Modes of crustal accretion and their implications for hydrothermal circulation

Theissen-Krah, Sonja; Rüpke, Lars; Hasenclever, Jörg

doi:10.1002/2015gl067335

Cited by 23 publications

(30 citation statements)

References 31 publications

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“…A permeability of ∼10 −16 m 2 as derived from our models, is about an order of magnitude lower than the value required to match AML depths in 2‐D accretion models incorporating realistic hydrothermal flow [e.g., Theissen‐Krah et al ., ]. One possible reason for this discrepancy between thermal models is the low Nusselt numbers (i.e., Nu ≅ 2‐3) characteristics of our convective couplings.…”

Section: Discussionmentioning

confidence: 99%

“…In the accretion models initially developed by Morgan and Chen [] and further improved and exploited by Theissen‐Krah et al . [], the dynamical viscosity is exactly the critical value of 10 16 Pa.s. In Rabinowicz et al .…”

Section: The “Two‐layers” Fluid‐porous/magmatic‐hydrothermal Conceptmentioning

confidence: 99%

“…[] and Theissen‐Krah et al . [] where hydrothermal, cellular‐type, flow dynamics is coupled to crustal accretion.…”

Section: Introductionmentioning

confidence: 99%

“…Theissen‐Krah et al . [] propose a refined version of the formalism of Theissen‐Krah et al . [], in which various modes of crustal accretion are possible and test the effects of crystallizing the lower crust either (i) totally in the AML at the top of the gabbroic magma chamber (the “gabbro‐glacier model”) [e.g., Morgan and Chen , ] or (ii) only partly in the AML with the rest crystallizing in situ, at any depth between the moho and the top of the gabbro section (the “sheeted‐sills model”) [e.g., Kelemen et al ., ].…”

Section: Introductionmentioning

confidence: 99%

“…A few studies have attempted to address the question of the thermal regime of the coupled system composed by (i) the ductile, magmatic lower crust, and (ii) the hydrothermal, brittle upper crust. Because of the conceptual, theoretical, and numerical challenges of coupling magmatic and hydrothermal processes, these studies are restricted to two-dimensional geometries, along the across-axis dimension as in Cherkaoui et al [2003] and Theissen-Krah et al [2011, 2016 where hydrothermal, cellular-type, flow dynamics is coupled to crustal accretion. Cherkaoui et al [2003] use a steady state approach in which new lithosphere accretes continuously and is advected horizontally with spreading velocity.…”

Section: Introductionmentioning

confidence: 99%

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Can high‐temperature, high‐heat flux hydrothermal vent fields be explained by thermal convection in the lower crust along fast‐spreading Mid‐Ocean Ridges?

Fontaine

Rabinowicz

Cannat

2017

Geochem Geophys Geosyst

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To cite this version:Fabrice Fontaine, M. Rabinowicz, M. Cannat. Can high-temperature, high-heat flux hydrothermal vent fields be explained by thermal convection in the lower crust along fast-spreading Mid-Ocean Ridges?. Geochemistry, Geophysics, Geosystems, AGU and the Geochemical Society, 2017Society, , 18 (5), pp.1907Society, -1925 Abstract We present numerical models to explore possible couplings along the axis of fast-spreading ridges, between hydrothermal convection in the upper crust and magmatic flow in the lower crust. In an end-member category of models corresponding to effective viscosities l M lower than 10 13 Pa.s in a meltrich lower crustal along-axis corridor and permeability k not exceeding 10 216 m 2 in the upper crust, the hot, melt-rich, gabbroic lower crust convects as a viscous fluid, with convection rolls parallel to the ridge axis. In these models, we show that the magmatic-hydrothermal interface settles at realistic depths for fast ridges, i.e., 1-2 km below seafloor. Convection cells in both horizons are strongly coupled and kilometerwide hydrothermal upflows/plumes, spaced by 8-10 km, arise on top of the magmatic upflows. Such magmatic-hydrothermal convective couplings may explain the distribution of vent fields along the East (EPR) and South-East Pacific Rise (SEPR). The lower crustal plumes deliver melt locally at the top of the magmatic horizon possibly explaining the observed distribution of melt-rich regions/pockets in the axial melt lenses of EPR and SEPR. Crystallization of this melt provides the necessary latent heat to sustain permanent 100 MW vents fields. Our models also contribute to current discussions on how the lower crust forms at fast ridges: they provide a possible mechanism for focused transport of melt-rich crystal mushes from moho level to the axial melt lens where they further crystallize, feed eruptions, and are transported both along and off-axis to produce the lower crust.

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Section: Discussionmentioning

confidence: 99%

Section: The “Two‐layers” Fluid‐porous/magmatic‐hydrothermal Conceptmentioning

confidence: 99%

“…[] and Theissen‐Krah et al . [] where hydrothermal, cellular‐type, flow dynamics is coupled to crustal accretion.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Can high‐temperature, high‐heat flux hydrothermal vent fields be explained by thermal convection in the lower crust along fast‐spreading Mid‐Ocean Ridges?

Fontaine

Rabinowicz

Cannat

2017

Geochem Geophys Geosyst

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Axial Melt‐Lens Dynamics at Fast Spreading Midocean Ridges

Koepke

Zhang

2020

Dynamic Magma Evolution

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Correlations between oceanic crustal thickness, melt volume, and spreading rate from global gravity observation

Zhou

Zlotnik

et al. 2020

Mar Geophys Res

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Besides mantle depletion, oceanic crustal accretion at mid-ocean ridges is a function of spreading rate and mantle temperature, which are intertwined in affecting melt production and oceanic crustal thickness. Sparse and irregular seismic and geochemical observations on a global scale show no clear correlation between crustal thickness and spreading rate along slow to fast-spreading centers. Here, we compile a global oceanic crustal thickness model from gravity data to revisit this possible correlation at a higher resolution and a global scale. Gravity-observed melt volume shows a clear positive correlation with spreading rate, implying that spreading rate is 2 the dominant factor in melt production. However, we found a clear negative correlation between oceanic crustal thickness and spreading rate from slow to fastspreading centers. This trend is further consolidated by increasing Curie point depth, a geothermal proxy, and ridge depth with increasing spreading rate. Thus, the decreasing mantle temperature probably also contributes to crustal thinning from slow to fast-spreading centers. Low inferred melt volumes beneath fast-spreading centers are consistent with a 20°C drop in mantle temperature, which may be caused by highly efficient hydrothermal cooling.

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Modes of crustal accretion and their implications for hydrothermal circulation

Cited by 23 publications

References 31 publications

Can high‐temperature, high‐heat flux hydrothermal vent fields be explained by thermal convection in the lower crust along fast‐spreading Mid‐Ocean Ridges?

Can high‐temperature, high‐heat flux hydrothermal vent fields be explained by thermal convection in the lower crust along fast‐spreading Mid‐Ocean Ridges?

Axial Melt‐Lens Dynamics at Fast Spreading Midocean Ridges

Correlations between oceanic crustal thickness, melt volume, and spreading rate from global gravity observation

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