Hydrocarbons of the hypersaline environment of the Tyro deep-sea depression (eastern Mediterranean)

In order to trace the organic matter sources in the sediments of the Tyro deep-sea depression in the Mediterranean Sea, the authors studied their hydrocarbon and carotenoid composition. Two depositional environments were recognized in the basin: a typical marine and a hyperhaline. Algal and bacterial biomarkers, such as regular C-25 isoprenoid, squalane, lycopane, isolycopane, tetraterpenoid and tetrapyrrolic pigments, monoalkylcyclohexanes, tricyclic diterpanes, sterenes, hopenes, bio- and geohopanes that are typical of saline environments were found in the 0.60- to 0.75-m core interval presumably containing bacterial mat interlayer. By analogy with the hydrocarbon composition of the Messinian evaporitic deposits of the Mediterranean, we hypothesized that the organic matter of the evaporites of these deposits in the Tyro depression walls was redeposited to the sapropels of the depression.