The surfaces of the deep ice cores from Greenland and Antarctica were contaminated during drilling at concentration levels several orders of magnitude greater than those found in the uncontaminated ice. Several procedures for removing these contaminants were studied. Ultrasonic vibration followed by self-cleaning in meltwater was found to be the most effective procedure for removal of surface contamination. (Author).

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"This report documents most of the ice cores so far collected on a world-wide basis, as well as providing information on literature sources and on the currents status of research activities which may affect the types of data that can be archived."--Foreword.

Over 100 samples taken at about 15-m intervals in the portion of the Camp Century ice core between 70- and 1360-m depths were analyzed for their Na(+), K(+), Ca(2+) and Mg(2+) contents by atomic absorption spectroscopy. Based on independent stable isotope analyses these maxima occurred over the last third of the Wisconsin glaciation.