Mineralogy and diagenesis of slope sediments at DSDP Leg 84 holes
| Cobertura |
MEDIAN LATITUDE: 12.234857 * MEDIAN LONGITUDE: -89.833977 * SOUTH-BOUND LATITUDE: 9.728200 * WEST-BOUND LONGITUDE: -91.392800 * NORTH-BOUND LATITUDE: 13.285300 * EAST-BOUND LONGITUDE: -86.090700 * DATE/TIME START: 1982-01-13T00:00:00 * DATE/TIME END: 1982-02-17T00:00:00 |
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| Data(s) |
10/12/1985
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| Resumo |
The distribution and composition of minerals in the silt and clay fraction of the fine-grained slope sediments were examined. Special interest was focused on diagenesis. The results are listed as follows. (1) Smectite, andesitic Plagioclase, quartz, and low-Mg calcite are the main mineral components of the sediment. Authigenic dolomite was observed in the weathering zones of serpentinites, together with aragonite, as well as in clayey silt. (2) The mineralogy and geochemistry of the sediments is analogous to that of the andesitic rocks of Costa Rica and Guatemala. (3) Unstable components like volcanic glass, amphiboles, and pyroxenes show increasing etching with depth. (4) The diagenetic alteration of opal-A skeletons from etching pits and replacement by opal-CT to replacement by chalcedony as a final stage corresponds to the typical opal diagenesis. (5) Clinoptilolite is the stable zeolite mineral according to mineral stability fields; its neoformation is well documented. (6) The early diagenesis of smectites is shown by an increase of crystallinity with depth. Only the smectites in the oldest sediments (Oligocene and early Eocene) contain nonexpanding illite layers. |
| Formato |
application/zip, 5 datasets |
| Identificador |
https://doi.pangaea.de/10.1594/PANGAEA.803841 doi:10.1594/PANGAEA.803841 |
| Idioma(s) |
en |
| Publicador |
PANGAEA |
| Direitos |
CC-BY: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted |
| Fonte |
Supplement to: Helm, Roger (1985): Mineralogy and diagenesis of slope sediments offshore Guatemala and Costa Rica, Deep Sea Drilling Project Leg 84. In: von Heune, R; Aubouin, J; et al. (eds.), Initial Reports of the Deep Sea Drilling Project, Washington (U.S. Govt. Printing Office), 84, 571-594, doi:10.2973/dsdp.proc.84.115.1985 |
| Palavras-Chave | ##1; #2; - = no chlorite; + = chlorite identified after heating to 500°C by d-001 or d-002; + + = chlorite identified by d-003 in untreated samples; + + + = chlorite is the main 7-A mineral; 7Å; Al2O3; Aluminium oxide; A mineral composition of Mg0.69 means 0.69 mole % MgCO3 in the calcite. Ca55 means 55 mole % CaCO3 in the dolomite lattice; Ba; Barium; Boundary layer, lower; Boundary layer, upper; Bound low; Bound upp; Calcium oxide; CaO; Chl; Chlorine; Chlorite; Chromium; Cl; Clasts; Co; Cobalt; Comment; Copper; Cr; Cu; Deep Sea Drilling Project; Depth; DEPTH, sediment/rock; Description; Dol; Dolomite; DSDP; Epoch; Event; Fe2O3; Fossils; Ill; Illite; Iron oxide, Fe2O3; K2O; Label; Lattice order; Magnesium oxide; Manganese; Manganese oxide; mbsf; MgO; Min assembl; Mineral; Mineral assemblage; Mineral name; Minerals; Mn; MnO; Na2O; Nd; Neodymium; Ni; Nickel; Nonexpandable, maximum; Nonexpandable, mean/minimum; ODP sample designation; P2O5; Phosphorus oxide; Potassium oxide; Rb; Ref ind; Refractive index; Rubidium; S; Sample code/label; see reference(s); Silicon dioxide; SiO2; Sme; Smectite; Sodium oxide; Sr; Sr/Ca; Strontium; Strontium/Calcium ratio; Sulphur, total; Swelling (Å), (060); Swelling (Å), glycolated (001); Swelling (Å), original (001); TiO2; Titanium oxide; Total iron; V; Vanadium; X-ray diffraction (XRD); Y; Yttrium; Zinc; Zirconium; Zn; Zr |
| Tipo |
Dataset |
