Secondary mineral assemblages in a volcanic sequence of ODP Hole 104-642E

• Main Authors: Desprairies, Alain, Tremblay, P, Laloy, C
• Format: Other/Unknown Material
• Language: English
• Published: PANGAEA 1989
• Subjects: 104-642E; 81-553A; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Joides Resolution; Leg104; Leg81; North Atlantic/PLATEAU; Norwegian Sea; Ocean Drilling Program; ODP; North Atlantic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.737391; https://doi.org/10.1594/PANGAEA.737391

Mineralogical and geochemical analyses of alteration products from upper and lower volcanic series recovered during ODP Leg 104 reveal variations both in composition and order of crystallization of clay minerals vesicles and voids filling and replacing glass. These results provide information about successive alteration stages of rocks and interlayered volcaniclastic sediments. The first stage, related to initial basalt-seawater interaction, is characterized by development of Fe-smectites, especially Fe-rich saponite. A second stage of intermittently superimposed subaerial weathering is marked by iron-oxides-halloysite-kaolinite formation. The third episode, interpreted as hydrothermal on the basis of O-isotopic data, is defined by postburial coprecipitation of Fe-poor, Mg-rich saponite and celadonite. A distinct final and pervasive hydrothermal stage, occurring mainly in the lower series and dominated by Al-smectites-zeolites assemblage, indicates changes toward a more reducing alteration environment.