Sedimentology and organic geochemistry of superficial deposits in Nador Lagoon (northeastern Morocco)

The Nador lagoon is situated at the eastern end of the Moroccan Rift along the Mediterranean coast. The superficial deposits are characterised by three types of litho-facies: sand, clay-sand and clay-silt-sand. The clay minerals show a homogeneous distribution with abundant illite and, in decreasing order, kaolinite, chlorite and smectite. The highest organic matter content does not exceed 10%. Organic C, total N, humic components analysis and "Rock-Eval" pyrolysis characterise the organic matter, compared to the superficial sediments. Most of the organic matter occurs as humic-acid and humin. Its distribution is controlled by the physicochemical conditions and by the importance and composition of the detrital inputs. (C) 1998 Elsevier Science Limited.