scholarly journals Evidence from accreted seamounts for a depleted component in the early Galapagos plume

Geology ◽  
2016 ◽  
Vol 44 (5) ◽  
pp. 383-386 ◽  
Author(s):  
David M. Buchs ◽  
Kaj Hoernle ◽  
Folkmar Hauff ◽  
Peter O. Baumgartner
Keyword(s):  
Galapagos Plume

scholarly journals Insights into the Galápagos plume from uranium-series isotopes of recently erupted basalts

2011 ◽  
Vol 12 (9) ◽  
pp. n/a-n/a ◽  
Author(s):  
Heather K. Handley ◽  
Simon Turner ◽  
Kim Berlo ◽  
Christoph Beier ◽  
Alberto E. Saal
Keyword(s):  
Uranium Series ◽  
Galapagos Plume

scholarly journals Lithological structure of the Galápagos Plume

2013 ◽  
Vol 14 (10) ◽  
pp. 4214-4240 ◽  
Author(s):  
Christopher Vidito ◽  
Claude Herzberg ◽  
Esteban Gazel ◽  
Dennis Geist ◽  
Karen Harpp
Keyword(s):  
Galapagos Plume

scholarly journals High 3He/4He in central Panama reveals a distal connection to the Galápagos plume

2021 ◽  
Vol 118 (47) ◽  
pp. e2110997118
Author(s):  
David V. Bekaert ◽  
Esteban Gazel ◽  
Stephen Turner ◽  
Mark D. Behn ◽  
J. Marten de Moor ◽  
...  
Keyword(s):  
Mantle Flow ◽  
Transport Mechanisms ◽  
Lithosphere Thinning ◽  
Enriched Mantle ◽  
Deep Interior ◽  
Southern Central ◽  
Galapagos Plume ◽  
Central Panama ◽  
Slab Window ◽  
Lava Geochemistry

It is well established that mantle plumes are the main conduits for upwelling geochemically enriched material from Earth's deep interior. The fashion and extent to which lateral flow processes at shallow depths may disperse enriched mantle material far (>1,000 km) from vertical plume conduits, however, remain poorly constrained. Here, we report He and C isotope data from 65 hydrothermal fluids from the southern Central America Margin (CAM) which reveal strikingly high 3He/4He (up to 8.9RA) in low-temperature (≤50 °C) geothermal springs of central Panama that are not associated with active volcanism. Following radiogenic correction, these data imply a mantle source 3He/4He >10.3RA (and potentially up to 26RA, similar to Galápagos hotspot lavas) markedly greater than the upper mantle range (8 ± 1RA). Lava geochemistry (Pb isotopes, Nb/U, and Ce/Pb) and geophysical constraints show that high 3He/4He values in central Panama are likely derived from the infiltration of a Galápagos plume–like mantle through a slab window that opened ∼8 Mya. Two potential transport mechanisms can explain the connection between the Galápagos plume and the slab window: 1) sublithospheric transport of Galápagos plume material channeled by lithosphere thinning along the Panama Fracture Zone or 2) active upwelling of Galápagos plume material blown by a “mantle wind” toward the CAM. We present a model of global mantle flow that supports the second mechanism, whereby most of the eastward transport of Galápagos plume material occurs in the shallow asthenosphere. These findings underscore the potential for lateral mantle flow to transport mantle geochemical heterogeneities thousands of kilometers away from plume conduits.

Providencia Island: A Miocene Stratovolcano on the Lower Nicaraguan Rise, Western Caribbean—A Geological Enigma Resolved

2021 ◽  
Author(s):  
Alan L. Smith ◽  
M. John Roobol ◽  
Glen S. Mattioli ◽  
George E. Daly ◽  
Joan E. Fryxell
Keyword(s):  
Partial Melting ◽  
Alkali Basalt ◽  
Volcanic Rocks ◽  
Lava Flows ◽  
Alkali Basalts ◽  
Valley Fill ◽  
Island Group ◽  
Western Caribbean ◽  
History Of ◽  
Galapagos Plume

ABSTRACT The Providencia island group comprises an extinct Miocene stratovolcano located on a shallow submarine bank astride the Lower Nicaraguan Rise in the western Caribbean. We report here on the geology, geochemistry, petrology, and isotopic ages of the rocks within the Providencia island group, using newly collected as well as previously published results to unravel the complex history of Providencia. The volcano is made up of eight stratigraphic units, including three major units: (1) the Mafic unit, (2) the Breccia unit, (3) the Felsic unit, and five minor units: (4) the Trachyandesite unit, (5) the Conglomerate unit, (6) the Pumice unit, (7) the Intrusive unit, and (8) the Limestone unit. The Mafic unit is the oldest and forms the foundation of the island, consisting of both subaerial and subaqueous lava flows and pyroclastic deposits of alkali basalt and trachybasalt. Overlying the Mafic unit, there is a thin, minor unit of trachyandesite lava flows (Trachyandesite unit). The Breccia unit unconformably overlies the older rocks and consists of crudely stratified breccias block flows/block-and-ash flows) of vitrophyric dacite, which represent subaerial near-vent facies formed by gravitational and/or explosive dome collapse. The breccias commonly contain clasts of alkali basalt, indicating the nature of the underlying substrate. The Felsic unit comprises the central part of the island, composed of rhyolite lava flows and domes, separated from the rocks of the Breccia unit by a flat-lying unconformity. Following a quiescent period, limited felsic pyroclastic activity produced minor valley-fill ignimbrites (Pumice unit). The rocks of Providencia can be geochemically and stratigraphically subdivided into an older alkaline suite of alkali basalts, trachybasalts, and trachyandesites, and a younger subalkaline suite composed dominantly of dacites and rhyolites. Isotopically, the alkali basalts together with the proposed tholeiitic parent magmas for the dacites and rhyolites indicate an origin by varying degrees of partial melting of a metasomatized ocean-island basalt–type mantle that had been modified by interaction with the Galapagos plume. The dacites are the only phenocryst-rich rocks on the island and have a very small compositional range. We infer that they formed by the mixing of basalt and rhyolite magmas in a lower oceanic crustal “hot zone.” The rhyolites of the Felsic unit, as well as the rhyolitic magmas contributing to dacite formation, are interpreted as being the products of partial melting of the thickened lower oceanic crust beneath Providencia. U-Pb dating of zircons in the Providencia volcanic rocks has yielded Oligocene and Miocene ages, corresponding to the ages of the volcanism. In addition, some zircon crystals in the same rocks have yielded both Proterozoic and Paleozoic ages ranging between 1661 and 454 Ma. The lack of any evidence of continental crust beneath Providencia suggests that these old zircons are xenocrysts from the upper mantle beneath the Lower Nicaraguan Rise. A comparison of the volcanic rocks from Providencia with similar rocks that comprise the Western Caribbean alkaline province indicates that while the Providencia alkaline suite is similar to other alkaline suites previously defined within this province, the Providencia subalkaline suite is unique, having no equivalent rocks within the Western Caribbean alkaline province.

Existence of complex spatial zonation in the Galápagos plume

Geology ◽  
2000 ◽  
Vol 28 (5) ◽  
pp. 435 ◽  
Author(s):  
Kaj Hoernle ◽  
Reinhard Werner ◽  
Jason Phipps Morgan ◽  
Dieter Garbe-Schönberg ◽  
Julie Bryce ◽  
...  
Keyword(s):  
Spatial Zonation ◽  
Galapagos Plume

The volatile contents of the Galapagos plume; evidence for H2O and F open system behavior in melt inclusions

2009 ◽  
Vol 287 (3-4) ◽  
pp. 442-452 ◽  
Author(s):  
A.M. Koleszar ◽  
A.E. Saal ◽  
E.H. Hauri ◽  
A.N. Nagle ◽  
Y. Liang ◽  
...  
Keyword(s):  
Open System ◽  
Melt Inclusions ◽  
System Behavior ◽  
Galapagos Plume

scholarly journals Cocos Plate Seamounts offshore NW Costa Rica and SW Nicaragua: Implications for large-scale distribution of Galápagos plume material in the upper mantle

Lithos ◽  
2015 ◽  
Vol 212-215 ◽  
pp. 214-230 ◽  
Author(s):  
Antje Herbrich ◽  
Kaj Hoernle ◽  
Reinhard Werner ◽  
Folkmar Hauff ◽  
Paul v.d. Bogaard ◽  
...  
Keyword(s):  
Costa Rica ◽  
Upper Mantle ◽  
Large Scale ◽  
Cocos Plate ◽  
Galapagos Plume

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

2014 ◽  
Vol 41 (1) ◽  
pp. 57 ◽  
Author(s):  
James A. Walker ◽  
Esteban Gazel
Keyword(s):  
Costa Rica ◽  
El Salvador ◽  
Subduction Zone ◽  
Subduction Zones ◽  
Central American ◽  
Volcanic Front ◽  
New Findings ◽  
Galapagos Plume ◽  
Subduction Input ◽  
Central American Subduction Zone

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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