Isotope ratios of smectites, calcites and whole rocks from DSDP Legs 51 and 52, Atlantic Ocean

• Main Authors: Staudigel, Hubert, Muehlenbachs, Karlis, Richardson, Stephen H, Hart, Stanley R
• Format: Dataset
• Language: English
• Published: PANGAEA 1981
• Subjects: 51-417_Site; 51-417A; 52-417D; 52-418A; 53-418A; COMPCORE; Composite Core; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Leg51; Leg52; Leg53; North Atlantic/CONT RISE; North Atlantic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.667373; https://doi.org/10.1594/PANGAEA.667373

Delta180 and 87Sr/86Sr isotopic data from smectites, calcites, and whole rocks, together with published isotopic age determinations, alkali element concentration data and petrographic observations suggest a sequential model of ocean floor alteration. The early stage lasts about 3 m.y. and is characterized by palagonite and smectite formation, and solutions with a large basaltic component, increasing with temperature which varies from 15° to 80° C at DSDP site 418A. Most carbonates are deposited after this stage from solutions with a negligible basaltic Sr component and temperatures of 15° to 40° C. Water of seawater Sr and O isotopic composition is shown to percolate to at least 500 m into the basaltic basement. No evidence was found for continuing exchange of strontium or oxygen after 3 m.y.