Correlation between the age of the subducting Cocos plate and the geometry of the Wadati-Benioff zone under Nicaragua and Costa Rica

Protti, Marino; Gïendel, Federico; McNally, Karen

doi:10.1130/spe295-p309

Cited by 136 publications

(194 citation statements)

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“…These lateral variations correlate with an increase in the crustal thickness of the Cocos plate and a shallowing of the Wadati-Benioff Zone [Protti et al, 1995]. The seismically active slab dips at $65°near the Nicaraguan border and shallows to a few degrees inboard of the Cocos Ridge.…”

Section: Tectonic Setting and Previous Studymentioning

confidence: 94%

From seamount accretion to tectonic erosion: Formation of Osa Mélange and the effects of Cocos Ridge subduction in southern Costa Rica

Vannucchi¹,

et al. 2006

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The Costa Rica portion of the Middle America Trench (MAT) is characterized by active tectonic erosion, a process that causes the removal of material from the base of the upper plate as the plate boundary migrates upward. Offshore studies demonstrate accelerated subduction erosion starting at the Miocene‐Pliocene boundary, as the result of subduction of thickened Galapagos related crust, as presently represented by the Cocos Ridge. The subduction of the Cocos Ridge also caused uplift and exposure of the outer forearc on the Osa Peninsula, which offers a window to explore the tectonic evolution of the area. The rocks outcropping on Osa Peninsula are a middle Eocene–middle Miocene mélange dominated by basalt, chert, and limestone resulting from accretion of seamounts. The accretion‐dominated period of the MAT evolution ended at the Miocene‐Pliocene boundary, when thickened crust, a paleo‐Cocos Ridge, produced at the Galapagos hot spot arrived at the trench. The thick crust caused uplift and severe tectonic erosion of the accretionary edifice allowing exhumation of the Osa Mélange. The change from accretion to erosion caused the outer forearc to be offset along subvertical faults that define small (kilometer to tens of kilometers size) blocks that are going through differential vertical movements in response to the morphology of the subducting ridge. Subduction accretion and erosion are two processes that can alternate in time and space or coexist along the same margin, so that mass removal can develop on a previously growing margin and completely remove an accretionary prism.

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Section: Tectonic Setting and Previous Studymentioning

confidence: 94%

From seamount accretion to tectonic erosion: Formation of Osa Mélange and the effects of Cocos Ridge subduction in southern Costa Rica

Vannucchi¹,

et al. 2006

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“…These observations led Bilek et al (2003) to suggest that this event represented rupture of topographic highs that act as asperities (Lay and Kanamori, 1980;Lay et al, 1982). Offshore the Osa Peninsula, earthquake hypocenters and aftershock clustering are located in regions of seismically imaged lower plate relief Husen et al, 2002;Protti et al, 1995).…”

Section: Seismogenic Zone and Earthquakesmentioning

confidence: 99%

“…Costa Rica is a seismically active area with a history of Mw > 7 earthquakes and along-strike changes in the seismogenic zone (Protti et al, 1995;Newman et al, 2002). Offshore of the Osa Peninsula, the 20 August 1999 Mw 6.9 Quepos interplate thrust earthquake ( Fig.…”

Section: Seismogenic Zone and Earthquakesmentioning

confidence: 99%

Expedition 344 summary

Li¹,

Malinverno²,

Torres³

et al. 2013

Proceedings of the IODP

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Expedition 344 summaryProc. IODP | Volume 344 2 from velocity-strengthening to velocity-weakening friction, and shear becomes localized. The onset of seismogenic behavior is correlated with the intersection of the 100°-150°C isotherm and the subduction thrust (Hyndman et al., 1997;Oleskevich et al., 1999). With increasing depth down the subduction thrust, the frictional characteristics undergo a second transition either due to the juxtaposition with the forearc mantle or because the rocks are heated to 350°-450°C and can no longer store elastic stresses needed for rupture. Transitional regions between the three zones have conditional stability and can host rupture but are generally not thought to be regions where large earthquakes initiate.Although this three-zone two-dimensional view of the subduction thrust provides a reasonable framework, it is simplistic. Rupture models for large subduction earthquakes suggest significant fault plane heterogeneity in slip and moment release that in three dimensions is characterized as patchiness (Bilek and Lay, 2002). Additionally, we now know the transition zone from stable to unstable sliding is not simple but hosts a range of fault behaviors that includes creep events, strain transients, slow and silent earthquakes, and low-frequency earthquakes (Peng and Gomberg, 2010;Beroza and Ide, 2011;Ide, 2012).Fundamentally unknown are the processes that change fault behavior from stable sliding to stick-slip behavior. Understanding these processes is important for understanding earthquakes, the mechanics of slip, and rupture dynamics. For a fault to undergo unstable slip, fault rocks must have the ability to store elastic strain, be velocity weakening, and have sufficient stiffness. Hypotheses for mechanisms leading to the transition between stable and unstable slip invoke temperature, pressure, and strain-activated processes that lead to downdip changes in the mechanical properties of rocks. These transitions are also sensitive to fault zone composition, lithology, fabric, and fluid pressures.The composition of the material in the fault zone and its contrast with the surrounding wall rock play a key role in rock frictional behavior. The frictional state of the incoming sediment changes progressively with increasing temperature and pressure as it travels downdip. Important lithologic factors influencing friction are composition, fabric, texture, and cementation of rocks, as well as fluid pore pressure (Bernabé et al., 1992;Moore and Saffer, 2001;Beeler, 2007;Marone and Saffer, 2007;Collettini et al., 2009). For example, fault rocks with high phyllosilicate content are generally weaker than rocks with low phyllosilicate content (Ikari et al., 2011). Sediment properties including porosity, permeability, consolidation state, and alteration history also exert a strong influence on fault zone behavior. At erosive margins, where the plate boundary cuts into the overriding plate, the composition and strength of the upper plate is also important (McCaffrey, 1993).Field observations and la...

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“…By coupling CO 2 and He measurements (isotopes and relative abundances), we can identify and quantitatively assess the various contributors to the magmatic output from the various subduction zone reservoirs : (a) the mantle wedge, (b) the overlying arc crust through which the magmas erupt and (c) the subducting slab^both the oceanic basement and sedimentary veneer of the slab. Helium isotopes are sensitive indicators of mantle derivation and crustal in£uences, whereas N 13 C values can be used to identify mantle (M), marine carbonate/limestone (L) and organic sedimentary (S) components [11].…”

Section: Introductionmentioning

confidence: 99%

Contrasting He–C relationships in Nicaragua and Costa Rica: insights into C cycling through subduction zones

Shaw

Hilton

Fischer

et al. 2003

Earth and Planetary Science Letters

162

160

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We report 3 He/ 4 He ratios, relative He, Ne, and CO 2 abundances as well as N 13 C values for volatiles from the volcanic output along the Costa Rica and Nicaragua segments of the Central American arc utilising fumaroles, geothermal wells, water springs and bubbling hot springs. CO 2 / 3 He ratios are relatively constant throughout Costa Rica (av. 2.1U10 10 ) and Nicaragua (av. 2.5U10 10 ) and similar to arcs worldwide (V1.5U10 10 ). N 13 C values range from 36.8x (MORB-like) to 30.1x (similar to marine carbonate (0x)). 3 He/ 4 He ratios are essentially MORBlike (8 þ 1 R A ) with some samples showing evidence of crustal He additions^water spring samples are particularly susceptible to modification. The He^CO 2 relationships are consistent with an enhanced input of slab-derived C to magma sources in Nicaragua ((L+S)/M = 16; where L, M and S represent the fraction of CO 2 derived from limestone and/or marine carbonate (L), the mantle (M) and sedimentary organic C (S) sources) relative to Costa Rica ((L+S)/ M = 10). This is consistent with prior studies showing a higher sedimentary flux to the arc volcanics in Nicaragua (as traced by Ba/La, 10 Be and La/Yb). Possible explanations include: (1) offscraping of the uppermost sediments in the Costa Rica forearc, and (2) a cooler thermal regime in the Nicaragua subduction zone, preserving a higher proportion of melt-inducing fluids to subarc depths, leading to a higher degree of sediment transfer to the subarc mantle. The absolute flux of CO 2 from the Central American arc as determined by correlation spectrometry methods (5.8U10 10 mol/yr) and CO 2 / 3 He ratios (7.1U10 10 mol/yr) represents approximately 14^18% of the amount of CO 2 input at the trench from the various slab contributors (carbonate sediments, organic C, and altered oceanic crust). Although the absolute flux is comparable to other arcs, the efficiency of CO 2 recycling through the Central American arc is surprisingly low (14^18% vs. a global average of V50%). This may be attributed to either significant C loss in the forearc region, or incomplete decarbonation of carbonate sediments at subarc depths. The implication of the latter case is that a large fraction of C (up to 86%) may be transferred to the deep mantle (depths beyond the source of arc magmas). ß

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Correlation between the age of the subducting Cocos plate and the geometry of the Wadati-Benioff zone under Nicaragua and Costa Rica

Cited by 136 publications

References 0 publications

From seamount accretion to tectonic erosion: Formation of Osa Mélange and the effects of Cocos Ridge subduction in southern Costa Rica

From seamount accretion to tectonic erosion: Formation of Osa Mélange and the effects of Cocos Ridge subduction in southern Costa Rica

Expedition 344 summary

Contrasting He–C relationships in Nicaragua and Costa Rica: insights into C cycling through subduction zones

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