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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Volcanoes are part of it but the majority of new dirt comes from plants and animals decaying back into dirt/soil.
There are places in the oceans where the continental shelves move across each other with one being forced under the other and back into the mantle where it melts and becomes lava for volcanoes to spew out again to repeat the cycles. new life is always forming and taking resources out of the dirt to form and dying and turning back into dirt.
Dust you are and to dust you shall return.
A late part of the answer is continental drift. Earth comprises multiple large tectonic plates that move relative to each other.
The Indian plate moves toward the Eurasian plate at a rate of 5cm/per year. This means an enormous amount of material needs to be displaced each year. The material is pushed up and the Himalayas are formed. The mountains are then eroded and deposit material in other locations.
Planrs can go below another plate like what happened once on the coast of South America. The crust will melt when it gets deep down enough and you get volcanoes. The Andes can be eroded away and deposit material over the eastern part of South America.
So parts of earth’s surface get new material on it while other parts are destroyed. It is a constant process on earth with material that move around
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.
Two primary drivers on a consistent basis and then big dumps from volcanoes every so often.
Organic matter breaks down. Leaves turn into dirt, just to help you remember that a little bit, as does most (pretty much all?) other organic matter that is broken down in the environment. That’s a shit ton of mass every year across much of the planet.
Dust/sand/wind blown sediment w/e you wanna call it is a huge element, probably the primary one but imagine it’s highly specific to different regions. What fuels the dust is all sorts of shit, rocks break down too. Plus then deserts. The Sahara alone is dumping dust all over the world, even if most ends up in oceans, it’s still 400-700 x 10^6 tons/year of dust just from the Sahara and twice that from all deserts combined and tons does end up on land (bringing nutrients and other good stuff in the process)
These things spread out over millions/bullions of years is how you get these layers and periods of volcanic activity are also obvious for this reason because they dump a ton in a short amount of time
Tectonics feels more like a shuffling of these layers ontop of eachother or apart (like Africa’s rift valley where we got tons of old human fossils from) rather than really creating the layers as you describe anyways but either way an element
It doesn’t,
lighter minerals move up with water, temperature, and time, heavier minerals move downward.
The reasons why most things across the world get buried deeper with time is because of ether their weight, or how they get affected by temperature and water.
It wouldn’t even make sense to say that it’s due to volcanos because we haven’t had volcanoes covering the *entire* Earth in 600 Million years.
And higher level dirt doesn’t just blanket the entire rest of the planet. Enlventually that would of leveled off, which it did, the earth’s crust is relatively smoother than the skin of an apple
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