Publication Date:
2024-05-08
Description:
Four small scoria cones in the western outskirts of Al Madinah City, the Kingdom
of Saudi Arabia, form a distinct young volcanic landmark. These volcanoes, despite
their very small size, provide one of the most fundamental sources of information
about the early eruption mechanism of rising mafic magma in the context of an
active volcanic field located next to a city with over one million people. An initial
study of the area in 2012–2013 confirmed that these sites had a significant phreatomagmatic
phase in their opening stage, leaving behind characteristic pyroclastic
successions likely to be covered by subsequent eruptive products. The fact that in
this location, unequivocal evidence emerged to show that explosive magma-water
interaction driven eruptions occurred in the largely magmatic (“dry”) explosive
style, and volcanic field evolution confirmed that this site has high geoheritage value.
Since the first research was 20 years ago, a restudy of the present-day condition
of the scoria cone was conducted. Applying satellite imagery, remote sensing and
direct site visit, we find that about a third of the cone surface area has been modified
and at least a quarter of its volume has vanished. Further excavation for cone
material however opened the entire western side of the cone, exposing a nearly
5-m-thick succession of accidental lithic pyroclast-dominated lapilli tuff and tuff
breccia, confirming that this location had a significant phreatomagmatic phase in
its opening eruptions. This location shows graphically the need for geoconservation
to preserve such sites that are potentially the only, or best locations to show the
potential eruptive styles and scenarios of future eruptions if they occur in similar
environments.
Description:
Published
Description:
29-52
Description:
OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametrici
Description:
JCR Journal
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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