Mineralogical and geochemical fingerprints of mantle metasomatism beneath Nyos volcano (Cameroon volcanic line)

2011 ◽  
pp. 193-210 ◽  
Author(s):  
M.I. Teitchou ◽  
M. Grégoire ◽  
R. Temdjim ◽  
R.T. Ghogomu ◽  
C. Ngwa ◽  
...  
Keyword(s):  
Mantle Metasomatism ◽  
Cameroon Volcanic Line

Fracture network mapping using remote sensing in three crater lakes environments of the Cameroon volcanic line (central Africa)

2021 ◽  
Vol 14 (6) ◽  
Author(s):  
Marthe Mbond Ariane Gweth ◽  
Jorelle Larissa Meli’i ◽  
Valentin Oyoa ◽  
Diab Ahmad Diab ◽  
Daniel Herve Gouet ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Central Africa ◽  
Fracture Network ◽  
Crater Lakes ◽  
Cameroon Volcanic Line ◽  
Network Mapping

Probabilistic seismic hazard assessment for the main cities along the continental section of the Cameroon volcanic line

2021 ◽  
Vol 14 (9) ◽  
Author(s):  
Etoundi Delair Dieudonné Ndibi ◽  
Eddy Ferdinand Mbossi ◽  
Nguet Pauline Wokwenmendam ◽  
Bekoa Ateba ◽  
Théophile Ndougsa-Mbarga
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard Assessment ◽  
Probabilistic Seismic Hazard ◽  
Cameroon Volcanic Line

The Metasomatized Mantle beneath the North Atlantic Craton: Insights from Peridotite Xenoliths of the Chidliak Kimberlite Province (NE Canada)

2019 ◽  
Vol 60 (10) ◽  
pp. 1991-2024 ◽  
Author(s):  
M G Kopylova ◽  
E Tso ◽  
F Ma ◽  
J Liu ◽  
D G Pearson
Keyword(s):  
North Atlantic ◽  
Thermal State ◽  
Mineral Chemistry ◽  
Mantle Metasomatism ◽  
Labrador Sea ◽  
The North ◽  
Rock Types ◽  
History Of ◽  
The North Atlantic ◽  
North Atlantic Craton

Abstract We studied the petrography, mineralogy, thermobarometry and whole-rock chemistry of 120 peridotite and pyroxenite xenoliths collected from the 156–138 Ma Chidliak kimberlite province (Southern Baffin Island). Xenoliths from pipes CH-1, -6, -7 and -44 are divided into two garnet-bearing series, dunites–harzburgites–lherzolites and wehrlites–olivine pyroxenites. Both series show widely varying textures, from coarse to sheared, and textures of late formation of garnet and clinopyroxene. Some samples from the lherzolite series may contain spinel, whereas wehrlites may contain ilmenite. In CH-6, rare coarse samples of the lherzolite and wehrlite series were derived from P = 2·8 to 5·6 GPa, whereas predominant sheared and coarse samples of the lherzolite series coexist at P = 5·6–7·5 GPa. Kimberlites CH-1, -7, -44 sample mainly the deeper mantle, at P = 5·0–7·5 GPa, represented by coarse and sheared lherzolite and wehrlite series. The bulk of the pressure–temperature arrays defines a thermal state compatible with 35–39 mW m–2 surface heat flow, but a significant thermal disequilibrium was evident in the large isobaric thermal scatter, especially at depth, and in the low thermal gradients uncharacteristic of conduction. The whole-rock Si and Mg contents of the Chidliak xenoliths and their mineral chemistry reflect initial high levels of melt depletion typical of cratonic mantle and subsequent refertilization in Ca and Al. Unlike the more orthopyroxene-rich mantle of many other cratons, the Chidliak mantle is rich (∼83 vol%) in forsteritic olivine. We assign this to silicate–carbonate metasomatism, which triggered wehrlitization of the mantle. The Chidliak mantle resembles the Greenlandic part of the North Atlantic Craton, suggesting the former contiguous nature of their lithosphere before subsequent rifting into separate continental fragments. Another, more recent type of mantle metasomatism, which affected the Chidliak mantle, is characterized by elevated Ti in pyroxenes and garnet typical of all rock types from CH-1, -7 and -44. These metasomatic samples are largely absent from the CH-6 xenolith suite. The Ti imprint is most intense in xenoliths derived from depths equivalent to 5·5–6·5 GPa where it is associated with higher strain, the presence of sheared samples of the lherzolite series and higher temperatures varying isobarically by up to 200 °C. The horizontal scale of the thermal-metasomatic imprint is more ambiguous and could be as regional as tens of kilometers or as local as <1 km. The time-scale of this metasomatism relates to a conductive length-scale and could be as short as <1 Myr, shortly predating kimberlite formation. A complex protracted metasomatic history of the North Atlantic Craton reconstructed from Chidliak xenoliths matches emplacement patterns of deep CO2-rich and Ti-rich magmatism around the Labrador Sea prior to the craton rifting. The metasomatism may have played a pivotal role in thinning the North Atlantic Craton lithosphere adjacent to the Labrador Sea from ∼240 km in the Jurassic to ∼65 km in the Paleogene.

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.

A new occurrence of yimengite-hawthorneite and crichtonite-group minerals in an orthopyroxenite from kimberlite: Implications for mantle metasomatism

2019 ◽  
Vol 104 (5) ◽  
pp. 761-774 ◽  
Author(s):  
Dmitriy I. Rezvukhin ◽  
Taisia A. Alifirova ◽  
Andrey V. Korsakov ◽  
Alexander V. Golovin
Keyword(s):  
Mantle Metasomatism

Mantle metasomatism: Isotope and trace-element trends in xenoliths from Kimberley, South Africa

1990 ◽  
Vol 85 (1-2) ◽  
pp. 19-34 ◽  
Author(s):  
C.J. Hawkesworth ◽  
A.J. Erlank ◽  
P.D. Kempton ◽  
F.G. Waters
Keyword(s):  
South Africa ◽  
Trace Element ◽  
Mantle Metasomatism

Pyroxenite in the mantle source of basanites at the Youkou maar, Adamawa Volcanic Massif (Cameroon Volcanic Line, West Africa)

2021 ◽  
Vol 583 ◽  
pp. 120478
Author(s):  
Patrick Merlin Wagsong Njombie ◽  
Robert Temdjim ◽  
Nicaise Blaise Ngongang Tchuimegnie ◽  
Stephen F. Foley ◽  
François Xavier Onana Mebara
Keyword(s):  
West Africa ◽  
Mantle Source ◽  
Cameroon Volcanic Line
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