Oceania



Australia, New Guinea, Tasmania and the Aru Islands are one and the same landmass, Sahul, covering a total of four million square miles. On Great Lakes Earth, the distance between it and Antarctica is 700 miles. This is because of the historical difference between our Earth and Great Lakes Earth. Back home, Tasmania, Australia and New Guinea broke off from Antarctica between 40 and 30 million years ago. On Great Lakes Earth, that happened between 20 and 15 million years ago.


Sahul’s highest point, Mount Kosciuszko, measures 23,984 feet above sea level. However, it, as well as the rest of the Great Dividing Range, would have been mostly coastal, as the entire Darling River and Lake Eyre basins are underwater, separated by a narrow peninsula.


The other major ranges of Australia, Hamersley and Macdonnell, are also far taller than back home—respectively, they reach elevations of 13,445.6 and 16,480 feet above sea level. Mount Ossa, the highest point in what we’d call Tasmania, rises up to 17,404 feet above sea level.


Where we’d expect to find the Gulf of Carpentaria, we find instead Lake Carpentaria, covering an area of less than 45,000 square miles and 82 feet below sea level at the deepest.


New Guinea, other than being connected to mainland Australia, isn’t that much different from back home. That said, its mountains, like so many others, are so much higher. Its highest point, Puncak Jaya, stands 20,908 feet above sea level.


750 miles southwest of Sahul is Broken Island, a 250-mile-wide piece of Kerguelen that is currently 900 miles northeast of its original parent. It’s a very mountainous island, with a maximum height of 10,000 feet above sea level. It rose from the surface thanks to magma during the Golden Age of Granite.


On the opposite direction is perhaps the most familiar contribution to the Golden Age of Granite. Back home, Zealandia was a very real continent. But between 50 and 35 million years ago, it sank to the bottom of the South Pacific, leaving only six percent of it above the surface. This six percent—a total of 113,514 square miles—consists of the islands of New Zealand and New Caledonia. But that’s not what happened here on Great Lakes Earth. From 50 to 35 million years ago, multiple episodes of magmatic intrusions had thickened the granite, floating it back up to the surface. The uplifts were so successful that 94% of the continent currently stands above the surface, and Mounts Panié and Cook, its two highest peaks, stand not 5,341 or 12,218 feet above sea level, as is the case back home, but 17,522 and 25,232 feet.


There is another large island in Oceania on Great Lakes Earth. Once a basaltic province that sank during the Cretaceous Period, granitic magma lifted the Manihiki Plateau up to the surface. Measuring in at 300,000 square miles in area, it stands no taller than 980 feet above sea level.


There is another basaltic plateau uplifted by granitic magma, Ontong Java. It measures in at 580,000 square miles in area and doesn’t get any higher than 5,600 feet above sea level. With Australia and New Guinea being placed more southerly, it doesn’t stand so close to a subduction zone as it does back home, which means that the Solomon Islands either never existed on Great Lakes Earth or are submerged beneath the waves. The uplfitings of both Ontong Java and Manihiki are the only explanations we can think of as to why Galapagos never existed and why the Hawaiian hotspot expired a long time ago.