Quite a learning experience doing an earthcache. I now have more respect for those who have taken their time to do them. They can be quite time consuming but so worth it.
To complete this cache you will need to bring with you a watch that can measure seconds and a container of a known volume that you can use to hold water. We used a 4 liter ice cream bucket to do our collection.
Artesian Well
An Artesian Well is a well in which water rises under its own pressure, without pumping. If the pressure is great enough, the water will rise all the way to the surface and flow freely from the well. The name "artesian" is derived from Artois, France, where such wells were sunk as early as 1126. An artesian well is drilled into an aquifer, a water-bearing layer of porous rock. The aquifer lies between two impervious layers of rock through which water cannot pass. The artesian system (the aquifer and the impervious layers) slopes, and the well is sunk at a point where the aquifer is lower than the place where water, from rain or melting snow, enters the system. The weight of the water held in the upper portions of the aquifer results in the pressure that forces water to rise in the well. Where there is a natural opening in the impervious layer above an aquifer, water is sometimes forced to the surface, forming an artesian spring.
It flows because the pressure in the aquifer (water bearing soil or rock), which is covered by a confining layer (clay or other impervious material), is greater than atmospheric pressure at the land. A spring is formed when the water reaches the surface through a fracture or porous layer. These types of springs usually occur along faults (a fracture in the earth), or in areas of great topographic relief such as cliffs or valleys.
The geologic conditions necessary for an artesian well are an inclined aquifer sandwiched between impervious rock layers above and below that trap water in it. Water enters the exposed edge of the aquifer at a high elevation and percolates downward through interconnected pore spaces. The water held in these spaces is under pressure because of the weight of water in the portion of the aquifer above it. If a well is drilled from the land surface through the overlying impervious layer into the aquifer, this pressure will cause the water to rise in the well. In areas where the slope of the aquifer is great enough, pressure will drive the water above ground level in a spectacular, permanent fountain. Artesian springs can occur in similar fashion where faults or cracks in the overlying impervious layer allow water to flow upward. Water from an artesian well or spring is usually cold and free of organic contaminants, making it desirable for drinking.
Spring Classifiations
Springs are classified in several ways. Artesian spring and gravity spring. The gravity spring is formed by water soaking into the ground until the water encounters a confining layer that will not let the water seep further down. The water then flows across the top of the confining layer until it reaches the ground surface. Examples of gravity springs are springs found in hillsides or cliffs.
Geology of the Area
The Wolfville Ridge is underlain by resistant slate belonging to the Halifax Group (Cambro-Ordovician, about 500 million years old), and outcrops of these rocks can be seen near the entrance to the park and on the slope just south of the stile. The scenic Gaspereau Valley to the south, where the earthcache is located, and eastward lies a syncline of more easily eroded sandstone and shale of the Horton Bluff Formation (early Carboniferous, about 340 million years). More slate and granite, the latter part of the South Mountain Batholith (Devonian), are on the high ground further south. Still younger rocks lie to the north. The boundary between the Halifax Group and the Wolfville formation (Triassic, about 200 million years) crosses the Acadia University campus which is only a few kilometers from the earthcache site. The softer sandstone and conglomerate of the Wolfville Formation dip gently north and underlie the southern part of the Annapolis Valley. They are succeeded by the red siltstone of the Blomidon Formation (Triassic) and capped by erosion-resistant basalt flows of the North Mountain Formation (Jurassic) that begin about halfway up the face of North Mountain. The landforms of the area around Wolfville have been strongly influenced by the varying resistance to erosion of the types of rocks present.
The Annapolis Valley consists of four main geological/ topographical regions: the North Mountain range, which is a ridge of highly fractured basalt; the South Mountain range, which is a ridge primarily underlain by granite bedrock, with some areas of slate and quartzite; the Gaspereau Valley (South Mountain slope), which is underlain by slate, sandstone, and carbonate rocks; and the Valley Proper, which is a lowland area sheltered between the two mountain ranges characterized by sandstone and fertile, well-draining soils.
The most important aquifers are found within the Wolfville Formation, which covers almost all the Valley floor.
The Triassic rocks consist of a sequence of interbedding coarse and fine grained lithologies. Water quality and yields may therefore vary over short distances, both stratigraphically and geographically. Overlying the Halifax Formation in the Wolfville area are quartzite and slate called the White Rock Formation, which had been known as the Whiterock quartzite. It had been defined as the White Rock Formation “two massive quartzite beds with slate between them.” This was later referred to as the “double quartzite”.
The White Rock Formation is now included in a newly defined Rockville Notch Group.
The land owner saw the water going to waste and created what you will find at the site so people are able to gather the water for their use. At the location of this spring it used to just flow out of the ground and made its way via a stream it created and flowed into the gaspereau river.
Springs are also classified by the volume of the water they discharge. The scale for spring flow is as follows:
Magnitude Flow rate Liters per second
1st Magnitude 2800 l/s
2nd Magnitude 280 to 2800 l/s
3rd Magnitude 28 to 280 l/s
4th Magnitude 6.3 to 28 l/s
5th Magnitude 0.63 to 6.3 l/s
6th Magnitude 0.063 to .63 l/s
7th Magnitude 0.008 to 0.063 l/s
8th Magnitude 0.008 l/s
0 Magnitude no flow {sites of past historic flow}
To log this this Earthcache:
- Do you think this is an artesian spring or a gravity spring?
- What was the flow rate of the spring when you visited in liters/second (L/s). To determine this measure the time it takes to fill your container. Divide the volume of your container (in liters) by the time it took to fill the container (in seconds). You might want to try this several times and use an average time for your calculation.
- Given the flow that you measured, what is the magnitude of this spring?
- Where did Gaspereau derive its name from?
- Something Gaspereau is known for.
[REQUIRED] In accordance with the updated guidelines from Geocaching Headquarters published in June 2019, photos are now an acceptable logging requirement and WILL BE REQUIRED TO LOG THIS CACHE. Please provide a photo of yourself or a personal item in the picture to prove you visited the site.
Please e-mail me the answers. Do not post the answers in your log or it will be deleted as spoils the fun for the next cacher.