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Antarctica Volcanic Eruption the Largest in the Holocene – Timing and
Widespread effects
According to Antoniades et al.
the volcanic eruption that led to the collapse of the Deception Island
volcano, Antarctica, was on a comparable scale to some of the largest
eruptions that have occurred on Earth over the last several thousand
years. The age of this eruption has not been determined, in spite of its
magnitude and potential for far-reaching environmental effects. In this
paper Antoniades et al. presents the results of their analysis of nearby
lake sediments in which they identified a singular event that resulted
from the collapse of the Deception Island caldera which occurred 3,980 ±
125 calibrated years BP. The tephra that was erupted record the distinct
geochemical composition of the ejecta from the eruption that formed the
caldera, and the sediments of the lake immediately overlying of the
collapsed tephra recorded an extreme seismic episode. The newly
constrained caldera collapse is now the largest volcanic eruption in
Antarctica during the Holocene. Evidence revealed in the marine and
lacustrine sediments by examination of palaeorecords for contemporaneous
seismicity around the Antarctic Peninsula; synchronous glaciochemical
volcanic signatures also record the eruption in ice cores that are
spread around Antarctica, which reached more than 4,600 km from the
source. It is suggested by the widespread footprint that this eruption
would have had significant climatic and ecological effects across a vast
area of the south polar region.
Pervasive climatic, ecological and economic effects can result from
large volcanic eruptions (Robock, 2000). Crop failure, starvation,
disease and civil unrest and has been linked to the rise and fall of
civilisations, can result from climate cooling that is caused by
volcanic aerosols (Oppenheimer, 2015; Büntgen, 2016). High latitude
volcanic eruptions may also have environmental consequences that are
wide-ranging and trigger pronounced cooling at hemispheric scales (Sigl,
2015; Pausata et al., 2015; Oman et al., 2005), though there are often
major climate impacts associated with topical volcanoes. Understanding
of environmental and climate impacts of many polar volcanic events,
however, is limited by a lack of precision in regards to the age of past
eruptions as well as the uncertainty of the provenance of many tephra
layers in ice and sediment cores (Sigl et
al., 2016; Smellie, 1999).
The largest active volcano in the Antarctic Peninsula region is
Deception Island; with a basal diameter of 30 km it is on the scale of
the volcanoes that have produced the largest eruptions on Earth in the
past several thousand years (Smellie, 2001; Martί, Geyer & Aguirre-Diaz,
2013; Kandlbauer & Sparks, 2014; Smellie et al., 2002). Located in the
South Shetland Islands (SSI), it is in a region that is volcanically
active where there are 9 active volcanoes that are known in the SSI and
several more adjacent to the Northern Antarctica Peninsula (Smellie et
al., 1999). According to Antoniades et
al. the potential for
eruptions of Deception Island to affect climates around Antarctica and
beyond was demonstrated by the identification of its tephra layers in
marine and lacustrine sediments that are located up to ~1,300 km from
the volcano (Smellie et al., 1999; Olivia-Urcia et al., 2015; Björck,
Sandgren & Zale, 1991; Liu et al., 2016; Moreton & Smellie, 1998) as
well as Antarctica Peninsula ice cores and East Antarctica, and
including the South Pole (Smellie et al., 1999; Narcisi et al., 2005;
Mulvaney et al., 2012).
Since the 19th century Deception Island has erupted more than
20 times, which includes 3 eruptions between 1967 and 1970 and seismic
crises in 1992, 1999 and 2015 (Martί, Geyer & Aguirre-Diaz, 2013;
Bartolini et al., 2014; Almendros et al., 2018). These recent eruptions
have been of relatively modest magnitude, but the event that formed the
caldera that is yet to be firmly dated ejected a dense-rock equivalent
(DRE) of 30-60 km3 of magma, which is equivalent to the
catastrophic eruption of Tambora in 1815 that resulted in global cooling
and the “the year without summer” (Robock, 2000; Oppenheimer, 2015;
Martί, Geyer & Aguirre-Diaz, 2013; Kandlbauer & Sparks, 2014; Smellie et
al., 2002). It has never been firmly established what the age of this
major Deception Island eruption is. The event has been placed by
estimates between the Late Pleistocene and 3,370 BP, the most widely
repeated age has been 10,000 year (Smellie et
al., 2002; Olivia-Urcia et
al., 2015; Moreton, 1999; Roberts et al., 2017). Rapid volcano-tectonic
subsidence along the tectonically-influenced faults that were
pre-existing resulted in a modern caldera that was 8-10 km in diameter
that is of similar dimensions to those of Santorini and Krakatau (Smellie
et al., 2002 & references
therein). Caldera collapses that are on this scale are often associated
with intense seismic swarms that include multiple high magnitude
earthquakes (Hildreth & Fierstein, 2012), and it is implied by the large
volume of magma that is erupted what the likelihood of significant,
widespread climate impacts of are.
Byers Peninsula, which is on Livingston Island ~40 km northwest of
Deception Island, is ideally located to record the history of the
Deception Island volcano eruptions due to the proximity and the presence
of many lakes. In this study Antoniades et
al. examined sediments from
lakes on Byers Peninsula where there are detailed long-term
environmental records of Deception Island volcanic activity in the form
of tephra deposits. Direct compositional comparisons between tephras
from the Byers Peninsula and those of Deception Island to provide age
constraints that significantly improved age constraints for the eruption
that formed a caldera. In this paper data is presented from 4 lakes on
Byers Peninsula, Escondido, Cerro Negro, Chester and Limnopolar, in
which there are 3 major tephra horizons which are referred to as T1, T2
and T3 and whose composition indicated that a Deception Provenance, were
correlated based on geochemistry and physical properties (Liu et al.,
2016). This integration of cumulative evidence that had been derived
from geochemical, petrological and palaeolimnological studies provides
significant new insights into the chronology and physical processes that
occurred during the collapse of the Deception Island caldera.
Antoniades, D., et al. (2018). "The timing and widespread effects of the
largest Holocene volcanic eruption in Antarctica." Scientific Reports
8(1): 17279.
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Author: M.H.Monroe Email: admin@austhrutime.com Sources & Further reading |