Geochemical and geophysical estimates of lithospheric thickness variation beneath Galápagos

Gibson, S. A.; Geist, D.

doi:10.1016/j.epsl.2010.10.002

Cited by 93 publications

(143 citation statements)

References 82 publications

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“…These predictions arise out of the dynamics of mantle flow and melting: the southern edges of the hotspot melting zone are more influenced by EC, where this material is the primary material melting, and the central, north, and northeast side of the hotspot see a relatively greater contribution from DC, where DC and EC are melting at more similar rates (Figures 13.3J-K). An analogous process for creating more depleted compositions between the hotspot center and the ridge axis has been proposed in recent geochemical studies [Hoernle et al, 2000;Gibson and Geist, 2010]. The predicted arc of high 206 Pb/ 204 Pb around the perimeter of the hotspot melting zone crudely resembles the horseshoe shape of the observed isotope pattern around the Galápagos Archipelago (Figure 13.1B).…”

Section: Model 2: High Viscosity In the Shallowest Upper Mantle Withsupporting

confidence: 65%

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

Ito

Bianco

2014

The Galápagos

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Section: Model 2: High Viscosity In the Shallowest Upper Mantle Withsupporting

confidence: 65%

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

Ito

Bianco

2014

The Galápagos

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“…We start with a mantle mineral mode consistent with a fertile lherzolite (ol: 0.55; opx: 0.25; cpx: 0.15; gt: 0.05). The primitive mantle starting composition and chondrite normalization for Lu and Hf are from Sun and McDonough [1989], and partitioning coefficient mineral are from Gibson and Geist [2010] and McKenzie and O'Nions [1991] (Table SI12).…”

Section: Results Of the Major Elements Forward Modelingmentioning

confidence: 99%

Petrological constraints on melt generation beneath the Asal Rift (Djibouti) using quaternary basalts

Pinzuti

Humler

Manighetti

2013

Geochem Geophys Geosyst

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[1] The temporal evolution of the mantle melting processes in the Asal Rift is evaluated from the chemical composition of 56 new lava flows sampled along 10 km of the rift axis and 9 km off-axis (i.e., erupted within the last 620 kyr). Petrological and primary geochemical results show that most of the samples of the inner floor of the Asal Rift are affected by plagioclase accumulation. Trace element ratios and major element compositions corrected for mineral accumulation and crystallization show a symmetric pattern relative to the rift axis and preserved a clear signal of mantle melting depth variations. While FeO, Fe 8.0 , Zr/Y, and (Dy/Yb) N decrease from the rift shoulders to the rift axis, SiO 2 , Na/Ti, Lu/Hf increase and Na 2 O and Na 8.0 are constant across the rift. These variations are qualitatively consistent with shallow melting beneath the rift axis and deeper melting for off-axis lava flows. Na 8.0 and Fe 8.0 contents show that beneath the rift axis, melting paths are shallow, from 81 6 4 to 43 6 5 km. These melting paths are consistent with adiabatic melting in normal-temperature fertile asthenosphere, beneath an extensively thinned mantle lithosphere. On the contrary, melting on the rift shoulders (from 107 6 7 to 67 6 8 km) occurred beneath thicker lithosphere, requiring a mantle solidus temperature 100 6 40 C hotter. In this geodynamic environment, the calculated rate of lithospheric thinning appears to be 4.0 6 2.0 cm yr À1 , a value close to the mean spreading rate (2.9 6 0.2 cm yr À1 ) over the last 620 kyr.

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“…Partition coefficients were taken from the compilation of ref. 39 and the garnet-spinel transition depth was set from 86-100 km in the model runs, based on the experimental results of ref. 40.…”

Section: Methodsmentioning

confidence: 99%

Melting during late-stage rifting in Afar is hot and deep

Ferguson

Maclennan

Bastow

et al. 2013

Nature

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Geochemical and geophysical estimates of lithospheric thickness variation beneath Galápagos

Cited by 93 publications

References 82 publications

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

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

Petrological constraints on melt generation beneath the Asal Rift (Djibouti) using quaternary basalts

Melting during late-stage rifting in Afar is hot and deep

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