Maoke

History

The past. The ice age: as the cold deepened, the forest line on the Maoke Mountains came down, and by 27,354 years ago the forest ended near 2,300 metres, about 1,600 metres lower than today. Almost a fifth of the plate lay above it: grassland with tree ferns, and ice caps on the highest peaks around Puncak Jaya. In New Guinea’s mountains the forest began to climb back 17,113 years ago; the ice had shrunk to the highest summits by about 13,000 years ago, and by 9,603 years ago the forest reached 4,000 metres. The last small glaciers on Puncak Jaya, about 19 square kilometres around 1850, were expected in 2019 to vanish within a decade. The lines that stand for the forest turn to the colour of grassland, all at once, and only across those spans.

12 million years ago

The mountains of central New Guinea began to rise as the edge of Australia entered a subduction zone.

8 million years ago

Full collision began, thickening the crust and building the high Central Range.

Sources: Hope 2014, Arctic, Antarctic, and Alpine Research 46:777; Chappell 2005 and Hope and Haberle 2005, Papuan Pasts, Pacific Linguistics 572; Haberle 1993, PhD thesis, Australian National University; Klein and Kincaid 2006, Journal of Glaciology 52:65; Permana et al. 2019, PNAS 116:26382 · Cloos et al. 2005, GSA Special Paper 400