Clay mineralogy of carbonate-rich sediments of ODP Leg 101 sites

• Main Author: Füchtbauer, Hans
• Format: Other/Unknown Material
• Language: English
• Published: PANGAEA 1988
• Subjects: 101-626B; 101-626C; 101-627A; 101-627B; DRILL; Drilling/drill rig; Joides Resolution; Leg101; North Atlantic Ocean; Ocean Drilling Program; ODP; North Atlantic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.742945; https://doi.org/10.1594/PANGAEA.742945

The insoluble residues of samples from ODP Sites 626 and 627 can be subdivided into four groups: (1) illite, 7 A minerals, quartz and feldspar; (2) smectite and zeolite (clinoptilolite); (3) palygorskite and in places sepiolite; and (4) glauconite and pyrite. Whereas group 1 is clearly terrigenous and group 4 authigenic, group 2 is most probably authigenic, as indicated by its abundance in samples with small insoluble residues and its appearance in SEM photographs. Group 3 is authigenic in Albian peritidal dolomite and possibly terrigenous in middle Miocene slumps and debris flows. Smectite crystallinity increases with age. This increase, however, is less pronounced in the Bahamian carbonate-rich samples than in the carbonate-poor silts south of Guatemala (DSDP Leg 84, Sites 569 and 570, the only comparable investigation) as far as can be judged from such a small number of samples.