Hi Spiros,

As far as I know hydrothermal activity might increase the metal content of the adjoining sediments from the usual. So you can check the Fe,Mn,Al content of the sediments from XRF. But its impact is more easily understood from the trace and Rare Earth element compositions. Also you can check the mineralogy of the sediments, unusual enrichment of sulfides or barites or any other leaching texture may indicate some kind of fluid interaction with the sediments. See some previous works from the same area which might give you some idea about the sediment characteristics.

Hello,

As Simontini said, I think you basically look for high Fe, Mn and trace element contents.

The following book is also very helpful (especially table 2.4 and figure 2.12):

http://www.springer.com/gp/book/9789401798488

Hello Spiros,

A good analogue to sediments affected by hydrothermal activity are those containing sea-floor metallogenic umbers - such as those exposed in the Troodos of Cyprus. I'm sure there are publications detailing the composition of these - such analyses could then be compared with your examples.

Another way of determining a possible hydrothermal signal would be to normalise those samples you think affected with unaffected bulk sediment for the same/nearby locality (this will highlight which elements are enriched/depleted).

I agree with the previous respondents, elevated Fe, Mn, etc are the obvious signals (those elements/minerals that ppt around black smokers), but hydrothermal activity may also leach mobile elements such as Na, Ca, and K - though seawater may buffer extreme depletion; nevertheless, such effects do occur in terrestrial successions affected by hydrothermal circulation.