Facies Geochimiche Mineralogiche in Adriatico Centro Settentrionale.
Marcaccio M.; Spagnoli F; Giordano P.; Frascari F.; F. Zaffagnini. Dinelli;
Early diagenesis can be investigated by pore water analyses while benthic fluxes can be determined by direct measurements or pore water modelisation. From the integration of past researches different diagenetic environments and benthic fluxes have been individuated in Adriatic and Ionian seas; they resulted from different: particulate and dissolved continental inputs; distances from sediment sources (mainly the Po River); bottom sediment composition (carbonatic or silicoclastic); organic matter composition; depth; oxygenation of water column.
In Northern and Central Adriatic Sea It is possible to distinguish: 1) the area on the North of the Po River, characterized by carbonate sediments, low reactive organic matter inputs and carbonate precipitation. In front of main rivers higher organic matter contents are present and create oxic and suboxic environments; 2) the proximal area in front of the Po River, characterized by high organic matter and silicate inputs producing strong early diagenesis processes and benthic fluxes. In this area frequent anoxic environments are reached; 3) the distal costal area South of the Po River, where lower fresh organic matter and silicate inputs originate weaker early diagenesis processes and nutrient benthic fluxes; 4) the Mid-Adriatic Depression area, characterized by oxic conditions in uppermost centimetres of the sediment consequent to very low inputs of fresh organic matter and low sediment accumulation rates.
The Southern Adriatic basins are characterized by oxic and suboxic-non sulphidic organic matter degradation. The most intensive degradation processes occur in the Otranto Channel. In the Ionian basin the sediment remineralisation processes takes place mainly by means of oxic reactions.
Calculated benthic fluxes reflect the early diagenesis processes: they show a northern-southern and shallow-deep trend characterized by decreasing remineralisation processes with progressive weaker oxygen fluxes into the sediments and DIC fluxes outside the sediments while ammonium and nitrate fluxes are complicated by the nitrification/denitrification processes.
2010 - Abstract in atti di convegno
I giornata della geochimica ambientale, Roma, 22/11/2010
Keywords: Gochimica, Mar Adriatico