The Toba super-eruption: Micro-scale traces of a global-scale climate event?

Kim M. Cobb

Stacy Carolin, Jessica Moerman, Ellery Ingall, Luke Chambers, Amelia LongoGeorgia Inst. of Technology

Nele Meckler, Jess F. AdkinsCaltech

Lydia FinneyArgonne National Lab

Victoria SmithOxford

Syria Lejau, Jenny Malang, Brian Clark, Alison PritchardGunung Mulu National Park

Andrew TuenUniversity Sans Malaysia

The Tobasuper-eruption:

73.88 ± 0.6 kybp(Storey et al., 2012)

~3,000km3 DRE

VEI of 8

Mulu

Miller and Wark, 2008

Miller and Wark, 2008

Relative eruption magnitudes

Did Toba play a role in an observed “bottleneck” inhuman mitochondrial genetic diversity?

Maybe. [Ambrose 1998]

No. [Petraglia et al., 2007]

see review by Williams et al., 2012

NOTE: H. floresiensislived during this time,discovered in cavewithin Toba ash fall zone

Volcanoes impact global climate: Instrumental data

100x smaller than Toba

300x smaller than Toba

Kelly et al., 1996eruption

Volcanoes impact global climate: Paleoclimate data

IPCC, 2013

data-model comparison provides critical constraints on climate sensitivity: temperature response to changein radiative forcing

Volcanoes impact global climate,but how much?

Fact: models tend to cool more than paleoclimate data suggest

problem with models?(e.g. Timmreck et al., 2010)

or data?(Mann et al., 2012, 2013;Anchukaitis et al., 2012)

IPCC, 2013

Robock et al., 2009

Modeling Toba’s effects in CCSM3

dire effects in first 10yrsdissipate in ~30yrs

BEFORE

+1-4yr

Robock et al., 2009

huge vegetation response across entire tropics in model

need to look i) regionally ii) at hydroclimateiii) and model δ18OR forcomparison to proxy records

Modeling Toba’s effects in MPI-ESM

Timmreck et al., 2012

smaller global responsethan CCSM3, but verylarge in some regions

global TToba

Borneo stalagmites as records of regionalclimate and environmental history

U/Th dated

many overlappingsamples to testreproducibility

oxygen isotopesreflect regionalhydroclimate(Moerman et al.,2013, 2014)

stalagmite oxygenisotope recordsreproducible

reveal many largemillennial-scaleexcursionstowards dryconditions(blue bars = Heinrich events)

Carolin et al., Science 2013

MULU

GREENLAND

HULU

MULU

largest anomalyassociated withToba super-eruption

also captured asout-sized eventin Hulu stalagmiteoxygen isotopes

dry conditionsfor ~1,000yrs

GREENLAND

HULU

MULU

A closer look

Carolin et al., 2013

Wang et al., 2001Wang et al., 2008

Huang et al., 2001

NGRIP, 2004

EPICA, 2006Svensson et al., 2012

ash layer in South China Sea corresponds to initiation of cooler reconstructed SST

Carolin et al., 2013

Wang et al., 2001Wang et al., 2008

Huang et al., 2001

NGRIP, 2004

EPICA, 2006Svensson et al., 2012

multiple sulfate peaks in Antarctic ice core tiedto sulfate peaks in Greenland relationship to Toba

eruption(s)?

A closer look

Research questions:

1) How many times did Toba erupt ~74,000yrs ago?And with what relative sizes?

2) What were the regional hydroclimate impacts ofthe eruption(s)?

3) Did Toba-related climate effects in the WesternPacific have an effect on global climate?Did Toba shape the timing or depth of GS20?

Approach:

Find Toba’s volcanic markers in the Borneo stalagmites.

Compare to oxygen isotope-based climate record in same stalagmites.

Available stalagmites

GOT ASH? Preliminary synchrotron Fe data

Preliminary SIMS Sulfur profile

10μm beam = ~2.2yrs20μm sampling res = 4yrs

data from Stacy Carolin

initiation of regionaldrying

~550yrs

Tobaeruptions?

younger older

Next steps:

Geochemically fingerprinti) Toba ash samplesii) Mulu clay samples

Compare to synchrotron/SIMS scans across iii) Toba horizoniv) known hiatuses

Elements of interest(Fe, Si, S, Br, K, Al)*see review by Frisia et al., 2012

Lane et al., 2013Mermut and Cano, 2001