Understanding Earth's Structures and Continental Drift Evidence
School
Rutgers University**We aren't endorsed by this school
Course
730 101
Subject
Geology
Date
Dec 10, 2024
Pages
2
Uploaded by HighnessElectron9504
Planet Earth: Earth’s Structures●Criteria for Classifying Earth's Interior Layers:●Chemical Composition●Physical Properties●Based on Chemical Composition:●Crust: Composed of Silicon (Si) and Oxygen (O)●Mantle: Contains Silicon (Si), Oxygen (O), Magnesium (Mg), Aluminum (Al), and Iron (Fe)●Core: Comprised of Iron (Fe) and Nickel (Ni)●Based on Physical Properties:●Lithosphere: Solid and Rigid●Asthenosphere: Plastic and Weak●Mesosphere: Plastic and Weak●Outer Core: Liquid●Inner Core: Solid●Methods and Evidence for Identifying Layers:●Detailed methods not specified in the provided information.Drifting Continents & Spreading Seas●Development of Plate Tectonics Theory:●The theory was developed in the 1960s.●It explains the locations of earthquakes, volcanoes, and mountain belts.Alfred Wegener and Continental Drift Hypothesis●Wegener's Hypothesis:●All continents were once a supercontinent called 'Pangaea', which later drifted apart.●Supported by the fit of continents like North America, South America, Africa, and Europe.●Evidence for Wegener's Hypothesis:●Fit of the Continents: Notable similarities in the shapes of continents.●Distribution of Ancient Climatic Belts: Explained by the reconstruction of Pangaea.●Fossil Distribution: Similar fossils found oceans apart, supporting the idea of joined continents.●Matching Geologic Units: Similar rock units in Africa and South America.●Rejection of Wegener's Theory:●Initially rejected due to inability to explain the mechanism of continent movement.●Arthur Holmes' Proposal:●Suggested 'Mantle Convection' as a mechanism for moving continents in 1928, but regarded it as speculative without independent evidence.Modern Evidence Supporting Continental Drift
●Key Evidence:●Discovery of Mid-Ocean Ridges (MOR) by Marie Tharp and others.●Study of Paleomagnetism.●Discovery of MOR:●Noted by Marie Tharp as bathymetrically higher than the surrounding seafloor.●Identified as geologically active with earthquake epicenters located over deep valleys in the MOR.●Paleomagnetism:●Involves studying magnetism in rocks to learn about Earth's past magnetic field.●Evidence includes polar wandering vs. continental drift and paleomagnetic reversals.●Support for Plate Tectonics:●Apparent Polar Wander Paths differed for different continents.●Magnetic reversals showed mirrored patterns across mid-ocean ridges.●Glacial Striations:●Provided evidence for the distribution of glaciers, supporting the continental drift hypothesis.