(Table 2) Chemical composition of phosphates from the Namibian and Chilean shelves

• Main Authors: Baturin, Gleb N, Dubinchuk, V T
• Format: Dataset
• Language: English
• Published: PANGAEA 2005
• Subjects: AK4-250; Akademik Kurchatov; AKU4; Aluminium oxide; Archive of Ocean Data; ARCOD; Area/locality; Atlantic Ocean; Calcium oxide; Carbon; organic; total; Carbon analyser AN-7529; 7560; Carbon dioxide; Cerium; Chile shelf; Dredge; DRG; Elevation of event; Epoch; Event label; Grab; Inductively coupled plasma - mass spectrometry (ICP-MS); Iron oxide; Fe2O3; Lanthanum; Latitude of event; Longitude of event; Magnesium oxide; Manganese oxide; Mikhail Lomonosov; ML26; ML26_2048; Namibian shelf; Phosphorus oxide; PL4-12; Potassium oxide; Sample type; Silicon dioxide; Sodium oxide; Thorium; Titanium dioxide; Uranium; Yttrium; Pacific
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.763666; https://doi.org/10.1594/PANGAEA.763666

This study on phosphorites of different compositions and ages from shelf sediments and seamounts of the Pacific Ocean by means of analytical electron microscopy showed that these phosphorites contain ultra-microscopic inclusions of authigenic minerals and, more rarely, of rare earth element (REE) minerals. In some of phosphorite samples of Pleistocene-Pliocene age from the Namibian shelf both kinds of minerals were found. Uranium minerals were represented by uraninite, coffinite, and ningioite; those of REE - by monazite, xenotime, and bastnesite, which points to their potential accumulation not only as isomorphous admixtures in calcium phosphate but also as independent mineral phases. Coexistence of the minerals noted in shelf phosphorites is caused by repeated changes in redox conditions during formation and then redeposition of phosphate concretions. Presence of uranium minerals in phosphorites from seamounts shows that during an initial step of formation of these phosphorites environment was rather suboxic or reductive than oxic.