Zircon In Rocks

 

Relevancy G.S. Paper 1,3

Why in news?

• A 4.2 billion-year-old zircon has been found in a rock from Odisha offers fresh clues about the earth’s origins.

Zircon in rocks:

• A rock sample which was recovered nearly eight years ago from Champua in Odisha’s Kendujhar district has been in news.
• Scientists have found in the rock a grain of magmatic zircon that is an estimated 4,240 million years old.
• It has been deemed a discovery of great promise to study the earth’s early years.
• Zircon is a mineral that contains traces of radioactive isotopes.
• Geologists from the University of Calcutta and Curtin University, Malaysia, along with researchers from the Chinese Academy of Geological Sciences, Beijing, made the discovery.
• Earlier, the only instance of zircon older than this discovery was the one found in Jack Hill, Western Australia.
• Jack hill Zircon is 4,400 million years old and is the oldest known rock sample.
• But the zircon in India is from metamorphosed sedimentary rock, unlike the Singhbhum which was formed from magma.
• Thus, the Singhbhum rock from where the zicron was recovered is the second oldest and its zircon, the oldest magmatic zircon on earth.
• The analyses was done by Chinese scientists.
• It confirmed the presence of two zircon grains that were 4,240 million and 4,030 million years old.
• This adds valuable information about the presence of water in the first few hundred million years of the Earth’s history.
• It will also give us clues to when plate tectonics began.

Zircon:

• Zircon is ubiquitous in the crust of Earth.
• It occurs as a common accessory mineral in igneous rocks (as primary crystallization products), in metamorphic rocks and as detrital grains in sedimentary rocks.
• Large zircon crystals are rare.
• Zircon is also very resistant to heat and corrosion.
• Zircon is mainly consumed as an opacifier, and has been known to be used in the decorative ceramics industry.
• Other applications include use in refractories and foundry casting and in nuclear fuel rods, catalytic fuel converters and in water and air purification systems.
• Zircon is one of the key minerals used by geologists for geochronology.