Volcanoes: Identifying and Evaluating Their Significant Geoheritage Features from the Large to Small Scale

Abstract

Across the globe, volcanoes and volcanic terrains present one of the most complex geological systems on Earth that, depending on magma type, viscosity, and water and gas content, form a diverse range of products in terms of geomorphology, lithologic suites, structures, and stratigraphy. In broad terms, magmas, with their diagnostic composition, derive from specific tectonic settings, e.g., basalt-dominated oceanic crusts, acidic magma from continental plates, and andesitic convergent-plate margins. In addition to magma composition and volcanic rock types, there is a wide range of volcanic products, manifest at all scales, dependent on how magma interacts with the Earth’s surface, varying, for instance, from lava flows such as vesicular lava beds and flow-banded to flow-laminated lava beds, to breccias, tephra (ejecta) deposits, and bombs, amongst others, each commonly with their diagnostic small-scale lithological/structural features. This wealth of rock types, stratigraphy, and structures linked to geologic setting, potentially has geoheritage significance, and we provide here methods tailored for volcanoes and volcanic rocks of identifying, classifying and evaluating the complex and heterogeneous nature of volcanoes so that the full complement of their geology for a given region can be appreciated and incorporated into thematic geoparks, Nature Reserves and protected areas. For sites of geoheritage significance, we present (1) a globally-applicable Geoheritage Tool-kit to systematically identify volcanic geoheritage sites, (2) a technique to classify/categorise geoheritage sites, and (3) a semi-quantitative method to evaluate the geoheritage significance of volcanic sites.

Volcanic Geoheritage in the Light of Volcano Geology

“…A general workflow outlined in several studies recommends the steps to follow to develop a volcanic geodiversity estimate for a region Semeniuk 2007, 2019;Brocx et al 2021). The model proposed here consists of at least three major stages.…”

“…In many cases subjectivity can be difficult to abandon so it is considered an achievement if the subjectivity can be reduced to a level where the resulting selection and associated valorization results in more or less the same results for each new study on the same location. Recently a series of works has been published proposing some sort of geoheritage toolkit that helps the user to work out the strategy and the actual valorization of geosites (Brocx and Semeniuk 2007;Brocx et al 2021). The toolkit was tailored specifically to volcanoes to systematically identify and assess sites of geoheritage significance (Brocx et al 2021).…”

“…Recently a series of works has been published proposing some sort of geoheritage toolkit that helps the user to work out the strategy and the actual valorization of geosites (Brocx and Semeniuk 2007;Brocx et al 2021). The toolkit was tailored specifically to volcanoes to systematically identify and assess sites of geoheritage significance (Brocx et al 2021). This toolkit is based on the identification of the (1) conceptual categories of sites of volcanic geoheritage significance, (2) the scale of volcanic geoheritage features recognized and (3) the recognition of the volcano (or volcanic geoheritage features) significance.…”

“…Fig. 11 Modified volcanic geoheritage toolkit that is based on the concept of Brocx et al (2021). One of the main differences in this modified version that it takes the scale measured to the specific volcanic geology problems, process and measurable features.…”