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 …. Observe all sides of the rock at the posted coordinates. a. Based on your observations and the reading, what kind of inclusions are embedded within the parent rock? Explain your choices. / b. Are they located only on the surface? / c. Estimate the size of the largest inclusion.
2. MESSAGE …. There are nearly a hundred boulders lining the driveway from gate to parking lot. a. Choose one of these boulders. / b. What inclusion/oddity is embedded in the parent rock? / c. Explain your choice
3. LOG …. Post a picture of the rock oddity you found and described in your message. This picture is your log signature.
OPTIONAL - Please respect the time and effort involved in 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. This is a memorable addition to your log and will make other hearts smile.
GLACIER OR NO GLACIER
"During the most recent glaciation of the area (Wisconsinan - appox. 16,000 years ago) this was the location where the glaciers began to retreat. Glaciers carry large amounts of soil and rock within them. As the glaciers retreat the soil and rock is released from the ice ..."
The park is beautfully landscaped devoid of any large boulders. Hence, the boulders lining the driveway from gate to parking lot are probably locally sourced from the establishment of this park.
GEOLOGICAL INCLUSIONS / ODDITIES
There are a myriad of processes that cause a different type of rock to be embedded within the parent rock. There are also a myriad of processes that cause different colors and markings on the parent rock.
BLEBS and LENSES
BLEBS are small bubble-like inclusions of one mineral within a larger mineral.
LENSES are deposits that are thick in the middle and thin at the edges, resembling a convex lens in cross-section.
CONCRETIONS
A concretion is a hard, compact mass of matter formed by the precipitation of mineral cement within the spaces between particles. They are found in clay strata that was originally mud laid down on the sea floor millions of years ago. Concretions vary in size and shape, but most usually spherical.
CALCIUM CARBONATE DISCS - These concretions aka fairy stones consist of small single or multiple discs often with concentric surface grooves. They can appear as shallow bowl-like depressions formed when calcium carbonate minerals in the rock weathered quicker than the non-calcareous parts of the rock. This process is called differential weathering.
CANNONBALL CONCRETIONS - These concretions are large round concretions resembling cannonballs. They were created by early cementation of sand and silt by calcite.
ELONGATE CONCRETIONS - These concretions form parallel to sedimentary strata due to the flow of groundwater.
HIATUS CONCRETIONS - These concretions are characterized by exhumation, exposure and reburial. They are most commonly found during periods in which calcite sea conditions prevailed, such as the Ordovician, Jurassic and Cretaceous. Fossils are often associated with these formations.
KANSAS POP ROCKS - These concretions are typically associated with thin layers of altered volcanic ash. Shape is generally oblate spheroids with variable sizes. Called "pop rocks" because they explode when thrown in a fire or produce sparks and a burning sulfur smell if cut or hammered.
MOQUI MARBLES - These concretions were created by the precipitation of iron dissolved in groundwater. They are varied in both shape and size.
ROSE ROCKS - These concretions are made of crystals that resemble a rose in bloom. The rock’s petal-shaped clusters is due to the intergrowth of crystals. The mineral comprising the rose was precipitated in interconnected voids in the rock.
FOSSILS
Formed when a plant or animal dies and is buried in mud and silt. Soft tissues quickly decompose leaving the hard bones or shells behind. Over time sediment builds over the top and hardens into rock.
A relatively common occurrence is white calcite replacing the shell.
ORGANICS
Rocks are often covered with lichen and other organics, which sometimes appear like occlusions.
STAINING
IRON - Most sedimentary rocks contain iron in varying degrees. This mineral may appear in patterns or dispersed randomly throughout the parent rock. Color appears in various reddish hues.
MANGANESE - Forms similar to iron staining, but from manganese rich solutions (water) percolating through the sandstone. This mineral may appear in patterns or dispersed randomly throughout the parent rock. Color appears in various blackish hues.
WATER SCULPTURE
Water is responsible for eroding the rock creating a myriad of formations. Erosion of rock occurs from falling water (waterfalls), meandering water (rivers), and wave action (seas). Glaciers scraping across rock leave glacial striations.
XENOLITHS and PHENOCRYSTS
XENOLITHS are rock fragments of metamorphically altered rock that gets caught in the cooling magma or lava. As the magma cools, the igneous rock forms around the rock fragments.
PHENOCRYSTS are mineral crystals in igneous rock that began growing early in the cooling history of the rock, before the fine-grained groundmass crystallized around them. Or they may have arrived by gravity, either floating to the top or sinking to the bottom of a magma chamber.
RESOURCES ... University Treatise ... Embedded Oddities ... BSHC - Limestone ... Turtle Shell ... ASP Rock Water Erosion ... Dots and Stripes ... Glacier or No Glacier Earthcache