What is the definition of absolute dating

Similarly, in geology, if distinctive granitic pebbles can be found in the sediment beside a similar granitic body, it can be inferred that the granite, after cooling, had been uplifted and eroded and therefore was not injected into the adjacent rock sequence.Although with clever detective work many complex time sequences or relative ages can be deduced, the ability to show that objects at two separated sites were formed at the same time requires additional information.

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Continents move, carried on huge slabs, or plates, of dense rock about 100 km (62 miles) thick over a low-friction, partially melted zone (the asthenosphere) below.

In the oceans, new seafloor, created at the globe-circling oceanic ridges, moves away, cools, and sinks back into the mantle in what are known as subduction zones (i.e., long, narrow belts at which one plate descends beneath another).

Episodes of global volcanic activity, rifting of continents, folding, and metamorphism are defined by absolute ages.

The results suggest that the present-day global tectonic scheme was operative in the distant past as well.plate tectonics has had a profound impact on the scientific understanding of our dynamic planet.

By contrast, crustal destruction occurs at the margins of two colliding continents, as, for example, where the subcontinent of India is moving north over Asia.

Great uplift, accompanied by rapid erosion, is taking place and large sediment fans are being deposited in the Indian Ocean to the south.

The two approaches are often complementary, as when a sequence of occurrences in one context can be correlated with an absolute chronlogy elsewhere.

Local relationships on a single outcrop or archaeological site can often be interpreted to deduce the sequence in which the materials were assembled.

When rocks are subjected to high temperatures and pressures in mountain roots formed where continents collide, certain datable minerals grow and even regrow to record the timing of such geologic events.

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