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Reader Supplement HERE & NOW GlaciersVicki M. Harder |
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Reader Supplement HERE & NOW GlaciersVicki M. Harder |
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Widespread glaciation of the continents has occurred numerous times in the geologic past with evidence as far back as the Precambrian. But what are the causes of glaciation? Are glacial episodes cyclic? And what changes to the landscape occur after they disappear? Why is it important to study glaciers and glaciation today? |
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Discussed in the Science News reader article "Demise of the ice age sparked great quakes" is a glaciation effect that has gone somewhat unrecognized until recently. The glaciers that covered northern Scandinavia during the Ice Age put the underlying ground under a great deal of stress. After the removal of the glaciers approximately 9,000 years ago old faults were reactivated, creating large earthquakes. Glaiciologists have modeled the glacial ice occurrence in northern Canada indicating the thickness and areal extension of the ice during the last ice age.
To determine the cause(s) of glaciation one must have the timing of glaciation accurately determined. As discussed in the Science News reader article "A date for the ice ages" scientists have developed a new technique that they believe accurately dates the most recent interglacial periods. The team of oceanographers use radioactive elements in seafloor sediments. As with any new technique, it will have to undergo additional tests to determine just how useful this will be. |
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