Episodic Quaternary volcanism in France and Germany

Abstract

Intra-plate volcanism in western Europe shows statistically significant episodicity during the Quaternary period. By comparing the known ages for eruptions in France and Germany, which are compiled here, with a composite oxygen isotope record, we have investigated the link between this episodic volcanism and the climate record over the last two million years. We show that increased volcanism between 415-400 ka and 17-5 ka correlates with warming phases at the end of the last Weichselian (Devensian) and earlier Elsterian (Anglian) glacial stages. The three significant caldera explosions in the eastern Eifel, Germany, are all associated with warming phases at the onset of interglacials. The growth and decay of nearby ice sheets suggest that surface changes in continental mass distribution during glacial Milankovich cycles could provide a mechanism for this correlation by means of the distal effects of flexural loading on the lithosphere.

Feedback between deglaciation, volcanism, and atmospheric CO2

“…This result is consistent with regional studies (e.g. Gardeweg et al, 1998;Jellinik et al, 2004;Bacon and Lanphere, 2006;Nowell et al, 2006;Licciardi et al, 2007), earlier inferences drawn from the Bryson and Bryson (1998) database of volcanic eruptions, and the volcanic index reconstructed from the Greenland ice core (Zielinksi et al, 1997). Depressurization associated with ablation of glaciers and ice caps could cause decompressional melting of the mantle sufficient to sustain a factor of five increase in volcanic output for 5 ky.…”

“…Large eruptions appear to have occurred with a quasi-100 ky period at Mount Mazama (Bacon and Lanphere, 2006), Western Europe (Nowell et al, 2006), and the South Eastern United Sates (Jellinik et al, 2004), indicating that at least some low-frequency volcanic systems are candidates for being paced by the glacial cycles. Increased eruptions during deglaciation, either directly forced by deglacial processes or paced to coincide with deglaciation, would lead to greater CO 2 emissions if they tap deep, pressurized magmatic reservoirs that still retain their CO 2 or if the eruption leads to depressurization of magmatic chambers and encourages the generation of new melt.…”

“…If subtle changes in weather and climate are sufficient to influence the timing of volcanism, even larger effects could be expected from the massive changes associated with deglaciation (Hall, 1982). Indeed, deglaciation is observed to coincide with increased volcanism in Iceland (Sigvaldason et al, 1992;Gudmundsson, 2000;Sinton et al, 2005;Licciardi et al, 2007), France and Germany (Nowell et al, 2006), the Western United States (Jellinik et al, 2004;Bacon and Lanphere, 2006), and Chile (Best, 1992;Gardeweg et al, 1998). Of these, the clearest demonstration comes from Iceland, where dates from lava flows (Sigvaldason et al, 1992), sulphate concentrations in Greenland ice cores (Zielinksi et al, 1997), and table mountains (Licciardi et al, 2007) are all consistent with increased volcanism during or following deglaciation.…”

Evaluating the link between the sulfur-rich Laacher See volcanic eruption and the Younger Dryas climate anomaly

“…NH continental ice sheet decay induced continental lithospheric unloading and may have triggered highlatitude NH volcanism (Zielinski et al, 1997;Sternai et al, 2016), highlighting the intriguing possibility that eruptions such as the LSE were not randomly distributed geographically and temporally but instead were intrinsically linked to deglaciation. This perspective is strongly supported by a previous observation that the three largest eruptions (including the LSE) in the East Eifel Volcanic Field (Germany) were all associated with warming during glacial terminations and the reduction in ice mass in northern Europe (Nowell et al, 2006).…”

Postglacial eruptive history of the Askja region, North Iceland

“…The clearest demonstration of increased volcanism following a period of rapid deglaciation is observed in Iceland (e.g. Slater et al 1998;Maclennan et al 2002;Sinton et al 2005); similar effects have been documented in continental Europe (Nowell et al 2006); eastern California (Jellinek et al 2004); and, to a lesser extent, at volcanic arcs including the southern Chilean, Cascade and Kamchatka arcs (Watt et al 2013). An expected corollary of subaerial deglaciation is decreased magmatic productivity at ocean ridges due to the additional loading associated with rising sea levels.…”