Analisi geochimiche su materia organica (delta 13 C org) e indagini su framboidi di pirite come proxi di anossia della sezione Pignola 2, bacino di Lagonegro, Potenza

In the Carnian (Upper Triassic) a period of increasing rainfall, named Carnian Pluvial Episode (CPE), is evidenced by lithological changes in various successions in the world. The environmental change seems to be closely associated with a global carbon cycle perturbation that was identified in stratigraphic successions of the Southern Alps of Italy, Northern Calcareous Alps of Austria, Hungary, South China and UK. This thesis presents organic carbon isotope data and ocean redox condition based on framboidal pyrite from Pignola 2, a Carnian deep-water stratigraphic section. Organic carbon isotope data show two negative δ13Corg shift within the CPE. The first, of about 3.5‰, within the Julian 2, and the second, of about 2‰, at the Julian/Tuvalian boundary. The investigation of framboidal pyrite suggests anoxic condition at the base of the CPE. These observations verify that sedimentological changes related to the CPE coincide with the carbon cycle perturbation and therefore occurred synchronously also in the Pignola 2 section. The injection of light CO2 into the Carnian atmosphere-ocean system may have been directly responsible for both the recorded two negative δ13Corg shift and the increase in rainfall. The consequent increased continental weathering led to the transfer of large amounts of siliciclastics sediments into the basins, while the increased run-off and nutrient flux triggered the development of anoxia