Here’s an interesting graphic from Shiaiwa et al (Ann Glac 2002) showing dO18 for the top 30+ meters of the Glaciar Tyndall, Patagonia (by comparison, the Kilimanjaro glacier is only about 50 m thick and Thompson’s Himalaya glaciers (other than Guliya Core 2) are about 100-150 meters thick. You will notice sharper dO18 definition in the 10 meters of the core.
Shiraiwa et al (Ann Glac 2002) reported that a 45.97m long ice core was recovered from the accumulation area of Glaciar Tyndall (50 59 05S,73 31 12W; 1756 ma.s.l.), Campo de Hielo Patagonico Sur (southern Patagonia icefield), during December1999.
By the way, this diagram covers about two years of accumulation. Shiraiwa et al:
Annual increments defined by the d18O and D-excess peaks suggest that the minimum net accumulation rates at this location were 17.8 m a-1 in 1997/98-1998/99 and ~11.0 m a-1 in 1998/99-1999/2000.
They expected relatively high accumulation rates, but not this high.