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Barrett, T J; Friedrichsen, Hans (1982): Elemental and isotopic compositions of metalliferous and pelagic sediments from the Galapagos mounds area, data of DSDP Leg 70 [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.695931, Supplement to: Barrett, TJ; Friedrichsen, H (1982): Elemental and isotopic compositions of some metalliferous and pelagic sediments from the Galapagos mounds area, DSDP Leg 70. Chemical Geology, 36(3-4), 275-298, https://doi.org/10.1016/0009-2541(82)90052-3

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Abstract:
Nontronite, the main metalliferous phase of the Galapagos mounds, occurs at a subsurface depth of ~2–20 m; Mn-oxide material is limited to the upper 2 m of these mounds. The nontronite forms intervals of up to a few metres thickness, consisting essentially of 100% nontronite granules, which alternate with intervals of normal pelagic sediment. The metalliferous phases represent essentially authigenic precipitates, apparently formed in the presence of upwelling basement-derived hydrothermal solutions which dissolved pre-existent pelagic sediment.
Electron microprobe analyses of nontronite granules from different core samples indicate that: (1) there is little difference in major-element composition between nontronitic material from varying locations within the mounds; and (2) adjacent granules from a given sample have very similar compositions and are internally homogeneous. This indicates that the granules are composed of a single mineral of essentially constant composition, consistent with relatively uniform conditions of solution Eh and composition during nontronite formation.
The Pb-isotopic composition of the nontronite and Mn-oxide sediments indicates that they were formed from solutions which contained variable proportions of basaltic Pb, introduced into pore waters by basement-derived solutions, and of normal-seawater Pb. However, the Sr-isotopic composition of these sediments is essentially indistinguishable from the value for modern seawater. On the basis of 18O/16O ratios, formation temperatures of ~20–30°C have been estimated for the nontronites. By comparison, temperatures of up to 11.5°C at 9 m depth have been directly measured within the mounds and heat flow data suggest present basement-sediment interface temperatures of 15–25°C.
Project(s):
Deep Sea Drilling Project (DSDP)
NOAA and MMS Marine Minerals Geochemical Database (NOAA-MMS)
Coverage:
Median Latitude: 0.643070 * Median Longitude: -86.125529 * South-bound Latitude: 0.533300 * West-bound Longitude: -86.410000 * North-bound Latitude: 1.613200 * East-bound Longitude: -86.090000
Date/Time Start: 1979-11-15T00:00:00 * Date/Time End: 1979-11-29T00:00:00
Event(s):
70-506 * Latitude: 0.609800 * Longitude: -86.099800 * Date/Time: 1979-11-15T00:00:00 * Elevation: -2710.0 m * Penetration: 36.7 m * Recovery: 22.7 m * Location: North Pacific/MOUND * Campaign: Leg70 * Basis: Glomar Challenger * Method/Device: Drilling/drill rig (DRILL) * Comment: 7 cores; 27.9 m cored; 8.8 m drilled; 81.5 % recovery
70-506B * Latitude: 0.610200 * Longitude: -86.091300 * Date/Time: 1979-11-15T00:00:00 * Elevation: -2711.0 m * Penetration: 20.7 m * Recovery: 20.2 m * Location: North Pacific/MOUND * Campaign: Leg70 * Basis: Glomar Challenger * Method/Device: Drilling/drill rig (DRILL) * Comment: 6 cores; 20.7 m cored; 0 m drilled; 97.6 % recovery
70-506C * Latitude: 0.607700 * Longitude: -86.091300 * Date/Time: 1979-11-15T00:00:00 * Elevation: -2710.0 m * Penetration: 31.3 m * Recovery: 29.7 m * Location: North Pacific/MOUND * Campaign: Leg70 * Basis: Glomar Challenger * Method/Device: Drilling/drill rig (DRILL) * Comment: 8 cores; 31.3 m cored; 0 m drilled; 95 % recovery
Comment:
From 1983 until 1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions. At the time it was the most extended data compilation on ferromanganese deposits world wide. Initially published in a proprietary format incompatible with present day standards it was jointly decided by AWI and NOAA to transcribe this legacy data into PANGAEA. This transfer is augmented by a careful checking of the original sources when available and the encoding of ancillary information (sample description, method of analysis...) not present in the NOAA-MMS database.
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
7 datasets

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Datasets listed in this publication series

  1. Barrett, TJ; Friedrichsen, H (1982): (Table 1, part a) Electron microprobe analyses of adjacent nontronite granules from a stratigraphically deep nontronite sample DSDP 507D-6-2, 135-137 cm. https://doi.org/10.1594/PANGAEA.695867
  2. Barrett, TJ; Friedrichsen, H (1982): (Table 1, part b) Electron microprobe analyses of adjacent nontronite granules from a stratigraphically shallow nontronite sample DSDP 509B-2-1, 44-48 cm. https://doi.org/10.1594/PANGAEA.695868
  3. Barrett, TJ; Friedrichsen, H (1982): (Table 2, part a) Electron microprobe analyses of Mn-oxide crust fragments from DSDP Holes 507D and 509B. https://doi.org/10.1594/PANGAEA.695896
  4. Barrett, TJ; Friedrichsen, H (1982): (Table 2, part b) Electron microprobe analyses of individual nontronite granules (6-10 mm diameter) from DSDP Holes 507D and 509B. https://doi.org/10.1594/PANGAEA.695897
  5. Barrett, TJ; Friedrichsen, H (1982): (Table 5) Oxygen- and hydrogen-isotopic compositions of metalliferous and pelagic sediments as well as nontronite formation temperatures in the Galapagos mounds area, DSDP Leg 70. https://doi.org/10.1594/PANGAEA.695926
  6. Barrett, TJ; Friedrichsen, H (1982): (Table 4) Pb-, Sr- and O-isotopic compositions, and Rb and Sr contents of some basalts from the Galapagos mounds area, DSDP Leg 70. https://doi.org/10.1594/PANGAEA.695925
  7. Barrett, TJ; Friedrichsen, H (1982): (Table 3) Pb- and Sr-isotopic compositions of selected samples of nontronite, Mn-oxide crust, Mn-Fe-oxide mud, and pelagic sediments from the Galapagos mounds area, Leg 70. https://doi.org/10.1594/PANGAEA.695904