Patterns in Galápagos Magmatism Arising from the Upper Mantle Dynamics of Plume‐Ridge Interaction

Ito, Garrett; Bianco, T. A.

doi:10.1002/9781118852538.ch13

Cited by 15 publications

(27 citation statements)

References 68 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although this model reasonably explains the along‐axis width of plume‐ridge interaction zones as a function of varying ridge spreading rate and changing plume volume flux [ Feighner and Richards , ; Ribe , ; Ito and Lin , ; Ito et al ., ], additional physical processes are needed to produce narrow volcanic lineaments such as the WDL, the RR, and the HR. This is supported by recent 3‐D numerical simulations of purely solid‐state flow by Ito and Bianco [] for the Galápagos plume with no narrow regions of melt accumulation as required to form lineaments. Furthermore, these simulations have difficulties in matching the detailed spatial pattern of geochemical variations.…”

Section: Models For Lineament Formation During Plume‐ridge Interactionmentioning

confidence: 99%

Plume‐ridge interaction via melt channelization at Galápagos and other near‐ridge hotspot provinces

Mittal

Richards

2017

Geochem Geophys Geosyst

View full text Add to dashboard Cite

The interaction of mantle plume driven flow with upwelling flow due to a nearby mid‐ocean ridge occurs for many mantle plumes including Galápagos and Iceland. This interaction is typified by trace element and isotopic signatures demonstrating the “contamination” of normal ridge composition by relatively enriched plume material. However, another common signature of plume‐ridge interaction is volcanic lineaments linking ridges and nearby plumes, perhaps most conspicuously the Wolf‐Darwin lineament (WDL) at Galápagos and the Rodrigues Ridge (RR) at La Réunion. These enigmatic features remain unexplained. Plume‐ridge interaction is commonly modeled in terms of interaction between solid‐state plume flow and divergent ridge flow, but such models do not likely lead to the kind of solid‐state flow channelization that might explain narrow features such as the WDL and RR. Likewise, models involving tapping of anomalously hot and/or fertile asthenosphere between the plume and ridge due to lithospheric faulting appear to be inconsistent with a variety of evidence. We propose an alternative model in which the lineaments are the surface expressions of localized melt channels in the asthenosphere formed due to instabilities in a two‐phase partially molten system. A thermodynamic analysis shows that given the magma fluxes inferred to be associated with structures such as WDL and RR, these melt channels can be maintained over plume‐ridge distances up to ∼1000 km. These results suggest that plume‐ridge interaction in general, possibly including transport of plume‐derived material along ridge axes (e.g., Iceland), may involve transport in high‐melt‐fraction channels, as opposed to just solid‐state mantle flow.

show abstract

Section: Models For Lineament Formation During Plume‐ridge Interactionmentioning

confidence: 99%

Plume‐ridge interaction via melt channelization at Galápagos and other near‐ridge hotspot provinces

Mittal

Richards

2017

Geochem Geophys Geosyst

View full text Add to dashboard Cite

show abstract

“…The most recent numerical simulations of Galápagos plume‐ridge interaction involve solid‐state transport of plume material consisting of veins of geochemically enriched material set in a depleted matrix [ Ito and Bianco , ]. The two models described by Ito and Bianco [] involve melting of plume material with (i) low viscosity and no dependence on water content and (ii) high viscosity in the shallowest mantle with the dependence of water content.…”

Section: Constraints On the Geometry And Kinematics Of Galápagos Plummentioning

confidence: 99%

“…At least five different models of plume‐ridge interaction have been proposed for Galápagos. These include: (i) flow of plume material in a sublithospheric channel [ Morgan , ; Schilling et al ., ; Verma and Schilling , ; Braun and Sohn , ]; (ii) a spreading “puddle” model involving radial flow away from the plume stem [ Schilling et al ., ; Shorttle et al ., ]; (iii) eastward bending of the plume head in the direction of motion of the Nazca Plate [ Richards and Griffiths , ; Geist , ; White et al ., ; Harpp and White , ]; (iv) gravitational spreading along the base of the lithosphere [ Bercovici and Lin , ]; and (v) solid‐state transport of plume material beneath a dehydrated, high‐viscosity mantle lid [ Kokfelt et al ., ; Ito and Bianco , ; Villagómez et al ., ; Byrnes et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Mantle plume capture, anchoring, and outflow during Galápagos plume‐ridge interaction

Gibson

Geist

Richards

2015

Geochem Geophys Geosyst

View full text Add to dashboard Cite

Compositions of basalts erupted between the main zone of Gal apagos plume upwelling and adjacent Gal apagos Spreading Center (GSC) provide important constraints on dynamic processes involved in transfer of deep-mantle-sourced material to mid-ocean ridges. We examine recent basalts from central and northeast Gal apagos including some that have less radiogenic Sr, Nd, and Pb isotopic compositions than plume-influenced basalts (E-MORB) from the nearby ridge. We show that the location of E-MORB, greatest crustal thickness, and elevated topography on the GSC correlates with a confined zone of lowvelocity, high-temperature mantle connecting the plume stem and ridge at depths of $100 km. At this site on the ridge, plume-driven upwelling involving deep melting of partially dehydrated, recycled ancient oceanic crust, plus plate-limited shallow melting of anhydrous peridotite, generate E-MORB and larger amounts of melt than elsewhere on the GSC. The first-order control on plume stem to ridge flow is rheological rather than gravitational, and strongly influenced by flow regimes initiated when the plume was on axis (>5 Ma). During subsequent northeast ridge migration material upwelling in the plume stem appears to have remained ''anchored'' to a contact point on the GSC. This deep, confined NE plume stem-to-ridge flow occurs via a network of melt channels, embedded within the normal spreading and advection of plume material beneath the Nazca plate, and coincides with locations of historic volcanism. Our observations require a more dynamically complex model than proposed by most studies, which rely on radial solid-state outflow of heterogeneous plume material to the ridge.

show abstract

“…These models are broadly divided into 1) transport to the GSC along channels within the base of the lithosphere (e.g., Morgan, 1978;Schilling et al, 1982;Verma and Schilling, 1982;Braun and Sohn, 2003); 2) deflection of the Galápagos plume head primarily eastwards due to eastward migration of the Nazca Plate but with some of the material in the north reaching the ridge axis (Richards and Griffiths, 1989;Geist, 1992;White et al, 1993;Harpp and White, 2001); 3) gravity driven plume dispersal along the base of the lithosphere (Bercovici and Lin, 1996;Hoernle et al, 2000); 4) radial outflow of plume material away from its stem along the base of the lithosphere to the spreading center (Schilling et al, 2003;Shorttle et al, 2010); 5) subsolidus transport of plume material beneath a viscous residual plug to the ridge (Kokfelt et al, 2005;Ito and Bianco, 2014;Villagomez et al, 2014;Byrnes et al, 2015); and 6) melt transport via veins and channels below the anhydrous peridotite solidus (Gibson et al, 2015).…”

mentioning

confidence: 99%

A 1.5 Ma record of plume-ridge interaction at the Western Galápagos Spreading Center (91°40′–92°00′W)

Herbrich

Hauff

Hoernle

et al. 2016

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

Patterns in Galápagos Magmatism Arising from the Upper Mantle Dynamics of Plume‐Ridge Interaction

Cited by 15 publications

References 68 publications

Plume‐ridge interaction via melt channelization at Galápagos and other near‐ridge hotspot provinces

Plume‐ridge interaction via melt channelization at Galápagos and other near‐ridge hotspot provinces

Mantle plume capture, anchoring, and outflow during Galápagos plume‐ridge interaction

A 1.5 Ma record of plume-ridge interaction at the Western Galápagos Spreading Center (91°40′–92°00′W)

Contact Info

Product

Resources

About