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By:
Mary
Age: 13
Grade: 8
New York |
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Granite schist |
I SLIPPED INTO MY SKI JACKET AND STUFFED SOME GLOVES DEEP IN MY POCKETS.
My mother honked the horn of the car,
and I ran out, locking the door behind me. The ride was only about
five minutes. As we approached, I could smell the salt air even
from inside the warm car. Mom parked the car, and I ran toward
the beach. It was cold; the wind was hitting my face and making
my cheeks tingle. I walked along the picturesque beach as the
sun was setting to the west of me. The waves crashed upon the
beach, and there were whitecaps as far as the eye could see. With
my head down and my back hunched over, I looked at the rocky sand.
I saw a couple of rocks I knew and put them into the bag I had
brought along. By the time I knew it, I had so many rocks I filled
up the entire bag! The skies grew dark, and my mother called me
to go home. |

Conglomerate |
I laid out all the rocks on the kitchen table as the
fire from the fireplace blazed next to me. I looked at each one carefully,
examining each one's unique features. I discovered that you don't
need to read a long, tedious book to learn about the history of
Earth. Rocks and fossils provide much of Earth's history. Each
rock had its own story to tell. |
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The region in which the rocks were collected
is a beach on the northern part of Lloyd Neck.
Lloyd Neck is located on the north shore of Long Island in New
York. There are many different landforms on the Neck. There are
clay cliffs to the west of my beach. Much of the clay cliffs in
the basin area have eroded. Whatever clay there is on my beach
I am sure it was deposited on the water's edge by the sea. Unfortunately,
each time another big storm hits the north shore another part
of history washes away. The waves of Long Island Sound can act
like bulldozers eating away the clay and the rocks like locusts
in green fields in the spring. However, the ongoing storms do
continually supply newly unearthed sediment to the beach. Other
important landforms in the area are the large boulders on the
beach. These boulders are most likely remains from the glacier
that formed Long Island. A glacier is made up of snow and ice.
At the end of the Ice Age, the glacier that covered North America
melted, advanced, and retreated many times. As they moved, the
glaciers dug out Long Island Sound, which was once a valley. The
material they carried created a long ridge called a terminal moraine
(a terminal moraine marks the line where the glacier finally stops
and begins to recede north again). It flowed south and pushed
many rocks and boulders in front of it. All of the rocks and boulders
on Long Island were from another place. This is how Long Island
was formed. Some specific evidences of the existence of glaciers
in this area are the chatter marks, or little white marks, found
on the rose quartz. These chatter marks were created when other
rocks and sediment scraped the rose quartz as the glacier pushed
the rocks along. |

Rose Quartz: the orange in the rock is iron oxide, white marks
are chatter marks

Red shale |
In the region where I collected my samples, there is a great variety
of sedimentary and metamorphic rocks, although there are some
igneous rocks, too. Depositing sediment forms a sedimentary rock;
sediment is earth that has been sculpted, broken up, and transported
by wind, water, or ice. Conglomerate rock found in my sample area
is a perfect example of a sedimentary rock. The purple cement
that glues the sediment together in the conglomerate rock is called
iron oxide (iron and oxygen). Iron oxide can also be an orange
color making the rock look like it is rusted. A metamorphic rock
is any rock that is transformed by pressure and heat into a rock
with new features and minerals. Mica gneiss rock is an example
of a metamorphic rock. An igneous rock is made from liquid rock
that has cooled. An igneous rock can be volcanic or plutonic.
A plutonic rock is formed by the solidification of a molten magma
deep within Earth and is crystalline throughout. A volcanic rock
is formed by solidification of a molten magma that has poured
out as lava over Earth's surface from a volcano or from any surface
eruption. The diorite porphyry is an example of an igneous rock. |
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Here are some descriptions of the rocks I collected:
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Rose quartz is a beautiful pink and orange color like a sunset
on a summer's eve. It feels as though the sea has washed over
it a thousand times and made it smooth as a rose petal. However,
there are evident chatter marks that look like white little specks.
They look like shredded coconut.
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Mica gneiss |
Mica gneiss is a sparkler on the Fourth of July. The bands of
minerals in the rock are clearly visible and look like an Oreo
cookie. The texture of the rock is like the series of speed bumps
in our school parking lot. The mica gneiss is an example of a
metamorphic rock.
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| Red shale is as flat as a penny and as smooth as a gumball inside
your mouth. The red shale is a sedimentary rock. Its nickname
is Indian paint pot because the Indians that inhabited Long Island
used it as war paint and for decorative purposes. The paint can
be extracted by rubbing the two stones together and then wetting
the stone.
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Petrified wood

Gneiss: dark lines indicate cracks

Amphibolite

Diorite porphyry: white marks represent minerals in the rock

Schist |
Conglomerate rock is like a hard piece of gum that holds together
tons of pebbles. It feels as bumpy as a cobblestone road and is
an example of sedimentary rock.
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| Petrified wood is just like a piece of wood but is surprisingly
hard and dense. Millions of years ago during the Cretaceous period,
the wood was buried and slowly water containing minerals seeped
through the ground. The minerals in the water replaced the wood
over time, and the wood became hard rock. The petrified wood may
have been buried in the clay cliff for thousands of years until
one of the storms ripped it out.
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| The gneiss rock looks like ripples on the water after a stone
is skipped upon the surface. It is a Ruffle potato chip but with
bigger ridges. The gneiss is a metamorphic rock. |
| Granite schist is like a cookie with tons of different chips that
represent the many minerals present in the rock. The granite schist
is a great example of a metamorphic rock because of the intergrown
bands of minerals seen on the side of the rock.
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| Amphibolite is like a very fine marbleized notebook because of
the black and white specks and swirls seen in the rock. Mica is
definitely present in the rock because of the glitter specks that
catch the light. This is a nice specimen of a metamorphic rock.
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| Diorite porphyry is an igneous rock. Although we don't have volcanoes
on Long Island, the glacier that formed Long Island could have
deposited it here from Connecticut, which used to have volcanoes.
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Schist is like a shimmery gown worn at a fancy ball. Unlike the
granite schist, this rock is a white color.
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| Long Island is a museum and a laboratory. By studying the rocks
of the area, one can discover the tremendous climatic and topographical
changes that have taken place over time. Studying the rocks is
like watching a dramatic documentary of the physical history of
Long Island, but geology is an ongoing science. The beach is a
very dynamic system. It is constantly changing as more materials
are deposited on its shores. Glaciers produce landforms that are
unique and leave behind a wide variety of materials of all sizes
(from clay to boulder) and rock type. This variety of materials
is discovered only over time. The history of Long Island is not
complete. We are discovering new facts every day. |
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References
Audubon Society Field Guide to North American Rocks and Minerals.
New York: Alfred A. Knopf, Inc., 1979.
The Evolution of L.I. Sound.
http://www.lihistory.com/l/hsl04a.html
Tofel, J. E., (1998). Personal interview
Van Diver, Bradford B. Roadside Geology. Missoula, Montana: Mountain
Press Publishing Company, 1985.
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