Measurements of [SO42−] and [NO3−] in firn samples spanning the period 1895-1978 were taken from the Dye 3 1978 core down to 70 m [REF].
In 1979, the initial Dye-3 deep bedrock drilling was started using a 22.2 cm diameter CRREL thermal (US) coring drill to produce an 18 cm diameter access hole, which was cased, to a depth of 77 m.