Continental Drift PDF
Document Details
Uploaded by AdmirableAltoFlute
Elite Private School
Tags
Summary
This document is a presentation or lecture outline on continental drift, covering the hypothesis put forth by Alfred Wegener and the evidence supporting it, including the fit of continents, glacial evidence, fossil evidence, paleoclimatic evidence, and matching geology. It then explains how these ideas were eventually accepted and integrated into the study of plate tectonics.
Full Transcript
Continental Drift The hypothesis that continents are mobile. Proposed by German meteorologist Alfred Wegener. Wegener hypothesized a former supercontinent Pangaea. Idea was based on abundant evidence. “Fit” of the continents. Location of glaciations...
Continental Drift The hypothesis that continents are mobile. Proposed by German meteorologist Alfred Wegener. Wegener hypothesized a former supercontinent Pangaea. Idea was based on abundant evidence. “Fit” of the continents. Location of glaciations. Fossil evidence. Rock type and structural similarities. Paleoclimatic evidence. Physical Geology Continental Drift Wegener’s idea was debated and ridiculed. Most scientists didn’t believe him. Lack of a mechanism for drift a major criticism. Wegener died in 1930 at the age of 40. Lacking an advocate, the drift hypothesis faded. His idea was revived in the 1950s. Physical Geology Continental Drift Now we can measure drift; Wegener was right! Sea-floor spreading. Subduction. Plate Tectonics. Physical Geology Continental Drift-Continental “Fit” Wegener noted the continents seem to fit together. He argued that the fit could not be coincidental. Present shorelines make a rough fit. The continental shelf edges make a better fit. Physical Geology Continental Drift-Glacial Evidence Permian glacial till is found on 4 continents. The tills in Africa and India are now near equator. A cooler earth? No, tropical plants are also preserved. Physical Geology Continental Drift-Paleoclimatic Evidence Placing Pangea over the Permian South Pole… He correctly predicted… Tropical coals. Tropical reefs. Subtropical deserts. Subtropical evaporites. Physical Geology Continental Drift-Fossil Evidence Identical fossils found on widely separated land. These organisms could not have crossed an ocean. Physical Geology Continental Drift-Matching Geology Geologic phenomenon match across the Atlantic. Geologic structures. Rock types. Rock ages. Continuity of mountain ranges. Physical Geology
