Oman diopsidites: a new lithology diagnostic of very high temperature hydrothermal circulation in mantle peridotite below oceanic spreading centres

Python, Marie; Ceuleneer, Georges; Ishida, Yoshito; Barrat, Jean‐Alix; Arai, Shoji

doi:10.1016/j.epsl.2006.12.030

Cited by 85 publications

(125 citation statements)

References 55 publications

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“…They are instead similar to diopsidites and anorthite diopsidites described from the mantle section of the Oman ophiolite (Python et al, 2007a(Python et al, , 2011.…”

Section: Petrographymentioning

confidence: 99%

“…The locality of the study area along Wadi Fizh is shown. The sampling points of the mantle diopsidites in Wadi Sudum in the Hilti block and anorthite diopsidites in Wadi Halhal in the Haylayn block are also shown (Python et al, 2007a).…”

Section: +mentioning

confidence: 99%

“…However, the diopsidites, which are a product of hydrothermal alteration of peridotite, have not yet been reported from the Fizh block (cf. Python et al, 2007a).…”

Section: Geological Backgroundmentioning

confidence: 99%

“…Diopsidites, mainly composed of diopsides, have been discovered as dikes within the mantle section in the Oman ophiolite (Python et al, 2007a). These diopsidites were formed by reactions between Ca -rich hydrothermal fluids and peridotites at various temperatures, from approximately 600 °C to higher than 900 °C (Python et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

“…The anorthitebearing diopsidites are similar to gabbros in terms of the plagioclase/clinopyroxene ratio, but resemble the diopsidites defined by Python et al (2011) in diopsidic nature of clinopyroxenes. We call them as anorthite diopsidites in this paper and discuss their petrogenesis by making a comparison with mantle diopsidites (Python et al, 2007a) from the northern Oman ophiolite to understand the activity of high -temperature hydrothermal fluids from the suboceanic uppermost mantle to the lowermost crust.…”

Section: Introductionmentioning

confidence: 99%

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Crustal diopsidites from the northern Oman ophiolite: Evidence for hydrothermal circulation through suboceanic Moho

Akizawa

Arai

Tamura

et al. 2011

Journal of Mineralogical and Petrological Sciences

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This paper details a new discovery of anorthite -bearing diopsidites (= anorthite diopsidites) from the lowermost crust along Wadi Fizh in the northern Oman ophiolite. The anorthite diopsidites occur as networks within layered gabbros 50 m above the gabbro/peridotite boundary, and are mainly composed of high -Mg diopsidic clinopyroxenes and anorthites with various amounts of uvarovite. They are intermediate in mineral chemical characteristics between the crustal gabbros and the diopsidites, and interpreted as an interaction product between hightemperature Ca -rich hydrothermal fluids and peridotites within the mantle section. The anorthite diopsidites were probably formed by interaction between the fluids involved in diopsidization within the mantle section and the layered gabbro. The fluids responsible for the formation of the anorthite diopsidite were also Ca -rich and carried Cr to form uvarovite from the underlying mantle section. High -temperature hydrothermal circulation plays an important role in the transportation of elements, e.g., Ca and Cr, from the upper mantle to the lower crust across the Moho in the ocean floor.

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“…They are instead similar to diopsidites and anorthite diopsidites described from the mantle section of the Oman ophiolite (Python et al, 2007a(Python et al, , 2011.…”

Section: Petrographymentioning

confidence: 99%

Section: +mentioning

confidence: 99%

“…However, the diopsidites, which are a product of hydrothermal alteration of peridotite, have not yet been reported from the Fizh block (cf. Python et al, 2007a).…”

Section: Geological Backgroundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Crustal diopsidites from the northern Oman ophiolite: Evidence for hydrothermal circulation through suboceanic Moho

Akizawa

Arai

Tamura

et al. 2011

Journal of Mineralogical and Petrological Sciences

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Mineralogical assemblages forming at hyperalkaline warm springs hosted on ultramafic rocks: A case study of Oman and Ligurian ophiolites

Chavagnac

Ceuleneer

Monnin

et al. 2013

Geochem Geophys Geosyst

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[1] We report on the mineralogical assemblages found in the hyperalkaline springs hosted on Liguria and Oman ophiolites based on exhaustive X-ray diffraction and scanning electron microprobe analyses. In Liguria, hyperalkaline springs produce a thin brownish calcite precipitate that covers the bedrock due to the concomitant atmospheric CO 2 uptake and neutralization of the hyperalkaline waters. No brucite and portlandite minerals are observed. The discharge of alkaline waters in Oman ophiolite forms white-orange precipitates. Calcium carbonate minerals (calcite and/or aragonite) are the most abundant and ubiquitous precipitates and are produced by the same mechanism as in Liguria. This process is observed as a thin surface crust made of rhombohedral calcite. Morphological features of aragonite vary from needle-, bouquet-, dumbbell-, spheroidal-like habitus according to the origin of carbon, temperature, and ionic composition of the hyperalkaline springs, and the biochemical and organic compounds. Brucite is observed both at hyperalkaline springs located at the thrust plane and at the paleo-Moho. The varying mixing proportions between the surface runoff waters and the hyperalkaline ones control brucite precipitation. The layered double hydroxide minerals occur solely in the vicinity of hyperalkaline springs emerging within the bedded gabbros. Finally, the dominant mineralogical associations we found in Oman (Ca-bearing carbonates and brucite) in a serpentinizing environment driven by the meteoric waters are surprisingly the same as those observed at the Lost City hydrothermal site in a totally marine environment.

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Clinopyroxenites (diopsidites) and metabasites from the East Sarmatian Orogen, East European Craton

Terentiev

Santosh

2016

Geol. J.

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The East Sarmatian Orogen was built through successive subduction and collision processes at the junction of the Sarmatia and Volga‐Uralia segments of the East European Craton. In this paper we present petrological and geochemical characteristics of diopsidites and host amphibolites from the central part of this orogen. We report a new occurrence of metabasites (meta‐gabbros and amphibolites) and anorthite–bytownite‐bearing diopsidites from the Palaeoproterozoic Vorontsovka terrane of the East Sarmatian Orogen. The diopsidites occur as networks of veinlets and dykes within the metabasite layers (thickness up to 100 m) and are composed predominantly of high‐Mg diopside (Mg# up to 0.87) and calcic plagioclase (An99–73) with traces of K‐feldspar, titanite, calcite, quartz with retrograde chlorite and epidote. The diopsidites are low in Ti and K and high in Mg (Mg# greater than 0.82) rocks. They have low REE; positive Ce, U and Sr anomalies; and negative Th, Nb and Ti anomalies. The meta‐gabbros and amphibolites are composed of calcic amphibole, albite, quartz, biotite, zoisite, prehnite and ore minerals (sulphides + ilmenite). The amphibolites are low Al, low K, magnesian–ferroan (Mg# = 0.46–0.75) and medium Ti (TiO2 0.75–1.37 wt.%) (SiO2 40.1–47.3 wt.%). The meta‐gabbros exhibit slight LREE and LILE enrichment, particularly in Rb, Ba and Sr. The amphibolites are tholeiitic in composition and have N‐MORB‐like REE and HFSE features, with high 143Nd/144Nd (0.512736) and positive εNd(T) (6.0). The diopsidites reported in our study compare with convergent‐margin rocks formed via metasomatic processes associated with slab subduction. The metabasite protoliths represent oceanic crust with N‐MORB‐type features with the LILE enrichment accompanying the subduction zone process. Copyright © 2016 John Wiley & Sons, Ltd.

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Oman diopsidites: a new lithology diagnostic of very high temperature hydrothermal circulation in mantle peridotite below oceanic spreading centres

Cited by 85 publications

References 55 publications

Crustal diopsidites from the northern Oman ophiolite: Evidence for hydrothermal circulation through suboceanic Moho

Crustal diopsidites from the northern Oman ophiolite: Evidence for hydrothermal circulation through suboceanic Moho

Mineralogical assemblages forming at hyperalkaline warm springs hosted on ultramafic rocks: A case study of Oman and Ligurian ophiolites

Clinopyroxenites (diopsidites) and metabasites from the East Sarmatian Orogen, East European Craton

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