Yes and thats what I cant understand. There shouldnt be any after 60 million years at a minimum rate of 0.01mm per year. That would not only take the sediment layer but also over half the mountain. How thick could a sediment layer be. The Grand Canyon is only about 1800 meters. Ocean sediments average around 450m and up to 1000m.
What were the higher layers if not sediments. If the earth was already formed from solid rock and then it gets ground down by erosion to become sediments. Those sediments then are layed on the surface. I guess if a volcano came it could cover the surface with metamorphic rocks. But from what we see around the planet it seems most of the sediments are on the surface.
The remaining sedimentary rock could have been protected by metamorphic rock layers that are now gone. Metamorphic rock will last longer because it is harder to erode.
Volcanoes do not produce metamorphic rock. They produce igneous rock. Metamorphic rock is often created from sedimentary rock, which certainly is the case with Mt Everest.
You can but like I said it wouldn't be that often. It would only be evident where volcanic activity happens or some other means where igneous rocks were able to spill out onto the surface. There will also be some areas where the earths movement has caused some rocks to shift and be tilted and then overturned. But this would also be something that only happened here and there. The sedimentary layers is what we often see when there are valleys and canyons like the Grand Canyon. They are the layers where the fossils are found. There are often thousands of square km of sediment layers spanning across continents. As the link I posted said most of the surface is of sedimentary layers.
I thought the sediments were where the fossils were going right down to the Cambrian period and beyond that. That depth is still not that great. The type of layers I am talking about on mountains are the ones that have fossils in them. So they wont be that deep and therefore that thick. The Cambrian layers can be seen in the Grand Canyon.
That doesn't seem to be the case for the Grand Canyon which is said to have similar layers going across north America. These layers are the different sediments layed directly on top of each other. The contact points are flat and dont show any signs of anything but the sediments that they are made up of be it the Tapeat sandstone, red wall limestone's and the Coconino sandstones ect. In fact from memory the metamorphic rocks in the canyon are at the bottom and the sediment layer were layed down on top of these. So it would seem most sediment layers are on the surface of the earth. Most sediment layers would have been at the bottom of the ocean when they were raised, thats why they have the seas life fossils in them.
I do grasp what you are saying. But that still doesn't account for the sediments being up on the mountain after 60 million years. When it talks about erosion rates and that Everest can lose over 1/2 of its size over millions of years then it doesn't matter what rock is there. If it loses that much mountain its going to be eroding sediments, igneous and metamorphic rocks to do that. It doesn't matter if the sediments are covered with some other form of rock. It will slow down the rate of erosion but we are still talking about the average minimum rate of erosion of 0.01mm. At that rate it would have eroded the entire height of Mt Everest in over 88 million years.
Here is an example where basalts are on top of sedimentary rock layers:
Well because the example is showing how vast those sediment layers are across North America it is also more or less showing that its the same across the globe.
Yes the minimum rate of erosion of about 0.01mm per year even when the rocks are non sedimentary. That still would wipe out any sediment layers in well over half the mountain. I would say the sediment layers we are talking about will be close to the surface because they have fossils in them. So any covering will be minimal. That and the sediments should have eroded in 60 million years. If they have remained after all this time then there must be another reason. A relatively thin layer of harder rock would not be enough to prevent it from eroding away. Unless there was no erosion.
I'm getting the erosion rates from this site which has a paper attached showing the erosion and its rates of the Himalayas.
Just to clarify things all I am doing is asking the obvious questions. I am not making any conclusions.
