This is an Earthcache – as such, there is no physical cache. Instead after reading the lesson and examining the vernal pool at the posted coordinates, you will then answer 3 earth science questions and message me the answers. This earthcache is located on the Sensory Explorers Trail in Sky Meadows State Park with permission. When entering the trail, please follow the one way direction signage along the trail. For more information about hours of operation, entrance fees (also listed at the bottom of the cache page), and park rules please visit this Sky Meadows State Park LINK.
A vernal pool is a form of temporary, freshwater wetland that contains water for a portion of the year and supports an array of wildlife and plants, some specially adapted for these habitats and many being rare species in Virginia. Sky Meadows vernal pools provide habitat for salamanders, frogs, and other creatures.
Vernal Pools form in sinkholes when a layer of clay forms several feet below the surface, and creates a perched surface water table that fills up these sinkholes during the inundated (wet) season. Due to different hydrologys, some sinkhole ponds may have ground water connections, while others fill from surface runoff. Vernal Pools start to fill with water in late fall, then dry up in the summer. Since they are not permanent water bodies, fish cannot survive in them. Without fish around to eat their eggs and larvae, many species of amphibians use these pools to breed.
Typically a vernal pool will go through three phases each year:
Inundated Phase - it is inundated with rain and snow in the Winter which fill up the pool.
Flowering Phase - It slowly dries in the spring.
Dry Phase - it will completely dry up in the summer/fall.
Vernal pools may be found throughout Virginia, but they are more common east of the fall line along the flatter coastal plain. Here, Sky Meadows State Park straddles the boundary of the Blue Ridge and Piedmont Provinces. These mountains may have once been as tall as the Himalayas, but they have been gradually worn down through ongoing erosion from wind, water and chemical weathering. The soil deposits around this pool consist of material that has been washed down from the adjoining upland slopes. The soils down here have properties that can be closely related to the character of the parent rock of the Blue Ridge.
Formation of Vernal Pools:
A key formation of the vernal pools is due to the layer beneath the pool. It is either bedrock or a hard layer of clay in the soil that helps keep the water in the pool. Clay soils bind closely together and become impermeable to water. Soils here at Sky Meadows have developed over granitic rock, granite, granite gneiss, or schistose granite.
When it rains, the water percolates until it reaches the claypan and sits there, filling up with material and water. Fauquier County has a seasonal climate and averages 114 days of precipitation (rain, snow, sleet, or hail that falls to the ground) per year with an annual rainfall of 44 inches (The US average is 38 inches of rain per year). May is the wettest month in Fauquier County with 4.5 inches of rain, and the driest month is February with 2.8 inches.
The five most common reasons of how Vernal Pools form:
Floodplains - when a stream overflows its banks entering the floodplain. Some of the overflow pockets do a good job of retaining water and become vernal pools. If this continues over the years it can lead to the creation of vernal pool habitats in the form of oxbow wetlands.
Glaciers - glaciers created many isolated depressions through freezing, thawing and erosion that fill with rainwater and snowmelt. This process is similar, in fact, to the way in which kettles are created. NOTE: the closest glacial advance to Sky Meadows was over 80 miles north of here.
Sag Ponds - sag ponds form when surface water gathers in depressions formed by easily dissolved bedrock (such as limestone) underneath an impermeable soil layer. Eventually the soil sags and water gathers in the depression.
Pingos – Pingos are formed by freezing and thawing processes on moist mountainous slopes. The upper layers of soil thaw first and slowly slide over the underlying frozen soil. The result is a landscape peppered with crescent-shaped wetlands.
Human Activities - some vernal pools are created deliberately by people who wish to create wildlife habitat or to replace a seasonal wetland that was destroyed. Other pools are inadvertently created during any kind of surface disruption (mining, roadside ditches, agricultural fields, etc.) that creates shallow depressions that hold water long enough to support seasonal pool wildlife.
LOGGING REQUIREMENTS:
To log this Earthcache: Read the geology lesson above. Answer all three questions posted below. Answers can be sent via e-mail or messenger contacts on my Geocaching profile within a reasonable time. Group answers are fine, but do not post the answers to the questions in your logs.
QUESTION 1. Observe how deep the pool is. From what you have learned, what phase do you think this pool currently going through?
A. Inundated Phase
B. Flowering Phase
C. Dry Phase
QUESTION 2. Examine the soil in and around the edge of pool. Do you believe that this pool is connected to the water table? (Remember... if a vernal pool is connected to the water table you will find plenty of sand or gravel around the edges of the pool!)
QUESTION 3. Of the common formations listed, which of these is the most likely way this vernal pool formed?
OPTIONAL PHOTO: Posting a photo that readily indicates that you (and anyone else logging the find) are at the location.
TO EARN NOVACON TEAM HIT POINTS
For those participating in the 2024 NoVAGO Annual Series, please post a photo to the cache page of you showing your NOVACON badge and
Performing your best Superhero Pose on the Vernal Pool Observation Deck to receive a redemption code to boost your team’s hit points. Selfie pics are not very epic. Please have someone else or use a timer to capture you in a photo that inspires greatness. Here are some common hero poses:
Awesnap has earned GSA's highest level:
REFERENCES:
1. Vernal Pool Kids Video, VernalPoolChronicles, September 2013, Youtube.com
2. Bryophytes within the Vernal Pools in the Agate Desert Area of Jackson County, Oregon , Dr. Judith Harpel, University of Washington, September 2008, fws.gov
3. Ecohydrology of Vernal Pools: , Niall McCarten, Applications to Conservation, Management, Restoration and Monitoring, Department of Land, Air, Water Resources, University of California, fws.gov
4. Vernal Pool Investigators, Table Rocks, BLM Medford District, Worksheet PDF, blm.gov
5. The Importance of Vernal Pools, K.Wells, Virginia State Parks Blog, website, dcr.virginia.gov
6. Overview Fauquier County Sky Meadows State Park, Geography, 2015, website, skymeadows.info
HOURS AND FEES AS OF SEPTEMBER 2024:
Sky Meadows State Park is open daily from 8 a.m. to dusk, and the entrance fee for the park is $10.