Rona, Peter A; Harbison, Reginald N; Bassinger, Bobby G; Scott, Robert B; Nalwalk, Andrew J (1976): (Table 2, Annex), Manganese crusts and manganese coated rocks recovered from study area (lat 26°N) [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.848297, Supplement to: Rona, PA et al. (1976): Tectonic fabric and hydrothermal activity of Mid-Atlantic Ridge crest (lat 26°N). Geological Society of America Bulletin, 87, 661-674, https://doi.org/10.1130/0016-7606(1976)87%3C661:TFAHAO%3E2.0.CO;2
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Published: 1976 (exact date unknown) • DOI registered: 2015-09-08
Abstract:
An asymmetric tectonic fabric was delineated by narrow-beam bathymetric profiles in a 180-km2 area of the Mid-Atlantic Ridge crest at lat 26°N. Features of the tectonic fabric are a continuous rift valley offset by small (<10-km) transform faults and minor fracture zones expressed as valleys with intervening ridges that trend normal and oblique to the two sides of the rift valley. The discharge zone of a postulated sub-sea-floor hydrothermal convection system is focused by faults on the southeast wall of the rift valley and driven by intrusive heat sources beneath the rift valley.
The rift valley has a double structure consisting of linear segments, bounded by ridges, and basins at the intersections of the minor fracture zones. The double structure of the rift valley acts like a template that programs the reproduction of the tectonic fabric. The minor fracture zones form an asymmetric V about the rift valley at variance with the symmetric small circles formed by major fracture zones. To reconcile the asymmetry of minor fracture zones with the symmetry of major fracture zones, it is proposed that the minor fracture zones have been preferentially reoriented by an external stress field attributed to interplate and intraplate motions. Major fracture zones remain symmetric under the same stress field owing to differential stability between minor and major structures of oceanic lithosphere.
Source:
Grant, John Bruce; Moore, Carla J; Alameddin, George; Chen, Kuiying; Barton, Mark (1992): The NOAA and MMS Marine Minerals Geochemical Database. National Geophysical Data Center, NOAA, https://doi.org/10.7289/V52Z13FT
Further details:
Warnken, Robin R; Virden, William T; Moore, Carla J (1992): The NOAA and MMS Marine Minerals Bibliography. National Geophysical Data Center, NOAA, https://doi.org/10.7289/V53X84KN
Project(s):
Coverage:
Median Latitude: 25.972071 * Median Longitude: -44.981458 * South-bound Latitude: 25.198333 * West-bound Longitude: -45.738333 * North-bound Latitude: 26.281600 * East-bound Longitude: -44.675000
Minimum Elevation: -3410.0 m * Maximum Elevation: -2500.0 m
Event(s):
TAG1972-13 (T3-72D 253-13) * Latitude: 26.133300 * Longitude: -44.750000 * Elevation: -3080.0 m * Location: Atlantic Ocean * Campaign: TAG1972 (Trans-Atlantic Geotraverse 1972) * Basis: Discoverer (1966) * Method/Device: Dredge, chain bag (DRG_C)
TAG1972-19 (T3-72D 255-19) * Latitude: 26.281600 * Longitude: -45.105000 * Elevation: -3410.0 m * Location: Atlantic Ocean * Campaign: TAG1972 (Trans-Atlantic Geotraverse 1972) * Basis: Discoverer (1966) * Method/Device: Dredge, chain bag (DRG_C)
TAG1972-20 * Latitude: 25.663333 * Longitude: -45.738333 * Elevation: -3040.0 m * Location: Atlantic Ocean * Campaign: TAG1972 (Trans-Atlantic Geotraverse 1972) * Basis: Discoverer (1966) * Method/Device: Dredge, chain bag (DRG_C)
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.
Parameter(s):
| # | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
|---|---|---|---|---|---|---|
| 1 | Event label | Event | Rona, Peter A | |||
| 2 | Mass | Mass | kg | Rona, Peter A | ||
| 3 | Description | Description | Rona, Peter A |
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
16 data points
Data
| 1 Event | 2 Mass [kg] | 3 Description |
|---|---|---|
| TAG1972-13 | 76.68 | Hydrothermal manganese crust; pillow basalt with glass rim; palagonite with glass. |
| TAG1973-2A | 40.12 | Slabs of hydrothermal manganese; basalt talus with matrix of hydrothermal manganese |
| TAG1973-3A | 23.09 | Slabs of hydrothermal manganese; fragments of pillow basalt with and without glass. |
| TAG1972-19 | 0.64 | Weathered basalt with manganese crust (not hydrothermal) |
| TAG1972-20 | 0.96 | Weakly consolidated foraminiferal calcareous mudstone with burrows and manganese crusts. |
| TAG1972-22 | 1.29 | Burrowed manganese-coated limestone. |
| TAG1972-23 | 0.16 | Burrowed manganese-coated limestone. |
| TAG1975-1A | 100.00 | Mnoxide present as crust on alt. basalt talus and veins in the fragments; lower layer of Mnoxide crust <10mm thick composed of hydroth. Mn; up. layer of Mnoxide crust <2mm thick comp. of hydrog. Mn |