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Palaeoenvironments of the Mediterranean Basin at the Messinian hypersaline/hyposaline transition: evidence from natural radioactivity and microfacies of post‐evaporitic successions of the Adriatic sub‐basin
Author(s) -
Sampalmieri Gianluca,
Iadanza Annalisa,
Cipollari Paola,
Cosentino Domenico,
Lo Mastro Sergio
Publication year - 2010
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/j.1365-3121.2010.00939.x
Subject(s) - geology , authigenic , marl , evaporite , structural basin , benthic zone , mediterranean climate , paleontology , oceanography , mediterranean sea , salinity , fauna , marine transgression , anoxic waters , geochemistry , sedimentary rock , ecology , biology
Terra Nova, 22, 239–250, 2010 Abstract At the end of the Messinian salinity crisis, changes in the palaeoceanography and palaeoclimate induced a transition from hypersaline to hyposaline conditions in the Mediterranean water body. Detailed investigation of natural radioactivity and microfacies analyses of two early post‐evaporitic Messinian sections show that the transition occurred in poorly oxygenated and well‐stratified water masses. These transitional deposits, which mainly consist of marls and CaCO 3 ‐rich horizons, are generally well laminated and totally barren in benthic and planktonic fauna. The presence of barite, small (5–8 μm) authigenic framboidal pyrite, and high values of U indicate persistent anoxic conditions during the early post‐evaporitic Messinian stage in the Adriatic sub‐basin of the Mediterranean Sea. The presence of post‐evaporitic well‐laminated barren deposits from both Mediterranean borderland sections and ODP sites suggests that these anoxic conditions extended to other sub‐basins of the Mediterranean region.