The Nador lagoon is one of the most important ports on the coast of Morocco, and the second lagoon in North Africa by extension (1115Km 2 ). The lagoon is bordered to the north-west by the volcanic products of the Gourougou volcano complex (887 m asl) and south-east by the Jurassic carbonate succession of marine environment belonging to the Complex of Kebdana (932 m asl); the rest of the area around the lagoon is flat and is characterized by arenaceous-pelitic deposits linked to the Miocene and Quaternary magmatic activities. The rocks outcropping in the hinterland are generally characterized by low concentrations of metals, and are no exception most of the volcanic rocks of the Gourougou Complex, constituted mainly by latitic tuffs and trachytes, and rare basalts and andesite of the promontory of Atalayoum that are not volumetrically significant. A natural potentially impacting source of heavy metals is located in the northwestern part of the lagoon, where outcrops skarn with magnetite mineralization, widely exploited since ancient times (EL ALAMI et alii, 1998; EL RHAZI & HAYASHI, 2002; GILLA et alii, 2004). To fully describe the quality of Nador lagoon sediments, 49 samples along the banks and on the bottom of the lagoon were gathered and their distribution was analysed and compared with the patterns of water circulation in the lagoon. The samples were subjected to petrographic and geochemical characterization by x-ray Fluorescence (XRF) by means of an ARL Advant X Spectrometer model. Furthermore, data distribution was obtained using GIS tools (ArcGis software, version 9.3) and thematic maps were created. The data showed that, despite the prevalence of contributions from the Miocene-Quaternary sedimentary sequences, characterized by low content of heavy metals, the samples contained high quantities of heavy metals, evidencing diffuse human related pollution problems. © 2012 Società Geologica Italiana, Roma.
The lagoon of Nador (Morocco): Geochemical and petrographic analysis of sediments and environmental conditions
MARIN, Emanuela;MARROCCHINO, Elena;VACCARO, Carmela
2012
Abstract
The Nador lagoon is one of the most important ports on the coast of Morocco, and the second lagoon in North Africa by extension (1115Km 2 ). The lagoon is bordered to the north-west by the volcanic products of the Gourougou volcano complex (887 m asl) and south-east by the Jurassic carbonate succession of marine environment belonging to the Complex of Kebdana (932 m asl); the rest of the area around the lagoon is flat and is characterized by arenaceous-pelitic deposits linked to the Miocene and Quaternary magmatic activities. The rocks outcropping in the hinterland are generally characterized by low concentrations of metals, and are no exception most of the volcanic rocks of the Gourougou Complex, constituted mainly by latitic tuffs and trachytes, and rare basalts and andesite of the promontory of Atalayoum that are not volumetrically significant. A natural potentially impacting source of heavy metals is located in the northwestern part of the lagoon, where outcrops skarn with magnetite mineralization, widely exploited since ancient times (EL ALAMI et alii, 1998; EL RHAZI & HAYASHI, 2002; GILLA et alii, 2004). To fully describe the quality of Nador lagoon sediments, 49 samples along the banks and on the bottom of the lagoon were gathered and their distribution was analysed and compared with the patterns of water circulation in the lagoon. The samples were subjected to petrographic and geochemical characterization by x-ray Fluorescence (XRF) by means of an ARL Advant X Spectrometer model. Furthermore, data distribution was obtained using GIS tools (ArcGis software, version 9.3) and thematic maps were created. The data showed that, despite the prevalence of contributions from the Miocene-Quaternary sedimentary sequences, characterized by low content of heavy metals, the samples contained high quantities of heavy metals, evidencing diffuse human related pollution problems. © 2012 Società Geologica Italiana, Roma.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
