Rock story -- Nugget Sandstone of Red Butte east of the University of Utah.
Where was this rock found?
Red Butte Creek drains an area east of the University of Utah, and Red Butte is a prominent orange-red mountain to the south of the creek. Red Butte Garden and Arboretum is located at the mouth of Red Butte Creek and Fort Douglas is located between the mountain front and the University of Utah. The Red Butte Gardens and Arboretum provide an excellent outdoor classroom. The nearby hills outside the gardens provide for good, safe, plentiful rock collecting.
General observations:
Chunks of sandstone, pale red and orangish, lie scattered on the hill slopes. Walls along the paths in the Red Butte Garden are made of this material (not necessarily from Red Butte) and one trail leads to a quarry where pioneers mined chunks of this sandstone for building foundations and walls. You can see these stones in the foundations and walls of buildings in old Fort Douglas.
What you observe:
1. I see layers ... lots of them .. about 1/4 inch wide ... consisting of light pinkish orange bands separated by the skinniest of light brown bands. 2. The rock cracks along these layers pretty easily. 3. The rocks cracks across these layers depending how I whack it with a rock hammer. 4. It's easy to see why it made good building stone because it can be shaped into blocks quite easily. 5. It isn't really difficult to break ... not all that hard ... as ifit isn't held together very well. 6. With a hand lens, I see scads of sand grains. 7. The grains are all about the same size ... very small, sand size. 8. The grains all appear to be the same material ... quartz. 9. With the hand lens, the darker, very thin bands don't look any different than the lighter colored, broader bands. So, if I expected to see different material, I'm disappointed. It might be just a little bit finer grain size. 10. With the hand lens, there's lots of void space between the quartz grains. 11. With the hand lens, there's some whitish cement between some of the grains ... the grains are not welded together. It's almost hard to see what does hold the rock together ... probably the little bit of cement. 12. !fthis rock were put in water, it looks like the water could gradually infiltrate this rock. 13. Where the rock is broken, it breaks around the quartz grains, not through them. The surface is quite rough. 14. The rock doesn't seem to bust up by getting round. It seems to crack and break in chunks. 15. It looks like it would disintegrate into just a little pile of sand.
Where is the rock on the rock cycle now?
Now, it's a chunk of sediment. It came off a hillslope, so it is presently the product of transport by gravity and perhaps by water running down the slope.
Where was the rock on the rock cycle when it was bedrock?
It was a sedimentary rock
Tell me more:
The rock is made up of tiny sand grains, all about the same size (tiny) and same composition. It looks like it was either a beach or a sand dune. You could argue either way. My hunch is that it was a sand dune ... the layering is like a sand dune, the reddish color (although color is a trickster) indicates its probably was deposited where the little bit of iron in it could oxidize (tum rusty red).
Where is the rock heading on the rock cycle?
It's now a chunk of sediment. I bet it will be disintegrated into sand. That sand will be carried into the valley. It will go one of two ways on the rock cycle ... and these are the only paths: • it will get buried by hundreds, probable thousands of feet of sediment, ground water percolating through it will deposit cement between the grains and it will become firm and the sand particles will be part of a firm and coherent mass of sedimentary bedrock, or, " it will be buried for a while, but then it will be exposed and eroded again and be reworked as sediment. AND then ... if it goes the route of a) sedimentary bedrock ... it then will have two paths it can take ... " to become a metamorphic rock, or, " to be eroded and become sediment. OR ... if it went the route of b) sediment. .. it then will have two paths it can take ... " to become a sedimentary rock, or, " to be eroded again and become sediment again.
Sedimentary Example | Metamorphic Example | Ignous Example