Excess Argon in Submarine Basalt Pillows
Four deep-sea basalt pillows from near the axis of the East Pacific Rise were investigated for the presence of excess radiogenic argon. Excess argon in the rocks is verified by the presence of an argon gradient. The highest concentrations of radiogenic argon occur in the pillow margins, and at depths of 5 to 8 cm within the pillows, no radiogenic argon can be measured. The complete degassing of the insides of deep-sea pillow basalts suggests that K-Ar ages of deep-sea rocks may be valid if large samples are used.