A cross section of the Namama Thrust Belt (Mozambique)

Cadoppi, Paola; Costa, Mario; Sacchi, Rosalino

doi:10.1016/0899-5362(87)90090-x

Cited by 22 publications

(19 citation statements)

References 15 publications

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“…Inrepele Formation (CADOP-PI et al, 1987) and polygenic conglomerates are the signs of the effect of this tectonic event on the sedimentation process. The 'isochron' provided by the Mamala Formation (1003 + 39 Ma) and the regression line of the Rio Molocue Group (959 +_ 159 Ma) probably date the peak of metamorphism that followed the peak of deformation in the Namama Belt (CADOPPI et al, 1987). Emplacement of 'type two' domal granites followed.…”

Section: Discussionmentioning

confidence: 97%

“…Heating has been tentatively ascribed by CADOPPI et al (1987) to mafic underplating in the absence of orogenic development and hence thickening of the crust. The question of the origin of this heating indeed, is one of wider implication and is by no means confined to Africa.…”

Section: Discussionmentioning

confidence: 98%

“…All of these rocks, except (3), underwent the 'Namama' (Lurian) tectonism, during which they developed a foliation (F2) and a typical, stretching lineation with remarkably constant, E-W trend. On textural grounds, the 'Namama' fabric overprinted an older foliation (F1) in (1) and (4), but not in (2) (CADOPPI et al, 1987). Both in the basement and its cover, amphibolite-facies metamorphism overlasted deformation, and evolved towards a higher thermal gradient, as borne out by frequent growth of static, 'hot' assemblages (andradite + hedenbergite in gneisses, red biotite + garnet + sillimanite _+ staurolite + cordierite in schists).…”

Section: Geological Setting and Sample Descriptionmentioning

confidence: 98%

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Rb/Sr dating of the Upper Proterozoic basement of Zambesia, Mozambique

Costa¹,

Ferrara²,

Sacchi

et al. 1992

Geol Rundsch

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ZusammenfassungDas proterozoische Grundgebirge der Provinz Zambesi (Mosambique) befindet sich in der N/ihe des sfidlichen Endes des sogenannten Mozambique Belt. Rb/Sr Daten aus 66 Ganzgesteins-und einigen Mineralanalysen zeugen yon einer magmatischen und metamorphen Episode die sich dem ,,Kibaran" (ca. 1000 Ma) zuordnen lfigt, und wie sich im folgenden zeigt, hilfreich bei der Modellisierung der spritproterozoischen Entwicklung ist. Um 1100 bis 1050 Ma erfolgte ein prfiorogener kalkalkalischer Magmatismus, bestehend aus Graniten und Granodioriten, die heute deformiert vorliegen. Diese Phase wurde yon rhyolithischem Vulkanismus begleitet. Von 1000 bis 950 Ma folgte der H6hepunkt der Deformation und Metamorphose, begleitet yon einer bedeutenden 2. Generation posttektonischer Granite. Bedingt durch ein weiteres thermales Ereignis intrudierte die letzte Granit-und Pegmatitgeneration vor 500 bis 450 Ma.Im metamorphen Grundgebirge ist das Eduktalter vermutlich aufgrund der starken isotopischen Homogenisierung von Sr wfihrend der Kibara-Zeit nicht erhalten. Seine maximale Differentiationszeit vom Mantel mug vor 1600 Ma gewesen sein.Die sehr niedrigen Gehalte der initialen Sr-Isotopenverh/iltnisse lassen die Abwesenheit von archaischen Krustenvorl~ufern vermuten, und unterstfitzen die sehr junge, bis jetzt Prfi-Pan-Afrikanische Entwicklung des stidlichsten Mozambique Belts. AbstractThe Proterozoic basement of the Province of Zambezia (Mozambique) is located near the southern end of the so called Mozambique Belt. RbSr data derived from the analyses of 66 whole rocks and a few mineral samples bear witness of a magmatic and metamorphic episode referable to the 'Kibaran' (ca. 1000 Ma) and helped to model the lateProterozoic evolution as follows. At 1100-1050 Ma a pre-orogenic, calc-alkaline magmatism was responsible for the emplacement of now deformed granite and granodiorite. This phase was accompanied by rhyolitic volcanism. A subsequent peak of deformation and metamorphism occurred at 1000-950 Ma and was associated with a second generation of substantially post-tectonic granites. A thermal event resulting in the emplacement of a final generation of granites and pegmatites can be dated to around 500-450 Ma.The metamorphic basement has not preserved its protolith age, probably as a result of extensive isotopic homogeneization of Sr in Kibaran times. Its maximum time of differentiation from the mantle should be around 1600 Ma.The very low values of initial Sr isotopic ratios suggest the absence of Archean crustal precursors and support the rather young, yet pre-Pan-African evolution of the southernmost Mozambique Belt.

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 98%

Section: Geological Setting and Sample Descriptionmentioning

confidence: 98%

See 1 more Smart Citation

Rb/Sr dating of the Upper Proterozoic basement of Zambesia, Mozambique

Costa¹,

Ferrara²,

Sacchi

et al. 1992

Geol Rundsch

Self Cite

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“…O Grupo de Molócuè representa uma sequência de camada intermédiaria de rochas metapelítica, calc-silicato e félsica, de gnaisses metavolcânicas máfica e ultrámafica supracrustais e localmente cortadas por Namama Thrust Belt. O Suite do Culicui consiste de granitos migmatí-ticos a não migmatíticos e de gnaisses e leuco-granitos augen (Cadoppi et al 1987, Kröner et al 1997, Direção Nacional de Geologia & Council for Geoscience 2007.…”

Section: Geologia E Mineralizaçãounclassified

Mapeamento aero-geofísico de pegmatitos mineralizados na Província Pegmatítica de Alto Ligonha, no norte de Moçambique

Eberle

Daudi

Muiuane

et al. 2010

RBG

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Resumo No passado recente, uma extensa parte do território de Moçambique, foi coberta de levantamento aéreo de dados magnéticos e radiométricos de alta densidade. Desde assim, um valor, tem sido a preocupação da Direção Nacional de Geologia fazer a interpretação dos dados, acrescentando, assim,um valor adicional nos mapas aerogeofísicos para o uso das companhias mineiras. A Direção Nacional de Geologia (DNG) e a Universidade Eduardo Mondlane (UEM) num esforço conjunto com o Conselho de Geociência da Africa do Sul (CGS) fizeram o presente estudo dos campos pegmatíticos de Alto Ligonha, norte de Moçambique, dentro do Cinturão de Namama da era Meso-Proterozóico, para apoiar o sector de mineração da região. A integração de dados aerogeofisicos foi alcançada usando o alogaritmo média k aplicando a classificação não supervisionada dos dados obtida. A amostragem e avaliando por meio da análise discriminante para ganhar um critério de susceptibilidade da classificação obtida... A amostragem das concentrações de eTh e eK (em ppm) mais os dados da suscepetibilidade magnética aparente e da derivada vertical, resultaram num mapa de 850.000 vetores multivariados e um determinado número de classes. Este mapa ilustra claramente que há maior probabilidade dos pegmatitos mineralizados ocorrer nos afloramentos de gneisses anfibolíticos. A integração automatizada dos dados aero-geofísicos usando o alogaritmo média k, provou ser um método rápido, direto e efetivo para compilação de mapa integrado com valor adicionado. A experiência adquirida com o estudo dos pegmatitos de Alto Ligonha encoraja a adoção desta nova metodologia para aplicar em outros locais do Cinturão de Moçambique. Assim, este método faria parte integrante do processo de mapeamento em Moçambique.Palavras-chave: Aerogeofísica, integração de dados, classificação média k, análise discriminante, pegmatito, Cinturão de Moçambique. Abstract Airborne geophysical mapping of mineralized pegmatite in the Alto Ligonha pegmatite province, northern Mozambique.Major parts of Mozambique were recently flown to acquire high resolution airborne magnetic and radiometric data. Since then it has been the intent of the National Geology Directorate of Mozambique (DNG) to interpret these data generating value-added maps that are easier to use by the exploration and mining industries than mere airborne geophysical grid data and maps. DNG and Maputo-based EduardoMondlane University (UEM) entered a joint venture with the South African Council for Geoscience (CGS) to conduct a case study over the meso-Proterozoic Alto Ligonha pegmatite province in northern Mozambique to support the regional mining sector. Integration of the airborne geophysical data was achieved using the K-means algorithm for explorative unsupervised crisp clustering of the airborne geophysical data. Discriminant analysis was then used to obtain the degree of class membership of each sample previously classified by K-means. Prior to clustering, Th-and K-surface concentrations as well as apparent magnetic susceptibility and fi...

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“…600 Ma metasedimentary rocks of marine affinity (Cobue and Geci Groups: Melezhik et al 2006;Boyd et al 2010). In the southwest, the southern basement is dissected by the Namama Belt (Cadoppi et al 1987), a sinistral, steep, probably postcollisional shear zone (Macey et al 2010).…”

Section: Geological Backgroundmentioning

confidence: 99%

Postcollisional High-Grade Metamorphism, Orogenic Collapse, and Differential Cooling of the East African Orogen of Northeast Mozambique

Ueda

Jacobs²,

Thomas³

et al. 2012

The Journal of Geology

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A B S T R A C TThe postcollisional tectonic development of northeast Mozambique and subsequent cooling from high-temperature metamorphism is delineated with an extensive new set of U-Pb titanite, 40 Ar/ 39 Ar hornblende, and 40 Ar/ 39 Ar mica analyses. The complex data suggest a polyphase metamorphic history from the late Neoproterozoic to the Ordovician within the East African-Antarctic Orogen (EAAO), with marked differences between the major constituent blocks. In all the data sets, samples from the basement south of the Lú rio Belt show generally younger ages than those from the north, resulting from a late metamorphic event and slow cooling between ca. 520 and 440 Ma. The ages north and south of the Lú rio Belt are consistently offset by ca. 30-70 Ma, a difference that is maintained and even appears to increase during cooling from very high temperatures to ca. 350ЊC. Based on the first-order assumption that all the ages are cooling ages, cooling rates in the south are estimated at ca. 7Њ-8ЊC/Ma, while those north of the Lú rio Belt are faster at ca. 16ЊC/Ma. The data are consistent with previous geochronological, petrographic, and field data and suggest a late high-temperature/low-pressure metamorphic event that affected only the basement rocks south of the Lú rio Belt and portions of the latter. This late metamorphism and subsequent delayed, slower cooling agree well with a model of elevated heat flow following lithosphere delamination in the southern part of the orogen, which also explains the observed widespread granitoid magmatism, migmatization, and renewed deformation in the southern basement.

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A cross section of the Namama Thrust Belt (Mozambique)

Cited by 22 publications

References 15 publications

Rb/Sr dating of the Upper Proterozoic basement of Zambesia, Mozambique

Rb/Sr dating of the Upper Proterozoic basement of Zambesia, Mozambique

Mapeamento aero-geofísico de pegmatitos mineralizados na Província Pegmatítica de Alto Ligonha, no norte de Moçambique

Postcollisional High-Grade Metamorphism, Orogenic Collapse, and Differential Cooling of the East African Orogen of Northeast Mozambique

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