Plate Tectonics

  • Abraham Ortelius

    Suggested that all the continents were once all together.Also known as Pangea. They all drifted apart from earthquakes and floods.
  • Period: to

    Nicolaus Steno

    The law of superposition is in a sequence of sedimentary layers, each layer of rock is older than the layer above it and younger than the rock layer below it.
  • James Hutton

    Uniformitarion Principle- the geological forces at work in the present day are the same as those in the past.
    The law of Crosscutting- If a body of rock is cut through another rock , then it must be younger in age through which it cuts and displaces.
    Relative Age Dating Strata-Sedimentary rocks below are older, and rocks above are younger.
  • Alfred Lothar Wegener

    Was one of the first to suggest continental drift and plate tectonics. He suggested that a supercontinent he called Pangaea had existed in the past, broke up starting 200 million years ago, and that the pieces ``drifted'' to their present positions. He cited the fit of South America and Africa. Also the continental drift theory.
  • Arthur Holmes

    He believed in the Pangaea theory, in addition he studied rocks and minerals.
    Convection currents theory- A magma is heated it tends to rise, then cools then sinks again
  • Harry Hess

    Seafloor Spreading. If the oceans have existed for at least 4 billion years,as most geologists believed, why is there so little sediment deposited on the ocean floor? Hess reasoned that the sediment has been accumulating for about 300 million year at home
  • Dan McKenzie

    He concluded that there are two layers in the mantle, each of them in motion, which contribute to continental drift. He postulated that rotational vectors explain the behavior of plates and explains the formation of ridges, trenches and transform faults. He refuted two other models of the earth that were apparently prevalent at the time; one posited that the earth was a homogeneous sphere,and the other that the core is inviscid and that the mantle is homogeneous.