What is it?
Its volcanic lava, more specifically Pillow lava, also called
Pillow Basalt.
Basalt is a fine grained igneous rock that is made up of several
minerals; some of them are feldspar, iron and magnesium. Basalt
forms from rapidly cooling magma that ranges in temperature between
1100 deg. - 2400 deg. F
Because Basalt is formed by cooling quickly it is fine grained,
and can come in a few colors but is mostly dark gray and has kind
of a glassy look to it.
Igneous rock is formed by magma or lava cooling and becoming
solid. Igneous rocks are one of the most common rocks on the Earth.
Another example of an igneous rock is granite. It is not formed the
same way basalt is formed, but we have a lot of that in Maine.
When I think of volcanoes I think of a mountain with the top
blown off, and molten rock oozing down the side of it.
I’ve learned that not all volcanoes are like that, some
times they are just a weak spot on the earth’s surface that
allows magma to come up form the earth’s core, These spots
are called vents.
I just spoke of lava and magma and you may be wondering what
difference is between the two. Lava is a word scientist’s use
for molten rock that breaks through the earth surface and magma is
the word scientist’s use for molten rock that is underground.
Not all magma and lava are the same; they are made up of different
types of rocks and gases. That is why some flow slowly like honey
or syrup and some flow faster like paint and some really
don’t flow at all, they just get pushed along by the lava
coming out of the vent.
Pillow lava gets it’s name because it looks like pillows
that are stacked side by side on their edge.
Pillow lava is formed underwater and gets its shape because it
is cooled quickly.
What happens is that lava comes up out of a vent in the earths
crust and the outside starts to harden because the water is cold.
The middle takes longer to harden so the magma keeps getting pushed
out. Think of it like blowing up a balloon. The outside of the lava
balloon keeps the hot lava inside and the balloon gets bigger and
bigger until it is easier for the lava coming out of the vent to
start a new pillow (balloon) right beside the first one. Sometimes
a hole will break in the "balloon" at the top or on the side and
the hot lava will flow out creating a new formation on top of one
of the older ones.
This picture is what we think it may look like when pillow lava
forms.
This site is estimated by the Maine geological team to be about
500 million years old.
That was during the Middle Cambrian period. From what I have
read there was a lot going on with the earth at that time.
You may be wondering what pillow lava is doing here in the
mountains of Maine. As you read above, pillow lava is formed under
water and there is only a river and small pond close to this site.
Well, a lot has changed since this lava was formed. I can only
guess, but it would seem that this area was under some sort of
water. It may have been the ocean or a lake. This was way before
the time known as the "Ice age" that happened around 20,000 years
ago. Consider this as you stand at the site. All the mountains you
see may have been islands. Another possibility is that this lava
formation was created somewhere else and moved here over years, by
a glacier. There are ways to tell if that may have happened. We
talked about how pillow lavas look like balloons when they are
formed. So if the rocks look to be upside down balloons we can
guess that the formation has been moved and is not in the position
that is was in when it was formed. Because the pillows may not look
exactly like a balloon or they may be on their side. Another thing
to look for is air pockets where gasses escaped. These are most
commonly found at the top of the pillows.
To claim the cache you have to answer one of two questions.
please send an email to our profile telling us the length and
height of this formation. Or tell us if this formation looks as if
it was formed here, or if it was moved here by some natural
force.
Parking
Please be careful parking on the side of the road, especially in
the winter months. There is a small area to park just south of the
formation. This is a section of the old state road. Just pull in
and park to the right. From there it is a short walk up the old
state road and down a trail to the cache site. There is a camp down
a separate trail off this road, please respect their privacy and
don't go near the camp. The coordinates are below.
Leave no trace
Remember this is an Earth cache and you won’t find any
containers at this site.
Respect the land and please don’t remove any rocks from
the site.
Thanks for stopping by. We hope you enjoyed our cache.