Page 325 - Volcano and Geothermal Tourism

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Volcano Tourism in the New

Kanawinka Global Geopark of

Victoria and SE South Australia

Bernie Joyce this should also be followed by a further
classification of the effects of erosional processes
Introduction through time. Volcanic landforms are mainly
constructional, produced by processes, which have
Landforms due to volcanism have been constructed built up deposits on pre-existing landscapes. Some
during all phases of the Earth’s history, and are destructional, for example, maar craters formed
subjected through time to erosional processes by phreatomagmatic explosions often extend
which have modified the original landforms. below the original ground surface, and may
Volcanic features are in large part constructional expose underlying rock in their inner walls.
but sit on earlier landscapes which have often Calderas are generally destructional, collapsing
influenced cone-building, ash deposits and lava over subsurface spaces formerly occupied by
flows; for example, existing valleys may often ascending magma. Erosional processes are
control lava flows. responsible for post-eruption landform changes,
There is an increasing tendency to include
volcanoes in both natural protection areas, and in and a sequence of changes over time (a
chronosequence) in landforms, weathering, soils
tourism, wherever they exist in significant and drainage development can be used to estimate
numbers or as measured by activity. The actual the time which has passed since volcanic activity
mechanism to achieve this is increasingly a occurred and so help in estimating the possibility
variant of the national parks that are found in of future eruption (Joyce, 2005).
virtually all countries across the Globe. Australia’s A further level of classification of volcanoes
first geopark is on the broad Western Plains of and their deposits is provided by the chemical
Victoria and the adjacent part of south-eastern composition of the ascending magma, which
South Australia in the south of the country, and directly influences the violence of eruption, and
this includes some 100 well-studied volcanoes thus the landforms constructed. Magma
ranging in age from five million years to just a compositions may range from basalt (basic magma),
few thousand years old.
giving mild eruptions with generally small
Classifying volcanic landforms volcanoes and extensive mobile flows, to rhyolite
and andesite (acid magma), giving violent eruptions
A system of classification of landforms due to and over long periods of time constructing large
volcanic processes provides a necessary starting volcanoes, with little lava flow but possibly
point for any discussion of volcanic features, and extensive ash deposits including ignimbrite sheets,

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