Logging Requirements:
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State the type of falls (see description)
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Why is the water in the falls brown (choose from reasons listed below)?
a. Tannins from the surrounding paper birch and aspen trees has colored the water
b. Iron “rust” from sedimentary rocks has been released into the streams
c. Peat / Sphagnum Moss has released acids and tannins from its lower layers has colored the waters
d. Sediment from topsoil and gravel (erosion) has caused the brown color
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Please state the NAME of the earthcache when you message or email me. I own a LOT of earthcaches so I need help knowing which one you are experiencing.
Hydrology:
(For logging requirement #1) According to Wikipedia, there are several types of waterfalls. I will narrow it down to four possibilities:
Horsetail: Descending water maintains some contact with bedrock.
Block: Water descends from a relatively wide stream or river.
Cascade: Water descends a series of rock steps.
Tiered: Water drops in a series of distinct steps or falls.
(For logging requirement #2) Rivers become brown for a variety of reasons that involve a combination of geology, hydrology, and sometimes even biology.
Possibility A – In the autumn, deciduous trees such as oaks, aspens, paper birch, as well as the conifer tamarack loose their leaves in preparation for winter. On the Avalon Peninsula, there are a lot of trees, and thus a lot of leaves. When leaf tannin is the reason for coloring the water, there are significant trees growing right up to the banks of the river/stream, and piles of leaves can often be seen stuck in crevices and other places where the water has slowed down. Probably the most popular falls to demonstrate this type of “brown falls” is located in Upper Peninsula Michigan, USA – Tuquamenon Falls.
Possibility B – Mafic rocks contain iron. If you have ever seen a bridge that contains iron, you know that it turns brown with a layer of rust that has been exposed to oxygen. Feric rocks (those with iron) occur in all types of rocks, including periodotite and serpentinite as illustrated on the western side of the province at Tables trail in Gros Morne National Park. If you see a lot of oranish red rock that looks “rusted” than this is the reason for the brown water
Possibility C – glaciers left basins across the peninsula, that have filled with water. Over the centuries, they have filled with water. Often they are connected by streams and rivers (fens) although bogs also develop (closed systems). In either event, sphagnum moss grows into the bodies of water. It grows from the tips, where gas cell keep it afloat, though the older parts of the moss have died and sunk down into the water body. Because of the cold climate, acidic/tanic nature of the dead organic matter, bacteria fail to develop, meaning the peat builds up in dense deep mats. These acids and tanins are brown and when they come into contact with flowing water, can release those acids/tanins into the river. If this is the reason, then moss and hard erosion resistant rocks will be present, but there will NOT be significant “drop” from the shore to the bottom of the river (minimal erosion).
Possibility D – Sedimentary rocks such as siltstone, sandstone break down easily when they come into contact with flowing water. The speed of the river’s flow and the amount of water flowing affect how quickly erosion takes place, meaning that sediment (both soil and rock) are torn from the land and “flushed” downstream. Sediments are deposited when rivers change speed or flow quantity. However, when rushing, sediment remains suspended in the river and thus colors the water. If this is the option, you will see soil (dirt) and sedimentary rocks on the banks of the river.