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| Sedimentary rock formation. |
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| Can you think of why fossils only form in sedimentary rock? |
Ice wedging (the breaking down of
rock due to the expansion of ice) will eventually break this rock down into sediment. What kind of rock will
this sediment eventually form? What forms of mechanical and chemical weathering will eventually break down this
rock?
| Sequoia National Park, Mineral King Area. |
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| What will eventually happen to this rock? |
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2: Sedimentary Rock:
Erosion, deposition, compaction and cementation...
Change sediment to rock in an awesome transformation.
Layers of sediment does water and wind deposit.
Methodically working in predetermined requisite.
Now the upper layers will squeeze down on the lower causing quite
a bit of compaction.
But cementation is usually necessary before the rock is in full
culmination.
The leaking minerals causes all this to happen working kind of
like a slow motion drip,
As the sediment binds together, no longer loose but in a solidly
occurring grip.
Common sedimentary rocks include coal, limestone, conglomerate,
sandstone and shale.
These rocks give us the opportunity to peak behind the past’s
mysterious vale.
Unlocking, in its layered treasured information, how the Earth’s
exterior shell came to be,
Allowing two legged creatures to evolve, which look something
like you.. and…me.
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Any rock will change when subjected to additional pressure
and heat,
Producing change in molecular bonds that are interesting and quite neat,
Making changes in the rock’s mineral structure by changing the molecular bond,
Often producing rocks that we humans benefit from and have grown very fond.
Marble and slate are two rocks that have gone through the metamorphic process,
One was limestone, and the other shale will I readily profess.
High heat inside the Earth produce the loin’s share of chemical change,
Kind of like intense heat changing clay to pottery of varying quality range.
Remember, however, that the rock’s elements do not change,
Although the rock’s molecules are thoroughly rearranged.
Metamorphic rocks are often found near volcanic and subduction zones,
As well as zones of convergence, like mountains, look for them as you roam.
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The below exhibit on the Rock Cycle
shows that all rocks begin and end their existence as liquid magma. Rocks may seem unchanging but over millions of years,
they actually do change. Study the exhibit below and read the Rock Cycle poem to understand how.
| Exhibit of the Rock Cycle. |
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| Every rock starts off and ends as liquid magma. |
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4: Rock Cycle
It’s because the Earth’s crust is made of rock that
we can on it stand.
We are on this planet because rock forms that something we call
land.
On the mighty gas planets, like Jupiter and Saturn, not a single
speck of life can we find.
Never mind something developing as wondrous and awesome as the
mysterious human mind.
All rocks on this Earth were once liquid magma and back to magma
will they become.
That’s called the “Rock Cycle” for a rock can
never say, “I am now completely done.”
For the same chunk of magma will take many forms in its existence
which is almost infinite.
Heat and pressure inside Earth change rock from one type to another;
these forces are indiscriminate.
For example, when shale becomes slate or limestone becomes marble,
a metamorphosis has taken place.
This process takes many many years, rocks change extremely slowly,
never in great haste.
Compaction and cementation of sediment forms what are known as
sedimentary rocks.
Sandstone and limestone are examples of this , nature has its
own internal clock.
Please remember, dear reader, that every rock started its existence
in liquid magma form,
And every rock will return back to the form in which it was originally
born.
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5: Rock Knowledge
The Earth is built of a material scientists call rock.
Every rock has a story about the past we hope to some day unlock.
Scientists read rocks to try to understand the geological past,
Examining them for clues of long ago since Earth’s primordial
blast.
How Earth’s climate and geography changed will rocks offer
many clues,
And what goes inside Earth? I only wish I knew..
As much as a rock which has formed over many millions of years,
But a rock is not alive like us and cannot think or shed tears.
However, a rock can offer a wealth of information to the observant
and trained eye,
And begin to answer the many questions we have about Earth; most
which begin with “Why?”
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We wouldn't be here if
it wasn't for soil since this is where our food grows. Notice most soil has quite a bit of air in it. Silt is
dirt from stream or lake beds. It can be very valuable soil and often contains essential nutrients. The fertility
of soil generally depends on the nutrient and organic matter content. Different plants thrive in different types of
soil.
| Soil composition of relatively fertile soil. |
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| The composition of these substances will change depending on soil type. |
Most soils are classified by the amount
of humus it holds. Humus is the organic part of the soil. This means it is composed of decayed plants, animal
wastes and microbes that break down this material into soil. To grow crops, you usually need soil that is high in humus
although there are some crops, such as barley and oats, that can grow in rocky soil. Soil can also be classified by
the rock material it is made of. The bay area soil is high in clay because shale is the most common rock in this area.
(Shale is high in clay content.)
| Soil types in North America. |
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| The amount of humus in soil often determines its fertility. |
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6: SOIL
Dirt is a mixture of air, clay, decayed plants and rock.
It holds life’s secret that we’ve learned to unlock.
Fertile soil and water are necessary to grow food.
Essential for all living things, both beautiful and crude.
The first thing that happens is bedrock(3) eroding,
Slowly, this will be mixed with many plants corroding.
Nay, this process does not happen in the blink of an eye,
But to understand, remember, matter never really dies.
Rather it changes form, takes on a new look.
Forms new bonds like a person who gave and took.
As plants die, they add nutrients to the soil,
Decomposing as they ease the farmer’s toil.
Because just eroded rock will not grow very much.
You'll need the organic matter if plants you are to touch.
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