This phenomenon is so simple I feel like an idiot trying to describe it but I want to know the name of the process so I can search for a video to understand it better.
Observations: Geologists measure the age of the earth by studying the layers of the earth’s crust. Archeologists dig down and find remnants of the past under layers of dirt.
Assumptions: There are younger layers of dirt on top of the earth’s crust and older layers underneath. This seems like a continuous natural cycle of creation of a new top layer of crust.
Question: Where does all the dirt that becomes the next layer of sediment come from? Where is this perpetual supply of new dirt coming from?
It’s not like there is an endless supply of dirt stored in the sky and it’s constantly falling.
Do winds lift layers of dirt from one area of the earth and drop that dirt in another? That would just be a dirt exchange where one area wouldn’t have new layers of crust and another area would. That doesn’t seem correct with how ubiquitous the concept of layers of crust is.
Is it volcanoes that shoot dirt from the earth’s mantle into the sky then it slowly settles on the ground creating the next layer? If so that would mean the oldest layers of the crust at the bottom become liquified then are expelled into the air and settle as the newest layer of crust in the “dirt cycle” of crust formation. This would make crust creation continuous so it’s plausible but doesn’t feel completely correct.
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The “dirt cycle” you’re thinking of is essentially part of the rock cycle.
Rocks in areas such as mountain ranges are broken down by the movement of air, water, and ice, transported downhill, and deposited in sedimentary basins. Earth’s crust.
Earth’s crust is broken up into a system of tectonic plates, which move at a few centimeters per year. In zones where plates collide, rock can be compressed, causing folding and thrust faulting that creates mountain ranges. These mountains can erode to produce sediment. Thick enough piles of sediment, under heat and pressure, become sedimentary rock.
Magmatism, the production of molten rock, does play a role as well. Rock in Earth’s upper mantle (which, contrary to popular belief is mostly solid) melts. The resulting magma can then erupt on the surface from volcanoes, or it may solidify within the crust and form intrusive igneous rock. Some rock within the crust is melted in this process as well.
Additionally, in collisions where at least one tectonic plate is made of oceanic crust (at places called subduction zones), old oceanic crust sinks into the mantle. Meanwhile volcanic activity forms new oceanic crust at mid-ocean ridges.
Continental crust, which is thicker and less dense than oceanic crust, does not sink back into the mantle but it does get eroded. A variety of processes, mostly at subduction zones, can create new continental crust.
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