A multi-proxy record of MIS 11e12 deglaciation and glacial MIS 12 instability from the Sulmona basin (central Italy)

A multi-proxy record (lithology, XRF, CaCO3 content, carbonate delta18O and delta13C) was acquired from asediment core drilled in the intermountain Sulmona basin (central Italy). Tephrostratigraphic analyses ofthree volcanic ash layers ascribe the investigated succession to the MIS 12-MIS 11 period, spanning theinterval ca. 500e410 ka. Litho-pedo facies assemblage indicates predominant lacustrine deposition,interrupted by a minor sub-aerial and lake low stand episode. Variations in major and minor elementsconcentrations are related to changes in the clastic input to the lake. The oxygen isotopic composition ofcarbonate (delta18Oc) intervals is interpreted mainly as a proxy for the amount of precipitation in the high altitude catchment of the karst recharge system. The record shows pronounced hydrological variability atorbital and millennial time-scales, which appears closely related to the Northern Hemisphere summerinsolation pattern and replicates North Atlantic and west Mediterranean Sea Surface Temperature (SST)fluctuations. The MIS 12 glacial inception is marked by an abrupt reduction of precipitation, lowering ofthe lake level and enhanced catchment erosion. A well-defined and isotopically prominent interstadialwith increased precipitation maybe related to insolation maxima-precession minima at ca. 465 ka. Thisinterstadial ends abruptly at ca. 457 ka and it is followed by a phase of strong short-term instability.Drastic lake-level lowering and enhanced clastic flux characterized the MIS 12 glacial maximum.Lacustrine deposition restarted about 440 ka ago. The MIS 12eMIS 11 transition is characterized by arapid increase in the precipitation, lake-level rise and reduction in the clastic input, interrupted by ashort and abrupt return to drier conditions. Comparison with marine records from the Iberian marginand western Mediterranean suggests that major events of ice rafted debris deposition, related tosouthward migrations of the polar front, match the harshest periods in central Italy. This indicates strongteleconnections between Northern hemisphere ice sheet dynamics, North Atlantic oceanic conditionsand Mediterranean continental hydrology