U/pb dating of precambrian rocks from northern cameroon, orogenic evolution and chronology of the pan-african belt of central africa

1987 ◽  
Vol 37 (1) ◽  
pp. 71-87 ◽  
Author(s):  
S.F. Toteu ◽  
A. Michard ◽  
J.M. Bertrand ◽  
G. Rocci
Keyword(s):  
Central Africa ◽  
Precambrian Rocks ◽  
Pan African ◽  
Northern Cameroon

Pre-Katangan geochronology of Zambia and adjacent parts of Central Africa

1968 ◽  
Vol 5 (3) ◽  
pp. 621-628 ◽  
Author(s):  
J. R. Vail ◽  
N. J. Snelling ◽  
D. C. Rex
Keyword(s):  
Lake Tanganyika ◽  
Central Africa ◽  
New Age ◽  
Orogenic Belt ◽  
Eastern Africa ◽  
Sedimentary Sequence ◽  
Precambrian Rocks ◽  
Late Precambrian ◽  
Orogenic Belts ◽  
Age Determinations

The significance of new age determinations on pre-Katangan (Late Precambrian) rocks and minerals from Zambia and adjacent parts of Tanzania and Rhodesia is discussed. In northwestern Rhodesia, the Lomagundi-Piriwiri sediments were deposited between 2500 and 2000 m.y. ago and were folded along meridional trends at circa 1940 m.y. A later episode of folding and metamorphism along similar trends occurred about 1700 m.y. ago, but only affected the western part of the sedimentary sequence (the Piriwiri Series). This latter date is comparable to that which appears to characterize the Tumbide trend, a N- to NE-trending fold system, in Zambia.In Zambia the Tumbide trend is the oldest tectonic episode preserved in the basement and is found only in isolated blocks and cores into which later tectonisms have not penetrated. The dominant pre-Katangan tectonism is represented by the NE to ENE Irumide trend. Such tectonic trends are particularly well developed in the Irumide Orogenic Belt of northern Zambia and adjacent Tanzania. Age determinations set a younger limit of circa 900 m.y. to this trend and the existence of an Irumide Cycle between about 1600 and 900 m.y. is suggested. The possibility that the relatively unmetamorphosed sediments of the Upper Plateau Series and Abercorn Sandstones at the southern end of Lake Tanganyika, the Mafingi Series of northern Malawi, and the Konse Series of Tanzania, represent near-contemporaneous platform deposition associated with the Irumide belt is considered.From this and other recent studies the distribution of orogenic belts in central and eastern Africa can be revised and a number of features of their pattern and inter-relationships noted.

scholarly journals Genome-wide ancestry of 17th-century enslaved Africans from the Caribbean

2015 ◽  
Vol 112 (12) ◽  
pp. 3669-3673 ◽  
Author(s):  
Hannes Schroeder ◽  
María C. Ávila-Arcos ◽  
Anna-Sapfo Malaspinas ◽  
G. David Poznik ◽  
Marcela Sandoval-Velasco ◽  
...  
Keyword(s):  
Direct Evidence ◽  
Central Africa ◽  
Caribbean Island ◽  
Dna Analyses ◽  
Genome Wide ◽  
Saint Martin ◽  
Genetic Origins ◽  
Northern Cameroon ◽  
The Caribbean ◽  
Source Populations

Between 1500 and 1850, more than 12 million enslaved Africans were transported to the New World. The vast majority were shipped from West and West-Central Africa, but their precise origins are largely unknown. We used genome-wide ancient DNA analyses to investigate the genetic origins of three enslaved Africans whose remains were recovered on the Caribbean island of Saint Martin. We trace their origins to distinct subcontinental source populations within Africa, including Bantu-speaking groups from northern Cameroon and non-Bantu speakers living in present-day Nigeria and Ghana. To our knowledge, these findings provide the first direct evidence for the ethnic origins of enslaved Africans, at a time for which historical records are scarce, and demonstrate that genomic data provide another type of record that can shed new light on long-standing historical questions.

Outline of the geochronology and tectonic units of the basement complex of northeast Africa

1976 ◽  
Vol 350 (1660) ◽  
pp. 127-141 ◽  
Keyword(s):  
Regional Metamorphism ◽  
Central Africa ◽  
Geological Mapping ◽  
Fold Belt ◽  
Basement Complex ◽  
Southern Sudan ◽  
Pan African ◽  
Mozambique Belt ◽  
Unknown Area ◽  
Eastern Uganda

Results of new geological mapping with the help of air and satellite photo­graphy in Sudan together with information from adjacent territories has enabled a map to be drawn showing the dominant basement tectonic trends in a previously geologically unknown area. Over 100 age deter­minations, including 25 unpublished analyses, allow the recognition of Eburnian age events in Central Africa Republic and southeast Libya similar to the 1950 million year (Ma) old Ruwenzori Belt in Uganda and similar events in Zaire. A northeast trending fold belt is recognized in Central Africa, western Sudan and southeast Egypt in which 1000 Ma ages are found. The Pan African age Mozambique belt truncates older structures in eastern Uganda and southern Sudan but is covered by a greenschist volcanic assemblage along the Red Sea coast in which 550 ± 150 Ma old granites and regional metamorphism occur.

scholarly journals Petrology and Geochemistry of Hama Koussou Dolerite Dyke Swarms (North Cameroon, Central Africa)

2019 ◽  
pp. 1-19
Author(s):  
Fagny Mefire Aminatou ◽  
Bardintzeff Jacques-Marie ◽  
Nkouandou Oumarou Faarouk ◽  
Lika Gbeleng Thomas D’Aquin ◽  
Ngougoure Mouansie Samira
Keyword(s):  
Central Africa ◽  
Alkali Feldspar ◽  
Rift System ◽  
Spinel Lherzolite ◽  
Dolerite Dyke ◽  
Pan African ◽  
Tholeiite Basalt ◽  
Petrology And Geochemistry ◽  
African Rift ◽  
Geochemical Analyses

The Pan African granitoid basement of Hama Koussou Cretaceous half basin in North Cameroun (Central Africa) is transected by near N-S, NE-SW and ENE-WSW giant doleritic dykes trending along the same Pan African directions. Hama Koussou dolerites are compliant with the regional distension that occurred after the Pan African basement consolidation prior to the development of West and Central African Rift System at Late Jurassic-Early Cretaceous times. Studied lavas are composed of large clinopyroxene oïkocrysts, plagioclase and alkali feldspar laths and oxides phenocrysts exhibiting ophitic, sub-ophitic and intercertal textures. Microprobe chemical analyses carry out on the main mineral phases show that clinopyroxenes are diopside and augite, plagioclases are labradorite, andesine, oligoclase and albite and alkali feldspars are mainly sanidine with a few percent of orthoclase. ICP-MS and ICP-AES geochemical analyses of Hama Koussou lavas exhibit basalt, basaltic trachyandesite and trachyandesite compositions of continental tholeiite features. Tholeiite basalts of Hama Koussou are the results of high partial melting of E-MORB mantle source of spinel lherzolite composition, located at 65-55 km depth. More evolved tholeiite lavas of Hama Koussou basin are the products of tholeiite basalt differentiation trough assimilation and fractional crystallization coupled with fluids circulation.

Sign in / Sign up

Export Citation Format

Share Document