Which is the largest continent? The smallest?

World Map Topographic Map — Are you able to inform which continents are largest and smallest based mostly on this topographic map of the world, or is there greater than meets the attention? (Picture credit score: FrankRamspott)

A whole lot of tens of millions of years in the past, a supercontinent known as Pangaea shaped. For about 125 million years, it contained virtually all the dry land on Earth. Since then, chunks of Pangaea have drifted aside and recombined in new methods. So which is the biggest continent at present? And what in regards to the smallest?

The reply is determined by what counts as a continent. In response to the CIA World Factbook (opens in new tab), the biggest continent is Asia. Asia covers greater than 17 million sq. miles (44 million sq. kilometers). Africa is the next-largest continent, then North America, South America, Antarctica, Europe and Australia.

However geographers have argued in regards to the continents since antiquity. Writing within the sixth century B.C., the Greek historian Herodotus questioned why the names Asia, Africa and Europe needs to be given to, “what is mostly a single land mass; and why, too, the Nile and the Phasis — or, based on some, the Maeotic Tanis and the Cimmerian Strait — ought to have been fastened upon for the boundaries.” In response to the guide “The Fantasy of Continents; A Critique of Metageography (opens in new tab)” (College of California Press, 1997), divisions between continents are based mostly largely on custom and tradition.

Continents are massive areas of land principally surrounded by water — however that definition leaves room for interpretation. At present, Europe and Asia are generally mixed (opens in new tab) and known as “Eurasia.” Likewise, many youngsters in Latin American international locations like Chile (opens in new tab) study the Americas as one continent as an alternative of two. Mixed, the Americas have an space of simply over 16 million sq. miles (42 million sq. km) — bigger than Africa however nonetheless smaller than Asia.

In some interpretations, Australia is the smallest continent, at just below 3 million sq. miles (8 million sq. km). Geologists outline continents otherwise, nevertheless, and add at the very least yet another continent that’s even smaller.

Associated: The place are most of Earth’s volcanoes?

Continents, based on geologists

“Continents have a selected crustal construction,” stated Joann Inventory (opens in new tab), a professor of geology and geophysics on the California Institute of Know-how. “They’re composed of rocks which might be much less dense than the rocks within the ocean basins.”

Each sorts of rock exist on tectonic plates, items of Earth’s crust that float round on the recent magma beneath the planet’s floor. For geologists, continents are massive areas of contiguous continental crust. Utilizing that definition, geologists acknowledge a continent known as Zealandia that’s even smaller than Australia.

When tectonic plates stumble upon one another, areas made from ocean crust usually get shoved beneath continental crust and again into the magma. “They get recycled,” Inventory informed Reside Science. Continents, alternatively, have a tendency to remain on the floor of the Earth. Regardless that continental rock is normally gentle sufficient to remain above sea stage, it would not all the time stay above water.

Rising seas can cowl continental rock. Continental rock may stretch and skinny, pushing it partly beneath sea stage. That is the case round New Zealand. New Zealand’s islands are literally the tallest factors on a principally submerged continent with an space of just about 2 million sq. miles (5 million sq. km). In response to analysis printed within the Geological Society of America (opens in new tab) in 2017, that continent is named Zealandia, and “geologists do contemplate it a continent,” Inventory stated.

Whereas New Zealand has a land mass lower than 4% as massive as Australia’s, Zealandia is about two thirds the dimensions of Australia. “There’s this Regulation of the Sea Treaty the place international locations can declare continental areas which might be hooked up to their continents beneath sea stage,” Inventory stated. New Zealand efficiently expanded (opens in new tab) its underwater territory by mapping Zealandia’s edges.

The smallest continents

But when Zealandia counts as a continent, is it the smallest continent? Or are there even smaller continents within the working? When massive continents break aside, it seems to be like a shattered plate — there are massive items like Africa, medium-size items like Zealandia, and many tiny shards of continental rock. These shards are often known as microcontinents. Some are islands; others are totally beneath sea stage.

Inventory stated most geologists do not actually consider microcontinents as continents. As an alternative, they reserve the label for giant chunks — in essence, “ones that geologists may research and see how they match again collectively.” In response to the geologists who argued to incorporate Zealandia as a continent in 2017, there is not a powerful consensus on whether or not something smaller ought to rely.

Nonetheless, finding out microcontinents is helpful. In response to Inventory, figuring out that rocks are continental in origin — versus, say, volcanic, just like the Hawaiian Islands — might help geologists establish the place assets equivalent to minerals or fossil fuels may be discovered.

Inventory research one of many smallest microcontinents recognized up to now: a small island within the Gulf of California known as Isla Ángel de la Guarda (additionally known as Archangel Island) that has an space of simply 359 sq. miles (930 sq. km), or about the identical dimension as town of Indianapolis. It shaped, Inventory stated, as a result of a sport of geologic tug-of-war. Initially, “the Baja California Peninsula was caught to the remainder of Mexico,” she stated. All of California was a part of the North American tectonic plate. Then, “the Pacific Plate grabbed it” about 10 million years in the past.

Analysis from Inventory and her colleagues, printed within the journal Tectonics (opens in new tab) in 2022, means that the rift between the 2 plates later moved once more round 2 million years in the past, leaving a small chunk of continental crust from Baja California — Isla Ángel de la Guarda — again on the North American plate, surrounded by ocean crust, in impact making it a microcontinent. “That may occur in slip-strike faults,” Inventory stated. Or, in tug-of-war phrases: “the Pacific Plate gave it again.”

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