SCIENCE

Scientists Discover Possible ‘Lost Continent’
Researchers may have discovered granite remnants of a “lost continent” off the coast of Brazil this week.

How do continents get lost in the first place? (They lie low after bad break-ups.)

Discussion Ideas:

• Granite boulders discovered far off the coast of Rio de Janeiro, Brazil, may be remnants of a giant continent that was “lost” as movements in the Earth’s lithosphere (crust and upper mantle) ripped it apart between 100 million and 200 million years ago. The CNN video identifies this ancient “lost continent” as Gondwana, part of the “supercontinent” of Pangaea. Look at our map gallery on “Earth’s Tectonic Plates,” which illustrates the movements of tectonic plates from 600 million years ago through today. Gondwana is not identified in the map gallery. On what slide would students label Gondwana?
  • According to the article and video, Gondwana was the southern part of Pangaea, which started to rift, or break apart, about 200 million years ago. The fourth slide, “Geologic Plates 200 million years ago,” is probably the best place to identify Gondwana. By the next slide, South America and Africa have entirely split and Gondwana has been “lost” in the early Atlantic Ocean.
• We know Gondwana included the modern continents of South America and Africa. What other modern continents survived the “loss” of Gondwana? Look at the “Geologic Plates 200 million years ago” map for clues.
  • Australia and Antarctica were also a part of Gondwana. The so-called Indian Subcontinent of south Asia (really, the Indian tectonic plate) was a part of Gondwana, too.
• Continents continue to drift and rift today. Places where the Earth’s crust is splitting are called rift valleys. Read our short encyclopedic entry on rift valleys. Where do students think a continent is being rifted apart and “lost” today?
  • The Great Rift Valley in eastern Africa (technically, the East African Rift) is tearing apart the continent. Geologists say that the continent we know today as Africa will, like Gondwana, be “lost” in millions of years. Two distinct landmasses will likely remain: the Nubian tectonic plate, which will carry most of what we think of as Africa, and the Somali tectonic plate, which will carry the Horn of Africa.