GEOL 101 Lecture Notes - Lecture 9: Continental Drift, Focal Mechanism, Plate Tectonics
Document Summary
There are two aspects of plate tectonic theory that come from its historical development. Data hypothesis theory law. Data- observations of the natural world that may be quantitative or qualitative. Hypothesis- an explanation of a set of data; must be tested. Theory- a hypothesis or set of hypotheses that have withstood many tests and can be used to make predictions. Law- a theory that endures repeated testing over a long period of time. 1858- antonio snider-pellegrini made the first before and after maps of south america and africa. This map was not really noticed until the debate about continental drift was basically over. 1906- discovery that rocks can record the magnetic field direction by bernard brunhes. However, at the time they had little effect on the debate to come over continental drift but later, starting in the 1950s, played an important role in both continental drift and seafloor spreading.
