High-Pressure Dehydration Melting of Metapelites: Evidence from the Migmatites of Yaounde (Cameroon)

Barbey, Pierre; Macaudière, J.; Nzenti, Jean Paul

doi:10.1093/petrology/31.2.401

Cited by 127 publications

(61 citation statements)

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“…This makes the mesosomes depart from simple mixing lines between the metapelites and the anatectic leucogranites. A high abundance of either plagioclase or K-feldspar in leucosomes seems to be a common feature in migmatitic terrains [Ashworth, 1985;Barbey et al, 1990] which has led to the conchision that most of the leucosomes do not represent anatectic melts but are variably modified by crystal fractionation [Sawyer, 1987] which is also a premise for the lack of garnet retrograssion during cooling [Powell and Downes, 1990].…”

Section: Chemical Relationshipsmentioning

confidence: 99%

Geochemical and isotopic disequilibrium in crustal melting: An insight from the anatectic granitoids from Toledo, Spain

Barbero¹,

Villaseca²,

Rogers³

et al. 1995

J. Geophys. Res.

107

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Abstract. In the Hercynian Anatectic Complex of Toledo (ACT) the anatectic granitoids include leucogranitic leucosomes, leucogranitic massifs, and restite-rich granites. They show a broad range of initial Sr and Nd isotope ratios from 0.71 I to 0.720 and 0.51164 to 0.51203, respectively, which clearly indicate the absence of isotopic homogenization in the melts. Broadly, the ranges reflect the isotopic variation of the metapelitic protoliths. If crusta! melting occurs under water-undersaturated conditions, as is the case of the ACT, the generated melts do not isotopically and chemically equilibrate with the granulitic residuum. The preservation of heterogeneities could arise through a number of pmcesses. (1) duration of the process:in which the presence of melts with disequilibrium features, and the high solid content of several of the granites in the ACT point to a very short-lived magmatic system, (2) limited

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Section: Chemical Relationshipsmentioning

confidence: 99%

Geochemical and isotopic disequilibrium in crustal melting: An insight from the anatectic granitoids from Toledo, Spain

Barbero¹,

Villaseca²,

Rogers³

et al. 1995

J. Geophys. Res.

107

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“…Exhumation and thrusting of granulites over the craton is associated to a subsequent regional scale folding of the nappe resulted in the forming of upright to recline folds. The gradual P-T decrease recorded during the second phase folding [26] [27] suggests that the Yaoundé HP-HT granulites were uplifted (exhumation) during regional shortening.…”

Section: 5d Modelingmentioning

confidence: 99%

Magnetic Anomaly Interpretation of the Northern Congo Craton Boundary: Results from Depth Estimation and 2.5D Modeling

Antoine¹,

Albert²,

Victor³

et al. 2017

GEP

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A magnetic-based geophysical study was performed across the southern part of Cameroon to investigate the boundary between the Archean Congo craton and the Pan-African metamorphic belt. Magnetic gradient techniques including Euler deconvolution and Tilt derivative have been applied to an aeromagnetic data profile to determine the depth of sources and their lateral extension. 2.5D magnetic modeling shows that the prominent magnetic positive anomalies observed on total magnetic map of south Cameroon are produced by deep and strongly magnetic bodies under the Pan-African formations mainly an important dyke formation structure with a high susceptibility of 0.041 (SI units), at an average depth of 4148 m and with a lateral extension of about 10 km. These bodies are interpreted to have emplaced at high crustal levels in a continental collision zone and were subsequently metamorphosed at granulite grade conditions, during the Pan-African orogeny about 620 Ma ago.

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“…To date, the equilibrium conditions of the Pan -African gneisses in the Nkambe area have not been studied. However, kyanite -bearing metamorphic rocks are often reported in the Pan -African belt (e.g., Nzenti et al, 1988;Barbey et al, 1990;Mvondo et al, 2003Mvondo et al, , 2007, suggesting a minimum equilibrium pressure of 0.77 GPa at 700 °C (Pattison, 1992). Additionally, Barbey et al (1990) reported highpressure dehydration melting of metapelites around 1.0 -1.2 GPa/800 °C from the Yaoundé region in Cameroon.…”

Section: P-t Estimationsmentioning

confidence: 99%

“…However, kyanite -bearing metamorphic rocks are often reported in the Pan -African belt (e.g., Nzenti et al, 1988;Barbey et al, 1990;Mvondo et al, 2003Mvondo et al, , 2007, suggesting a minimum equilibrium pressure of 0.77 GPa at 700 °C (Pattison, 1992). Additionally, Barbey et al (1990) reported highpressure dehydration melting of metapelites around 1.0 -1.2 GPa/800 °C from the Yaoundé region in Cameroon. Nzenti et al (1988) and Mvondo et al (2003) estimated similar equilibrium conditions at 1.0 -1.2 GPa/750 -800 °C and 0.9 -1.2 GPa/675 -800 °C, respectively, for the PanAfrican metamorphic rocks in the same region.…”

Section: P-t Estimationsmentioning

confidence: 99%

Emplacement P-T conditions of Pan-African biotite-amphibole granitoids in the Nkambe area, Cameroon

Tetsopgang¹,

Enami²,

Njonfang³

2011

Journal of Mineralogical and Petrological Sciences

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Biotite -and amphibole -bearing monzogranite, quartz monzonite, and tonalite intrude into the biotite granitoids and biotite -hornblende gneisses of the Pan -African belt in the Nkambe area, northwestern Cameroon. The common mineral assemblage in these rocks is amphibole + biotite + plagioclase + K -feldspar + quartz + zircon + apatite; however, their modal composition varies in each rock -type. Most amphibole grains are relatively homogeneous and locally have slightly Al -rich rims. They are mostly ferro -edenite or ferropargasite, and in a tonalite sample, there is magnesiohornblende with less aluminous and more magnesian composition. The amphibole + biotite + plagioclase + K -feldspar + quartz assemblage was affected by several pressure -sensitive and H 2 O -free reactions. The ferro -edenite -and/or ferropargasite -bearing samples show similar pressure -temperature (P -T) ranges of 0.46 -0.50 GPa/655 -690 °C and 0.43 -0.69 GPa/675 -705 °C. In contrast, the magnesiohornblendebearing tonalite records lower temperature conditions of 0.77 GPa/610 °C, which is attributed to subsolidus reequilibration during cooling. The P -T estimates for the biotite -amphibole granitoids in this and previous studies suggest that relatively high -pressure granitoids are widespread in the Nkambe area.

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High-Pressure Dehydration Melting of Metapelites: Evidence from the Migmatites of Yaounde (Cameroon)

Cited by 127 publications

References 0 publications

Geochemical and isotopic disequilibrium in crustal melting: An insight from the anatectic granitoids from Toledo, Spain

Geochemical and isotopic disequilibrium in crustal melting: An insight from the anatectic granitoids from Toledo, Spain

Magnetic Anomaly Interpretation of the Northern Congo Craton Boundary: Results from Depth Estimation and 2.5D Modeling

Emplacement P-T conditions of Pan-African biotite-amphibole granitoids in the Nkambe area, Cameroon

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