Originally Posted by paul1888
Just another thought. It states that these coins were found burried at a depth of 3 meters, which is about 9 feet. Having taken and taught a number of earth science courses as well as chemistry, I found it quite puzzling that oxygen dissolved in water could not find its way only nine feet underground. Surface water that is rich in dissolved oxygen will easily move through nine feet of soil.
If three meters of soil were a good preserver of metals, I don't think we would see so much corrosion and patina on base-metal flans or crystalization of billon flans from ground finds...