Download When Glaciers Ruled the World!

When Glaciers Ruled the
World!
Formation of the Boston Harbor
Islands
Millions and millions of years ago glaciers
ruled the world. Glaciers are ginormous
blocks of ice that are always moving. In
fact, glaciers formed one of my favorite
places in the world, Boston, along with
many of the Boston harbor islands!
It all started on a cold winter day…
Alfonso, the largest glacier of them all, was on a
stroll in the mountains. Alfonso was a bit of a
bully to the smaller rocks because after all, he was
over a mile tall. As he slid over rocks the impact
was so great that he would form scratches in the
rocks called abrasion. As the rocks cried in pain
Alfonso dropped pebbles, sand and dirt on them
called till. Till which is also called deposition
started to form beaches.
The rocks on a beach aren’t
perfect due to erosion by wind,
which can make small sand
particles blow around (loess),
erosion by water which can
form crevices and when water
fills them (*rills) and erosion
by waves which, like any other
type of erosion, causes the
rocks to crack and fall apart.
*When rills merge they form larger rills
known as gullies.
All of these rocks can
form spits and
longshore drifts which
are small pieces of land
attached to a larger
piece of land. An
example of this is cape
cod.
Even though Alfonso wasn’t the fastest glacier he
was always moving. He would push against dirt
and then when he got tired he would retreat. The
dirt that was pushed would cause moraines to
form.
Another one of Alfonso’s hobbies was forming
kettle ponds. When pieces of ice would break of
him they would form pits in the ground. When the
ice melted it would leave water in its place. These
were known as kettle ponds.
Then, after a long day of
picking up rocks, pebbles and
boulders, Alfonso came to a
stop when he saw this huge
rock (erratic) right in the
middle of his path! Alfonso
wondered who ever could
have deposited this boulder so
he looked around only to find
the prettiest glacier he had
ever seen...Gertrude!
Alfonso approached Gertrude,
tapped her on the shoulder and
asked if it was her who had
deposited that erratic. She
looked up at him mesmerized
by his glory. She nodded her
head slowly and also admitted
to being the one who put the
sand particles in the streams
(runoff). Gertrude apologized
and Alfonso, being the kind
and noble gentlemen that he is,
accepted her apology.
Together they formed drumlins which are pretty
much just huge piles of till. When these drumlins
got surrounded by water they were known as
drowned drumlins which are what many of the
Boston Harbor Islands are including...Georges
Island! Gertrude and Alfonso lived happily ever
after and as for there baby’s (the boston harbor
islands) well, lets just say they are grown up.
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