PERMISSION:
This earthcache was placed with permission of the Education Technician for the Shenandoah National Park.
EARTHCACHE REQUIREMENTS:
Each cacher must send in their own answers when logging this find. After you arrive at this creation of nature, enjoy this geological feature and what you will bring home with you through this experience. Review the materials below and answer by message/email the questions to the best of your ability. Please follow all logging requirements and do not post any answers in your log. Please stay on the trail to locate the earthcache.
ABOUT BIG MEADOWS, BLACKROCK:
Blackrock can be hiked using several different routes. While short routes are available inside the Big Meadows area, those wishing to seek a longer route can also reach it by hiking along the Appalachian Trail. If you are at the Big Meadows Lodge area, you could take the 0.2 mile uphill trek to the peak. Big Meadows Lodge is open seasonally (see the NPS web page for opening/closing dates) so parking at the Byrd Visitor Center at Big Meadows may be an option. If traveling by foot, please plan your route accordingly. You can also download a map of the area showing different routes to pick what is best for you.
ROCK FORMATIONS:
There are three general groups of rock types in the Shenandoah National Park. These include the mesoproterozoic granite gneiss and granitoids, neoproterozoic metasedimentary rocks in the Swift Run formation and metabasalt in the Catocin formation, and the siliciclastic rocks of the Lower Cambrian Chilhowee groups. The Catocin greenstone formation lies on a basement of granitic bed. The Catocin formation rock type is geographically significant as it is one of a limited areas in the mid-Atlantic where volcanic rock is found at the surface.
GNEISS:
Gneiss is a metamorphic rock formed by increasing heat and pressure. As this rock changed, embedded quartz minerals were also changed into various shapes (veins/pods/lenses) based on the pressure exerted. Gneiss is a common and widely distributed type of metamorphic rock. Gneiss is formed by high temperature and pressure causing a metamorphic process acting on formations composed of igneous or sedimentary rocks. Orthognesis is gneiss derived from igneous rock, such as granite. Paragneiss is gneiss derived from sedimentary rock, such as sandstone. Gneiss forms at higher temperatures and pressure than schist. Gneiss nearly always shows a banded texture with alternating lighter and darker colored bands without a distinct foliation.
Mesoproterozic Granite Gneiss and Granitoids:
The gneisses and granitoids mostly underlie the lowlands east of the Blue Ridge, but also rugged peaks like Old Rag Mountain.
Neoproterozic Metasedimentary Rock:
The sedimentary rocks experienced metamorphism and the rocks of the Chilhowee Group are called metasedimentary rocks. Today in Shenandoah National Park, the rocks of the Chilhowee Group form steep ridges and hollows that are covered in eroded rock debris called talus. These rocks have experienced weathering which has created soil able to support vegetation. However, the soils that have been produced are thin and sandy with resulting vegetation that grows in them being generally smaller and less diverse than vegetation growing in more fertile soil that are produced by weathering of volcanic rock.
Siliciclastic Rock:
The siliciclastic rocks underlie linear ridges from 800 to 400 meters in altitude. Ridges underlain by siliciclasatic rocks have abundant boulder fields. Siliciclastic rocks are clasatic noncarbonate sedimentary rock that is almost exclusively silica-bearing, either as forms of quartz or other silicate minerals. All siliciclastic rocks are formed by inorganic processes or deposited through some mechanical process, such as stream deposits or delta deposits that are subsequently lithified. These are standstone based rocks. The other silicate minerals that are generally present in siliciclastic sedimentary rocks are feldspar or biotite. Siliciclastic sediments are silica-based sediments, lacking carbon compounds which are formed from pre-existing rocks, by breakage, transportation and redeposition to form sedimentary rock.
LICHENS:
Did you know there are 270 different species of lichen in the Shenandoah National Park? The central district of the Shenandoah National Park are home to two of the rarest known species...map lichen (Rhizocaropon geographicum) and black crust (Melinelia stigia). When you make your way to a outcrop of rocks in the Shenandoah, you will most certainly find lichens. Lichens are a specific group of fungi and has a symbiotic (involving interaction between two different organisms living in close physical association) relationship with green algae. The algae provides carbohydrates from photosynthesis to the fungus, meanwhile the fungus provides nutrients from decomposion to the algae. Lichens are the first colonish on an exposed rock, secreting acids gradually breaking down the rock surface on which they grow. This contributes to soil development. Growth of lichen is incredibly slow. Mineral nutrition required by lichens is obtained through surrounding air and precipitation that they are exposed. They are extremely sensitive to poor air quality, especially from sulfur dioxide pollution. Lichens come in a variety of shapes and colors. They can grow flat against a smooth surface (crustose), extend from a surface like leaves (foliose) or develop a branched projection (fruticose). Common colors are black, white, orange, yellow, red, brown or green. The large brown oval leaf-like projections are often seen on large boulders known as rock tripe.
ROCK TRIPE:
Rock tripe is the common name for different types of lichens in the Umbilicaria genus that grows on rocks. Found throughout northern parts of North America, these lichens are edible when properly prepared. They have been used as a food source during times of famine, such as early American northern explorers. Rock tripe is commonly found on rock faces and cliffs abd is very sensitive to air pollution. If you see it growing abundantly, chances are very good that the air surrounding you is unpolluted.
QUESTIONS TO ANSWER:
1. What type of rock is present at the Blackrock summit?
2. How do you hypothesize these rock formations occurred?
3. Based on the lesson, describe any resulting soils and vegetation that may be present on the formation.
4. Do you see any evidence of rock tripe or lichen at or near this location? Describe what you observe.
5. Post a photo at or near the coordinates (you do not have to be in the photo unless you want to). This is your log signature.
GINGIN'S MESSAGE:
B - Beautiful creation of nature to stand and gaze as far as the eye can see
I - Intriguing formations to marvel and study
G - Giving rest to the mind and heart as it fills with joy
M - Miraculous formation taking place eons ago
E - Enriching us in so many ways
A - Amazement in the eyes of those beholding the views from this spot
D - Dependent is nature on us to take care of this fragile land
O - Only the sounds of the wind, the call of a bird, the swaying of trees
W - Wonderous location to watch clouds, birds on wing and changing seasons
S - Senses filled, hearts and spirits renewed through a feeling of being in the mountains
A - Always practice Leave No Trace ethics through your words and actions
R - Reaching out to do your part for generations to come
E - Each doing their share will go a long way for preservation
A - Art provided by Mother Nature through the changing colors of trees
B - Better left than found, pick up after yourself and dispose of properly
L - Loving the entire Shenandoah, just as if it belonged to you....because it does
A - Actions should always be positive
C - Carefully tread on the land to leave just footprints
K - Keepers of this land, each of us are
R - Realize that our time here to visit is brief, but memories last a lifetime
O - Onlookers of this incredible spot, appreciate it while you're there
C - Collect nothing, taking pictures or writing about them
K - Keep exploring, appreciating surroundings and those you are with....time is too short not to.
CONGRATULATIONS to ZippyFinn and QUE3NBE3 for being FTF 2-19-22.