『Abstract
Volcaniclastic sediments, broadly defined as clastic deposits
derived from the transport, deposition and/or redeposition of
the products of volcanic activity, have long been a Cinderella
of the geosciences. This status is a function of the inherent
complexity of the fragmentation, transport and depositional processes
that operate in volcanically-impacted environments and the comparatively
recent development of the discipline as a specialist area. Volcaniclastic
studies are truly interdisciplinary, drawing on many elements
of physical volcanology, fluid dynamics, classical clastic sedimentology,
hydrology and geomorphology.
In the past 30 years volcaniclastic studies have blossomed, partly
in response to a number of catastrophic and high-profile volcanic
eruptions, including Mount St. Helens in 1981, Nevado del Ruiz
in 1985 and Pinatubo in 1991, and partly due to integration with
the maturing science of fluid dynamics and an increased understanding
of the behaviour of particulate dispersions of volcanic eruptions
can have more severe, far-reaching, and prolonged impacts than
the initial volcanism. In parallel, studies of well-preserved
examples from the geological record extended our understanding
of landscape and environmental responses to styles and scales
of volcanism that have not been recorded historically, such as
the impacts of caldera-forming eruptions from silicic calderas.
As a consequence, studies have expanded beyond classical stratigraphic
and sedimentological studies of ancient successions in a variety
of plate tectonic settings to a more dynamic focus on process.
Ultimately, volcaniclastic successions are the product of the
interplay between the volcano, in terms of the style, magnitude
and explosivity of the eruption, and the environment, as expressed
by physiography, hydrology, energy, and accommodation space.
Keywords: Volcaniclastic sedimentation; Explosive volcanism; Stratigraphy;
Sedimentology; Natural hazards』
1. Introduction
2. Terminology
3. Plate tectonic setting of volcaniclastics
3.1. Convergent margins
3.2. Divergent margins
3.3. Intraplate volcanoes
4. The stratigraphic record of volcanic activity
4.1. Andesitic-dacitic stratovolcanoes
4.2. Lava domes
4.3. Intermediate and rhyolitic calderas
4.4. Monogenetic volcanoes
4.4.1. Scoria and cinder cones
4.4.2. Maars and tuff rings
4.4.3. Tuff cones
5. Developing concepts in volcaniclastic sedimentology
5.1. Non-standard density of volcanic particles
5.2. Marine tephras
5.3. Altered catchment hydrology
5.4. Sediment yields and drainage development
5.5. Debris avalanches
5.6. Lahars
5.7. Subaqueous explosive volcanism
5.8. Numerical modelling
5.9. Economic significance
6. Discussion and conclusions
Acknowledgements
References