Artifacts of a long-lost region may lurk beneath the Indian Ocean.
Tiny zircon crystals coughed up by volcanic eruptions on the island of Mauritius are about 2. 5 million to three billion years old. That's huge amounts of years older than the island itself, researchers report January 31 in Nature Sales and marketing communications. The zircons, the research workers propose, are remnants of an ancient continent called Mauritia that formed part of the nexus of Madagascar and India prior to the two landmasses split aside around 84 million years back (SN: 1/21/17, p. 18).
Comparing the crystals' age ranges with those of local landmasses, petrologist Lewis Ashwal of the University of the Witwatersrand, Johannesburg and colleagues retraced Mauritia's destiny. Volcanic eruptions and switching tectonic plates fragmented Mauritia, the researchers say, and the land was eventually buried under thick tiers of lava. Some of that land, including the zircon crystals, was reused into the rising penne of magma that supported the eruptions that eventually built Mauritius.
A small number of zircons dating back again practically 2 billion years had recently been uncovered in the island's sands. A lot of scientists raised concerns that those crystals were helped bring to the island from elsewhere as part of ship ballast or building material. Ashwal and acquaintances pried the newfound uric acid from rocky outcrops on the island, erasing any doubts of the zircons' origins.
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