[4][5] The original volcano on the site of Mount Giluwe formed roughly 650,000–800,000 years ago, probably as a stratovolcano of similar height to the current peak.

Extensive Pleistocene glaciation eroded away much of the peak, leaving a series of volcanic plugs which form the present-day summits.

Outlet glaciers extended down as low as 3,200–3,500 m (10,500–11,500 ft), leaving a variety of deposits including glacial till and moraines.

[4] Australian explorers Mick Leahy, and his brother Dan, were the first Westerners to reach the area and to discover and climb Mount Giluwe.

However, another explorer Jack Hides also laid claim to be the first to discover Mount Giluwe after viewing the peaks from the west in 1935.

Above this is the upper montane rainforest or moss forest, with stunted moss-shrouded trees such as Quintinia and conifers including Papuacedrus and Podocarpus.

Scarlet Rhododendron and Dimorphanthera abound in the gnarled dwarf forest and white beard lichens hang in the branches.