come on, let's get on the boat
our boat awaits us
the mountain that encloses Shasta Caverns looms
ahead
the little buses that take us up the hill are waiting
we are quite a ways up the hill on this side of the lake
a row of houseboats looks like toys from this distance
here we go into the mountain and down into the caverns
soda
straws
bacon and draperies
stalactites
stalactites and stalagmites growing together over time
form this column
"peanut brittle" forms on the bottom of the caverns from
the chemicals
close up of "draperies"
a cave veering off the beaten path
first "graffiti" signed by the explorers J. A.
Richardson and Craig Morton in 1878
more bacon and draperies
a
link to more photos and documents in PDF format
available here.
(pictures start on page 23)
some other notes about caverns:
Overview
Water seeping through cracks in a cave's surrounding
bedrock may dissolve certain compounds, usually
calcite and
aragonite (both
calcium carbonate), or
gypsum (calcium
sulfate). The rate depends on the amount of carbon
dioxide held in solution, on temperature, and on other
factors. When the solution reaches an air-filled cave, a
discharge of carbon dioxide may alter the water's
ability to hold these minerals in solution, causing its
solutes to
precipitate. Over time, which may span tens of
thousands of years, the accumulation of these
precipitates may form speleothems.
Typical forms
Speleothems take various forms, depending on whether
the water drips, seeps, condenses, flows, or ponds. Many
speleothems are named for their resemblance to man-made
or natural objects. Types of speleothems include:
-
Dripstone is calcium carbonate in the form of
stalactites or stalagmites
-
Stalactites are pointed pendants hanging
from the cave ceiling, from which they grow;
-
Soda straws are very thin but long
stalactites having an elongated cylindrical
shape rather than the usual more conical
shape of stalactites;
-
Helictites are stalactites that have a
central canal with twig-like or spiral
projections that appear to defy gravity;
- Chandeliers are complex clusters of
ceiling decorations;
-
Stalagmites are bluntly pointed mounds,
often beneath stalactites;
-
Columns result when stalactites and
stalagmites meet or when stalactites reach the
floor of the cave;
-
Flowstone is sheetlike and found on cave floors
and walls;
- Draperies or curtains are thin, wavy sheets
of calcite hanging downward;
- Bacon is a drapery with variously colored
bands within the sheet;
-
Rimstone dams, or gours, occur at stream
ripples and form barriers that may contain
water;
- Stone waterfall formations simulate frozen
cascades
-
Popcorn is small, knobby clusters of calcite;
-
Cave pearls are the result of water dripping
from high above, causing small "seed" crystals to
turn over so often that they form into near-perfect
spheres of calcium carbonate;
-
Dogtooth spar are large calcite crystals often
found near seasonal pools;
-
Frostwork is needle-like growths of calcite or
aragonite;
-
Moonmilk is white and cheese-like;
-
Snottites are colonies of
speleobacteria and have the consistency of
"snot", or mucous;
- ... and many more.
Speleothems made of pure calcium carbonate are a
translucent white color, but often speleothems are
colored by minerals such as
iron,
copper or
manganese, or may be brown because of mud and silt
particulate inclusions.
