EARTHCACHE REQUIREMENTS
Each cacher must send his/her own answers BEFORE logging a find. ... "Geocachers must complete the tasks before they log the EarthCache as found." (4.3. EarthCache logging tasks)
Enjoy the journey (learning adventure) as well as the destination (smiley earned). Remember to take only pictures and leave only footprints. To get credit for this Earthcache, complete the following tasks:
NOTE: Answers via message -and- log signature picture is required to post a find for this cache.
1. MESSAGE …. Look at the streamers attached to the cave opening. a. Which way are the streamers moving? / b. Explain what is happening.
2. MESSAGE …. How does cave breathing help geologists?
3. MESSAGE …. Will the opening be enlarged over time due to wind erosion?
4. MESSAGE …. a. What does the cave opening represent to the Lakota Nation? / b. What is the connection between the cave's interior and the Black Hills?
LOG …. Post a picture of you or your signature item at anything you find interesting at the Visitor Center. This picture is your log signature.
OPTIONAL - Please respect the time and effort involved in finding and creating this earthcache by adding A and B to your log.
A. JOURNEY OF THE MIND ... Science explains what we observe. Relate (in your own words) something you found interesting in the reading. This adds to your learning adventure and your log.
B. JOURNEY OF THE HEART ... Art shares our personal experience of what we see. Share something special you found on site, and why it is special to you ... prose / story / poem / picture. This is a memorable addition to your log and will make other hearts smile.
Journeys of Heart and Mind ...
Stories to Touch the Heart and Puzzles to Challenge the Mind / Rainbow Tree Story
ABOVE - 05/13/2021 ... BELOW - Driving Tour
WIND CAVE
"A warm shallow sea covered the area about 350 million years ago. Fragments of seashells, made of calcium carbonate, built up over time on the seafloor and eventually became limestone. Bodies of gypsum, made of calcium sulfate, also formed during this time when arid conditions caused seawater to evaporate and the minerals to crystallize. The gypsum formed irregular shaped masses within the limestone. The resulting rock is known as the Madison Limestone formation, or locally as the Pahasapa (Black Hills) Limestone.
"The gypsum masses were unstable. They grew and shrank as they absorbed and expelled water. This pressure fractured the gypsum and surrounding limestone. Like thick toothpaste, some gypsum squeezed into these cracks and crystallized in place. Later, water rich in carbonate ions converted all of the gypsum to calcite, or calcium carbonate. This set the stage for the cave and boxwork to form."
The seas advanced and retreated multiple times alternately depositing and eroding sediment. Portions of Wind Cave are over 300 million years old, making it one of the oldest in the world. The cave is also large and extremely complex, with 149 miles of known cave (as of 2019) sitting under just 1.25 square miles of land.
CAVE BREATHING
Caves “breathe" in the sense that air flows in and out as air pressure changes. The researchers have found that carbon dioxide pressures vary with external temperatures and ground cover, indicating a possible link between the carbon found in rock formations in the caves and seasonal changes. Changing weather patterns bring changes in the outside atmospheric pressure. When the outside pressure increases, air flows into the cave. When outside air pressure drops, air flows out of the cave. The cave "breathes" until inside and outside air pressures are equal.
Many caves are so large they have their own air pressure system. The direction of the wind differs depending on the barometric pressure on the surface. The air pressure system in large caves is always trying to maintain equal pressure with the surface. Researchers can get an estimate of how big the cave is by measuring the barometric airflow from the cave’s entrance. A large cave such as Wind Cave with only a few small openings will "breathe" more obviously than a small cave with many large openings.
"Barometric airflow through the natural entrance of Wind Cave not only gave the cave its name, but also provides an opportunity for determining the approximate volume or size of the cave passages. Monitoring and recording the barometric airflow through the cave natural entrances help us understand the volume of air in the cave and that can be used to calculate the total volume of cave passage. By using the amount of air that comes from the cave we can determine the volume of space in the cave. At this time we have determined that we have found less than 10% of the cave. However, that does not mean we can determine the mileage of the cave. We could have many very small passages or one great huge one. But it does give us an idea of how big the cave could be."
WIND EROSION
Wind erosion is a natural process that moves soil from one location to another by wind power. ... Wind erosion can be caused by a light wind that rolls soil particles along the surface through to a strong wind that lifts a large volume of soil particles into the air to create dust storms.
RESOURCES ... Geology / Wind / Cave Breathing