A comparison of the volcanic records over the past 4000 years from the Greenland Ice Core Project and Dye 3 Greenland ice cores.

Journal of Geophysical Research, Vol. 102, No. C12, p. 26,707-26,723, 1997

H.B. Clausen, C.U. Hammer, C.S. Hvidberg, D. Dahl-Jensen, J.P Steffensen
Departement of Geophysics, The Niels Bohr Institute of Astronomy, Physics and Geophysics, University of Copenhagen.
J. Kipfstuhl
Alfred-Wegener-Institut für Polar- und Meeresforschung, Bremerhaven, Germany.
M. Legrand
Laboratoire de Glaciologie et de Geophysique de l'Environnement, Centre National de la Recherche Scientifique St. Martin d'Héres, France.

Since 1980 the electrical conductivity method (ECM) has been used to infer volcanic acid signals in Greenland ice cores. The method reveals the great mejority of major volcanic eruptions, including several known from historic records. Subsequent ion chromatography analyses of the acid volcanic layers show the chemical composition, i.e.., the concentration of the colcanic acids H2 SO4, HCl, and HF plus, e.g., the nonvolcanically derived HNO3. While ECM data are available from a large number of shallow depth Greenland ice cores, covering the past 500-1500 years, only the Greenland Ice Core Project (GRIP), Greenland Ice Sheet Project 2 (GISP2), and Dye 3 deep ice cores exist for a detailed comparative study of volcanic signals in Greenland ice cores representing several thousand years. Comparison of the volcanic signals registered in the GRIP and GISP2 cores will be presented elsewhere. The latter cores were augered 30 km apart and essentially represent the same atmospheric conditions such as temperature, snow accumulation, and chemical composition of the air. Here we present a comparison between the major volcanic signals over the past 4000 years in the GRIP core from central Greenland and the Dye 3 core from SE Greenland in order to investigate the depositional differences. Many of the major signals are detected in both cores, but some of the differences in the records can be used to infer the latitudinal band of some eruption sites. Furthermore, the influence of the amount of annual precipitation and glaciological postdeposittional processes on the colcanic signals is discussed.