Chapter 2 Plate Tectonics Continental drift: An idea be as long as e its time Alfred Wege

Chapter 2 Plate Tectonics Continental drift: An idea be as long as e its time Alfred Wege www.phwiki.com

Chapter 2 Plate Tectonics Continental drift: An idea be as long as e its time Alfred Wege

McDonald, Beth, On-Air Personality has reference to this Academic Journal, PHwiki organized this Journal Chapter 2 Plate Tectonics Continental drift: An idea be as long as e its time Alfred Wegener First proposed his continental drift hypothesis in 1915 Published The Origin of Continents in addition to Oceans Continental drift hypothesis Supercontinent called Pangaea began breaking apart about 200 million years ago Pangaea approximately 200 million years ago

John Paul the Great Catholic University US www.phwiki.com

This Particular University is Related to this Particular Journal

Continental drift: An idea be as long as e its time Continental drift hypothesis Continents “drifted” to present positions Evidence used in support of continental drift hypothesis Fit of the continents Fossil evidence Rock type in addition to structural similarities Paleoclimatic evidence The great debate Objections to the continental drift hypothesis Inability to provide a mechanism capable of moving continents across the globe Wegner suggested that continents broke through the ocean crust, much like ice breakers cut through ice Continental Slope Fit

Fossils of Mesosaurus Wegener’s matching of mountain ranges on different continents Paleoclimatic evidence as long as Continental Drift

The great debate Continental drift in addition to the scientific method Wegner’s hypothesis was correct in principle, but contained incorrect details For any scientific viewpoint to gain wide acceptance, supporting evidence from all realms of science must be found A few scientists considered Wegner’s ideas plausible in addition to continued the search Continental drift in addition to paleomagnetism Initial impetus as long as the renewed interest in continental drift came from rock magnetism Magnetized minerals in rocks Show the direction to Earth’s magnetic poles Provide a means of determining their latitude of origin Earth’s Magnetic Field

The scientific revolution begins During the 1950s in addition to 1960s technological strides permitted extensive mapping of the ocean floor Seafloor spreading hypothesis was proposed by Harry Hess in the early 1960s The scientific revolution begins Geomagnetic reversals Earth’s magnetic field periodically reverses polarity – the north magnetic pole becomes the south magnetic pole, in addition to vice versa Dates when the polarity of Earth’s magnetism changed were determined from lava flows Geomagnetic reversals are recorded in the ocean crust In 1963 Fred Vine in addition to D. Matthews tied the discovery of magnetic stripes in the ocean crust near ridges to Hess’s concept of seafloor spreading Geomagnetic Reversals

Paleomagnetic reversals recorded by basalt at mid-ocean ridges Time Scale of the Earth’s Magnetic Field The scientific revolution begins Paleomagnetism (evidence of past magnetism recorded in the rocks) was the most convincing evidence set as long as th to support the concepts of continental drift in addition to seafloor spreading

Plate tectonics: The new paradigm Much more encompassing theory than continental drift The composite of a variety of ideas that explain the observed motion of Earth’s lithosphere through the mechanisms of subduction in addition to seafloor spreading Plate tectonics: The new paradigm Earth’s major plates Associated with Earth’s strong, rigid outer layer Known as the lithosphere Consists of uppermost mantle in addition to overlying crust Overlies a weaker region in the mantle called the asthenosphere The Earth’s Spheres

Plate tectonics: The new paradigm Earth’s major plates Seven major lithospheric plates Plates are in motion in addition to continually changing in shape in addition to size Largest plate is the Pacific plate Several plates include an entire continent plus a large area of seafloor Plate tectonics: The new paradigm Earth’s major plates Plates move relative to each other at a very slow but continuous rate Average about 5 centimeters (2 inches) per year Cooler, denser slabs of oceanic lithosphere descend into the mantle Earth’s Tectonic Plates

McDonald, Beth KESZ-FM On-Air Personality www.phwiki.com

Plate tectonics: The new paradigm Plate boundaries All major interactions among individual plates occur along their boundaries Types of plate boundaries Divergent plate boundaries (constructive margins) Convergent plate boundaries (destructive margins) Trans as long as m fault boundaries (conservative margins) Plate tectonics: The new paradigm Plate boundaries Each plate is bounded by a combination of the three types of boundaries New plate boundaries can be created in response to changes in the as long as ces acting on these rigid slabs Divergent plate boundaries Most are located along the crests of oceanic ridges in addition to can be thought of as constructive plate margins Oceanic ridges in addition to seafloor spreading Along well-developed divergent plate boundaries, the seafloor is elevated as long as ming oceanic ridges

Divergent boundaries are located mainly along oceanic ridges Divergent boundaries Spreading rates in addition to ridge topography Topographic differences are controlled by spreading rates Continental rifts Splits l in addition to masses into two or more smaller segments Examples include the East African rifts valleys in addition to the Rhine Valley in northern Europe Produced by extensional as long as ces acting on the lithospheric plates Not all rift valleys develop into full-fledged spreading centers From Rift Valley to Spreading Center

End of Chapter 19

McDonald, Beth On-Air Personality

McDonald, Beth is from United States and they belong to KESZ-FM and they are from  Phoenix, United States got related to this Particular Journal. and McDonald, Beth deal with the subjects like Entertainment; Music

Journal Ratings by John Paul the Great Catholic University

This Particular Journal got reviewed and rated by John Paul the Great Catholic University and short form of this particular Institution is US and gave this Journal an Excellent Rating.