Secondary minerals and geochemistry at DSDP Legs 68 and 69
Cobertura |
MEDIAN LATITUDE: 0.825493 * MEDIAN LONGITUDE: -53.963907 * SOUTH-BOUND LATITUDE: 0.000000 * WEST-BOUND LONGITUDE: -83.788300 * NORTH-BOUND LATITUDE: 1.920000 * EAST-BOUND LONGITUDE: 0.000000 * DATE/TIME START: 1979-07-08T00:00:00 * DATE/TIME END: 1979-10-07T00:00:00 |
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Data(s) |
09/07/1983
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Resumo |
Basalt samples recovered during DSDP Legs 68, 69, and 70 from a 550-meter-thick section in two holes near the Costa Rica Rift (Holes 501 and 504B) were found to contain the following secondary minerals: trioctahedral and dioctahedral smectite, chlorite, mixed-layer clays, talc, hematite, pyrite, foujasite, phillipsite, analcime, natrolite, thomsonite, gyrolite, aragonite, calcite, anhydrite, chalcocite, Fe-hydrosilicate, okenite, apophyllite, actinolite, cristobalite, quartz, and magnesite. A less positive identification of bismutite was made. A mineral rich in Mn and minerals with strong reflections at 12.9 Å and 3.20 Å remain unidentified. Trioctahedral smectite replaces glass and olivine in the basalt groundmass. The other secondary minerals occur in veins. The distribution of the secondary minerals in the basalt section shows both hydrothermal and oxidizing-nonoxidizing zonation. Most of the secondary minerals formed under alkaline, nonoxidizing conditions at temperatures up to 120° C. An acidic regime probably existed in the lowest portion of basalt. Oxidative diagenesis followed nonoxidative diagenesis in the upper part of the section. Oxidative diagenesis is characterized by the absence of celadonite, rare occurrences of dioctahedral smectite, and widespread hematite and phillipsite. |
Formato |
application/zip, 9 datasets |
Identificador |
https://doi.pangaea.de/10.1594/PANGAEA.816462 doi:10.1594/PANGAEA.816462 |
Idioma(s) |
en |
Publicador |
PANGAEA |
Direitos |
CC-BY: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted |
Fonte |
Supplement to: Kurnosov, Victor B; Kholodkevich, Igor V; Chubarov, Valerii M; Shevchenko, Alla Ya (1983): Secondary minerals in basalt from the Costa Rica Rift, Holes 501 and 504B, Deep Sea Drilling Project Legs 68, 69, and 70. In: Cann, JR; Langseth, MG; Honnorez, J; Von Herzen, RP; White, SM; et al. (eds.), Initial Reports of the Deep Sea Drilling Project (U.S. Govt. Printing Office), 69, 573-583, doi:10.2973/dsdp.proc.69.130.1983 |
Palavras-Chave | ## = Smectite and mixed-layer chlorite-montmorillonite; # = Trace of talc(?); <1 µm; 1 - 10 µm; 12.9A-min; 12.9 angstroem mineral; 3.2A-min; 3.2 angstroem mineral; 68-501; 69-504B; 69-505B; Act; Actinolite; Al2O3; Aluminium oxide; Analcite; Anh; Anhydrite; Anl; Apo; Apophyllite; Aragonite; Arg; Bismutite; Bulk; Cal; Calcite; Calcium oxide; CaO; Cct; Chalcocite; Chl; Chlorite; Color desc; Color description; Comment; Cristobalite; Crs; Deep Sea Drilling Project; Depth; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP; Electron microprobe; Event; Faujasite; Fe2O3; Fe hydrosilicate; Fe-hydrosilicate; FeO; Glomar Challenger; Gyrolite; Hem; Hematite, Fe2O3; Iron oxide, Fe2O3; Iron oxide, FeO; K2O; Leg68; Leg69; LOI; Loss on ignition; Magnesite; Magnesium oxide; Manganese oxide; MgO; Mgs; Mineral; Mineral name; Mn-mineral; MnO; Na2O; Natrolite; North Pacific/FLANK; North Pacific/GRABEN; Ntr; ODP sample designation; Okenite; Phillipsite; Php; Potassium oxide; Py; Pyrite; Quartz; Qz; Sample code/label; Sap; Saponite; Silicon dioxide; SiO2; Sme; Smectite; Sodium oxide; Thm; Thomsonite; TiO2; Titanium oxide; Total; Total iron; X-ray diffraction |
Tipo |
Dataset |