Describe how material on the surface of continental crust may be recombined with oceanic crustal material and recycled through the geologic cycle.
The correct answer and explanation is :
Material from the surface of the continental crust can be recombined with oceanic crustal material and recycled through the geologic cycle via processes such as erosion, sediment transport, subduction, and volcanic activity.
Explanation (300 words):
The geologic cycle is a continuous process that recycles Earth’s crust through plate tectonics, weathering, and internal heat dynamics. Continental crust material, primarily composed of granitic rocks, undergoes weathering and erosion due to wind, water, and ice. This breakdown produces sediments that are transported by rivers and deposited in ocean basins. Over time, these sediments accumulate on the oceanic crust, forming sedimentary layers.
At convergent plate boundaries, where an oceanic plate collides with a continental plate, the denser oceanic crust subducts beneath the lighter continental crust. As the oceanic plate descends into the mantle, it carries with it sediments and crustal material from both oceanic and continental origins. This subduction process subjects the material to intense heat and pressure, causing partial melting. The molten material can rise through volcanic arcs, contributing to the formation of new continental crust when it erupts as lava or plutonic intrusions.
Some of the subducted material is also recycled into the mantle, mixing with mantle material and potentially re-emerging as magma at mid-ocean ridges, where new oceanic crust forms through seafloor spreading. Additionally, tectonic uplift can expose buried rocks to weathering, restarting the cycle.
This continuous recycling of crustal material ensures that Earth’s surface is dynamically reshaped over millions of years, integrating continental and oceanic components into the rock cycle.