Crustal structure of the Caribbean–northeastern South America arc‐continent collision zone

Christeson, G. L.; Mann, Paul; Escalona, Alejandro; Aitken, T. J.

doi:10.1029/2007jb005373

Cited by 85 publications

(147 citation statements)

References 76 publications

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“…a more gradual increase to 7.0-7.2 km/s at the base of the crust, 27 km depth. Not surprisingly this crustal thickness and velocity structure is similar to the structure of La Blanquilla High, the eastward continuation of the ABC ridge [Clark et al, 2007], and also to the Aves ridge and Lesser Antilles arc [Christeson et al, 2008] (Figure 11a). This similarity reinforces the hypothesis that the ABC ridge is the westward continuation of the active island arc [Mann, 1999] and that the magmatic processes that are active today along the Lesser Antilles volcanic arc may be similar to those that built the ABC ridge in Cretaceous time.…”

Section: Abc Island Arc (Leeward Antilles)mentioning

confidence: 57%

“…A corollary of this model is that the Bonaire basin is the equivalent of the Grenada basin to the east, a hypothesis reinforced by the continuity of the magnetic and gravity anomalies from the volcanic arc of the Lesser Antilles through the Leeward Antilles [Sandwell and Smith, 1997]. However, the Grenada basin exhibits crustal structure consistent with oceanic crust formed in intra-arc settings [Christeson et al, 2008], which is substantially different from the structure of the Bonaire basin (Figure 11b), indicating that back arc extension did not rift similar crustal types, rifting was not homogeneous along the margin, or that the two basins are not part of a continuous tectonic feature along the plate boundary.…”

Section: Bonaire Basinmentioning

confidence: 98%

“…Efforts were made to develop a single processing flow that was applicable to the entire profile, consistent with the processing flow adopted for the rest of the BOLIVAR reflection profiles [Christeson et al, 2008;Clark et al, 2008a;Gorney et al, 2007]. Details of the main processing steps are shown in Table 2.…”

Section: Seismic Reflection Data Analysismentioning

confidence: 99%

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Crustal structure of the South American–Caribbean plate boundary at 67°W from controlled source seismic data

Magnani¹,

Zelt²,

Levander³

et al. 2009

J. Geophys. Res.

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[1] We present the results of new seismic reflection and wide-angle data across the SE Caribbean plate boundary. The 550 km long N-S profile crosses the structures involved in the active 55 Ma long continent-arc oblique collision between the Caribbean (CAR) and the South American (SA) plate. From the north to the south these structures include the accretionary prism, the extinct volcanic arc (Leeward Antilles arc), the Tertiary Bonaire basin, the continental-size dextral strike-slip fault system (San Sebastián-El Pilar fault), the allochthonous exhumed terranes, and the authocthonous fold and thrust belt (Caribbean Mountain system) and foreland basin. The wide-angle data show that these elements are characterized by different velocity structures and that they are separated by sharp lateral velocity variations. The Leeward Antilles arc exhibits a velocity structure similar to that of the Lesser Antilles active volcanic arc, indicating that the extinct arc has not been modified by the collision with the SA plate. The data show a $20 km change in crustal thickness across the San Sebastián fault, suggesting that the dextral strike-slip fault is a crustal feature that likely continues in the mantle as a primary strand of the plate boundary between the South American and the Caribbean plates. South of the strike-slip fault and beneath the exhumed eclogitic terranes, the data image a north dipping, high-velocity (>6.5 km/s) anomaly in the upper crust (3-11 km), indicating that high-pressure/low-temperature rocks are the likely lithologies responsible for the high seismic velocities and suggesting that exhumation of these assemblages is enabled by the strike-slip fault.

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Section: Abc Island Arc (Leeward Antilles)mentioning

confidence: 57%

Section: Bonaire Basinmentioning

confidence: 98%

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Crustal structure of the South American–Caribbean plate boundary at 67°W from controlled source seismic data

Magnani¹,

Zelt²,

Levander³

et al. 2009

J. Geophys. Res.

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“…3), which can be attributed to the level of maturity in arc crustal evolution , the amount of back arc extension (Nishizawa et al, 2007), and the magmatic production rate (Christeson et al, 2008). Mature island arc systems, such as the Izu-Bonin-Mariana system, have three crustal layers which were developed by partial melting of the initial immature basaltic arc crust .…”

Section: Island Arcs: Modern Examplesmentioning

confidence: 99%

“…The felsic mid-crustal unit is produced by repetitive anatexis of the mafic lower crust Rioux et al, 2010). Juvenile island arcs are believed to lack this felsic middle layer, as in the cases of the Lesser Antilles and Leeward Antilles (Magnani et al, 2009;Christeson et al, 2008) and parts of the Kyushu-Palau Ridge (Nishizawa et al, 2007). The mid-crustal layer of the mature Aleutian arc, on the other hand, is inferred to be of a more mafic than intermediate composition, based on the higher seismic velocities at depths of 11-20 km (Shillington et al, 2004).…”

Section: Island Arcs: Modern Examplesmentioning

confidence: 99%

Future accreted terranes: a compilation of island arcs, oceanic plateaus, submarine ridges, seamounts, and continental fragments

Tetreault

Buiter

2014

Solid Earth

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Abstract. Allochthonous accreted terranes are exotic geologic units that originated from anomalous crustal regions on a subducting oceanic plate and were transferred to the overriding plate by accretionary processes during subduction. The geographical regions that eventually become accreted allochthonous terranes include island arcs, oceanic plateaus, submarine ridges, seamounts, continental fragments, and microcontinents. These future allochthonous terranes (FATs) contribute to continental crustal growth, subduction dynamics, and crustal recycling in the mantle. We present a review of modern FATs and their accreted counterparts based on available geological, seismic, and gravity studies and discuss their crustal structure, geological origin, and bulk crustal density. Island arcs have an average crustal thickness of 26 km, average bulk crustal density of 2.79 g cm −3 , and three distinct crustal units overlying a crust-mantle transition zone. Oceanic plateaus and submarine ridges have an average crustal thickness of 21 km and average bulk crustal density of 2.84 g cm −3 . Continental fragments presently on the ocean floor have an average crustal thickness of 25 km and bulk crustal density of 2.81 g cm −3 . Accreted allochthonous terranes can be compared to these crustal compilations to better understand which units of crust are accreted or subducted. In general, most accreted terranes are thin crustal units sheared off of FATs and added onto the accretionary prism, with thicknesses on the order of hundreds of meters to a few kilometers. However, many island arcs, oceanic plateaus, and submarine ridges were sheared off in the subduction interface and underplated onto the overlying continent. Other times we find evidence of terrane-continent collision leaving behind accreted terranes 25-40 km thick. We posit that rheologically weak crustal layers or shear zones that were formed when the FATs were produced can be activated as detachments during subduction, allowing parts of the FAT crust to accrete and others to subduct. In many modern FATs on the ocean floor, a sub-crustal layer of high seismic velocities, interpreted as ultramafic material, could serve as a detachment or delaminate during subduction.

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Time scales of intra‐oceanic arc magmatism from combined U‐Th and (U‐Th)/He zircon geochronology of Dominica, Lesser Antilles

Howe

Schmitt

Lindsay

et al. 2015

Geochem Geophys Geosyst

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The island of Dominica, located in the intra-oceanic Lesser Antilles arc, has produced a series of intermediate (mostly andesitic) lava domes and ignimbrites since the early Pleistocene. (U-Th)/He eruption ages from centers across the island range from 3 to 770 ka, with at least 10 eruptions occurring in the last 80 ka. Three eruptions occurred near the southern tip of Dominica (Plat Pays Volcanic Complex) in the past 15 ka alone. Zircon U-Th ages from individual centers range from near-eruption to secular equilibrium implicating protracted storage and recycling of zircons within the crust. Overlapping zircon crystallization peaks within deposits from geographically separated vents (up to 40 km apart) indicate that magma associated with separate volcanic edifices crystallized zircon contemporaneously. Two lava domes from the southern sector of the island display exclusively young zircon rim ages (<50 ka) with narrow crystallization peaks consistent with the construction of a new magma reservoir. The younging of eruption and crystallization ages implies that the magmatic foci leading to the construction of this reservoir have migrated southward, arc-parallel over time. Overall, our data support geochemical models for the ongoing construction of a silicic intrusive complex, consisting of varying amounts of crystal mush, beneath the island. U-Pb zircon ages <1-2 Ma indicate that accumulation of this complex is entirely Quaternary in age. Together zircon U-Th and U-Pb ages for Dominica suggest that the magmatic processes and time scales operating in intra-oceanic arcs are similar to those documented for continental arcs.

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Crustal structure of the Caribbean–northeastern South America arc‐continent collision zone

Cited by 85 publications

References 76 publications

Crustal structure of the South American–Caribbean plate boundary at 67°W from controlled source seismic data

Crustal structure of the South American–Caribbean plate boundary at 67°W from controlled source seismic data

Future accreted terranes: a compilation of island arcs, oceanic plateaus, submarine ridges, seamounts, and continental fragments

Time scales of intra‐oceanic arc magmatism from combined U‐Th and (U‐Th)/He zircon geochronology of Dominica, Lesser Antilles

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