Isostatic Effects of Deposition and Erosion
When large amounts of sediment are deposited on a particular region, the immense weight of the new sediment may cause the crust below to sink. Similarly, when large amounts of material are eroded away from a region, the land may rise to compensate. Therefore, as a mountain range is eroded down, the (reduced) range rebounds upwards (to a certain extent) to be eroded further. Some of the rock strata now visible at the ground surface may have spent much of their history at great depths below the surface buried under other strata, to be eventually exposed as those other strata are eroded away and the lower layers rebound upwards again.
An analogy may be made with an iceberg - it always floats with a certain proportion of its mass below the surface of the water. If more ice is added to the top of the iceberg, the iceberg will sink lower in the water. If a layer of ice is somehow sliced off the top of the iceberg, the remaining iceberg will rise. Similarly, the Earth's lithosphere "floats" in the asthenosphere.
Read more about this topic: Isostasy
Famous quotes containing the words effects and/or erosion:
“Each of us, even the lowliest and most insignificant among us, was uprooted from his innermost existence by the almost constant volcanic upheavals visited upon our European soil and, as one of countless human beings, I can’t claim any special place for myself except that, as an Austrian, a Jew, writer, humanist and pacifist, I have always been precisely in those places where the effects of the thrusts were most violent.”
—Stefan Zweig (18811942)
“Inter-railers are the ambulatory equivalent of McDonalds, walking testimony to the erosion of French culture.”
—Alice Thompson (b. 1963)