A 110,000-Yr Record of Explosive Volcanism from the GISP2 (Greenland) Ice Core

Abstract

The time series of volcanically produced sulfate from the GISP2 ice core is used to develop a continuous record of explosive volcanism over the past 110,000 yr. We identified ∼850 volcanic signals (700 of these from 110,000 to 9000 yr ago) with sulfate concentrations greater than that associated with historical eruptions from either equatorial or mid-latitude regions that are known to have perturbed global or Northern Hemisphere climate, respectively. This number is a minimum because decreasing sampling resolution with depth, source volcano location, variable circulation patterns at the time of the eruption, and post-depositional modification of the signal can result in an incomplete record. The largest and most abundant volcanic signals over the past 110,000 yr, even after accounting for lower sampling resolution in the earlier part of the record, occur between 17,000 and 6000 yr ago, during and following the last deglaciation. A second period of enhanced volcanism occurs 35,000–22,000 yr ago, leading up to and during the last glacial maximum. These findings further support a possible climate-forcing component in volcanism. Increased volcanism often occurs during stadial/interstadial transitions within the last glaciation, but this is not consistent over the entire cycle. Ages for some of the largest known eruptions 100,000–9000 yr ago closely correspond to individual sulfate peaks or groups of peaks in our record.

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

“…If a feedback was active following volcanic eruptions during the 6th century, the Little Ice Age, and the Holocene in general, the intermediate ice volume and transitional climate characteristic of the last deglaciation should have amplified any volcanic aerosol forcing. This perspective is consistent with previous observations, including those of Zielinski et al (1996), who noted that when the climate system is in a state of flux, it is more sensitive to external forcing and that any post-volcanic cooling would be longer lived. Importantly, Rampino and Self (1992) stated "Volcanic aerosols may also contribute a negative feedback during glacial terminations, contributing to brief episodes of cooling and glacial readvance such as the Younger Dryas Interval".…”

“…This gradual cooling was sometimes interrupted and acceler-982 J. U. L. Baldini et al: Evaluating the link between the sulfur-rich Laacher See volcanic eruption ated by YD-type events forced by high-latitude volcanism, possibly linked to crustal stresses induced by deglaciation (Zielinski et al, 1996). Some deglaciations did not experience a YD-type event, and we speculate that this was perhaps due to short-lived ideal ice volume conditions not coinciding with an eruption.…”

Hypothesized climate forcing time series for the last 500 years

“…Ice cores offer a valuable opportunity to reconstruct volcanic aerosols through the measurement of volcanic sulfate (SO42-) deposited on glacial ice in the years immediately following an eruption. The high temporal resolution (annual to biennial), the length of the records, and the low temporal error (e.g., + 2 years for uppermost part of the Greenland Ice Sheet Project Two (GISP2) core [Zielinski, 1995] [Zielinski, 1995[Zielinski, , 1996. Finally, Ro•ock and Free [1995,1996] pioneered the use of sulfate data from multiple ice cores to construct a record of volcanic activity.…”

Volcanic eruptions recorded in the Illimani ice core (Bolivia): 1918–1998 and Tambora periods

“…Conversely, the acid layers of volcanic origin (H 2 SO 4 spikes) serve as reference horizons for dating polar ice cores (Schwander et al, 2001). Several continuous longterm records of past volcanic activity have been deduced from acidity measurements along deep ice cores recently recovered in both polar regions (Zielinski et al, 1996;Clausen et al, 1997). Large volcanic eruptions of global significance may sometimes also be detected in polar ice cores by their glass or silicate grain deposits (de Angelis et al 1985;Palais et al, 1990;Silva and Zielinski, 1998;Zielinski et al, 1997).…”