What process did James Hutton propose replenishes the rock on Earth's surface?
1 Answer
James Hutton proposed two mechanisms, Volcanic activity and geosyncline uplift.
Explanation:
Previous to Hutton the prevailing theories were based on water deposition of sedimentary layers being responsible for the rock layers of the earth.
Hutton proposed that volcanic activity was the source of rock layers on the earth. The layers produced by the volcanic activity were then eroded forming the sedimentary layers.
Hutton introduced the idea of uniformitarism. That the present was the key to past in interpreting the rock layers. The idea that erosion occurred very slowly based on uniform process greatly increased the estimates of the age of the earth.
Hutton proposed that the erosion formed the sedimentary layers in geological formation called geosynclines. These layers were thought to accumulate until the lighter density of the sedimentary layers cause to geosyncline to be thrust up forming the continental crust.
The theory of geosynclines has been totally replaced starting in the 1960's by modern plate tectonics. The oceanic sedimentary layers are now thought to be subducted under the continental plates. What is observed in the present is not able to explain the thick sedimentary layers found on the continental plates.
