Crustal recycling by subduction erosion in the central Mexican Volcanic Belt

Abstract

Recycling of upper plate crust in subduction zones, or 'subduction erosion', is a major

Late Cenozoic tephrostratigraphy offshore the southern Central American Volcanic Arc: 2. Implications for magma production rates and subduction erosion

“…The CAVA extends from Panama to Guatemala and parallels the deep‐sea Middle American Trench (MAT) at a distance of 150–200 km (Figure ), which is the best‐studied erosive subduction margin [ Ranero and von Huene , ; Vannucchi et al ., ; Straub et al ., ]. The CAVA is the result of the subduction of the oceanic Cocos plate beneath the Caribbean plate at a convergence rate of 70–90 mm/a [ Barckhausen et al ., ; DeMets , ] (Figure a).…”

Implications of Hf Isotopes for the Evolution of the Mantle Source of Magmas Associated with the Giant El Teniente Cu-Mo Megabreccia Deposit, Central Chile

“…In summary, the Hf isotopic data are consistent with Sr, Nd and Pb isotopic data, and suggest the incorporation of small but progressively increasing proportions of continental crust in the mantle source of the mafic magmas erupted in the vicinity of El Teniente between 15 and 2.3 Ma. Trench sediment recycling has been confirmed by the detection of cosmogenic 10 Be in many, including Andean arc, lavas [59][60][61], and comprehensive trace-element and isotopic studies have also provided evidence for the incorporation of fore-arc eroded crust in the subarc mantle source of both Andean [3][4][5]7,8,10,11] and arc volcanoes along other convergent plate boundaries [58,[62][63][64]. The model developed for the El Teniente area suggests that increasing rates of subduction erosion through time has resulted in variable, but nevertheless relatively small (1 to ≤6 wt.…”

“…In the central Mexican magmatic belt, west of where subduction erosion rates are estimated as 79-88 km 3 /km/m.y., and where Hf concentration and isotopic data are available for both pelagic and terrigenous sediment, as well as coastal continental rocks, Straub et al [58] concluded that tectonically eroded continental crust, consisting of coastal and off-shore granodiorite plutons, was the dominant control on the isotopic composition of the calc-alkaline arc magmas, and that neither intra-crustal assimilation nor subducted trench sediment played a significant role in the genesis of these magmas. For the El Teniente rocks, we calculated a model assuming for Hf contents the average estimated values for primitive mantle and the average upper crust for the subducted crust and sediment, as well as a low crustal 176 Hf/ 177 Hf isotopic ratio similar to that determined by Straub et al [58] for Mexican basement biotite gneisses (Table 5). This model can generate results ( Figure 9) consistent with those previously determined for the Sr and Nd isotopic systems for which more published values for the materials involved in Andean magmagenesis are available [10,[21][22][23].…”

“…%), amounts of subducted crust having significantly affected the isotopic composition of the mantle source of the mafic magmas through time. Models for magmagenesis in other arcs, for instance the central Mexican volcanic belt, have suggested much larger amounts of recycled crust involved in the generation of both mafic and intermediate arc magmas; from >60% in conjunction with diapiric uprise and melting of subducted crust [58] to 100% resulting in the generation of andesites by bulk melting of subducted crust "relaminated" below the mantle wedge [63].…”

Oxygen isotope trajectories of crystallizing melts: Insights from modeling and the plutonic record

“…Oceanic arc lava data is from Eiler et al, 2000. Continental arc lava data is from Eiler et al, 2005;Portnyagin et al, 2007;Auer et al, 2009;Johnson et al, 2009;Ruscitto et al, 2010;Martin et al, 2011;and Straub et al, 2015. For the latter, olivines with δ 18 O values above that of the range for mantle xenolith olivine were screened to only include those with high Mg# (>80) or hosted within high Mg# (>65) lavas.…”