2007-02-08 13:24:14 · 7 answers · asked by eagleman88 1 in Science & Mathematics ➔ Earth Sciences & Geology
Shale
2007-02-08 13:27:09 · answer #1 · answered by MsE 3 · 0⤊ 3⤋
Neither, some sandstone is older than shale... some shale is older than sandstone. Sandstone is made up of sand sized pieces of rocks/minerals, while shale is made up of tiny rock/mineral fragments that would have been mud or clay before it hardened into rock (this is why shale is often called "mudstone").
The age of either sedimentary rock would depend on how long ago it formed... some sandstone is very old and some shale is very young - and vice versa.
2007-02-08 14:23:19 · answer #2 · answered by brooks b 4 · 6⤊ 0⤋
Good question.
Consider: Sandstone is a rock made up of sand sized particles cemented together by some material (most commonly calcite or silica) or made to adhere to one another by a very finely-ground matrix material deposited with it.
Shale, however, though consisting of very fine particles of any composition in theory, usually consists mainly of clay minerals, which are the decomposition product of many other minerals.
Decomposition takes longer than erosion (because it is a physical as well as chemical process). Of course some decomposition helps erosion to occur, as well.
All in all sand probably was formed before clay, and sandstone probably was formed before shale.
Remember, though, in geological terms they both began forming as soon as other types of rocks began to be exposed to erosive forces and to decomposition.
2007-02-08 15:08:41 · answer #3 · answered by David A 5 · 0⤊ 2⤋
Sandstone rocks are sedimentary rocks made from small grains of the minerals quartz and feldspar. They often form in layers as seen in this picture. They are often used as building stones.
Shale rock is a type of sedimentary rock formed from clay that is compacted together by pressure. They are used to make bricks and other material that is fired in a kiln.
How Sedimentary Rock Is Formed
For thousands, even millions of years, little pieces of our earth have been eroded--broken down and worn away
by wind and water. These little bits of our earth are washed downstream where they settle to the bottom of the rivers, lakes, and oceans. Layer after layer of eroded earth is deposited on top of each. These layers are pressed down more and more through time, until the bottom layers slowly turn into rock.
2007-02-08 13:30:33 · answer #4 · answered by Anonymous · 0⤊ 2⤋
The shale and limestone are older than the sandstone..
2007-02-08 13:31:02 · answer #5 · answered by kathy p 3 · 0⤊ 4⤋
Shale because it is more dense than sandstone.
2007-02-08 13:27:51 · answer #6 · answered by (A) 7 · 0⤊ 3⤋
depends on which was deposited first.
2007-02-09 06:56:53 · answer #7 · answered by rockjock_2000 5 · 2⤊ 0⤋