Bradley Lake: Strange Beginnings
-
Difficulty:
-
-
Terrain:
-
Size: 
(other)
Please note Use of geocaching.com services is subject to the terms and conditions
in our disclaimer.
Creation
Lakes exist in a myriad of shapes and sizes, with no two being exactly alike. This uniqueness contributes to their beauty and intrigue. A lake’s shape is often a direct result of the manner in which it was formed. Lake-forming forces can include glacial movement, plate tectonics, volcanic activity, human intervention and plant and animal activity.
Glacial Activity
The encroaching and retreating ice sheets of the last ice age, with their enormous downward pressure, carved many depressions in the Earth’s surface. Melting ice then collected within these gouged depressions to form lakes. This type of lake is called a “Glacial Scour Lake”. The Great Lakes are of this type of lake.
Tectonic Movement
Movement of tectonic plates is another significant lake-forming force. When adjacent plates move and separate, a steep, narrow gap results. When water fills this gap, a new lake is formed. This type of lake is called a “Graben”. Some of the largest, deepest, and oldest lakes on Earth are Graben lakes. The most famous of the Graben lakes are Lake Baikal (Eastern Russia) and the African rift valley lakes (Lakes Victoria, Tanganyika, and Malawi).
Volcanic Activity
Indirectly related to tectonic activity, volcanic activity can create lakes in a couple of different ways. One such creation process occurs when ejected magma leaves behind a fissure that eventually fills with water. This process creates what is called a “Maar Lake”. Another creation process occurs when the roof of a dead volcanic crater collapses, creating a large Caldera (bowl). This Caldera then fills with water and forms what is called a “Crater Lake”. Both “Maar” and “Crater” type lakes are typically deep in relation to their surface area. High concentrations of volcanic minerals and few nutrients mean that they are typically clear and deep blue in color. As its name implies, Crater Lake in Oregon is one such lake.
River Erosion
Another creation process occurs when river flow collects, transports and deposits sediments downstream, damming tributary streams. As a result, new lakes are formed behind these “Dams”. This type of lake is known as a “Lateral Lake”. Another creation process occurs at bends in rivers when sediment deposition occurs on the slower moving inside curve of a water flow and erodes the faster moving, outside curve of a water flow. Eventually this deposition and erosion cause the rivers course to alter and eventually reconnect back into itself, creating a loop if you will. This creates a new flow passage and abandons the old, cut off loop portion of the river. This loop section then becomes what is called an “Oxbow Lake”. Another lake building process occurs when deposition of sediments closes off otherwise natural water flow at the mouths of rivers or on deltas. These are referred to as “Alluvial Fan” or “Fluviatile Lakes”. These lakes are generally young in origin and disappear with flooding or higher water flow. Lake formation can also occur when erosion beneath a waterfall, creates a “Plunge-Pool Lake”.
Man-Made Lakes
These types of lakes can be formed through damming, or other processes, which lead to the pooling of water in a location, intentional or unintentional. Examples include reservoirs or impoundments that are constructed for drinking water, power generation, fisheries or other recreational activities. They can also include farm ponds, ornamental lakes and quarry lakes. Natural Lakes
Natural formed lakes are formed from the activities of plants and animals, such as beavers. Beavers often dam rivers, leading to the formation of lakes behind the dam. Given enough time, sediments and plant material settle against the dam, forming a levee and a natural reservoir.
Wave Carved Lakes
Wave action, along ocean shorelines, can also lead to lake formation through erosion and damming of estuaries and river deltas. These lakes may be semi-saline brackish water lakes.
Wind Carved Lakes
The force of wind has the power to create basins by moving sand (dunes) and dirt from geographically flat areas, creating shallow lakes called “Deflation basins” or “Playas”. Often these types of lakes are Endorheic, meaning they do not drain into an ocean, but instead only lose water through the processes of evaporation or seepage.
Karst Type Lakes
Certain bedrock, Limestone in particular, is easily eroded by slightly acidic water. This erosion creates hollows where water collects and lakes form. This type of lake is called a “Solution Lake”. Solution lakes can occur on the surface or below ground and are typically circular in shape due to the even chemical erosion of rock at their edges. “Cenotes” and “Sinkholes” are generally considered Solution type lakes.
Demise
Lakes are short-lived features on the earth's surface and generally disappear in a relatively short period of geologic time. In a process called Eutrophication, a lake fills with organic and inorganic sediment, becoming a swamp or bog. Eventually it fills completely and dries out, becoming a field or meadow. Human activity has greatly increased the rate of Eutrophication globally, drastically altering the life span of many lakes worldwide.
The given coordinates will bring you to the parking area. Just to the North of these coordinates is an information plaque. The answers needed will come from this plaque and the readings above. Email your answers to the questions, to me, using the link in my profile only. If your answers are not recieved by me, your log will be deleted. Photos are accepted and appreciated as long as the plaque is not pictured. You do not have to wait for confirmation from me before logging this cache as completed. Most of all……learn……and enjoy the view.
#1. What did the original settlers call this body of water?
#2. In 1857, Bradley sold the only one to be found in Door County. What was it?
#3. Would you consider this to be a Glacial Scour, Graben, Maar, Crater, Lateral, Fluviatile, Plunge Pool, Wave Carved, Playa or Solution Type Lake?
#4. What man-made process added to the formation of this lake? (from the plaque
Additional Hints
(No hints available.)