Evidence of Continental Drift

Alfred Wegener supported his theory of continental drift with several pieces of evidence.

Evidence in the Fossil Record:

  1. In the fossil record of several continents, groups of plants and animals showed a simultaneous, orderly evolution.
    1. At some point in time their evolutionary paths diverged.
    2. Explain what happened.
  2. Paleontologists found fossils of some plants and animals that seemed to have an odd pattern of distribution.
    1. Species of ancient land plants and animals were found to span modern day oceans.
    2. Freshwater species were found on both sides of oceans.
    3. Explain what happened _______________.

Rock Strata Evidence:

  1. Wegener observed that rocks in Eastern Brazil matched those of northeastern Africa.
    1. Matching the rock involves examining the:
      1. rock types (sandstones, shale)
      2. rock ages
      3. sequence or layering of the rock types
      4. Bonus: a particular rock may have distinctive characteristics such as mineral or isotope complement (igneous) or grain characteristics (seds).
  2. Mountainous ranges of similar structure and composition exist in eastern North America, Britain and Scandinavia.
  3. Explain what happened _______________.

Evidence from Paleoclimates:

  1. The continents of the southern hemisphere show evidence of glaciation.
    1. The tell-tale striations that glaciers leave as they scrape across bedrock were confusing.
    2. It appeared as if there were glaciers at the equator and glaciers coming from the sea onto the land!
    3. These striations and glacial deposits are consistent with a Pangaean glaciation at the South pole.
  2. Corals are small animals that build up their homes from calcium carbonate (CaCO3) found in sea water.
    1. Large colonies of corals create vast reefs.
    2. Coral will live only in warm water, but ancient coral reefs are found in Europe and North America.
  3. Coal is the remains of swamp plants accumulating over eons, being buried and then compressed by overlaying rock.
    1. Vast coal fields exist in cold areas such as North America, Antarctica, and Siberia!
  4. Explain what happened _______________.