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fact midocean ridge system earthquakes radiometric rock Seafloor Spreading hot s

ID: 299645 • Letter: F

Question

fact                  midocean ridge system          earthquakes                radiometric

rock                 Seafloor Spreading                 hot spot                       sediment

increase          magnetic striping                     Plate Tectonics           World War II

magnetic         Harry H. Hess                         Global Positioning System

symmetrical    echo sounding                         Very Long Baseline Interferometry

Wegener’s hypothesis gained support with the discoveries of sea floor structures and processes during and following _____.   _____ a Princeton geologist, was able to conduct _____ investigations of the Pacific seafloor during his naval service in the Pacific war theater. Among his discoveries were thousands of inactive volcanoes called seamounts and flat-topped cones named guyots that supported the concept of volcanic mountain building by convection of magma from in the lithosphere and mantle.   He hypothesized that this convection could also create the ______ the single largest mountain chain on the planet found on the floor of each of the major ocean basins. In the 1960’s, his hypothesis called ______was tested and substantiated with ______ and _____ samples collected by the crew of the Glomar Challenger in the south Atlantic.   Among this evidence was the fact that sediment and rock ages _____ with increased distance from the ridge.

However, the evidence that geoscientists found to be most compelling was assembled by Vine and Matthews. These geologists mapped the _____ anomalies recorded by the iron minerals within the rock samples collected. The alternating patterns of these anomalies on both sides of the ridge were surprisingly _____ and unlike the randomness of iron mineral crystals previously collected in continental rocks. The pattern called _____ supported Hess’s hypothesis that convection in the mantle could break the lithosphere and cause the ocean floors to grow and widen on both side of the rift axis.

The findings by Hess, Vine, Matthews, and others in combination with non-random patterns of shallow and deep focus ____ charted by Kiyoo Wadati in the 1930’s and Hugo Benioff in the 1940’s led to the development of the unifying theory of _____. Since these discoveries, additional evidence has been collected including the _____ age dating of rocks produced by the Pacific ______ that creates the Hawaii – Emperor Seamount chain of volcanic islands as the plate moves toward the northwest. Today, geodetic instruments placed on each continent have provided direct measurements of the relative motion between plates using the methods of ______ and satellite positioning by _____. These data confirm the indirect evidence used to calculate plate velocities and has established plate motion as scientific _____.

Explanation / Answer

fact                  midocean ridge system          earthquakes                radiometric

rock                 Seafloor Spreading                 hot spot                       sediment

increase          magnetic striping                     Plate Tectonics           World War II

magnetic         Harry H. Hess                         Global Positioning System

symmetrical    echo sounding                         Very Long Baseline Interferometry

Answer :

Wegener’s hypothesis gained support with the discoveries of sea floor structures and processes during and following _ WORLD WAR II ____.

_ Harry H. Hess____ a Princeton geologist, was able to conduct _Magnetic striping____ investigations of the Pacific seafloor during his naval service in the Pacific war theater. Among his discoveries were thousands of inactive volcanoes called seamounts and flat-topped cones named guyots that supported the concept of volcanic mountain building by convection of magma from in the lithosphere and mantle.   He hypothesized that this convection could also create the _ midocean ridge system _____ the single largest mountain chain on the planet found on the floor of each of the major ocean basins. In the 1960’s, his hypothesis called _seafloor Spreading _____was tested and substantiated with _ sediment _____ and _ rock ____ samples collected by the crew of the Glomar Challenger in the south Atlantic.   Among this evidence was the fact that sediment and rock ages _increase____ with increased distance from the ridge.

However, the evidence that geoscientists found to be most compelling was assembled by Vine and Matthews. These geologists mapped the _magnetic____ anomalies recorded by the iron minerals within the rock samples collected. The alternating patterns of these anomalies on both sides of the ridge were surprisingly symmetrical_____ and unlike the randomness of iron mineral crystals previously collected in continental rocks. The pattern called _ magnetic striping  ____ supported Hess’s hypothesis that convection in the mantle could break the lithosphere and cause the ocean floors to grow and widen on both side of the rift axis. The findings by Hess, Vine, Matthews, and others in combination with non-random patterns of shallow and deep focus earthquake____ charted by Kiyoo Wadati in the 1930’s and Hugo Benioff in the 1940’s led to the development of the unifying theory of     Plate Tectonics   _____. Since these discoveries, additional evidence has been collected including the _radiometric____ age dating of rocks produced by the Pacific hotspot______ that creates the Hawaii – Emperor Seamount chain of volcanic islands as the plate moves toward the northwest. Today, geodetic instruments placed on each continent have provided direct measurements of the relative motion between plates using the methods of _ Very Long Baseline Interferometry___ and satellite positioning by Global Positioning System _____. These data confirm the indirect evidence used to calculate plate velocities and has established plate motion as scientific __ fact ___.