A Reactive Porous Flow Control on Mid-ocean Ridge Magmatic Evolution

Lissenberg, C. Johan; MacLeod, C. J.

doi:10.1093/petrology/egw074

Cited by 109 publications

(144 citation statements)

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“…The average grain sizes of plagioclase and clinopyroxene are 0.4-4.1 mm and 0.4-5.5 mm, respectively. The compositions of plagioclase and clinopyroxene show complex variations on grain scales, which were attributed to reactive transport of melts through crystal mushes in the lower oceanic crust by Lissenberg et al (2013) and Lissenberg and MacLeod (2016). To capture the stratigraphic variations of mean mineral compositions, we calculated the average concentrations of major elements and REE in plagioclase and clinopyroxene for individual samples (Table S3).…”

Section: Sample Characteristicsmentioning

confidence: 99%

“…7), which involves axial and off-axial magma bodies (e.g., Han et al, 2014) and a crustal-scale mush zone (e.g., Lissenberg et al, 2013;Lissenberg and MacLeod, 2016). As indicated by the stratigraphic variations of cooling histories, the mush zone is supplied by mantle-derived primary melts from the bottom and is efficiently cooled by hydrothermal circulations across the entire lower crust.…”

Section: Implications For Ocean Crust Formation At Fast-spreading Ridgesmentioning

confidence: 99%

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Formation of fast-spreading lower oceanic crust as revealed by a new Mg–REE coupled geospeedometer

Sun

Lissenberg

2018

Earth and Planetary Science Letters

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A new geospeedometer is developed based on the differential closures of Mg and rare earth element (REE) bulk-diffusion between coexisting plagioclase and clinopyroxene. By coupling the two elements with distinct bulk closure temperatures, this speedometer can numerically solve the initial temperatures and cooling rates for individual rock samples. As the existing Mg-exchange thermometer was calibrated for a narrow temperature range and strongly relies on model-dependent silica activities, a new thermometer is developed using literature experimental data. When the bulk closure temperatures of Mg and REE are determined, respectively, using this new Mg-exchange thermometer and the existing REE-exchange thermometer, this speedometer can be implemented for a wide range of compositions, mineral modes, and grain sizes. Applications of this new geospeedometer to oceanic gabbros from the fast-spreading East Pacific Rise at Hess Deep reveal that the lower oceanic crust crystallized at temperatures of 998-1353 • C with cooling rates of 0.003-10.2 • C/yr. Stratigraphic variations of the cooling rates and crystallization temperatures support deep hydrothermal circulations and in situ solidification of various replenished magma bodies. Together with existing petrological, geochemical and geophysical evidence, results from this new speedometry suggest that the lower crust formation at fast-spreading mid-ocean ridges involves emplacement of primary mantle melts in the deep section of the crystal mush zone coupled with efficient heat removal by crustal-scale hydrothermal circulations. The replenished melts become chemically and thermally evolved, accumulate as small magma bodies at various depths, feed the shallow axial magma chamber, and may also escape from the mush zone to generate off-axial magma lenses.

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Section: Sample Characteristicsmentioning

confidence: 99%

Section: Implications For Ocean Crust Formation At Fast-spreading Ridgesmentioning

confidence: 99%

Formation of fast-spreading lower oceanic crust as revealed by a new Mg–REE coupled geospeedometer

Sun

Lissenberg

2018

Earth and Planetary Science Letters

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“…The chemical information contained in incompatible element ratios is regarded to be dominated by mantle source depletion and enrichment processes with only minimal effects coming from partial melting or magma chamber processing that occur prior to eruption of MORB lavas. Some workers have questioned this long‐held notion arguing that magma chamber processes affect all but the most highly incompatible element ratios (e.g., Coogan & O'Hara, ; Lissenberg & MacLeod, ; O'Neill & Jenner, , ). Reactive porous flow in cumulate piles within MORB magma chambers potentially creates elemental fractionations among the least incompatible elements that differ from fractional crystallization due to buffering of the Mg# by olivine (Lissenberg & MacLeod, ).…”

Section: Discussionmentioning

confidence: 99%

“…Some workers have questioned this long‐held notion arguing that magma chamber processes affect all but the most highly incompatible element ratios (e.g., Coogan & O'Hara, ; Lissenberg & MacLeod, ; O'Neill & Jenner, , ). Reactive porous flow in cumulate piles within MORB magma chambers potentially creates elemental fractionations among the least incompatible elements that differ from fractional crystallization due to buffering of the Mg# by olivine (Lissenberg & MacLeod, ). The role of diffusive elemental fractionation in cumulate piles has been invoked by Coogan and O'Hara (), but zoning profiles of clinopyroxene in ODP 735B gabbros does not support a role for diffusive fractionation (Lissenberg & MacLeod, ) The reactive porous flow model proposed by Lissenberg and MacLeod () invoked zone refining for creating incompatible element enrichments in excess of fractional crystallization involving melt exchange with 4–8 equivalent volumes of pyroxene‐rich cumulates.…”

Section: Discussionmentioning

confidence: 99%

“…Following Lissenberg and MacLeod (), we calculated the effects of zone refining in a crustal magma chamber with mineral abundances from Lissenberg and MacLeod () and partition coefficients from Bédard (). Because of the high fraction of plagioclase in the models of Lissenberg and MacLeod (), the Ba/La ratio is predicted to decrease by factors of 2–3 with increasing zone refining, contrary to what is observed for the variations within individual segments (Figure a). Thus, zone refining cannot explain the Ba‐enrichment of E‐MORB compared to N‐ and D‐MORB observed in Figure a.…”

Section: Discussionmentioning

confidence: 99%

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Elemental Systematics in MORB Glasses From the Mid‐Atlantic Ridge

Yang

Humayun

Salters

2018

Geochem Geophys Geosyst

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In this study, a data set of 60 elements in 319 mid‐oceanic ridge basalt (MORB) glasses representing 144 chemically distinct lava flows from the Mid‐Atlantic Ridge was acquired by laser ablation inductively coupled plasma mass spectrometry. Our new data are comparable in terms of the number of elements analyzed to several recent MORB data sets, albeit limited in geographic coverage to the North Mid‐Atlantic Ridge. This extensive data set was used to examine the elemental systematics of depleted (D)‐, normal (N)‐, and enriched (E)‐MORBs. We show that elemental ratios sensitive to fluid transport in subduction zones (e.g., Th/U, Nb/U, Ba/Th, and Ba/La) are constant and similar to their primitive mantle values in N‐ and E‐MORBs, but depleted in accordance with their compatibility in D‐MORBs. The absence of evidence for subduction zone processing indicates the need to reassess the relation between MORB enrichment and recycled materials. Additionally, we reexamined the ratios of chalcophile and siderophile elements to lithophile elements of comparable compatibility, which are important in assessing planetary accretion, core formation, crust‐mantle differentiation, and hydrothermal ore formation processes. MORBs show significant negative anomalies of As, Tl, Pb, and Bi, but not of Sb, relative to lithophile elements of similar compatibility, which cannot be accounted for by melt depletion alone. The depletions of As, Tl, Pb, and Bi in MORB are complementary to significant enrichments observed in the continental crust, indicating that they have been transferred to the continental crust via fluid mobility in arcs or obduction of seafloor hydrothermal ores.

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Rates and Timescales of Magma Transfer, Storage, Emplacement, and Eruption

Petrelli

Zellmer

2020

Dynamic Magma Evolution

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A Reactive Porous Flow Control on Mid-ocean Ridge Magmatic Evolution

Cited by 109 publications

References 91 publications

Formation of fast-spreading lower oceanic crust as revealed by a new Mg–REE coupled geospeedometer

Formation of fast-spreading lower oceanic crust as revealed by a new Mg–REE coupled geospeedometer

Elemental Systematics in MORB Glasses From the Mid‐Atlantic Ridge

Rates and Timescales of Magma Transfer, Storage, Emplacement, and Eruption

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