Petrology of Mafic Dykes from the Njimom Area (West-Cameroon): A Contribution to the Characterization of Late Paleozoic and Mesozoic Magmatism in the Southern Continental Part of the Cameroon Volcanic Line
In the western Cameroon, crop out several dyke swarms of Paleozoic-Mesozoic age. These dykes intrude the Precambrian basement in the southern continental part of the Cretaceous Cameroon Volcanic Line. In the Njimom area, two groups of mafic dykes that crosscut the Neoproterozoic basement rocks have...
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ftunivnapoliiris:oai:www.iris.unina.it:11588/876812 2024-06-23T07:56:48+00:00 Petrology of Mafic Dykes from the Njimom Area (West-Cameroon): A Contribution to the Characterization of Late Paleozoic and Mesozoic Magmatism in the Southern Continental Part of the Cameroon Volcanic Line Keutchafo Noel-Aimee Kouamo Simeni Nicole Armelle Wambo Nforba Brillant Kandzi Noucoucouk Agathe Arrissa Sonmo Josiane Demlabin Tchaptchet Depesquidoux Tchato Tchouankoue Jean Pierre Cucciniello Ciro Keutchafo, Noel-Aimee, Kouamo Simeni, Nicole Armelle, Wambo Nforba, Brillant, Kandzi Noucoucouk, Agathe, Arrissa Sonmo, Josiane, Demlabin Tchaptchet, Depesquidoux, Tchato Tchouankoue, Jean, Pierre Cucciniello, Ciro 2022 http://hdl.handle.net/11588/876812 https://doi.org/10.3390/geosciences12010012 eng eng info:eu-repo/semantics/altIdentifier/wos/WOS:000747156200001 volume:12 journal:GEOSCIENCES http://hdl.handle.net/11588/876812 doi:10.3390/geosciences12010012 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85122686630 info:eu-repo/semantics/article 2022 ftunivnapoliiris https://doi.org/10.3390/geosciences12010012 2024-06-03T14:50:54Z In the western Cameroon, crop out several dyke swarms of Paleozoic-Mesozoic age. These dykes intrude the Precambrian basement in the southern continental part of the Cretaceous Cameroon Volcanic Line. In the Njimom area, two groups of mafic dykes that crosscut the Neoproterozoic basement rocks have been observed. A first group intrudes the mylonites whereas the second group intrudes the granites. The dykes are alkaline basalts and hawaiites. The mineralogical assemblage of both groups of dykes consists of plagioclase, clinopyroxene, altered olivine, and opaque oxides. The dykes that cross-cut the Precambrian mylonitic gneisses show moderate TiO2 (1.7-2.0 wt.%), low MgO (4.4-7.1 wt.%), and compatible trace element concentrations (e.g., Cr = 70-180 ppm; Ni = 30-110 ppm). The dykes that intrude the granites have TiO2 contents between 2.3 and 2.5 wt.% and moderate compatible trace element concentrations (e.g., Cr = 260-280 ppm; Ni = 170-230 ppm). MgO varies from 5.9 to 9.2 wt.%. All mafic dykes are enriched in light lanthanide element and show moderate Zr/Nb and high Zr/Y, Nb/Yb, and Ti/V ratios similar to those of average ocean island basalt (OIB)-type magmas. Some dykes that intrude the mylonites show evidence of contamination by continental crust. The composition of the clinopyroxenes of the dykes that intrude the mylonites clearly indicate different and unrelated parental magmas from dykes that intrude the granites. Contents and fractionation of the least and the most incompatible elements suggest low degrees of partial melting (3-5%) of heterogeneous source slightly enriched in incompatible elements in the spinel stability field. The geochemical features of Njimom dykes (in particular the dykes that intrude the granites) are similar to those of Paleozoic and Mesozoic dykes recorded in the southern continental part of the Cameroon Volcanic Line, suggesting multiple reactivations of pre-existing fractures that resulted in the fragmentation of western Gondwana and the opening of the South Atlantic Ocean. Article in Journal/Newspaper South Atlantic Ocean Ocean Island IRIS Università degli Studi di Napoli Federico II Geosciences 12 1 12 |
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IRIS Università degli Studi di Napoli Federico II |
op_collection_id |
ftunivnapoliiris |
language |
English |
description |
In the western Cameroon, crop out several dyke swarms of Paleozoic-Mesozoic age. These dykes intrude the Precambrian basement in the southern continental part of the Cretaceous Cameroon Volcanic Line. In the Njimom area, two groups of mafic dykes that crosscut the Neoproterozoic basement rocks have been observed. A first group intrudes the mylonites whereas the second group intrudes the granites. The dykes are alkaline basalts and hawaiites. The mineralogical assemblage of both groups of dykes consists of plagioclase, clinopyroxene, altered olivine, and opaque oxides. The dykes that cross-cut the Precambrian mylonitic gneisses show moderate TiO2 (1.7-2.0 wt.%), low MgO (4.4-7.1 wt.%), and compatible trace element concentrations (e.g., Cr = 70-180 ppm; Ni = 30-110 ppm). The dykes that intrude the granites have TiO2 contents between 2.3 and 2.5 wt.% and moderate compatible trace element concentrations (e.g., Cr = 260-280 ppm; Ni = 170-230 ppm). MgO varies from 5.9 to 9.2 wt.%. All mafic dykes are enriched in light lanthanide element and show moderate Zr/Nb and high Zr/Y, Nb/Yb, and Ti/V ratios similar to those of average ocean island basalt (OIB)-type magmas. Some dykes that intrude the mylonites show evidence of contamination by continental crust. The composition of the clinopyroxenes of the dykes that intrude the mylonites clearly indicate different and unrelated parental magmas from dykes that intrude the granites. Contents and fractionation of the least and the most incompatible elements suggest low degrees of partial melting (3-5%) of heterogeneous source slightly enriched in incompatible elements in the spinel stability field. The geochemical features of Njimom dykes (in particular the dykes that intrude the granites) are similar to those of Paleozoic and Mesozoic dykes recorded in the southern continental part of the Cameroon Volcanic Line, suggesting multiple reactivations of pre-existing fractures that resulted in the fragmentation of western Gondwana and the opening of the South Atlantic Ocean. |
author2 |
Keutchafo, Noel-Aimee, Kouamo Simeni, Nicole Armelle, Wambo Nforba, Brillant, Kandzi Noucoucouk, Agathe, Arrissa Sonmo, Josiane, Demlabin Tchaptchet, Depesquidoux, Tchato Tchouankoue, Jean, Pierre Cucciniello, Ciro |
format |
Article in Journal/Newspaper |
author |
Keutchafo Noel-Aimee Kouamo Simeni Nicole Armelle Wambo Nforba Brillant Kandzi Noucoucouk Agathe Arrissa Sonmo Josiane Demlabin Tchaptchet Depesquidoux Tchato Tchouankoue Jean Pierre Cucciniello Ciro |
spellingShingle |
Keutchafo Noel-Aimee Kouamo Simeni Nicole Armelle Wambo Nforba Brillant Kandzi Noucoucouk Agathe Arrissa Sonmo Josiane Demlabin Tchaptchet Depesquidoux Tchato Tchouankoue Jean Pierre Cucciniello Ciro Petrology of Mafic Dykes from the Njimom Area (West-Cameroon): A Contribution to the Characterization of Late Paleozoic and Mesozoic Magmatism in the Southern Continental Part of the Cameroon Volcanic Line |
author_facet |
Keutchafo Noel-Aimee Kouamo Simeni Nicole Armelle Wambo Nforba Brillant Kandzi Noucoucouk Agathe Arrissa Sonmo Josiane Demlabin Tchaptchet Depesquidoux Tchato Tchouankoue Jean Pierre Cucciniello Ciro |
author_sort |
Keutchafo |
title |
Petrology of Mafic Dykes from the Njimom Area (West-Cameroon): A Contribution to the Characterization of Late Paleozoic and Mesozoic Magmatism in the Southern Continental Part of the Cameroon Volcanic Line |
title_short |
Petrology of Mafic Dykes from the Njimom Area (West-Cameroon): A Contribution to the Characterization of Late Paleozoic and Mesozoic Magmatism in the Southern Continental Part of the Cameroon Volcanic Line |
title_full |
Petrology of Mafic Dykes from the Njimom Area (West-Cameroon): A Contribution to the Characterization of Late Paleozoic and Mesozoic Magmatism in the Southern Continental Part of the Cameroon Volcanic Line |
title_fullStr |
Petrology of Mafic Dykes from the Njimom Area (West-Cameroon): A Contribution to the Characterization of Late Paleozoic and Mesozoic Magmatism in the Southern Continental Part of the Cameroon Volcanic Line |
title_full_unstemmed |
Petrology of Mafic Dykes from the Njimom Area (West-Cameroon): A Contribution to the Characterization of Late Paleozoic and Mesozoic Magmatism in the Southern Continental Part of the Cameroon Volcanic Line |
title_sort |
petrology of mafic dykes from the njimom area (west-cameroon): a contribution to the characterization of late paleozoic and mesozoic magmatism in the southern continental part of the cameroon volcanic line |
publishDate |
2022 |
url |
http://hdl.handle.net/11588/876812 https://doi.org/10.3390/geosciences12010012 |
genre |
South Atlantic Ocean Ocean Island |
genre_facet |
South Atlantic Ocean Ocean Island |
op_relation |
info:eu-repo/semantics/altIdentifier/wos/WOS:000747156200001 volume:12 journal:GEOSCIENCES http://hdl.handle.net/11588/876812 doi:10.3390/geosciences12010012 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85122686630 |
op_doi |
https://doi.org/10.3390/geosciences12010012 |
container_title |
Geosciences |
container_volume |
12 |
container_issue |
1 |
container_start_page |
12 |
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1802650137529417728 |