Garnet sands of Myponga Beach
A small beach south of Adelaide whose sand is rich in pink to orange garnet. Most of those garnets did not come from South Australia: they grew about 590 million years ago in mountains now buried under the East Antarctic ice, and reached this coast in the ice sheets of the late Palaeozoic ice age.
Dated events and their evidence
- about 1,627,000,000 years ago mainstream
garnet grows in the Barossa Complex gneiss of the Myponga Inlier during metamorphism (Lu-Hf age 1627 ± 23 million years); a minority of the beach's garnets come from these local rocks source - about 590,000,000 years ago mainstream
the beach's main garnet population grows, about 590 million years ago, during an Ediacaran mountain-building event that has no known source in South Australia and is traced to East Antarctica source - about 300,000,000 years ago mainstream
ice sheets flowing from the south-east carry the garnet out of East Antarctica and leave it in the glacial Cape Jervis Formation, around the late Carboniferous to early Permian, about 300 million years ago source - 2024 CE mainstream
11 June: Verhaert and colleagues publish Lu-Hf dates of 557 detrital garnets from four South Australian beaches, Myponga Beach among them, and from the Cape Jervis Formation source
Where
35.3740° S, 138.3870° E
The point is Wikipedia's position for the locality of Myponga Beach, which runs about 18.7 km along the coast of Gulf St Vincent; the beach itself lies in Coweelunga Bay at the mouth of the Myponga River.
Sources
- https://doi.org/10.1038/s43247-024-01467-8
- https://theconversation.com/south-australias-enigmatic-pink-sand-was-born-in-ice-covered-antarctic-mountains-new-research-shows-230781
- https://en.wikipedia.org/wiki/Myponga_Beach,_South_Australia
- https://ozgeology.com/blogs/news/south-australia-s-pink-sands-beaches-born-from-ancient-antarctic-mountains
Each event carries Aion's own evidence grade (mainstream, disputed or speculative). This page repeats what the globe shows for this place.