Tephrostratigraphy, magmatic histories and volcanic-climate linkages using high-resolution records in southern Italy.

Abstract

The relationship between volcanic activity and climate change has long been a subject of scientific inquiry, though it remains a relatively underexplored aspect of Earth, particularly the influence of climate over volcanism. High-resolution records, which preserve information on palaeoclimate data and volcanic events, function as crucial archives for understanding this relationship. However, while these records have been examined in separate contexts using various methodologies, their potential interrelationship has often been overlooked or underexplored. Therefore, since these records are invaluable in reconstructing past climates and volcanic activities, they may provide great insights into the interconnectedness between these two dynamic systems. This thesis seeks to address this gap by utilizing innovative and complementary approaches to build a more comprehensive and updated history of palaeoclimate and volcanism in southern Italy. The study specifically focuses on high-resolution records from two distinct sources: distal tephra layers and pollen record from Lago grande di Monticchio; and a geochemical record from a stalagmite (cave deposit). Both of these sources offer invaluable high-resolution geochemical, vegetation and climate data that contribute to understanding both volcanic history and climate dynamics in the region. I present a detailed and updated geochemical analysis of 92 distal tephra from Lago Grande di Monticchio. This varved lake core holds a finely layered archive of volcanic activity, spanning the period of 3 ka – 133 ka BP, from the Campanian region and its surroundings in Southern Italy. Additionally, I use a different approach to assist the assignment of distal tephra to volcanic sources using machine learning models. This updated record resulted in an enhanced understanding of the timing, frequency, intensity, and impacts of volcanic eruptions, particularly of the Campi Flegrei and Ischia volcanoes. Furthermore, I present a trace element study of a high-resolution stalagmite record, which captures palaeoclimate signals in the same region. By analysing this speleothem and other palaeoclimate records, I link the Neapolitan Yellow Tuff caldera-forming event with climate shifts, identifying patterns that shed light on how volcanic activity may have influenced climate in the past and vice versa. The ultimate aim of this thesis is to test the relationship between volcanic events and climate change based on the geochemical data from palaeoclimate records in Southern Italy. I explore potential correlations and patterns, seeking to test existing hypotheses and offer new perspectives on the volcano-climate relationship. The findings from this research not only contribute to the refinement of this old dilemma but also provide important directions for future investigations into the complex interactions between volcanic activity and climate dynamics. By using multiple high-resolution datasets in tandem, this study aims to offer a more complete understanding of past volcanic and climatic changes in southern Italy.