Annotated record of the detailed examination of Mn deposits from DSDP Leg 1 (Holes 4 and 7A)

• Main Authors: Beall, A O, Fischer, A G
• Format: Dataset
• Language: English
• Published: PANGAEA 1969
• Subjects: 1-4; 1-7A; Comment; Deep Sea Drilling Project; Deposit type; DEPTH; sediment/rock; Description; DRILL; Drilling/drill rig; DSDP; Event label; File name; Glomar Challenger; Identification; Leg1; NOAA and MMS Marine Minerals Geochemical Database; NOAA-MMS; North Atlantic/BASIN; North Atlantic/CONT RISE; Position; Quantity of deposit; Sample code/label; Sediment type; Size; Substrate type; Uniform resource locator/link to image; Visual description; North Atlantic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.872605; https://doi.org/10.1594/PANGAEA.872605

Visual examination of the cores and microscopic examination of smear slides of the wide variety of sediments cored on Leg 1 revealed an equal range of particle origins, modes of transport, and manner of deposition. Brown deep-sea clays characterize the uppermost (Pliocene-Pleistocene) sediments of the Atlantic sites, and red deep-sea clay was cored below Middle Eocene sediments at Site 7. The main mineral constituents are clay minerals and quartz. The color results mainly from iron and manganese minerals. Manganese oxides are present in small nodules in theses red clays. The X radiographs of Site 4 and Site 7 commonly show a distinct granular texture, presumably because of the X-ray opaque limonite and pyrite grains. For Site 4 they also show larger ferruginous and possibly manganiferous nodules, some of which appear to be mineralized pumice fragments. With certain exceptions, the general composition of the brown and red clays cored on Leg 1 (the presence of much kaolinite and quartz, and scarcity of zeolite) suggests a largely terrigenous origin.