Scientists Discover ‘Drowned’ Microcontinent Near Madagascar
An ancient microcontinent located between Madagascar and India has been potentially discovered by scientists.
Researchers believe they discovered the continent after examining evidence from Mauritius, a volcanic island about 900 kilometres east of Madagascar.
According to Nature:
“The oldest basalts on the island date to about 8.9 million years ago, says Bjørn Jamtveit, a geologist at the University of Oslo. Yet grain-by-grain analyses of beach sand that Jamtveit and his colleagues collected at two sites on the Mauritian coast revealed around 20 zircons — tiny crystals of zirconium silicate that are exceedingly resistant to erosion or chemical change — that were far older.”
“The zircons had crystallized within granites or other igneous rocks at least 660 million years ago. One of these zircons was at least 1.97 billion years old.”
The group of researchers propose that geologically recent volcanic eruptions brought shards of the crust to Earth’s surface where the zircons eroded from their parent rocks to pepper the island’s sands.
In their paper, researchers suggest that many fragments actually lay behind the continental crust of the Indian Ocean. In fact, upon analyzing the Earth’s gravitation field, there appears to be several broad areas where the sea-floor crust is much thicker than other areas, sometimes by nearly 200 percent.
The thicker crustal anomalies are where researchers believe Mauritia lies.
Researchers, in an attempt to remain as true to their tests as possible, collected sand rather than pulverizing rocks. The group argues that zircons inadvertently trapped in rock-crushing equipment from previous studies did not contaminate their fresh samples.
Whether or not Mauritius exists is yet to be determined. If the research group’s process proves to be a success, other geological researchers believe sunken continents and microcontinents may one day be discovered in other regions.
The group’s full study can be read via Nature Geoscience.