The geological background of Manitoba has been altered by many major historical events. One event from the not too distance past was the time of the glaciers that scraped and scoured Manitoba, starting from the northern arctic and spreading southward almost to the Gulf of Mexico. These glaciers pushed down dirt, gravel and rocks and spread them out along the way then dropping them as they receded back to the arctic circle.
A second major event occurred immediately after the glaciers and was to some extent a result of the glaciers, or at least their melting, and that was the formation of Lake Agassi. This lake covered a greater portion of the Canadian and American midland prairies, sorting the glacial till by it's wave action.
With time, these two events alternately occurring and working together or on their own have caused the bedrock to be covered with differing layers of dirt, gravel and rocks. Each time there was a cycle, the heavier material was dropped first followed by the lighter material which form strata. The thickness of the strata was dependent on the time that was involved and the forces applied and what may have occurred afterwards. So what was created was differing layers on top of each other maybe with a layer of rock, maybe not; maybe a layer of sand, maybe not; maybe several layers of dirt and clay's, the possible combinations are endless.
Water is a strange medium, it looks clear until you examine it microscopically and then the differences can be quite extreme. As the water trickles it's way through the differing strata it “physically” moves particles from one layer to another but it also “chemically” moves solids that it dissolves and incorporates into it's structure. These solids are minerals and in suspension can be called salts.
This water with it's mineral salts stays trapped in the earths groundwater zones until the zone reaches the edge of a cutting or the soil layers become eroded or removed and the water allowed to flow or seep out. In normal circumstances, this mineral rich water will mix with surface runoff and be diluted where some of the minerals may settle out or precipitate to again form ground strata.
Sometimes this mineral water will flow out onto flat land or form shallow ponds. If this water does not now mix with surface water but just sits there, soon the heat of the sun will begin to evaporate the water molecules out of the mixture leaving the minerals. As the water is evaporated, more water is drawn up with it's salts and the process continues, just like when you water a plant in a pot, you put the water in the bottom saucer but it gets drawn up into the pot. Have you noticed the top layer of soil in a plant pot go yellow or whitish, this is mineral salts. Over time these mineral salts form thicker and thicker layers and areas like large salt flats develop. These salts can stick together to form a solid layer which can get impervious to the effects of future rain or surface water to dissolve it.
Along Highway #10 through Riding Mountain National Park are areas where road construction has cut through these ground water zones and allowed this mineral rich water to flow into the roadside ditches. In lower areas of these ditches, small pools form, evaporation takes place and the minerals are deposited.
Did you know that the human body has been determined to be 0.4% salt. Salt is a vital part of body chemistry, playing a key role in many functions, from the quality of blood to transmission of nerve signals. We humans are fortunate to be able to gather these “salt flat” deposits and can have a salt shaker on our dinner table. Animals are not that fortunate but still require salts for their body functions, bone growth and for ungulates, antler growth. Domesticated animals are regularly provided with “salt blocks” for them to lick and get the salts their bodies require.
So what do the wild animals do?
Depending on the situation, wild animals take advantage of these low lying areas where evaporation has left concentrations of these salts. If the area has standing water, it will be saturated in salts so the animals drink it, if there is no water, the animals will actually eat the dirt to get the minerals.
The problem that has developed is that the wild animals have found and remember where they get their salt from. In the northern areas where there is winter with ice and snow, it has been common practice to use salt to melt the ice on the roads. This road salt attracts animals to the melted salt water on the roads as well as the dried salt on vehicles. These interactions are of no advantage to the animals and may cost them their lives.
To get credit for this Earth Cache, you must send a message through geocaching to the cache owner with the answers to the following questions:
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What does the Park's sign call the paved parking area at GZ?
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How can you quickly identify a location that might be a “mineral/salt lick”?
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What can you say about the vegetation at a “mineral lick”? Why?
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To a “quack” doctor in medieval times, “leaching” used leaches to remove blood from a patient, explain the process of “leaching” in geology.
To travel through Riding Mountain National Park on #10 Highway, you do not need a Park Pass but if you intend to use any park facility you will need a pass.
Placed with permission of Parks Canada, RMNP VEPDO.