News Excerpt:
The Garnet found in the Pink sand of Australia proves it to be born in Antarctica mountains.
More about the news:
- The pink hue is due to garnet, a mineral found to be 590 million years old.
- Garnet is rare in beach sand, as it is destroyed by prolonged exposure to the waves and currents of the ocean.
About Garnet:
- Garnet is a mineral that typically appears deep red and forms in environments where large mountain ranges rise due to tectonic plate collisions.
- They may be colourless, black, and many shades of red and green.
- It is not commonly found in beach sand due to its susceptibility to ocean waves and current erosion.
- Garnet crystallizes at high temperatures and can occur as opaque, transparent, or translucent crystals, as well as in pebbles or clusters of intergrown crystals.
- There are six main types of garnet, each with slightly different chemical compositions. These types can sometimes mix, forming combinations like pyrope-almandine or pyrope-spessartine.
- Its formation:
- Garnets form in metamorphic rocks such as schist, amphibolite, and eclogite, as well as in certain igneous rocks like some granites and peridotites.
- The formation of garnet occurs deep within the Earth's crust, under conditions similar to those where diamonds are created.
- Garnet-rich sands often also contain epidote and magnetite.
- Australia is a significant global producer of garnets, contributing nearly half of the world's supply. Other major producers include India, the USA, and China.
- Uses:
- Manufacturing blasting media for industrial applications.
- Producing abrasives used in sandpaper and grinding wheels.
- Cutting stones for mosaics and decorative purposes.
- Creating wall plasters with decorative effects.
- Forming ceramics.
- Polishing picture tubes and glass surfaces.
- Providing anti-skid surfaces for roads and airstrips.
Possible ways through which Garnet could have reached the surface:
- Kimberlite Pipes: Garnets, along with diamonds, can travel to the Earth's surface through carrot-shaped volcanic structures known as kimberlite pipes which are found in South Australia.
- Erosion from Mountain Belts: Garnets are also abundant in regions where the Earth's crust is thick, such as under mountains. Over time, as these mountains wear down through erosion, garnets are exposed.
- The Adelaide Fold Belt: The beach garnets might have originated from the erosion of the Adelaide Fold Belt. This ancient mountain range formed between 514 million and 490 million years ago north of Adelaide.
- Glacial Transport: During the Late Paleozoic Ice Age about 280 million years ago, Australia and Antarctica were connected in the supercontinent Gondwana. Glaciers from East Antarctica likely transported garnet-bearing rocks northwestward towards present-day South Australia.
- Deposition and Erosion: Sedimentary rocks at Hallett Cove Conservation Park, formed around 280 million years ago, and similar deposits on Kangaroo Island contain garnets. These garnets were transported by ice flow and deposited in these areas.
