Variations in Crustal Thickness, Plate Rigidity, and Volcanic Processes Throughout the Northern Galápagos Volcanic Province

Mittelstaedt, E. L.; Soule, S. A.; Harpp, K. S.; Fornari, Daniel J.

doi:10.1002/9781118852538.ch14

Cited by 16 publications

(49 citation statements)

References 91 publications

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“…Significant deviations from initial disequilibria can only be generated through extended magma residence times and crustal assimilation. In conclusion, geochemical evidence suggests that melting of the WGSC source took place over a large depth range from ≥50-60 to ~10 km (the present crustal thickness at 92°W; Ito and Lin, 1995;Canales et al, 2002;Mittelstaedt et al, 2014). In contrast, melts forming Seamount 63 were generated at greater depth primarily within the garnet stability field (≥50-60 km).…”

Section: Melting Conditionsmentioning

confidence: 76%

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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

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Section: Melting Conditionsmentioning

confidence: 76%

“…Both areas are characterized by axial high morphology, increased crustal thickness (up to 8-9 km; Ito and Lin, 1995;Canales et al, 2002;Mittelstaedt et al, 2014) and excursions in various geochemical plume signals (Schilling et al, 2003;Christie et al 2005;Kokfelt et al, 2005;Ingle et al, 2010;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

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“…[] and Mittelstaedt et al . [], as well as earlier work by Canales et al . [], have provided information on the crustal and lithospheric structure of the oceanic plate in the region encompassing the Wolf‐Darwin lineament (see top plot in Figure for the crustal thickness map).…”

Section: Plume‐ridge Interaction In Galápagosmentioning

confidence: 99%

“…[] find that the free‐air gravity anomalies associated with the Galápagos lineaments are best fit using a flexure model with a spatially variable subsurface load likely corresponding to volcanic underplating beneath each seamount. Plate flexure models and mantle Bouger anomaly (MBA) inversions also suggest that the thermal thickness of the lithosphere is relatively uniform across the NGVP [ Mittelstaedt et al ., ]. Hence, the slope of base of the lithosphere toward the ridge in the NGVP may be smaller than predicted from a standard plate cooling model due to the thermal influence of the plume.…”

Section: Plume‐ridge Interaction In Galápagosmentioning

confidence: 99%

“…We may still expect an increasing or constant density of mapped faults throughout NGVP with an orientation parallel to the WDL. However, this can be biased by some fraction due to strongly varying orientations of the lithospheric stresses [ Mittelstaedt and Ito , ]. The region around the Galapagos Transform Fault has an anomalously large density of faults and may be the region in the NGVP with maximum extension [ Mittelstaedt et al ., ]. Hence, given the broad region of thermal and geochemical anomalies expected due to mixing of the plume material with the upwelling mantle, the most extensive volcanism may be expected along this region.…”

Section: Models For Lineament Formation During Plume‐ridge Interactionmentioning

confidence: 99%

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

Mittal

Richards

2017

Geochem Geophys Geosyst

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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.

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

Gibson

Geist

Richards

2015

Geochem Geophys Geosyst

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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.

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Variations in Crustal Thickness, Plate Rigidity, and Volcanic Processes Throughout the Northern Galápagos Volcanic Province

Cited by 16 publications

References 91 publications

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

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

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

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