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Volcanoes produce probably the most spectacular geological phenomena on Earth. Any of their eruptions can have a strong consequence on the surrounding environment, often captured in great detail in the sedimentary records of volcanically active regions. In addition, flank landslides and background erosive processes affecting volcanic sequences release volcanic particles that circulate within sedimentary environments up to billions of years after their generation. Therefore, exploring volcanically influenced sedimentary environments is an exciting and challenging scientific exercise requiring insights across multiple geological disciplines, drawing upon an increasing varied range of expertise and analytical approaches from across the geoscientific community. This book aims to provide an updated collection of works that illustrate the state-of-the-art in this topic, and to define the future directions of the geological sciences in utilizing and interpreting sedimentary records of volcanism.

The genesis of particles and their transport mechanisms are the two fundamental factors driving the accumulation of sediments associated with volcanism or derived from volcanic sources. These factors are therefore the most important criteria on which to base a useful classification of sediments in such environments. However, the relative significance of the nature of particles v. the transporting mechanism forming a deposit varies in existing terminological schemes: those schemes applied where volcanological contextual information is available tend to give precedence to the transportation process; whereas sedimentological schemes examining ancient deposits tend to focus principally on the nature of particles. Here, we provide an outline of the challenges in classifying volcanically derived sediments and put forward a scheme that aims to bridge current terminological differences and accommodate variable levels of uncertainty. This work defines three endmembers ( primary volcaniclastic , secondary volcaniclastic , volcanic epiclastic ) that correspond to (a) deposits whose particles are produced, transported and emplaced directly by volcanic mechanisms; (b) deposits whose particles are produced directly by volcanic events but transported and accumulated by non-volcanic mechanisms, either in continuum with the events or after interim storage; (c) deposits whose particles are produced by weathering/erosion of volcanic terrains and transportation of derived material by non-volcanic mechanisms. When the complex combination of genetic and transportation processes accumulating volcaniclastic sequences is not clear, but a strong relationship between an eruptive event and the studied volcaniclastic deposit can still be demonstrated, a further category ( volcanogenic ) has been introduced.

The Ofanto River drains volcanic rocks from the Monte Vulture, lacustrine–fluviolacustrine deposits associated with the same volcano and sedimentary deposits of the Southern Apennines and the Bradanic foredeep sequences. Comparing the modal composition of river sands and the outcrop area of different lithologies in the different sub-basins, an over-concentration of the volcaniclastic fraction, mainly represented by loose crystals of clinopyroxene, garnet and amphibole, is shown. This has been related to the preferential erosion of pyroclastic deposits, characterized by high production of sand-sized loose minerals, together with the carbonate lability and the low sand-sized detritus production from claystones and marls. The occurrence of volcaniclastic components upstream of Monte Vulture can be explained as a contribution from the lacustrine–fluviolacustrine deposits cropping out in the upstream sector or from pyroclastic fall deposits of Monte Vulture and/or Campanian volcanoes. This research shows that the volcanic record in the fluvial sands of the Ofanto River comes from weathering and sorting processes of volcaniclastic deposits rather than of the lavas building the main edifice. Therefore, caution must be taken during palaeoenvironmental and palaeoclimatic reconstructions when relating the type and abundance of the volcanic component in sediments to the weathering stage and evolutionary history of the volcano.