Petrogenesis of the amphibole-rich veins from the Lherz orogenic lherzolite massif (Eastern Pyrenees, France): a case study for the origin of orthopyroxene-bearing amphibole pyroxenites in the lithospheric mantle

2001 ◽  
Vol 140 (4) ◽  
pp. 383-403 ◽  
Author(s):  
J. Fabriès ◽  
J.-P. Lorand ◽  
M. Guiraud
Keyword(s):  
Lithospheric Mantle ◽  
Eastern Pyrenees

scholarly journals Lithospheric mantle refertilization by DMM-derived melts beneath the Cameroon Volcanic Line—a case study of the Befang xenolith suite (Oku Volcanic Group, Cameroon)

2021 ◽  
Vol 176 (5) ◽  
Author(s):  
Sylvin S. T. Tedonkenfack ◽  
Jacek Puziewicz ◽  
Sonja Aulbach ◽  
Theodoros Ntaflos ◽  
Mary-Alix Kaczmarek ◽  
...  
Keyword(s):  
Lithospheric Mantle ◽  
Size Variation ◽  
African Plate ◽  
Cameroon Volcanic Line ◽  
Origin And Evolution ◽  
Volcanic Group ◽  
Cenozoic Volcanism ◽  
Composition Of Minerals ◽  
Ree Patterns

AbstractThe origin and evolution of subcontinental lithospheric mantle (SCLM) are important issues of Earth’s chemical and physical evolution. Here, we report detailed textural and chemical analyses on a mantle xenolith suite from Befang (Oku Volcanic Group, Cameroon Volcanic Line), which represents a major tectono-magmatic structure of the African plate. The samples are sourced from spinel-facies mantle and are dominated by lherzolites. Their texture is cataclastic to porphyroclastic, and foliation defined by grain-size variation and alignment of spinel occurs in part of peridotites. Spinel is interstitial and has amoeboidal shape. Clinopyroxene REE patterns are similar to those of Depleted MORB Mantle (DMM) except LREEs, which vary from depleted to enriched. The A-type olivine fabric occurs in the subset of one harzburgite and 7 lherzolites studied by EBSD. Orthopyroxene shows deformation consistent with olivine. The fabric of LREE-enriched clinopyroxene is equivalent to those of orthopyroxene and olivine, whereas spinel and LREE-depleted clinopyroxene are oriented independently of host rock fabric. The textural, chemical and thermobarometric constraints indicate that the Befang mantle section was refertilised by MORB-like melt at pressures of 1.0–1.4 GPa and temperatures slightly above 1200–1275 °C. The olivine-orthopyroxene framework and LREE-enriched clinopyroxene preserve the protolith fabric. In contrast, the LREE-depleted clinopyroxene, showing discordant deformation relative to the olivine-orthopyroxene protolith framework, and amoeboidal spinel crystallized from the infiltrating melt. The major element and REEs composition of minerals forming the Befang peridotites indicate subsequent reequilibration at temperatures 930–1000 °C. This was followed by the formation of websterite veins in the lithospheric mantle, which can be linked to Cenozoic volcanism in the Cameroon Volcanic Line that also brought the xenoliths to the surface. This study therefore supports the origin of fertile SCLM via refertilization rather than by extraction of small melt fractions, and further emphasizes the involvement of depleted melts in this process.

Forsterite reprecipitation and carbon dioxide entrapment in the lithospheric mantle during its interaction with carbonatitic melt: a case study from the Sung Valley ultramafic–alkaline–carbonatite complex, Meghalaya, NE India

2020 ◽  
pp. 1-12
Author(s):  
Shubham Choudhary ◽  
Koushik Sen ◽  
Santosh Kumar ◽  
Shruti Rana ◽  
Swakangkha Ghosh
Keyword(s):  
Carbon Dioxide ◽  
Lithospheric Mantle ◽  
Experimental Studies ◽  
Carbonatite Complex ◽  
Kerguelen Plume ◽  
Ne India ◽  
Isotopic Analyses ◽  
Oxygen Isotopic ◽  
Carbonatite Magma

Abstract Carbonatite melts derived from the mantle are enriched in CO2- and H2O-bearing fluids. This melt can metasomatize the peridotitic lithosphere and liberate a considerable amount of CO2. Experimental studies have also shown that a CO2–H2O-rich fluid can form Fe- and Mg-rich carbonate by reacting with olivine. The Sung Valley carbonatite of NE India is related to the Kerguelen plume and is characterized by rare occurrences of olivine. Our study shows that this olivine is resorbed forsterite of xenocrystic nature. This olivine bears inclusions of Fe-rich magnesite. Accessory apatite in the host carbonatite contains CO2–H2O fluid inclusions. Carbon and oxygen isotopic analyses indicate that the carbonatites are primary igneous carbonatites and are devoid of any alteration or fractionation. We envisage that the forsterite is a part of the lithospheric mantle that was reprecipitated in a carbonatite reservoir through dissolution–precipitation. Carbonation of this forsterite, during interaction between the lithospheric mantle and carbonatite melt, formed Fe-rich magnesite. CO2–H2O-rich fluid derived from the carbonatite magma and detected within accessory apatite caused this carbonation. Our study suggests that a significant amount of CO2 degassed from the mantle by carbonatitic magma can become entrapped in the lithosphere by forming Fe- and Mg-rich carbonates.

scholarly journals Calculation of the rockwall recession rate of a limestone cliff, affected by rockfalls, using cosmogenic chlorine-36. Case study of the Montsec Range (Eastern Pyrenees, Spain)

Geomorphology ◽  
2018 ◽  
Vol 306 ◽  
pp. 325-335 ◽  
Author(s):  
Guillem Domènech ◽  
Jordi Corominas ◽  
Olga Mavrouli ◽  
Silke Merchel ◽  
Antonio Abellán ◽  
...  
Keyword(s):  
Recession Rate ◽  
Eastern Pyrenees ◽  
Limestone Cliff ◽  
Chlorine 36

Tracing ancient events in the lithospheric mantle: A case study from ophiolitic chromitites of SW Turkey

2016 ◽  
Vol 119 ◽  
pp. 1-19 ◽  
Author(s):  
Mehmet Akbulut ◽  
José María González-Jiménez ◽  
William L. Griffin ◽  
Elena Belousova ◽  
Suzanne Y. O’Reilly ◽  
...  
Keyword(s):  
Lithospheric Mantle ◽  
Sw Turkey

Thermal and metasomatic rejuvenation and dunitization in lithospheric mantle beneath Central Europe – The Grodziec (SW Poland) case study

Lithos ◽  
2017 ◽  
Vol 276 ◽  
pp. 15-29 ◽  
Author(s):  
Magdalena Matusiak-Małek ◽  
Mateusz Ćwiek ◽  
Jacek Puziewicz ◽  
Theodoros Ntaflos
Keyword(s):  
Central Europe ◽  
Lithospheric Mantle ◽  
Sw Poland

scholarly journals Metasomatic effects in the lithospheric mantle beneath the NE Bohemian Massif: A case study of Lutynia (SW Poland) peridotite xenoliths

Lithos ◽  
2010 ◽  
Vol 117 (1-4) ◽  
pp. 49-60 ◽  
Author(s):  
Magdalena Matusiak-Małek ◽  
Jacek Puziewicz ◽  
Theodoros Ntaflos ◽  
Michel Grégoire ◽  
Hilary Downes
Keyword(s):  
Bohemian Massif ◽  
Lithospheric Mantle ◽  
Peridotite Xenoliths ◽  
Sw Poland

scholarly journals Lithospheric mantle evolution monitored by overlapping large igneous provinces: Case study in southern Africa

Lithos ◽  
2009 ◽  
Vol 107 (3-4) ◽  
pp. 257-268 ◽  
Author(s):  
F. Jourdan ◽  
H. Bertrand ◽  
G. Féraud ◽  
B. Le Gall ◽  
M.K. Watkeys
Keyword(s):  
Southern Africa ◽  
Lithospheric Mantle ◽  
Large Igneous Provinces ◽  
Mantle Evolution ◽  
Igneous Provinces
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