28. Mineralogy and geochemistry of alteration products in leg 81 basalts 1

• Main Authors: Desprairies, A., Bonnot-Courtois, C., Jehanno, C., Vernhet, S., Joron, J.L., Sue, Laboratoire
• Other Authors: Université Paris-Sud - Paris 11 (UP11), Centre des Faibles Radioactivités, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Pierre Süe (LPS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
• Format: Book Part
• Language: English
• Published: HAL CCSD 1984
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Northeast Atlantic
• Online Access: https://hal.archives-ouvertes.fr/hal-03516507; https://hal.archives-ouvertes.fr/hal-03516507/document; https://hal.archives-ouvertes.fr/hal-03516507/file/dsdp81_28%283%29.pdf; https://doi.org/10.2973/dsdp.proc.81.128.1984

International audience Alteration products of basalts from the four holes drilled during Leg 81 were studied and found to be characterized by the widespread occurrence of trioctahedral clay minerals (Mg smectite to chlorite). In some cases zeolites (analcite, chabazite) are associated with the saponite. A more oxidizing stage is marked by a saponite-celadonite association, presenting the geochemical characteristics of hydrothermal processes. Later stages of alteration are represented by palagonitization and subaerial weathering at two sites. These different alteration processes of basalts from Leg 81 record the paleoenvironment during the first opening stages of the Northeast Atlantic Ocean in the Paleocene-Eocene periods.