THE GEOCHEMISTRY OF LEACHED DRAMMEN MARINE CLAY

IN A PROFILE AT TINGSHUSET, DRAMMEN, NORWAY, A RATHER UNIQUE CONDITION EXISTS WITH RESPECT TO SENSITIVITY AND SALT CONTENT OF THE CLAY DEPOSIT. THE CLAY IS ORIGINALLY DEPOSITED IN SEA WATER, AND THE SALT HAS SUCCESSIVELY BEEN LEACHED OUT FROM BENEATH DUE TO ARTESIAN OVERPRESSURE. AT A CERTAIN TIME THE ENTIRE PROFILE IS BELIEVED TO HAVE BEEN QUICK. HOWEVER, AT THE PRESENT TIME, THIS IS NOT THE CASE. BELOW THE QUICK ZONE THE SENSITIVITY HAS BEEN REDUCED TO LESS THAN 20 EVEN THOUGH THE SALT CONTENT IS VERY LOW THROUGHOUT THE PROFILE. THE PHENOMENON IS EXPLAINED BY IN-SITU PRODUCTION OF MAGNESIUM AND CALCIUM IONS PROBABLY DUE TO AGGRESSIVITY OF THE UPWARD STREAMING FRESH WATER ATTACKING THE MORE UNSTABLE MINERALS. /AUTHOR/