Chemistry of siliciclastic and volcanoclastic sediments of DSDP Site 47-397 ...

• Main Authors: De Ros, L F, Al-Aasm, Ihsan S
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 1997
• Subjects: Composite Core; Leg47; Glomar Challenger; Deep Sea Drilling Project DSDP; North Atlantic
• Online Access: https://dx.doi.org/10.1594/pangaea.763435; https://doi.pangaea.de/10.1594/PANGAEA.763435

The Lower Cretaceous and Miocene sequences of the NW African passive continental margin consist of siliciclastic, volcaniclastic and hybrid sediments. These sediments contain a variety of diagenetic carbonates associated with zeolites, smectite clays and pyrite, reflecting the detrital mineralogical composition and conditions which prevailed during opening of the North Atlantic. In the Lower Cretaceous siliciclastic sediments, siderite (-6 per mil to +0.7per mil d18O PDB, -19.6 per mil to +0.6 per mil d13C PDB) was precipitated as thin layers and nodules from modified marine porewaters with input of dissolved carbon from the alteration of organic matter. Microcrystalline dolomite layers, lenses, nodules and disseminated crystals (-3.0 per mil to +2.5 per mil d18O PDB, -7.2 per mil to +4.9 per mil d13C PDB) predominate in slump and debris-flow deposits within the Lower Miocene sequence. During the opening of the Atlantic, volcanic activity in the Canary Islands area resulted in input of volcaniclastic ... : Supplement to: De Ros, L F; Al-Aasm, Ihsan S (1997): Diagenesis of siliciclastic and volcaniclastic sediments in the Cretaceous and Miocene sequences of the NW African margin (DSDP Leg 47A, Site 397). Sedimentary Geology, 112(1-2), 137-156 ...