Before the Early Middle Pleistocene Transition: insights on the environmental variability and explosive activity in central Italy during the 1.5-2.1 Ma interval from the L'Aquila Basin lacustrine record

The Quaternary climate is featured by a notable change in frequency and amplitude of the glacial-interglacial cycles, known as the Early Middle Pleistocene Transition (EMPT), which since ?1.25 Ma to ?0.70 Ma gradually shifted from the quasi-symmetrical and weak amplitude cycles with a 41 kyr periodicity, to the strongly asymmetric, high amplitude cycles with a 100 kyr periodicity. While many records from different environmental settings are available for the post-EMPT period, still little is known for the longer Quaternary history preceding the EMPT, mostly because of the scarcity of high-resolution and precisely dated archives spanning this interval. The lacustrine successions hosted in post-collision tectonic basins of the Central Apennine, central Italy, have proven to be valuable archives of the dynamic and evolution of the regional climate, ecosystems, volcanism and tectonics during Quaternary. Here we present a new record from a 220 m-long core recovered from the lacustrine succession of the L'Aquila Basin, at Castelnuovo (CN) site. A multi-method dating approach, combining tephra 40Ar/39Ar dating, paleomagnetic stratigraphy, and the glacial-interglacial cyclical expression of paleo-environmental proxy data indicate that the whole CN succession spans the period ~1.5 Ma to ~2.1 Ma; i.e., 600 kyr of history shortly preceding the start of the EMPT. The multi-proxy data from CN core interval, including major and trace element and Sr-Nd isotope composition of the glass from six tephra layers, and CaCO3 content, scanning XRF element geochemistry, ?18Ocalcite and pollen analyses from the lacustrine sediments, provided us with a new record of the environmental-climate variability in central Italy spanning twelve glacial-interglacial cycles, from marine isotope stage (MIS) 51 to MIS 78, as well as the first distal evidence of the earliest known calc-alkaline volcanic explosive activity in Campanian Plain.