MOUNTAIN BUILDING AND EVOLUTION OF PEAK JAYA, OCEANIA

The Peak Jaya and its neighboring areas within the New Guinea island in Oceania are located at the junction of several lithospheric plates: Pacific plate, Australian plate and Southeast Asian plate. In the Peak Jaya are present a concentration of tectonic stress, an intensification of tectonic disturbance and a complicate tectonic evolution history. The mountain building of Peak Jaya is a product of subduction of north Australian passive continental margin into the area below the Melanesian island arc since the Miocene. Since 2.8 Ma, the rock uplift amplitude of the Peak Jaya has reached about 7 000 m with the uplift rate 2.5 mm/a and the exhumation rate 0.7 mm/a.Based on the dating of the Carboniferous-Permian obtained in the southern slope of Peak Jaya, the rock uplift amplitude has reached, since 2.3 Ma, 6 500 m with the uplift rate 2.8 mm/a and exhumation rate 1.7 mm/a. Further to the south, there exists a greenschist domain of probably Precambrian. The exhumation rate there has reached a faster rate, since the exhumed depth has already reached 9 km, the deepest part of the whole island. It is this violent down-cutting and exhumation that has made Peak Jaya the highest peak in Oceania by means of equilibrium elevation.