LITHOGEOCHIMIE DES SEDIMENTS ...
LITHOGEOCHIMIE DES SEDIMENTS DE PLATE-FORME DEPOSES AU SUD DU MASSIF DU BRABANT (BELGIQUE) PENDANT LE MESODEVONIEN ET LE FRASNIEN
L. DejongheMemoirs of the GSB n°23 - 1987
ABSTRACT.
In order to precise the geochemical evolution of the platform sediments deposited south of the Brabant massif during the Mesodevonian and the Frasnian, a lithogeochemical strategic prospection has been undertaken at the Geological Survey of Belgium. This one has been realized from 1980 to 1984, mainly into the Verviers synclinorium. On the whole, 1133 samples from 25 localities (outcrops and drillholes) have been analyzed for 27 elements. For each section, the results have been plotted against the stratigraphical column. It has permitted the visualization of the evolution of the geochemical background and the characterization of anomalous stratigraphical levels. Lastly, the establishment of diagrams of binary correlations has confirm the lithological control of some of the elements. Then, in the case of the background samples, and for some populations selected on the base of the age and the nature of the country rocks, various parameters of distribution have been calculated as well as the relevant matrix of correlation coefficient. A treatment of all the data by factor analysis has also been realized in complement of the others statistical treatments. Lastly, for alI the lithostratigraphical formations and for the main types of rocks, the backgrounds (geometric means) have been calculated into each locality and mapped with the aim to define eventual regional geochemical gradients.
