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USGS Geology in the Parks

View of Earth, 514 million years ago Tmescale timebar 514 million years ago

514 million years ago

Late Cambrian

What's going on here?

  • Seas flooded the continents during much of the Cambrian. The continents of Laurentia (the core of what is now North America), Baltica (Northern Europe), and Siberia split apart and a new ocean, the Iapetus Ocean, was born.
  • Notice that the core of North America, Laurentia, has moved northward so that it's sitting at the Equator. During the Cambrian much of the continent is flooded by a shallow, tropical sea. Thick deposits limestone formed from the remains of countless shelled marine animals that died and accumulated on the sea bottom. These ancient Cambrian limestones are preserved within many National Parks.
  • That huge continent straddling the South Pole and Equator is Gondwana, one of the supercontinent remnants from the Late Proterozoic.

Reconstructing ancient Earth

These remarkable figures are produced by C.R. Scotese and the PALEOMAP project. Geologists call these illustrations paleogeographic reconstructions, because they illustrate the reconstructed geography of our Earth at some time in the past.

Making a paleogeographic reconstruction begins by examining several lines of evidence including: paleomagnetism, magnetic anomalies, paleobiogeography, paleoclimatology, and geologic history. By combining all available evidence, geologists are able to construct paleogeographic maps, such as these, that interpret how the geography might have appeared at a specific location and time in the past. Paleogeographic maps are continually being refined as more evidence is collected.

To find out more about how paleogeographic reconstructions are made visit the PALEOMAP project site.

Move forward or back in time.
| Today | 0.018 | 14 | 50 | 69 | 94 | 152 | 195 | 237 | 255 | 306 | 356 | 390 | 425 | 458 | 514 | 650 |
Time in millions of years. Jump back to visit any time!

Scotese, C. R., 1997. Paleogeographic Atlas, PALEOMAP Progress Report 90-0497, Department of Geology, University of Texas at Arlington, Arlington, Texas, 37 pp.

| Into Earth | | Putting the pieces toge ther | | Action at the edges |
| National Parks by Tectonic Regions |
| Earth through time | | Detailed version: This Dynamic Earth |


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