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Saldanha
Name Alias(es):
Mount Saldanha
Mt Saldanha
Saldanha Mound
Saldanha Massif
NTO5
South FAMOUS
36 34'N, MAR
MGDS_FeatureID lowest in hierarchy:
Activity:
Max Temperature Category:
Latitude:
36.5667
Longitude:
-33.4333
Location on map:
Ocean:
Region:
National Jurisdiction:
Maximum or Single Reported Depth (mbsl):
2300
Tectonic setting:
Full Spreading Rate (mm/a):
20.5
Host Rock:
ultramafic-hosted
Deposit Type:
NotProvided
Notes on Vent Field Description:
located at top of a serpentinized massif; low-temperature (7–9 °C) hydrothermal activity has been provided by direct observation of hydrothermal fluid venting through small orifices in the ocean floor sedimentary cover; deposits on serpentinized peridotite and gabbro; large water column methane anomaly; in MOMAR area, which is designated for long-term monitoring efforts; Aballea et al. (1998) ranked hydrothermal activity as very "possible" in southern FAMOUS segment; not discovered during FLORES cruise (Fouquet et al. 1998); located at south end of FAMOUS segment at axial discontinuity, non-transform offset (NT05); Bougault et al. (1998): "Along the FAMOUS segment, the largest hydrothermal anomalies are recorded along the southern part of the segment with dynamic hydrocast DH 2, from A2 to C2 ... These anomalies seem to indicate a potential discharge area ... about 36°40′N"
Notes Relevant to Biology:
bacterial mats; see Biscoito, M et al. (2006)
Year and How Discovered (if active, visual confirmation is listed first):
1998 submersible Nautile
Discovery References (text):
(plume only) German et al, Earth Planet. Sci. Lett. 138, 93-104, 1996, Hydrothermal exploration near the Azores Triple Junction: tectonic control of venting at slow-spreading ridges?
Barriga, et al., (1998) Discovery of the Saldanha hydrothermal field on the FAMOUS segment of the MAR (36° 30′N), AGU-Fall Meeting, Eos. Trans vol. 79 (45), p. F67
(plume only) Chin et al., Earth Planet. Sci. Lett. 162, 1-13, 1998, Detection of hydrothermal plumes on the northern Mid-Atlantic Ridge: results from optical measurements.
Other References (text):
Bougault et al. (1998) FAMOUS and AMAR segments on the Mid-Atlantic Ridge: ubiquitous hydrothermal Mn, CH4, δ3He signals along the rift valley walls and rift offsets. Earth and Planetary Science Letters 161: 1-17
Fouquet et al. (1998) FLORES diving cruise with the Nautile near the Azores – First dives on the Rainbow field: hydrothermal seawater/mantle interaction. InterRidge News 7(1), p. 24-28
Gracia et al., Earth Planet. Sci. Lett. 177, 89-103, 2000, Non-transform offsets along the Mid-Atlantic Ridge south of the Azores (38°N–34°N): ultramafic exposures and hosting of hydrothermal vents, doi:10.1016/S0012-821X(00)00034-0
Dzhatieva et al. (2005) Active source electromagnetic survey of hydrothermal venting areas at the Saldanha Massif, Mid-Atlantic Ridge - the CD167/2004 cruise. InterRidge News 14: 12-14
(great map) Dias, AS and Barriga, FJAS (2006) Mineralogy and geochemistry of hydrothermal sediments from the serpentinite-hosted Saldanha hydrothermal field (36°34′N, 33°26′W) at MAR. Mar Geol 225(1-4): 157-175. http://doi.org/10.1016/j.margeo.2005.07.013
Biscoito, M et al. (2006) Preliminary biological characterization of the Saldanha hydrothermal field at the Mid-Atlantic Ridge (36 34'N, 32 26'W, 2200 m). Cah. Biol. Mar. 47:421-427.
Dias AS et al. (2010) Tracing fluid–rock reaction and hydrothermal circulation at the Saldanha hydrothermal field. Chemical Geology, 273(3-4), 168–179. http://doi.org/10.1016/j.chemgeo.2010.02.020
Dias AS et al. (2011) Geochemistry and stable isotope constraints on high-temperature activity from sediment cores of the Saldanha hydrothermal field. Marine Geology, 279(1-4), 128–140. http://doi.org/10.1016/j.margeo.2010.10.017
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