Início | AHU | IICT
IICT7699576994<>76996
TagInd1Ind2CodeValue
0010076995
00520120823034416.0
035 a0024476
035 a0031245
035 a0075325
100 a20050309 k y0pory0103 ba
1010 aeng
102 aPT
2001 aSynopsis of Lunda geology, NE Angola
eimplications for diamond exploration
fEurico Pereira, José Rodrigues, Bernardo Reis
330 aIn the present synthesis, the geology of Lunda (NE Angola) is presented and discussed with the objective of providing a better understanding of the regional occurrence of primary and secondary diamond deposits. The huge regional diamondiferous potential is viewed in a global perspective, firstly based on the edification of the Congo Craton from an Archaean nucleous, till several mobile belts accreted sucessively to that core. In this cranotic block the geothermal gradient variation and the stability curve of diamond are determinant both in the genesis and the transportation of this precious mineral up to the surface.
330 aFollowing this, we analyse the tectonosedimentary evolution of the Congo Basin, an enourmous depression in central Africa, where the deposition of thick sedimentary sequences is a consequence of an endorheic drainage, that begins in the upper Palaeozoic and has its maxium expression in the Meso-Cenozoic. The sedimentological processes, essentially terrigenous and continental, is controlled by the pre-Atlantic deformation of the Congo Craton and reaches a critical point with the opening of the South Atlantic since the Cretaceous. The oceanic rifting produces important tectonic consequences in the African plate, reactivating structures from previous orogenic cycles. These structures exerted the control of kimberlite emplacement and associated alkaline ring structures.
330 aThe sedimentological analysis and the lithostratigraphic definition of post-kimberlites sedimentary units are emphasised: Kwango Group, Kalahari Group and Quaternary deposits, formed in successive erosion/deposition cycles with consequence reworking of its diamond content. These are viewed with an exploration and economical potential.
330 aFinally, a critical balance is made and the economical consequences of these vast diamondiferous resources are discussed based on future economic perspectives.
461 aComunicações do Instituto Geológico e Mineiro. - Tomo 90 (2003), p. 189-212
efigs., tabelas
606 aGeologia
606 aReservas
606 aDiamantes
606 aAngola
700 1aPereira
bEurico
701 1aRodrigues
bJosé
701 1aReis
bBernardo
801 0aPT
bIICT
c20050309
gRPC
930 dCDI P65
93120050309
935k
936y
9370
938ba
955 c20070416
dADMIN
n3
966 b23/08/2012
lMLITD
sCDI P65
w2089871648
970 aMF
UMList: 0,1078 sec