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:
1. MESSAGE …. a. When (mya) was the Pahasapa Limestone formed? / b. What color is the Pahasapa Limestone? / c. You are near the cave's natural entrance which formed in a ravine. Explain why.
2. MESSAGE …. a. When (mya) was the Minnekahta Limestone formed? / b. What color is the Minnekahta Limestone? / c. What differences are observable between the Pahasapa Limestone and the Minnekahta Limestone?
3. MESSAGE …. a. When (mya) was the Minnelusa Formation formed? / b. What color is the Minnelusa Formation? / c. How are the layers different from those seen in the Minnekahta Limestone?
4. MESSAGE …. a. When (mya) was the Deadwood Sandstone formed? / b. What color is the Deadwood Sandsrone? / c. In what types of environments does sand accumulate?
5. MESSAGE …. a. When were the Pegmatites formed? / b. Choose a section and compare the percentage of each of the three minerals.
6. MESSAGE …. a. When were the Schists formed? / b. In what direction have the layers formed? / c. What does this tell about the direction from which the pressures came? / d. Folds (bending) often occur when the rocks undergo pressure. Are there small folds present? If so, how many.
7. MESSAGE …. a. When (mya) was the Spearfish Formation formed? / b. What color is the Spearfish Formation? / c. What is responsible for the color? / d. What evidence is there that water eroded the valley?
8. LOG …. Post a picture of you or your signature item at your favorite stop along the tour. Explain why you chose this spot. 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
THANK YOU Lennie Ramacher for permision to share this learning adventure.
A geologic map of the park: NPS Wind Cave National Park Geologic Map, where Mp is the Mississippian Pahasapa (Madison) Limestone, Phm is the Pennsylvanian Minnelusa Formation, Po is the Permian Opeche Shale, Pm is the Minnekahta Limestone, TRPs is the Triassic Spearfish Formation, Tw is the Tertiary White River Group, while Qal and Qt are Quaternary alluvial deposits ... Wikipedia
GEOLOGIC HISTORY OF THE BLACK HILLS
"During the Paleozoic Era, this area was a basin covered by a shallow sea that, over millions of years, deposited a thick blanket of sediments over the Precambrian igneous and metamorphic rocks. Then, about 70 million years ago, the earth's crust began to uplift into a dome. This uplift may have occurred when tectonic plates collided, forming the Rocky Mountains. As the force of the colliding plates increased, the Eastern plate rippled and formed the dome shaped Black Hills. Erosion eventually carried away many sediments in the central area of the hills, exposing the Precambrian rocks. Many of these stages of development can be readily seen in the park."
1. PAHASAPA LIMESTONE - MISSISSIPPIAN PERIOD
Limestone is a sedimentary rock deposited in oceans. It is mainly composed of calcium carbonate.
Pahasapa Limestone forms steep slopes or cliffs.
All Black Hills caves have formed in this layer 300 to 600 feet thick. Originally it was laid down on a shallow seabottom about 300 million years ago. Its name derives from the Lakota word meaning "Black Hills".
2. MINNEKAHTA LIMESTONE - PERMIUM PERIOD
This is a thinly bedded slabby limestone. Caves rarely form in this limestone because it is so thinly bedded that the ceilings would collapse.
3. MINNELUSA FORMATION - PENNSYLVANIAN/PERMIAN PERIODS
This formation consists of interbedded limestones, sandstones, shales. Each alternates with distinct horizontal layers.
4. DEADWOOD SANDSTONE - CAMBRIAN PERIOD
All sandstones are sedimentary rock composed mostly of grains of quartz varying in size.
5. PEGMATITES - PRECAMBRIAN
Pegmatites are part of the Precambrian core of the Black Hills. They are coarse grained igneous rocks that formed deep within the earth. The large crystals indicates they formed deep within the earth. Pegmatite consists of three common minerals - quartz (whitish/glassy), Feldspar (pink/shiny flat surfaces), tourmaline (black/long slender crystals).
6. SCHISTS - PRECAMBRIAN
Schist is also part of the Precambian core of the Black Hills. Schist is a metamorphic rock composed of shiny mica minerals.It has very fine layering indicating that great pressures occurred within the earth. Rock layers form at right angles to the source of pressure.
7. SPEARFISH FORMATION - PERMIAN/TRIASSIC PERIODS
This formation is composed of fine-grained shales and siltstones. The red color comes from iron oxides. Thus, this formation is often called Red Valley.
RESOURCES ... Wind Cave National Park Geology Driving Tour ... Historical Marker ... Minnekahta Roadcut ... Minnekahta pdf ... Minnelusa Formation ... Black Hills Part 1 ... Black Hills Part 2 ... Black Hills Part 3 ... Black Hills Part 4
https://vmnhpaleontology.wordpress.com/2012/06/22/the-black-hills-part-1/
https://vmnhpaleontology.wordpress.com/2012/06/26/the-black-hills-part-2/
https://vmnhpaleontology.wordpress.com/2012/06/29/the-black-hills-part-3/
https://vmnhpaleontology.wordpress.com/2012/07/05/the-black-hills-part-4/
https://rapidcityjournal.com/lifestyles/black-hills-geology-rocks/article_5a623f24-0aa9-56ad-958d-29e6917dba43.html
https://blackhillsvisitor.com/learn/black-hills-and-badlands-geology/2/
https://www.blackhillsbadlands.com/parks-monuments/wind-cave-national-park