Deep structure of the central Lesser Antilles Island Arc: Relevance for the formation of continental crust

Kopp, Heidrun; Weinzierl, Wolfgang; Bécel, A.; Charvis, Philippe; Evain, Mikaël; Flueh, Ernst R.; Gailler, Audrey; Galvé, A.; Hirn, A.; Kandilarov, Aleksandre; Klaeschen, Dirk; Laigle, Mireille; Papenberg, Cord; Planert, Lars; Roux, E.

doi:10.1016/j.epsl.2011.01.024

Cited by 92 publications

(151 citation statements)

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“…The shallow anomaly beneath the Guadeloupe Island extends southeastwards in the fore-arc domain, consistently with the large-scale CPD map of ArnaizRodriguez and Orihuela [2013]. In the fore-arc domain, where the shallowest doming (~18.5 km) of our CPD map occurs, the magnetic sources should be located in the crust assuming a thickness of the fore-arc crust in the vicinity of the Guadeloupe archipelago of 24-28 km [Kopp et al, 2011]. Elsewhere in the fore-arc domain, three secondary CPD minimas are also observed: two near the northern termination of the arc and a third one beneath the Tobago fore-arc basin.…”

Section: Resultssupporting

confidence: 52%

“…Beneath the active arc, the CPD falls between 19 and 26 km and would be mainly located within the arc crust, if one considers a crustal thickness of 20-28 km [Christeson et al, 2008;Kopp et al, 2011]. The most striking anomalies correspond to two CPD minima (< 20 km depth) located in the central LAA, beneath the active arc (Guadeloupe and Martinique islands).…”

Section: Resultsmentioning

confidence: 99%

“…Symithe et al [2015] proposed on the contrary that no northern LAA block exists, because in this area the mechanical coupling (from a seismological point of view) along the subduction interface is assumed to be weak (uncoupled interface). In the north-central parts of the LAA, Kopp et al [2011] imaged a laterally homogeneous crustal structure from the fore-arc up to the backarc domain, with a flat and deep Moho, whose geometry does not appear consistent with the…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…At the scale of the Lesser Antilles arc, the Moho depth is estimated between 24 and 34 km [Sevilla et al, 2010;Kopp et al, 2011].…”

Section: Accepted Manuscript 13mentioning

confidence: 99%

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Forearc structure in the Lesser Antilles inferred from depth to the Curie temperature and thermo-mechanical simulations

et al. 2017

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Section: Resultssupporting

confidence: 52%

Section: Resultsmentioning

confidence: 99%

Section: Accepted Manuscriptmentioning

confidence: 99%

“…At the scale of the Lesser Antilles arc, the Moho depth is estimated between 24 and 34 km [Sevilla et al, 2010;Kopp et al, 2011].…”

Section: Accepted Manuscript 13mentioning

confidence: 99%

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Forearc structure in the Lesser Antilles inferred from depth to the Curie temperature and thermo-mechanical simulations

et al. 2017

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“…However, more recent studies on individual islands have identified a number of local magmatic lineages suggesting that grouping Lesser Antilles rocks based solely on major element chemistry may mask complexities in magmagenesis Westercamp et al 1985) and sampling locations (orange stars-lava; blue stars-xenoliths) (Heath et al 1998;Howe et al 2015;Stamper et al 2014a;Toothill et al 2007). Geophysical studies (Arnaiz-Rodriguez and Orihuela 2013; Boynton et al 1979;Christeson et al 2008;Kopp et al 2011) reveal a strongly layered crust with a mean thickness of 29 km and pronounced mid-crustal discontinuities at depths of 2-20 km that vary along strike of the arc. The scale of compositional and structural variation is clearly seen towards the south of the arc from St. Vincent to Grenada, including the Grenadines archipelago.…”

Section: Geological Settingmentioning

confidence: 99%

Magma evolution beneath Bequia, Lesser Antilles, deduced from petrology of lavas and plutonic xenoliths

Camejo-Harry

Melekhova

Blundy

et al. 2018

Contrib Mineral Petrol

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms Vol.:(0123456789) 1 3Contributions to Mineralogy and Petrology (2018) AbstractExtrusive and intrusive igneous rocks represent different parts of a magmatic system and ultimately provide complementary information about the processes operating beneath volcanoes. To shed light on such processes, we have examined and quantified the textures and mineral compositions of plutonic and cumulate xenoliths and lavas from Bequia, Lesser Antilles arc. Both suites contain assemblages of iddingsitized olivine, plagioclase, clinopyroxene and spinel with rare orthopyroxene and ilmenite. Mineral zoning is widespread, but more protracted in lavas than xenoliths. Plagioclase cores and olivine have high anorthite (An ≤ 98) and low forsterite (Fo ≤ 84) compositions respectively, implying crystallisation from a hydrous mafic melt that was already fractionated. Xenolith textures range from adcumulate to orthocumulate with variable mineral crystallisation sequences. Textural criteria are used to organize the xenoliths into six groups. Amphibole, notably absent from lavas, is a common feature of xenoliths, together with minor biotite and apatite. Bulk compositions of xenoliths deviate from the liquid line of descent of lavas supporting a cumulate origin with varying degrees of reactive infiltration by evolved hydrous melts, preserved as melt inclusions in xenolith crystals. Volatile saturation pressures in melt inclusions indicate cumulate crystallization over a 162-571 MPa pressure range under conditions of high dissolved water contents (up to 7.8 wt% H 2 O), consistent with a variety of other thermobarometric estimates. Phase assemblages of xenoliths are consistent with published experimental data on volatile-saturated low-magnesium and high-alumina basalts and basaltic andesite from the Lesser Antilles at pressures of 200-1000 MPa, temperatures of 950-1050 °C and dissolved H 2 O contents of 4-7 wt%. Once extracted from mid-crustal mushes, residual melts ascend to higher levels and undergo H 2 O-saturated crystallization in shallow, preeruptive reservoirs to form phenocrysts and glomerocrysts. The absence of amphibole from lavas reflects instability at low pressures, whereas its abundance in xenoliths testifies to its importance in mid-crustal differentiation processes. A complex, vertically extensive (6 to at least 21 km depth) magmatic system is inferred beneath Bequia. Xenoliths represent fragments of the mush incorporated into ascending magmas. The widespread occurrence of evolved melts in the mush, but the absence of erupted evolved magmas, in contrast to islands in the northern Lesser Antilles, may reflect the relative immaturity of the Bequia magmatic system.

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Three-dimensional velocity structure of the outer fore arc of the Colombia-Ecuador subduction zone and implications for the 1958 megathrust earthquake rupture zone

Cano

Galvé

Charvis

et al. 2014

J. Geophys. Res. Solid Earth

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In 2005, an onshore, offshore 3-D refraction and wide-angle reflection seismic experiment was conducted along the convergent margin at the border between Colombia and Ecuador, over the rupture zone of the 1958, M w 7.6 subduction earthquake. A well-defined Vp velocity model of the plate boundary and upper and lower plates was constructed, down to 25 km depth, using first arrival traveltimes inversion. The model reveals a several kilometers thick, low-velocity zone in the upper plate, located immediately above the interplate contact. This low-velocity zone might be related to alteration and fracturing of the mafic and ultramafic rocks, which composed the upper plate in this area by fluids released by the lower plate with possible contributions from sediment underplating. Near the toe of the margin, the model shows a low-velocity gradient in the outer wedge, which is interpreted as highly faulted and fractured rocks. This low-velocity/low-gradient region appears to limit the oceanward extension of the rupture zones of the 1958 and 1979 earthquakes, possibly because coseismic deformation and uplift of the outer margin wedge dissipates most of the seismic energy.

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Deep structure of the central Lesser Antilles Island Arc: Relevance for the formation of continental crust

Cited by 92 publications

References 54 publications

Forearc structure in the Lesser Antilles inferred from depth to the Curie temperature and thermo-mechanical simulations

Forearc structure in the Lesser Antilles inferred from depth to the Curie temperature and thermo-mechanical simulations

Magma evolution beneath Bequia, Lesser Antilles, deduced from petrology of lavas and plutonic xenoliths

Three-dimensional velocity structure of the outer fore arc of the Colombia-Ecuador subduction zone and implications for the 1958 megathrust earthquake rupture zone

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