Pine Hill's lower Glacier
Erratic !!
(as viewed from the boards.)
Back Side of GE...
You will be finding and estimating Glacier Erratic rocks in the
park. You will start at the parking lot and enter the trail by the
Kiosk and find the massive Glacier Erratic.
This large granite boulder is resting above bedrock and marshes.
The large boulder was positioned when an ice sheet carrying rocks
eventually melted. Then, the debris within the melting glacier
settled out, placing the large rock on top of the ground.
What is a Glacier Erratic?
A glacial erratic is a piece of rock that deviates from the size
and type of rock native to the area in which it rests; the name
"erratic" is based on the errant location of these boulders. These
rocks were carried to their current locations by glacial ice, often
over hundreds of kilometres. Erratics can range in size from
pebbles to large boulders such as Big Rock (16,500 tons) in
Alberta.
Geologists identify erratics by studying the rocks surrounding the
position of the erratic and the composition of the erratic itself.
Erratics were once considered evidence of a massive flood
approximately 10,000 years ago, similar to the legendary floods
described in the texts of ancient civilizations throughout the
world. Ancient legends of an epic flood come from many cultures
including Mesoamerican, Sumerian (Epic of Gilgamesh), Hebrew (Old
Testament) and Indian culture. In the 19th Century, many scientists
came to favor erratics as evidence for the end of the last glacial
maximum (ice age) 10,000 years ago, rather than a flood. Geologists
have suggested that landslides or rockfalls initially dropped the
rocks on top of glacial ice. The glaciers continued to move,
carrying the rocks with it. When the ice melted, the erratics were
left in their present locations. (Ref: Wiki)
| Material |
Specific Gravity |
Tons / Cubic Yard |
| Andesite |
2.5 - 2.8 |
2.11 - 2.36 |
| Earth (dry) |
1.6 - 1.8 |
1.35 - 1.52 |
| Earth (wet) |
2 |
1.6875 |
| Gneiss |
2.6 - 2.9 |
2.19 - 2.44 |
| Granite |
2.6 - 2.7 |
2.19 -
2.28 |
|
Density (in lb/cu
ft.) = SG X 62.4 |
|
Density (SI units)
= SG X Density of water
(1.0 g/cc or 1000 kg/cubic
metre) |
Using the table above, and using the figures for Gneiss, take
rough measurement of the Pine Hill Glacier Erratic and estimate its
weight in tons. You are estimating only, no need to
leave the trail or the boards. Then find another
smaller glacier erratic, a rock that seems out of place in the park
and estimate its weight using Granite or Gneiss rock weights. (To
account for roundness, adjust the height of rocks to .60 their
guesstimated height.)
TO CLAIM THIE EARTHCACHE FOUND ....
› Submit 2 photos -one with you and the large GE near
the Kiosk and then one with your GPSr on a smaller GE in the park
somewhere. These can be posted online or emailed.
› Post the estimated tons of each of the 2
rocks. (est. cubic feet and multiply the tons.)
› Once you are home, google some of the other glacier
erratics in the US - they are pretty awesome - List the one you
might travel near next time in the log.
There are some large rocks but not all are GE's. Some are just
large rocks... GE's are normally out of place.
Thanks. |
|
I love it when a cache comes together, Strike
Anywhere!
The earthcache has been approved by
Michael Smith! Thanks for all your love and hard work of this great
park Michael.
If your picture is not ready then wait until you
have a photo. Logs with no photo of the actual cacher logging the
find or failure to answer questions will result in a log deletion.
Email me if you had any difficulties or problems, as I understand
that things can happen we don't expect. Thanks.