Lehman Caves EarthCache
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Difficulty:
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Terrain:
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Size: 
(other)
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Features found inside caves:
Soda straws
Thin-walled hollow tubes about 1/4" in diameter; soda straws grow
from ceilings of caves as water runs down inside them, depositing
rings of calcite at their tips. These incredible formations can be
over 20,000 years old and reach lengths over 20 feet. Backlit by
hidden lights in the cave, each appears to have a tiny diamond
suspended from its tip. (If one of these drops of water falls on
you, you are said to have received a "cave kiss"). Soda straws are
so fragile that sound waves or movements of the air around them can
cause them to break and fall.
Helicites
Twisted formations projecting at all angles from ceilings, walls
and over the floor of caves. The over-all formation seems to defy
the laws of gravity. Many helicites were growing out from the sides
of the soda straws; they look like tiny branches, and geologists
cannot explain why they grow up or outward instead of down, the way
normal cave formations do.
Stalactites
Formations that hang from cave ceilings and form as layers of
calcite are deposited. This occurs when the water flows over the
outside of soda straws after the hollow centers become partially,
or fully, plugged. Our guide shone his laser pointer on a living,
growing (wet) stalactite, and it was translucent; the whole
cone-shaped rock lit up. Then he shone his pointer on a "dormant,"
dry formation, and there was just a small red dot on the surface.
The difference was quite dramatic.
Stalagmites
Formations that rise from the cave floor and are often, but not
always, formed by dripping water from stalactites above.
Stalagmites are usually larger in diameter than stalactites, and
more rounded on top. As a child, I learned the following mnemonic
to keep the two straight: stalactites hold tight to the ceiling;
stalagmites might eventually make it up from the floor.
Bacon / Drapery
This formation forms when, over time, water flows down walls, over
floors and/ or other formations, and results in a build-up of
calcite. The different colored strips are a result of the presence
of different minerals, including iron oxide (red rust) in the
calcite; other colors include a wide assortment of creams, yellows,
and browns.
Columns
Formed by the joining of stalactites and stalagmites, or when a
stalactite connects with the cave floor or a stalagmite connects
with the cave ceiling.
Flowstone
This formation is formed when, over a period of time, water flows
down walls, over floors and other formations, and results in a
buildup of calcite. In contrast to the "cave bacon" or draperies
mentioned above, flowstone is usuall a thicker, heavier buildup.
Occasionally water flows over a stalagmite or column, and the
resulting formation looks like a tiered wedding cake or a series of
trees on a steep hill.
Shields
Shields consist of two round or oval parallel plates with a thin
medial crack between them. The medial crack is thought to be an
important clue to their formation. Shields tend to form in caves
with highly fractured limestone (like Lehman). Shields grow at all
sorts of angles from the ceiling, wall, and floor of the cave. The
most accepted theory for how shields form relates to fractures in
the bedrock. Water under hydrostatic pressure moves through thin
fractures in the limestone. As it enters the cave passage by means
of capillary action, the water deposits calcite on either side of
the crack, building plates of calcite with a thin, water-filled
crack between them. Shields may be decorated with popcorn or
helictites on the top and along the medial crack, and draperies and
stalactites on the bottom. Sometimes the speleothems on the bottom
plate get too heavy and pull the shield apart.
To log this cache you must:
1) Please post a picture of you or your group at the coords w/ a
GPSr in your log (but not required) & E-mail me the following
information:
2) What cave feature Lehman Caves is famous for?
3) Approx. how many of these features are inside the cave?
4) Who was the cave mapped by? (See plaque at cave enterance)
5) List the 3 items you CAN take into the cave.
6) Please finish the following: "Out of consideration for other
visitors.........."
Additional Hints
(No hints available.)