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| Image Courtesy of Beth Steinhauer, Black Hills National Forest (Forest Service of US Department of Agriculture) under Public Domain |
As you drive west from Rapid City, you notice a jagged stretch of sandstone peaks called the Hogback Ridge. After a short descent from those sandtone peaks, you come to an area comprised of another sedimentary rock, red shale, which makes a "Racetrack" around the Black Hills. If you keep driving west, there is a gradual incline made of limestone. This limestone formed 100-500 million years ago, from the shells of ancient marine animals. (Yes, we are still in the Black Hills of South Dakota.) Keep driving still, past this limestone plateau, and you will see the Central Crystalline Core of the Black Hills. This area is made of schist (a metamorphic rock) and granite (an intrusive igneous rock) that have aged for up to 2.5 billion years. The apparent color of this Central Core and the groves of Ponderosa Pine gave this area its name, the Black Hills. You might want to get out of the car and take a hike up to Harney Peak, the highest peak in between the Rocky Mountains and the Alps of Switzerland.
What are the events that led to the formation of these Black Hills? Why does it look the way it does? Like geologists, we will explore these questions today.
- Write a summary of how the Black Hills formed. What are the events that led to their formation?
- Would the Badlands exist if weathering/erosion had not taken place? Why/Why not?
- The major uplift of the Black Hills occurred 70 million years ago. What do you think that area of South Dakota looked like 40 million years ago? What do you think the Black Hills and Badlands will look like in another 40 million years?
43 comments:
There are layer of rocks. From bottom to top it is Schist, Limestone, Red Shale, than Sandstone. After all formed there was a large up rise. People think that there was molten lava that rose underneath all of the rock. It is half the size now because it has been weathered a lot. The Badlands would not exist if weathering/erosion had not taken place. This is so because That's pretty much how it formed in the first place. The weathering that took place on the the Black hills was called deferential weathering. I think the Black Hills and Badlands will keep eroding and with be a lot smaller in 40 million years. Also, There will probably be more mountains that will form in that area.
1. The black hills formed by weathering and erosion, and an uplift so that is how it got so tall.
2. no the bad lands would not exist if weathering and erosion would not have taken place because there would have not been an uplift.
3. it looked really tall 40 million year ago. and it will look flat 40 million years from now
1. they form by rocks forming after time
2. no it would of been flat land
3. 40 million years ago they weren't as big in 40 million years it will be even bigger
the shist was layered upon by the granite and limestone and red stone then the sandstone. then it uplifted. no they wouldn't because their material wouldn't have been eroded. they were really tall 40 mil ago I bet. in 40 mil it all will be pretty flat and the material will be elsewhere.
1.There was first the core granite and shist that cam up from the ground then another layer formed on top of that. Then there was sandstone and to top it of the top layer that of there was the very top layer(can't remember name of it) then years and years passed and it eroded and it had deposition take place to now that makes the black hills.
2.No because all the erosion from the black hills eroded an deposited over and made the badlands.
3. I think it probably looked pretty bare and rocky. I bet the black hills will still be there but there won't be very much left of it though.
1. The black hills were formed when magma rock pushing layers of rock up to make big hills.
2. No, because it would just be flat, there would bee no wearing away of the sediment to make it low.
3. I think the badlands would barely be there, and the hills would be huge. I think in 40 million years the hills will be gone. And the badlands would be very deep.
1. The black hills was formed by a long duration of weathering breaking down the rock. A lot of the rock used to be at the top but was broken down easier then other rock lower than the rock on the top. Eventually the toughest rock ends up on the top because it wasn't broken down because its tougher.
2. no because weathering and erosion is what caused it
3. i think it used to look like a bunch of soft rock then in the future it will we rock hard.
1) The Black Hills were formed from the schist and granite curving upwards making all of the other layers like the limestone, red shale, and sandstone.
2)Badlands would not have been formed without weathering/erosion because the weathering and erosion is what made and moved them.
3) 40 million years ago, the Black Hills were probably really tall and 40 million years from now they will probably be short.
it wanted to rise up and there was a bubble. the bubble did not pop. No the badlands would not have existed because without weathering and erosion things would not be broken down. I think it looked like a big hill of layers. I think that the Black Hills and Badlands will just keep adding on layers and will be even bigger.
1. we where near the edge of the sea. and we had heat and pressure. made in to schist and granite, limestone, red shale, sandstone. lava in the earth rose but didn't break the surface.
2.no because the they wouldn't have the same shape and amount of rocks.
3.40 years ago they would have more rock because they haven't been weathered an eroded as much.
millions of years ago different layers formed then uplift came then weathering happened to all of the types of the rocks are more resistance than others
The Black Hills formed by first it started out as schist and granite, than it got a little bit newer and that is limestone, then it keeps getting newer and now we have red shale and an even more uplift to sandstone. No because with erosion and weathering that´s what makes the mountains like peaks and without that stuff that wouldn´t happen. It would just be about to start the major uplift. The mountains will probably be even taller.
1) The Black Hills formed by weathering and erosion
2) No because the sediment wouldn't have been carried there
3) They looked taller and they will probably be a little
the dirffernt layers of rock had and uplift anraised the layers of rock. no becuase weathering had to make the rocks hard and holes in them. they will prob be down or at least get lower or even bigger.
There is so much pressure, it gets changed into rock. Granite and schist is on the bottom. Then above that is limestone. Next is the red shale and then lastly is the sandstone. It then elevates. It dips and the granite and schist is the higher part of the mountain. Weathering breaks down the red shale and it is now it is the weakest or smallest. No because weathering and erosion have made shaped them. South Dakota would have looked like a bunch of non grassy areas with a lot of hills. The Black Hills and Badlands will have lots of hills and mountains will many different shapes and sizes.
The black hills formed by weathering and erosion
No the sediment woudnt have been carried
possibly taller and different rocks on top. New rocks on top
1.The black hills had an uplift,which also caused some cracking(elevation 15,00ft). Now the granite and schist is taller then the red shale and the others because the granite and the schist used to be on the bottom and so they didn't get weathered as much.
2. no because the bad lands are only there because the sedimentary rock blew from the black hills to form the badlands
3.I think that 40million years ago the black hills were higher and the badlands were lower, but in 40 million year I think that the black hills will be shorter and the badlands will b taller
They formed from erosion and the other rock that is not strong eroded.
Cause the rock sedement from the black hills went to the badlands
It looked like a hill. It will have a whole and then the badlands will be bigger
1. The black hills were formed when layers of rocks kept piling up on top of each other, until there was an uplift with all the rocks.
2. No, because the bad lands are only there because the Black Hills eroded and the sentiment blew to the bad lands and created them.
3. I think 40 million years ago, the black hills had a higher elevation, and the bad lands were lower. 40 million yeas from not the black hills will be shorter and the bad lands will be taller.
The bad lands was orginaly a bunch of rocks on top of each other but the layers slowly wore away so it took the shape that it is.
The badlands wouldn't exist if the weathering didn't take place, well it could still be there but most likely no where as big as they are now.
In 40 million years the bad lands will be bigger and the black hills will be smaller and the gran. and sl. will be worn down more than it is now
The different layers of rock had and uplift and raised the layers of rock. No because rock is eroding away from the black hills and it gets deposited in the bad lands. I think it looked really flat because there was no uplift yet, in 40 million years it will be even taller.
Layers of rock uplifted and and formed a mountain then erosion moved the rocks around and then settled at the badlands.
The badlands would not exist if it wasnt for weathering. The reason I say that is that erosion moved sand stone to the badlands.
The black hills were double the size 40 million years ago. Then consistently keep getting smaller.
1. A long time ago, layers of rock formed on top of each other. Then there was an uplift that pushed all of the different rocks up high. Then through weathering and erosion, the rocks at the top that weren't as resistant got pushed away while granite and schist, that are more stable, are now the highest points.
2.No, because the badlands were formed through weathering and erosion when the rocks from the black hills eroded.
3. 40 million years ago it was taller and in 40 million years, the black hills and badlands will be more eroded away.
1.The Black Hills were formed by an uplift, and then the tectonic activity caused all of the layers of rock to rise.
2.The badlands would not exist if the uplift wouldn't have taken place because the layers of rock would not have rose.
3.The badlands looked very different 40 million years ago. They were probably bigger and taller back then. In another 40 million years, erosion will continue to take place and shape the black hills differently.
1. Was taken place by Weathering/Erosion.
2. No, without Weathering/Erosion it would not exists. It would have never formed.
3. South Dakota was probably under water, and the Badlands would probably be even higher and greater, taking up more space.
1. The black hills were formed by Erosion and weathering. all of the sediments come and over time the wind will wear the land and the roots of the grass will stay there but everything around it will cave in and it becomes a mountain.
2. The badlands wouldn't have existed because the only way it is shaped like it is is because of the wind and all of the sediments and all of the erosion that was happening. Its actually pretty cool all of it.
3. It would look thin and old looking. I think they would look new and pretty and maybe there would be water and trees and flowers not just desert. And be kinda cool and not hot all of the time.
The blacks hills were formed a long time ago, there was this rock and more rocks that builded up, and the eroded down into the black hills.
1. Over time the rock on the both went up with a up lift.
2. No because that's what made all land.
3. Yes I think they did but then weathering and erosion changed that.
Over time layers of rocked form on top of each other. Then erosion took place and the black hills look like what they look like now. 2. No they were formed by the erosion and weathering of the black hills. 3. I think it was all flatlands. I think the Black hills might be smaller and the badlands will be bigger.
1. The layers of rock were weathered down, so now all thats left is unreactive rock that can't or will take longer to be weathered down.
2. No they wouldn't, the weathering and erosion cause the shape of them.
3. It was probably all flat.
1. Through weathering and erosion.
2. No because the rocks would stay where they were.
3. The Black Hills would be a lot flatter.
Through weathering and erosion. The bad lands would not exist because all the rock form would be the same as it was a long time ago. It probably wasn't as jagged or narrow as it is now. As more weathering and erosion happens the more the landscape will change.
The Black hills were formed over the years. They first stared off as flat land, then moved into layered hills, then moved into sperated mountins.
no, the stone that being eroded deposted on that land which formed the bad lands.
I think the Black hill 40 million years ago was really tall. In 40 million years from now i think that the hills will srink!
The layers of rock were weathered down, so now all that is left is the unreactive rock, that takes longer to weather down. Due to this rock from years and years is brought to the surface.
No. The rocks would not erode, so the blackhills would not exist.
I think SD looked alot more rocky.
and in the next 40 years it will be even more flat, with older rocks on the surface! (:
#1 The black hills were formed first by shist and granite then the next layer is limestone, then red shale, then finaly sand stone.
#2 No it is the things that happen over time that make things the way they are now
#3 I think it will look nice with lots of plants and the bad lands and hills will be more and more warn down because of erosion
1. first, a layer of chuck norris is laid down. Then a layer of mr. hanniman was put down on top of that. After that a layer of mr.leach was put down. A layer of mr. ricketts was put down .to top it off, you have the best layer of all... a layer of mr. hoegh. then an uplift happened bringing it all, in the same sequence, was brought to a point. then erosion and weathering finished it of.
2 No. All the weathering done at the black hills made it like that.
3. it would look flat.
1. Erosion & Weathering took place.
2. No sir, because there would be no way that it could have formed if they werent available (:
3. It was flatter then it is now, and it will be higher in 40 million yearssss. (:
1. They formed with weathering and erosion. The top layers got broken down so the bottom layer got brought up.
2. No because then they wouldnt be broken down.
3. Really tall, really flat.
The black hills were formed by wind, water, and seidiment. The black hills used to be under water because they find fossils of sea creatures under water. I think that the black hills were a hilly, full of treey, and pretty land form. It would be cool to go back in time, and see what it looked like. In fact it would be cool to go back in time to see Sioux falls.
1 they went threw alot of weathering there are like 5 types of rocks in the mountains and a they all got blowen away and then they got bigger and stuff
2 no they would not because the black hills rock would not be blowen away and the badland would not have any rock where they are now
3 70 million years ago it would be huge just humugest 40 million years from now they will be even smaller then they are now!
1.they were formed by weathering,the different layers packed on top of each other and the rode away leaving the toughest layers.
2.no because if it didn't they different layers would still be there
3.they would have been larger, and in more years they will be smaller.
1. The Black Hills formed because of the many years that went by. All the years that went by the more the schist, red shale, limestone,sandstone, and all the other rocks that formed the Black Hills.
2. No the Badlands only exist because of Weathering and Erosion. They were formed because of the sediment that was blown from some place to Rapid City called Erosion. Then Weathering happened, I think because it started to rise and that is why they are so tall.
3. I think that it was way smaller 40 million years ago because it didn't have enough time to pile up that much. What I think it will look like in 40 million years from now I don't really know for sure. They could be smaller or they could be bigger.
1. It started off with granite and schist being the first layer. In the next layer comes the limestone. The 3rd layer that as put down had been Red Shale. Finally the final layer is put down called sandstone. It all happened through weathering and erosion. Also through the uplift that had pushed the sediments from the top down the sides. As that happened the sediments on the bottom came to the top.
2. No because the only reason the badlands became like that was through weathering and erosion.
3. It probably looked very flat 40 million years ago. In the next 40 million years it will probably get even bigger and wider.
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