic margins. Chapter 2 presents seismic images of a ~2-km-thick evaporite body in Guaymas Basin, central Gulf of California. In rifts, evaporites form under conditions unique to the latest stages of continental rupture, and the presence, age, thickness, and shape place new constraints on the history of early rifting there. Chapter 3 presents numerical experiments that show that diapirs can form in sediments on the down-going plate in subduction zones and rise into the mantle wedge, delivering the sedimentary component widely observed in arc magmas. Chapter 4 presents measurements of seismic anisotropy from wide-angle, active-source data from the Middle America Trench that address the hypothesis that the upper mantle is hydrated by seawater flowing along outer-rise normal faults. These measurements indicate that the upper mantle is ~1.57 to 6.89% anisotropic, and this anisotropy can be attributed to bendingrelated faulting and an inherited mantle fabric. Accounting for anisotropy reduces previous estimates for the amount of water stored in the upper mantle of the downgoing plate from ~2.5 to 1.5 wt%, a significant change in subduction zone water budgets. AcknowledgementsThis thesis punctuates my own transformation from student to new scientist, but it also marks a change from many other states of incipiency to nascence. In any transformation and in any new thing there is woe. This woe can be wisdom, but it can also be madness. Dan Lizarralde has a knack for sorting wisdom from madness, and he showed me how to see the difference and navigate the space in between. I am grateful that he took a chance on me, first as a summer student at WHOI and then as a graduate student, and he never stopped holding the proverbial carrot at just the right distance.Mark Behn and John Collins also understand wisdom and madness. They took an early interest in my work and have offered ceaseless encouragement since I first arrived at WHOI. They also provided the critical eyes that are essential to good science, and to the development of good scientists, and I am truly grateful for time I shared with these guys. Donna Shillington and Alison Malcolm had no hesitations about joining my thesis committee, and they have been nothing but supportive the whole time.I am lucky to have spent 5 months at sea with the fine officers and crews of the R/V Langseth, R/V Endeavor, and F/V Tiki. At WHOI, talented people like Jeff Dusenberry and Jonathan Murry kept our computers and code running. I am grateful that the folks in the education offices MIT and WHOI work hard to make the Joint Program the amazing experience it is. I am also thankful that the U.S. values scientists and students and supports us by giving grants like National Science Foundation (NSF) Division of Ocean Science (OCE) #824497 and NSF OCE-MARGINS #825178 and #841063 to Dan Lizarralde, as well as NSF Division of Earth Sciences #0652707 to Mark Behn.Camilo Ponton can talk science, but he was also there ...

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“…This structural control would lead to deep and widespread serpentinization of the mantle portion of the approaching plate, and hence an anomalously wet subduction input (Rüpke et al 2002;Ranero et al 2003). Subsequent geophysical investigations off Nicaragua lend support to this hypothesis (Grevemeyer et al 2005(Grevemeyer et al , 2007Ivandic et al 2008Ivandic et al , 2010Lefeldt et al 2009;Key et al 2012). Grevemeyer et al (2005) document lower than expected heat flow in the subducting Cocos Plate, which they attribute to enhanced hydrothermal circulation associated with bending-related faulting.…”

mentioning

confidence: 90%

“…Subsequent geophysical investigations off Nicaragua lend support to this hypothesis (Grevemeyer et al 2005(Grevemeyer et al , 2007Ivandic et al 2008Ivandic et al , 2010Lefeldt et al 2009;Key et al 2012). Grevemeyer et al (2005) document lower than expected heat flow in the subducting Cocos Plate, which they attribute to enhanced hydrothermal circulation associated with bending-related faulting. A series of studies document slow seismic velocities in the outer rise offshore Nicaragua, suggesting 15-30% serpentinization of Cocos Plate mantle to at least a few kilometres below the Moho (Grevemeyer et al 2007;Ivandic et al 2008Ivandic et al , 2010Van Avendonk et al 2011).…”

mentioning

confidence: 93%

Igneous Rock Associations 13. Focusing on the Central American Subduction Zone

Walker

Gazel

2014

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Central America has recently been an important focus area for investigations into the complex processes occurring in subduction zones. Here we review some of the new findings concerning subduction input, magma production and evolution, and resultant volcanic output. In the Nicaraguan portion of the subduction zone, subduction input is unusually wet, likely caused by extensive serpentinization of the mantle portion of the incoming plate associated with bending-related faulting seaward of the Middle America trench. The atypical influx of water into the Nicaraguan section of the subduction zone ultimately leads to a regional maximum in the degree of mantle melting. In central Costa Rica, subduction input is also unusual in that it includes oceanic crust flavored by the Galapagos plume. Both of these exotic subduction inputs are recognizable in the compositions of magmas erupted along the volcanic front. In addition, Nicaraguan magmas bear a strong chemical imprint from subducting hemipelagic sediments. The high-field-strength-element depletions of magmas from El Salvador through Costa Rica are related to local variations in the depth to the subducting Cocos plate, and, therefore, to segmentation of the volcanic front. Minor phases, probably amphibole or rutile, control these variable depletions. Silicic magmas erupted along the volcanic front exhibit the same along-arc geochemical variations as their mafic brethren. This and their mantle-like radiogenic isotopic compositions suggest the production of juvenile continental crust all along the Central American subduction zone. Punctuated times of enhanced magmatic input from the mantle may aid in crustal development.SOMMAIREL’Amérique centrale a récemment été le lieu de recherches sur les processus complexes se produisant dans les zones de subduction. Ici nous passons en revue certaines découvertes sur nature des intrants de subduction, la production et l’évolution des magmas, ainsi que les extrants volcaniques résultants. Dans le segment nicaraguayen de la zone de subduction, les intrants de subduction sont exceptionnellement humides, probablement à cause de la serpentinisation généralisée de la portion mantélique de la plaque en subduction, fissurée par flexure dans partie marine de la fosse océanique de l’Amérique centrale. L'afflux atypique en eau dans le segment nicaraguayen de la zone de subduction induit ultimement un maximum régional de la proportion de fusion du manteau. Dans la portion centrale du Costa Rica l’intrant de subduction est lui aussi atypique en ce qu’il comprend une croûte océanique teintée par le panache des Galápagos. Ces deux intrants de subduction atypiques sont répercutés dans la composition des magmas éjectés le long du front volcanique. En outre, les magmas nicaraguayens affichent une forte empreinte chimique héritée des sédiments hémipélagiques en subduction. Les appauvrissements en éléments à fortes liaisons atomiques des magmas, du El Salvador jusqu’au Costa Rica, sont liés à des variations localisées de la profondeur de la plaque en subduction de Cocos, et donc, à la segmentation du front volcanique. Des phases mineures, probablement amphibole et rutile, déterminent ces appauvrissements variables. Les magmas siliceux éjectés le long du même front volcanique montrent les mêmes variations géochimiques le long de l’arc que leur contrepartie mafique. De plus, les compositions radiogéniques de leurs contreparties mantéliques évoquent la production d’une croûte continentale juvénile le long de la zone de subduction de l’Amérique centrale. Des épisodes d’accroissements ponctuels des intrants magmatiques du manteau peuvent contribuer au développement d’une croûte.

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Heat flow and bending-related faulting at subduction trenches: Case studies offshore of Nicaragua and Central Chile

Cited by 105 publications

References 35 publications

An Evaluation of Proposed Mechanisms of Slab Flattening in Central Mexico

An Evaluation of Proposed Mechanisms of Slab Flattening in Central Mexico

Evolution of oceanic margins : rifting in the Gulf of California and sediment diapirism and mantle hydration during subduction

Igneous Rock Associations 13. Focusing on the Central American Subduction Zone

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