100- kyr cyclicity in volcanic ash emplacement: evidence from a 1.1\u2009Myr tephra record from the NW Pacific

Julie C Schindlbeck,Maryline J Mleneck-Vautravers,Steffen Kutterolf,Armin Freundt,Jerry F Mcmanus,Marion Jegen,Susanne M Straub

doi:10.1038/s41598-018-22595-0

Abstract

It is a longstanding observation that the frequency of volcanism periodically changes at times of global climate change. The existence of causal links between volcanism and Earth’s climate remains highly controversial, partly because most related studies only cover one glacial cycle. Longer records are available from marine sediment profiles in which the distribution of tephras records frequency changes of explosive arc volcanism with high resolution and time precision. Here we show that tephras of IODP Hole U1437B (northwest Pacific) record a cyclicity of explosive volcanism within the last 1.1 Myr. A spectral analysis of the dataset yields a statistically significant spectral peak at the ~100 kyr period, which dominates the global climate cycles since the Middle Pleistocene. A time-domain analysis of the entire eruption and δ18O record of benthic foraminifera as climate/sea level proxy shows that volcanism peaks after the glacial maximum and ∼13 ± 2 kyr before the δ18O minimum right at the glacial/interglacial transition. The correlation is especially good for the last 0.7 Myr. For the period 0.7–1.1 Ma, during the Middle Pleistocene Transition (MPT), the correlation is weaker, since the 100 kyr periodicity in the δ18O record diminishes, while the tephra record maintains its strong 100 kyr periodicity.

Highlights

Myr tephra record from the NWWe show that tephras of IODP Hole U1437B (northwest Pacific) record a cyclicity of explosive volcanism within the last 1.1 Myr. A spectral analysis of the dataset yields a statistically significant spectral peak at the ~100 kyr period, which dominates the global climate cycles since the Middle Pleistocene
Cyclic variations with periods of 104 to 105 years lie in the range of orbital forcings (Milankovitch cycles) of global climate
A critical factor in the evaluation of possible orbital periodicities in volcanic records is the length of the record, yet most of the published studies only encompass the last glacial period. Are these findings of climate/volcanism interaction true for earlier glacial periods? The marine tephra record of explosive arc volcanism recovered by IODP Hole U1437B near the Izu-Bonin arc provides such a long well-constrained stratigraphy of time‐varying volcanic activity that spans multiple glacial cycles and offers the opportunity for a crucial test of whether these findings of climate/volcanism interaction are a persistent feature of glacial intervals

Summary

Myr tephra record from the NW

We show that tephras of IODP Hole U1437B (northwest Pacific) record a cyclicity of explosive volcanism within the last 1.1 Myr. A spectral analysis of the dataset yields a statistically significant spectral peak at the ~100 kyr period, which dominates the global climate cycles since the Middle Pleistocene. To further investigate the temporal relation of increases in volcanic activity relative to glacial/interglacial transitions we calculated the correlation coefficient as a function of time lag between the δ18O time series and the ash time series (Fig. 4b, see Supplementary Information S1.2), i.e. we shift the entire tephra time series by a certain time lag and calculate the correlation with the unshifted δ18O record. We conclude that the observed correlation over the entire record is mainly due to a pronounced correlation post-MPT, which masks the poor correlation during MPT

Discussion

Conclusion