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Helm, Roger (1985): Mineralogy and diagenesis of slope sediments at DSDP Leg 84 holes [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.803841, Supplement to: Helm, R (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, https://doi.org/10.2973/dsdp.proc.84.115.1985

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Published: 1985 (exact date unknown) • DOI registered: 2013-01-10

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Abstract:
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.
Project(s):
Deep Sea Drilling Project (DSDP)
Coverage:
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
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
5 datasets

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Datasets listed in this publication series

  1. Helm, R (1985): (Table 2) Geochemistry at DSDP Leg 84 holes. https://doi.org/10.1594/PANGAEA.803837
  2. Helm, R (1985): (Table 5) Clay minerals in DSDP Leg 84 <2 µm fractions. https://doi.org/10.1594/PANGAEA.803840
  3. Helm, R (1985): (Table 1) Petrography at DSDP Leg 84 holes. https://doi.org/10.1594/PANGAEA.803836
  4. Helm, R (1985): (Table 4) Refractive indices of colorless glass shards at DSDP Leg 84 holes. https://doi.org/10.1594/PANGAEA.803839
  5. Helm, R (1985): (Table 3) Retractive indexes of sponge spicules at DSDP Leg 84 holes. https://doi.org/10.1594/PANGAEA.803838