Constraints on the origin of the oxidation state of mantle overlying subduction zones: An example from Simcoe, Washington, USA

Brandon, A. D.; Draper, D. S.

doi:10.1016/0016-7037(96)00056-7

Cited by 252 publications

(145 citation statements)

References 42 publications

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“…This is consistent with our oblique subduction model (Figure 2). Oxygen fugacity in convergent margin magmas is usually considerably higher than in mid-ocean ridge and other geological settings (Brandon and Draper 1996;Parkinson and Arculus 1999;Sun et al 2007b), likely due to subductionreleased fluids (Brandon and Draper 1996;Sun et al 2007b). Therefore, oxygen fugacity decreases gradually with increasing distance from the trench.…”

Section: Oblique Subduction Modelmentioning

confidence: 99%

Mesozoic large magmatic events and mineralization in SE China: oblique subduction of the Pacific plate

Wang

Ling

Ding

et al. 2010

International Geology Review

191

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Section: Oblique Subduction Modelmentioning

confidence: 99%

Mesozoic large magmatic events and mineralization in SE China: oblique subduction of the Pacific plate

Wang

Ling

Ding

et al. 2010

International Geology Review

191

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“…Allan et al (1988) also suggested that rapid growth of chromian spinel could lead to local depletion in Cr. Since this vermiform texture has been noted in lavas from many diverse localities, including the Cascades (Brandon & Draper 1996), the Costa Rica Rift (Furuta & Tokuyama 1983), the Mid-Atlantic Rift (Bryan & Moore 1977, Dick & Bryan 1978, Fisk & Bence 1980) and the Lamont chain of seamounts in the eastern Pacific (Allan et al 1988), the process that has led to this texture must be fairly common.…”

Section: Introductionmentioning

confidence: 97%

Growth Forms and Composition of Chromian Spinel in Morb Magma: Diffusion-Controlled Crystallization of Chromian Spinel

Roeder

Poustovetov

Öskarsson

2001

The Canadian Mineralogist

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Microphenocrysts of chromian spinel in glass from an East Pacific Rise lava and three Icelandic subglacial lavas show a variety of complex skeletal, hopper, vermiform and chain textures. These grains of chromian spinel are larger than those found in most basalts. Many crystals show significant zoning in Cr/(Cr + Al), and the variation in Cr/(Cr + Al) with respect to Fe 2+ /(Fe 2+ + Mg) is distinctive for each sample. The four samples are relatively primitive, with between 9 and 10 wt.% MgO in the glass. One very distinctive texture, a core surrounded by a vermiform rim, has been interpreted by a number of researchers as a reaction texture caused either by changes in pressure or magma mixing. The variety of chromian spinel textures, including the vermiform rim, has been duplicated in an experimental run using the sample from the East Pacific Rise. The sample was held at 1225°C for 67 hours and then cooled slowly over 8 hours to 1147°C. We conclude that the vermiform texture and the other chromian spinel textures in the experimental run and the lavas are growth textures and not reaction textures. The change in growth habit that produces the vermiform rim is interpreted as diffusion-controlled growth, leading to what metallurgists refer to as cellular growth. Chromian spinel is susceptible to diffusion-controlled growth because of the very large difference in concentration of Cr in the melt (0.02-0.06 wt.% Cr 2 O 3 ) and in chromian spinel (30-50 wt.% Cr 2 O 3 ) at equilibrium. Although the chromian spinel in the glass of each natural sample shows a large variation in Cr/(Cr + Al), and thus was not in equilibrium with the bulk melt, its Fe 2+ / (Fe 2+ + Mg) may have been close to equilibrium with the bulk melt before quenching. The chromian spinel crystallized over a span of hours to days before a rapid water quench upon eruption. The complex textures and zoning probably reflect the turbulent conditions during passage of the magma toward the Earth's surface.Keywords: chromian spinel, chromite, basalt, texture, vermiform, hopper, diffusion-controlled crystallization. SOMMAIREDes microphénocristaux de spinelle chromifère sont présents dans une matrice vitreuse d'une lave basaltique provenant de la ride Est-Pacifique et de trois échantillons de coulées mises en place sous un glacier en Icelande. Ces cristaux contiennent une variété de textures complexes en entonnoir, vermiformes et en chaînes; ils sont plus grossiers que ceux qui caractérisent la plupart des basaltes. Plusieurs cristaux montrent une zonation importante en Cr/(Cr + Al), qui varie de façon distincte avec Fe 2+ /(Fe 2+ + Mg) dans chaque échantillon. Les quatre échantillons sont relativement primitifs, le verre contenant entre 9 et 10% (poids) de MgO. On a généralement interprété la présence d'un coeur entouré d'un liseré vermiforme comme résultat d'une réaction suite à des changements en pression ou à un mélange de magmas. La diversité texturale du spinelle chromifère, y inclus la bordure vermiforme, a été reproduite dans un série d'expériences f...

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“…3b), but they are also of oxidizing nature. The oxidized nature of arc magmas and their mantle sources could be the result of the presence of H 2 O in their source region during partial melting (e.g., Brandon and Draper, 1996). The Nb trough shown by these rocks on the N-MORB normalized diagram (Fig.…”

Section: Characterization Of "Arc" Magmatism Of Me and Ogmentioning

confidence: 99%

Mantle-derived arc related mafic enclaves and host orthogneiss from the Shyok Suture Zone of NE Ladakh, India: An evidence of magma-mixing

Rao

Daga

Rai³

2013

Geochem. J.

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The Shyok valley in the northern Ladakh is a linear NW-SE trending suture zone (Shyok Suture Zone) and separates two distinct terranes, the southern continental margin of Eurasian Plate to north, and Ladakh magmatic arc to south. The crustal growth in the Shyok Suture Zone (SSZ) can be explained by two stage melting process involving the generation of orthogneiss (OG) with mafic enclaves (ME) (pre-collision), and temporal evolution towards increasingly more evolved felsic magmas during reworking processes (post-collision). In this paper, the geochemistry of various ME and host OG that fall within the Shyok-Darbuk corridor of the suture zone are discussed.The field, petrographic and geochemical data suggest that the ME and host OG are genetically related. The ME has formed by low degree of partial melting of a garnet-bearing source or from the partial melting of a basaltic source with a clinopyroxene-garnet eclogite as residue. The LILE and LREE enrichment of ME have been influenced by mantle-magma interaction during the passage of the hydrous primary arc-magma through the overlying lithosphere. The likely interpretation for the genetic linkage of ME and host OG is explained through the mixing of coeval mafic (enclave) and felsic melts, resulting in hybrid magma. Besides, several geochemical lines of evidence suggest that fractional crystallization of the resultant hybrid magma had played a complementary role in the evolution of these rocks.

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Constraints on the origin of the oxidation state of mantle overlying subduction zones: An example from Simcoe, Washington, USA

Cited by 252 publications

References 42 publications

Mesozoic large magmatic events and mineralization in SE China: oblique subduction of the Pacific plate

Mesozoic large magmatic events and mineralization in SE China: oblique subduction of the Pacific plate

Growth Forms and Composition of Chromian Spinel in Morb Magma: Diffusion-Controlled Crystallization of Chromian Spinel

Mantle-derived arc related mafic enclaves and host orthogneiss from the Shyok Suture Zone of NE Ladakh, India: An evidence of magma-mixing

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