Publication Date:
2020-07-24
Description:
The Central Indian Ridge between 21°- 24°S, near the
RodriguezT riple Junction, was investigatedb y RV SONNE
during the 1983 and 1986 cruises of the GEMINO project
(Geothermal Metallogenesis Indian Ocean) for the purpose
of locating sites of hydrothermal activity. In response to
reconnaissance data of conductive heat flow, sediment
cores, and hydrocasts, two intermediate spreading ridge segments
at 2l.5°S (area EX,/FX) and 23°S (area JX) were
selected for detailed exploration including mapping, sampling
and visual seafloor observation. Hydrothermally
influenced sediment cores and altered basalts were found
in both study areas. Total dissolvable Mn concentrations
up to 27.5 nmol/kg and CHa values up to 45.6 nL/L occur
within 450 m above bottom in the northern and southern
overlapping propagators in area EX/FX. In addition,
63He values up to 18.6% and a potential temperature
anomaly (0.01°C) were found. In area JX, maximum concentrations
of 36.1 nL/L CHa and 10.7 nmol,/kg total dissolvable
Mn in the water column seem to be related to a
central neovolcanic ridge close to a ridge-transform intersection.
At the eastern flank of this ridge, a significant
potential temperature anomaly of 0.04°C was measured.
The results obtained in areas EX/FX and JX provide evidence
for hydrothermal activity. However, in comparison
to the TAG hydrothermal field at the Mid-Atlantic Ridge
at 26°N, the data indicate a more restricted and probably
lower temperature hydrothermal discharge.
Type:
Article
,
PeerReviewed
Format:
text
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