Father's Day Series 2008 #1 - Inner Space Caverns EarthCache
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You do not need to do the tour to log this cache, but seeing the caverns is well worth it. The Adventure Tour will
take about 1 hour 15 minutes and is about 3/4 mile of paved trail walking. The cost currently ( 2008 ) is adults $14.95, kids $8.95
INNER SPACE CAVERN was discovered by the core drilling team when they were building IH35 in the Spring of 1963.
According to geologists, Inner Space Cavern is located in rocks that were first
deposited some ninety million years ago as lime and magnesium rich mud during an
age that is referred to as the Cretaceous period. Over the years this mud solidified into
limestone and dolomite. As time passed, this area was covered with sediments of
chalk, clay and sand to a depth of over a thousand feet. During the next sixty million
years, the layer of limestone was uplifted above sea level allowing the sediments to
erode, leaving the limestone exposed. Today this limestone is referred to as the
The next event in geologic history that had a direct effect upon the development of
Inner Space Cavern was a series of vertical faults that fractured the limestone from
Waco to Del Rio. Today geologists call this the Balcones Fault. These cracks allowed
the ground water to flow freely through the limestone, thus setting the stage for the
formation of the cavern.
Water itself is unable to dissolve enough limestone for the formation of a cave as large
as Inner Space. The dissolving action of the water comes from the carbon dioxide that
is added to the ground water from decaying plant matter on the ground, turning the
water into carbonic acid. Carbon dioxide in the air also turns rain water into carbonic
acid. Limestone is soluble in an acid solution. For those science types out there this is
the chemical reaction that occurs when weak carbonic acid comes in contact with it:
water + decaying matter = carbonic acid + limestone = calcium bicarbonate solution
H2O + CO2 = H2CO3 + CaCO3 = Ca++ + 2HCO3-
During the formation of what is now Inner Space Cavern, the acid content of the water
dissolved away the limestone starting with the cracks caused by the Balcones Fault. Once
the water no longer flowed through the passages in the cave, the formations began to develop.
There are parts of the cave that are unseen by visitors to INNER SPACE are totally different
from the tourist sections. The walkways and lights are not there; it is total darkness; there
is a lot of mud; and oftentimes it is not even possible to stand up and walk. Today, after
almost twenty years, the survey is still in progress. Over 7000 feet of new cave has been
added to the old map.
In addition to the earth formations discovered at Inner Space Caverns they also discovered the
bones of distinct animals like the Saber Tooth Tiger.
In order to claim this earthcache as a find, you must complete the following tasks.
Requirement #1 - Photo By The Marker: Go to N30 36.481 W097 41.280. There you will find a Texas Historical Marker.
With your find log, you need to post a photo of yourself standing in front of the marker, with the Inner Space Cavern display
case behind you.
Requirement #2 - Find the answer to: How old is the cave estimated to be?
Requirement #3 - Find the answer to: What percent of the cave is still growing?
Requirement #4 - Find the answer to: It was carved from water from what?
Requirement #5 - Find the answer to: What is in the cement slab around the display case and how many are there?
Requirement #6 - Find the answer to: What is the date on the bottom right corner on the historical marker?
Send answers to the above questions to me via my profile link.
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