Phosphorus Zoning From Secondary Olivine in Mantle Xenolith From Middle Atlas Mountains (Morocco, Africa): Implications for Crystal Growth Kinetics

Mavrogonatos, Konstantinos; Flemetakis, Stamatis; Papoutsa, Angeliki; Klemme, Stephan; Berndt, Jasper; Economou, Georgios; Pantazidis, Avgoustos; Baziotis, Ioannis; Asimow, Paul D.

doi:10.12681/bgsg.11933

Cited by 3 publications

(1 citation statement)

References 11 publications

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“…Electron probe microanalysis has revealed that olivine may carry a number of trace elements (e.g., Ni, Mn, Co, Ca, Ti, Al, Cr, P, and Na) which have been widely used as indicators of chemical and thermodynamic conditions of olivine crystallization [56][57][58][59][60][61][62][63][64][65][66]. Our analyses and comparison with relevant literature data (Figures 6A-C, 7A-C, and 8A-I) show that the olivine of Macaronesian volcanic rocks and xenoliths mainly contain minor amounts of Ni, Mn, and Ca, attributable to a solid solution with structurally related end members of the "Olivine Group", such as liebenbergite Ni2SiO4, tephroite Mn2SiO4, monticellite CaMgSiO4, and kirschsteinite CaFeSiO4 [67].…”

Section: The Significance Of Compositional Variations In Olivinementioning

confidence: 99%

Mineral Chemistry of Olivine, Oxy-Spinel, and Clinopyroxene in Lavas and Xenoliths from the Canary, Azores, and Cape Verde Islands (Macaronesia, North Atlantic Ocean): New Data and Comparisons with the Literature

Zaccarini,

Garuti,

Moser

et al. 2024

Minerals

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An electron microprobe study was carried out on olivine, clinopyroxene, and oxy-spinel occurring in basalts and dunite xenoliths from the archipelagos of the Azores, the Canary Islands, and Cape Verde. By comparing our results with previously published data from the volcanic islands of Macaronesia, we confirmed the validity of the compositions of olivine, clinopyroxene, and oxy-spinel as geochemical tracers. The origin of olivine, i.e., crystallized in the lithospheric mantle or in volcanic rocks, was successfully discriminated. Olivine from Lanzarote dunite xenoliths, which represent fragments of the mantle transported to the surface by host magmas, exhibited higher Fo% values (Fo91.02 to Fo91.94) and a different distribution of minor elements Ca, Ni, and Mn (CaO up to 0.42 wt%, NiO 0.07–0.41 wt%, MnO 0.06–0.3 wt%) when compared with olivine occurring as phenocrysts in basaltic lavas from the Macaronesian islands. The highly variable forsterite contents (Fo75.1 to Fo94.4) in olivine from gabbro and peridotite xenoliths found across the islands of Macaronesia were attributed to fractional crystallization that started in a deep magma reservoir, suggesting that these xenoliths represent cumulate rocks and not mantle fragments. Alternatively, these xenoliths may have been affected by the interaction with metasomatic fluids. The composition of clinopyroxene phenocrysts was used to decipher formation conditions under extensional tectonics. Their composition suggests that the host lavas have an alkaline to calc-alkaline signature. Furthermore, clinopyroxene euhedral shapes and compositions suggest an origin by fractional crystallization in a closed magmatic system. The composition alone of oxy-spinel from Macaronesian basalts and xenoliths was not sufficient to draw conclusions about the geodynamic environment where they were formed. Nevertheless, the relationship between oxy-spinel and olivine crystallized in equilibrium was successfully used as oxybarometers and geothermometers. The oxy-spinel–olivine pairs show evidence that the basaltic lavas were crystallized from melts with higher oxygen fugacity and different cooling histories than those of the mantle xenoliths, as the latter crystallized and re-equilibrated much slower than the basalts.

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Section: The Significance Of Compositional Variations In Olivinementioning

confidence: 99%

Mineral Chemistry of Olivine, Oxy-Spinel, and Clinopyroxene in Lavas and Xenoliths from the Canary, Azores, and Cape Verde Islands (Macaronesia, North Atlantic Ocean): New Data and Comparisons with the Literature

Zaccarini,

Garuti,

Moser

et al. 2024

Minerals

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Volcanic geosites assessment in the Plio-Quaternary Azrou-Timahdite Plateau (Middle Atlas, Morocco)

Baadi

Amine

Tefogoum

et al. 2021

Journal of African Earth Sciences

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Geomorphological Classification and Landforms Inventory of the Middle-Atlas Volcanic Province (Morocco): Scientific Value and Educational Potential

Amine

Hassani

Remmal

et al. 2019

Quaestiones Geographicae

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Through the tabular morphology of northwestern part of the Middle-Atlas in Morocco, numerous uncovered monogenetic volcanoes arise structured of pyroclastic product layers and lava flows. Our fieldwork results witness a wide-ranging volcanic shape spectrum, as cones, maars, tuff-rings, and cone-maar mixes, generally associated with a later lava flow discharge that could develop many surfaces and appearances. There are withal sundry eruptive products such as pahoehoe lava, scoria, tuff, lapilli, peperites, base-surges, bombs, etc. This monogenetic volcanic field of practically 1000 km2 offers remarkable eruptive landforms, referred to as the largest, and the youngest volcanic field in Morocco, which consists of a large area within the Ifrane National Park. This fieldwork study provides a renewed volcanic geomorphological classification table and GIS data to be used by a wide public range for both educational and geo-touristic interest and access effectively to such a high-mountain natural museum. In the event that these volcanic structures were appropriately dealt with, the high educational scientific content and the notable touristic vocation would almost certainly create business openings and new financial wages for neighborhood populaces. This work focuses to share our outcomes and emphases the scientific value about the monogenetic volcanic field around the tabular Middle-Atlas in Morocco.

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Phosphorus Zoning From Secondary Olivine in Mantle Xenolith From Middle Atlas Mountains (Morocco, Africa): Implications for Crystal Growth Kinetics

Abstract: Mantle xenolith samples in contact with

Cited by 3 publications

References 11 publications

Mineral Chemistry of Olivine, Oxy-Spinel, and Clinopyroxene in Lavas and Xenoliths from the Canary, Azores, and Cape Verde Islands (Macaronesia, North Atlantic Ocean): New Data and Comparisons with the Literature

Mineral Chemistry of Olivine, Oxy-Spinel, and Clinopyroxene in Lavas and Xenoliths from the Canary, Azores, and Cape Verde Islands (Macaronesia, North Atlantic Ocean): New Data and Comparisons with the Literature

Volcanic geosites assessment in the Plio-Quaternary Azrou-Timahdite Plateau (Middle Atlas, Morocco)

Geomorphological Classification and Landforms Inventory of the Middle-Atlas Volcanic Province (Morocco): Scientific Value and Educational Potential

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