Monday, November 7, 2011

The Geology of the Black Hills

Many of you have been out to the Black Hills. If you haven't (or if you can't remember what it is like), visualize the following scenario:
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.
Please watch the "Formation of the Black Hills" vodcast at our vodcast website or on your iPod. Then answer the following questions in your blog response.

  1. Write a summary of how the Black Hills formed. What are the events that led to their formation?
  2. Would the Badlands exist if weathering/erosion had not taken place? Why/Why not?
  3. 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?

50 comments:

Makkah S said...

1. The black hills were formed by weathering and erosion. Also by uplift.Rain and wind led to there formation.
2. Yes. They would still exist but they wouldn't look the same.
3. The mountains would look way bigger and not be the same shape and size. In 40 million yeAars from now they will not be as tall.

Allison&Emily 1ipad said...

1) The Black Hills were formed through weathering and erosion. The rain and wind caused the hills to move and change their formation. they were uplifted and changed.
2) Yes they would exist but they would look different and be shaped differently and wouldn't be as big and famous.
3) forty million years ago it was still as uplifted but not as much as it was before. It had started changed because of weathering. Forty million years from now it will not be as uplifted and will be way more weathered and eroded.

Riley F said...

1. Well, when all of those layers stacked up to make an elevation of 15,000 feet, and weathering brought it down, all of those layers fell down and was spread out to make the Black Hills.
2. No- because that weathering on the Hills made erosion, which brought all that sediment down to this place, which is now the Badlands.
3. 40 million years ago, I think that the land would be taller, possibly 9,000 ft high at it's max. In the next 40 million years, I would guess that the Hills and the badlands will be broken down more, and Harney Peak will be at 5,000 feet.

Trevor b said...

1
The layers of rocks were put there in layers over millions of years. Then the rocks lifer up because of uplifting, into a big dome. Then the rocks weathered away makingnthe many peaks we see today.
2
No it took the rain to make the peaks, if it wouldnt have eroded there would just be a really big hill there.
3
40 million years ago the black hills would look a really big hill bot a lot of peaks just a big grassy hill.
In 40 million years the black hills will have eroded to the point that they are just a big grassy hill with a few hills in it.

brooklynn mccaulley said...

1.) The black hills formed from layers of old rock with the newest rock on the top. When an uplift happens it pushes up all the layers, but then the layers of rock weather and then erosion pushes the layers to the side.
2.)No; because the rocks formed from the weatering and erosion of rock.
3.)40 million years ago I don't really have any idea what South Dakota looked like except maybe grassier. The badlands and black hills in 40 million years probably will be not as high or higher than they are now.

Anonymous said...

1.) The strong rock uplifted while the softer rock eroded away.

2.) yes because the rocks would've never eroded to form the badlands.

3.) I think the area of south Dakota was a lot bigger back then that it is now and u think it will will get smaller in the future.

Jessica S.

Neil L said...

Rock and magma was uplifted from the earth and cooled. The badlands wouldn't exsist because most of the rock there is from the black hills. Fourty million years ago the black hills would have been more round and dome shape and in fourty million years they will be almost gone.


Grand cranyon

Matt Fossell said...

The Black Hills were formed by granite a schite uplifted from the ground. They became the highest points in the Black Hills.

The Badlands wouldn't exist because erosion moved the sediment to the Badlands and deposition made it stay there.

I think 40 million years ago the Black Hills would have had each layer at the same point. I think the Black Hills will have the highest point being the granite and schiste.

Mariah H said...

1.The Black Hills were created through the process of weathering and erosion. Uplift caused many layers of rock to rise the surface.
2. No, the Badlands would not exist because sediment from the Black Hills created the Badlands.
3. I believe the Black Hills would have looked roughly the same but slightly shorter. Also I believe the Black Hills will continue to grow taller in the next 40 million years.

Caitlin Jeff is a boss 3rd period said...

1)the black hills were formed by thousands of years of erosion theres many layers of rocks and if the top layers erod and there is an up lift (well in this case that's what happend) that's how they came about.
2)They wouldn't exist there would just be flat land and nothing would have ever eroded.
3)back then I think this were bigger because stuff has been continuing to erode and with 40mill years of erosion away It would have been bigger... It will continue to be smaller in then next years to come.

Jaiden(: said...

1) The black hills were formed through weathering and erosion. The wind and rain caused the hills to reform.
2) the badlands wouldn't exist because the erosion that took place moved the rock and made It the way it is.
3)40 million years ago the black hills.... That question I do not know.... And 40 million years from I dont think there will be a black hills because of all the erosion!! .

Tyler B said...

Wow I've been to the black hills before and I didn't realize that there was that much change to it. And now I want to go to the badlands, and maybe I'll see the eroded sediment!

Kyle yasgar said...

1.) plate tectonics rubbed and pushed together forming large mOuntains in which erosion and weathering have been wearing away at for many many years.
2.)No, when the weathering and erosion have been wearing away tue sediment has to go somewhere so deposition carries it to the badlands.
3.) I believe that in 40 million years the black hills will wear away an be hills like in Sioux falls then in another 40 million years they will be flat.

Jordan St John said...

The Black Hills were formed by the up lift and erosion of the sandstone and red something.

The Badlands wouldn't have existed if erosion and weathering hadn't occured because it moved the sandstone.

It probably looked higher or lower, and maybe the lower bottom layers will be higher to the top.

Ryan B said...

The Black Hills were formed from different layers of rock that were uplifted from the ground about 70 million years ago.

The Badlands wouldn't exist with out weathering and erosion because weathered rock was moved and deposited in the area of the Badlands so with out them it wouldn't exist.

I think the Black Hiils looked like a really tall and smooth mountain range 40 million years ago, and think in another 40 million years the mountain ranges will be small little hills of granite that are half the hight of what the Badlands are now.

Walker Duehr said...

The black hills formed by layers of rock having the youngest rock on top then an uplift occurred erosion and weathering happened and shifted all the rock.

No because all the rocks in the badlands were formed by erosion and weathering in the black hills.

The black hills 40 millions year ago were probably very grassy and more rocks. In 40 million years the black hills will not be as tall do to erosion and weathering.

Walker Duehr said...

The black hills formed by layers of rock having the youngest rock on top then an uplift occurred erosion and weathering happened and shifted all the rock.

No because all the rocks in the badlands were formed by erosion and weathering in the black hills.

The black hills 40 millions year ago were probably very grassy and more rocks. In 40 million years the black hills will not be as tall do to erosion and weathering.

Nick leat said...

The black hills were formed from millions of years of weathering and erosion on the rocks and the rock getting pushed up.
2. The badlands would not exsist if the weathering and erosion on the black hill did not happen because of all the sediment going to that one spot.
3. 40 million years ago the hills were giant mountains of rock and there was no badlands. 40 million years from now the hills will be mounds of rock and the a badlands will be giant.

Hh said...

1. The blackhills were formed by weathering and erosion. Uplift rain and wind also had an impact.
2. No because weathering and erosion had to take place.
3. It wasn't as uplifted. But in the future I'm sure it will be.

Kristina Griesgraber said...

1.The black hills were created by years and years of weathering and erosion. It is also effected by an uplift.
2.It would exist but it would also look really different. Maybe more dome shaped rather than many jagged edges.
3.It was probably very flat. But in another 40 million years, it'll probably be very jagged, with few flat places

Kristin L said...

The Black Hills were formed by the buildup of rock. They now are being eroded away, removing the rock, and carrying it away.

No, the Badlands would not exist, because they are the way they are from the weathering and erosion of the Black Hills.

40 million years ago, I think that the Black Hills would have been at a even higher elevation than they are now, between 10,000 and 12,000 feet elevation, maybe.

In another 40 million years, I think that the Black Hills will be even less elevated. Weathering and erosion will remove the layers of rock.

Gavin B. said...

1. The black hills were formed by weathering and erosion. Also with uplift.Rain and wind helped there formation.
2. Yeah, They would still exist but they wouldn't look the same.
3. The mountains would look way bigger and not be the same shape and size. In 40 million years from now they will not be as tall and will be less pointy.

Robert Weaver said...

1. Weathering

2. The sedimte got eroded down there

3. I think the badlands were smaller and the black hills were bigger

Jamie spicer said...

When granite a schite is lifted is how the black hills are formed. I am going to say no because if they weren't taken any where they would just stay there and go away. The area is probably be very big and tall and wide, some what big but worn down. Short but still there.

Ashlyn w said...

1. There was an uplift of hot rock under the earth that made hills.
2. No because the rock went there.
3. I think that they will get smaller.

Sean p said...

-The black hills were formed by weathering and erosion. Also by a uplift of different types of rocks. -The badlands would not be here because erosion brought the sediment In it's place and the sediment stayed there since. - I think 40 million years ago the black hills were bigger. And 40 million years from now they will be smaller

Alex G./ Aditia said...

1.sediment built up on top of each other then a uplift happened aferwards weathering broke down the upper layers
2.no the whole thing is made by weathering
3.it probably looked taller
4.it will probably look much smaller and flatter because of weathering

Andee Capell said...

The black hills were formed when granite and schite rock uplifted from the ground. The badlands would not exist because erosion moved soil and sediment here and it stand by deposition. I think they were the closely the same to when the first uplift occured with little erosion changes. I think some point will be higher and others lower.

Zaccheaus Christopherson said...

1) uplift and shifting and erosion is what made the black hills
2) no it wouldn't be a mountain if it wasntfor erosion and weathering
3)I think it would be just a little hill, and I think it will uplift more


-Zaccheaus Christopherson

Craig jibben said...

The softer rockers were weathered away leaving the harder rocks.

2. Yes but it would be a lot higher and look a lot diffferent

3. 40 million years ago the black hills would have been taller and less weathered. In 40 million years the black hills will be more weathered and it will be a little shorter

Nick R said...

The black hills were formed by uplift ai the earth. No, because the eroding sandstone, red shale, and limestone was deposited there. It was a giant flat plain.

Brady Kafk said...

1.). The Black Hills were pushed upward from the heat in Earths core, and then from weathering Nd erosion.

2.). Yes, the area would exist but they would less of what they look like today and more blasé

3.) along time ago, the mountains were more unstable , but taller. In another forty years it will erode away more

Ethan said...

They formed from granite which was uplifted. The bad lands wouldn't exist if there wasn't erosion because erosion moved all the loose sediment to there and then deposition made it stay there.

Maddy & Tessa said...

1) The Black Hills were formed by weathering, erosion, and uplift.

2) No- Weathering and erosion broke and took the sediment and left it here to creat the badlands

3)40 million years ago that area was probably slightly bumby but not as much as today.
40 million years from now it will probably be a very small mountain range.

Anonymous said...

the black hills were formed by granite uplifted from the ground. than it became the tallest point at the black hills.

the badlands would not exist because erosion moved many of the sediment from the area to the badlands.

i think 40 million years ago the black hills would be smaller and it would be easier for erosion to take place

Alex Sanchez

Josh V. said...

1. The Black Hills were formed by weathering, erosion, and uplift.
2. I think the Black Hills would be a bunch of big hills and not so many smal ones.
3. I think the Black Hills were bigger before and they will
get smaller in the future.

Marin Forey said...

1. weathering and erosion carryed away the soft rock and caused it to form moutains
2.No because the weathering and erosion carryed the rock away to give it the unique form
3.40 million years ago the mountains were bigger. In another 40 million years they will be smaller then they are now

Gabe p said...

1 it was just some layers then uplift happened. After a while it eroded.
2 no because it would just be a pile of rock.
3 flat with a few bump. Flat completely

Tanner m said...

1.there were formed from weathering erosion and uplift
2.no there wouldn't be enough rocks
3. They will get smaller

Ethan said...

I think south Dakota was nothing but a grass land and also that it was flat. I think the bad lands will be more shaped and bigger in 40 million years.

Brady Gullekson said...

1.the black hills were formed by weathering, erosion, and up lift
2.no the weathering and erosion took the rock sediments
3.it was propably just some small hills

Sierra Baum and Ashlee Hausmann period 8 said...

1.Over time, rocks have piled and layered with other rocks. An uplift made it form into a hill, then weathering and erosion have caused it to break down and spread out.

2. No, because if the black hills weren't eroded, the badlands wouldn't exist. The badlands are mostly deposition from the black hills.

3. They would've been bigger, because erosion and weathering haven't had as much time to erode and weather the black hills. In the future, the would be smaller, because weathering and erosion had more time to erode and weather and overall shrink it down.

Melanie s. said...

1. The black hills is formes by uplift in the ground
2. I would say no because it cant be taken away from anywhere so no rock woud be lifted away
3. It woud be very large but worn down some. It would be cery small and worn down possible gone

Alyssa W said...

1.the Uplift of hot rock underneath the earth made the hills
2.no because the rock was there
3.I think they will get smaller

Anonymous said...

1: The Black Hills were formed by weathering, erosion, and uplift.

2: No- Because the erosion moved many of the sediment from the area to that general area.

3: 40 million years ago the area was probably a little rocky but nothing compared to what we have today
In 40 million years from now it will be just a small mountain range.
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timmy W said...

SUMMARY: The black hills were formed because an uplift occured and the land where the black hills are now rose. then as time went on the top layers eroded and were carried away, therefore the black hills aren't as high as they used to be... no because the land there would still be rissin and not flat like they are now... in another 40 million years the black hills will be even less high because weathering and erosion will still be taking place...

Jon Harriger said...

1.They were formed by weathering and erosion, also uplift.
2.No, erosion and weathering made it the way it is.
3.The Black Hills were bigger before and will get smaller, the Badlands could get smoother and less jagged.

Jocie B. Bailey Z. said...

1. The Black Hills were formed by weathering & erosion. Rain & wind led to their formation.
2. Yes they would, because it was just more taller than it is right now. Over time it got smaller caused by weathering and erosion.
3. It would be more hilly. But in 40 million years it wouldbe eroded & not so hilly.

Tevin Stults said...

1 The black hills were formed weathering and erosion
2 no because weathering and erosion made it that way
3 i think that the black hills would become smaller and the badlands would Be really flat.

Essence said...

1. The Badlands were form by use of wind,rain from weathering and erosion.
2. No because weathering and erosion have the take place in order for the sediments to be uplift.
3. I think the Badland in South Dakota 70 million years ago was more flat the it is today because of all the uplift, weathering, erosion that take place over time. 40 million years from now it would have more mountain or hill because of the three processes.

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