Rapid speleothem δ13C change in southwestern North America coincident with Greenland stadial 20 and the Toba (Indonesia) supereruption Polyak, Victor J. ; Asmerom, Yemane ; Lachniet, Matthew S. Abstract Publication: Geology Pub Date: September 2017 DOI: 10.1130/G39149.1 Bibcode: 2017Geo....45..843P