Geology, Access, Glaciers and climbing Of Puncak Jaya

Puncak Jaya is the highest point on the central range, which was created in the late Miocene Melanesian orogeny, caused by oblique collision between the Australian and Pacific plates and is made of middle Miocene limestones.

Access to the peak requires a government permit. The mountain was closed to tourists and climbers between 1995 and 2005. As of 2006, access is possible through various adventure tourism agencies.

While Puncak Jaya’s peak is free of ice, there are several glaciers on its slopes, including the Carstensz Glacier and the Northwall Firn. Being equatorial, there is little variation in the mean temperature during the year (around 0.5°C) and the glaciers fluctuate on a seasonal basis only slightly. However, analysis of the extent of these rare equatorial glaciers from historical records show significant retreat since the 1850s, around the time of the Little Ice Age Maximum which primarily affected the Northern Hemisphere, indicating a regional warming of around 0.6°C per century between 1850 and 1972.

The glacier on Puncak Trikora in the Maoke Mountains disappeared completely some time between 1939 and 1962. Since the 1970s, evidence from satellite imagery indicates the Puncak Jaya glaciers have been retreating rapidly. The Meren Glacier melted away sometime between 1994 and 2000. An expedition led by paleoclimatologist Lonnie Thompson in 2010 found that the glaciers are receding at a rate of seven meters per year and will disappear in four to five years.

Puncak Jaya is one of the more demanding climbs in one version of the Seven Summits peak-bagging list. (It is replaced by Mount Kosciuszko in the other version.) It is held to have the highest technical rating, though not the greatest physical demands of that list's ascents. The standard route is up the north face and along the summit ridge, which is all hard rock surface. Despite the large mine, the area is highly inaccessible to hikers and the general public, requiring a 100-km hike from the nearest town with an airport, Timika, to the base camp, which usually takes about four or five days each way.