Antartica and North America were connected 1.1 billion years ago

Here’s an interesting news about geography. A team of International researchers from California State University confirmed that North America and Antartica are connected 1.1 billion years ago! Wow! It’s a billion years ago and yet, they still discovered that these two continents are one! And this was before the super continent Panagea was formed!

If you don’t know what the hell is Panagea, it was the supercontinent that existed during the Paleozoic and Mesozoic eras about 250 million years ago, before the component continents were separated into their current state right now. Panagea in ancient greek means “Entire earth”.

Loewy, the leader of the researchers from CSU, and her colleagues discovered that rocks collected from both locations have the exact same composition of lead isotopes. The rocks to be the exact same age and have the same chemical and geologic properties, in an earlier analysis.

The estimation of 1.1 billion year old North American Mid-continent Rift System extends across the continent from the Texas to Great Lakes. Volcanic rocks associated with the rift are well exposed in the Keweenaw Peninsula of the Upper Peninsula of Michigan from which they take their name, the Keweenawan large igneous province.

The rift extends in the subsurface beneath Nebraska, Minnesota, Iowa, Kansas and Oklahoma to the Franklin Mountains near El Paso, Texas where related rocks are exposed. Loewy, Ian Dalziel, research professor at The University of Texas at Austin, Richard Hanson of Texas Christian University and colleagues from several overseas institutions, find that rocks barely peeking through the ice in Coats Land, a remote part of the Antarctic continent south of the Atlantic Ocean basin, reflect a former continuation of the North American rift system.

Dalziel and Leowy began working together several years ago for this research. The team use new lead (Pb) isotopic data from the 1.1-billion-year-old rocks from Coats Land, to constrain the positions of Laurentia and Kalahari in the 1-billion-year-old supercontinent, Rodinia. The Coats Land rocks are same in age to both the Keweenawan large igneous province of the North American mid-continent rift and the contemporaneous Umkondo large igneous somewhere in South Africa.

The Coats Land block collided with the Kalahari Precambrian craton of Africa during a collision for billions of years. Laurentia collided with Kalahari along Antarctica’s Maud mountain belt, which would represent a continuation of the 1-billion-year-old Grenville mountain belt of eastern and southern North America.

Comparison of the isotopic compositions unequivocally links the Keweenawan province and the Coats Land rocks. Together with paleomagnetic data this suggests that the Coats Land block was a piece of Laurentia near west Texas 1.1 billion years ago.

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