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Kinkaid Lake is a manmade lake built in 1968, the lake encompasses 2,750 acres. The Illinois Department of Natural Resources manages approximately 4,000 acres surrounding the lake, including the spillway.
The topography of the surrounding area varies from sandstone bluff formations to rolling hills surrounding the lake. The spillway is a sandstone waterway that has eroded to display the layering of clastic formations.
A spillway is a structure used to provide for the controlled release of flows from a dam or levee into a downstream area. Spillways are located at the top of reservoir pool and release floods, so that the water does not overtop and damage or destroy the dam.
There are two types of spillways: controlled and uncontrolled.
A controlled spillway has mechanical structures or gates to regulate the rate of flow. This design allows nearly the full height of the dam to be used for water storage year-round, and flood waters can be released as required by opening one or more gates.
An uncontrolled spillway, in contrast, does not have gates; when the water rises above the lip or crest of the spillway it begins to be released from the reservoir. The rate of discharge is controlled only by the depth of water within the reservoir
The posted coordinates will take you to a display of different Clastic rock formations.
Clastic sedimentary rocks are rocks composed predominantly of broken pieces or clasts of older weathered and eroded rocks. Clastic sediments or sedimentary rocks are classified based on grain size, clast and cementing material composition, and texture. Grain size determines the basic name of a clastic sedimentary rock. Grain size varies from clay in shales; through silt in siltstones; sand in sandstones; and gravel, cobble, to boulder sized fragments in conglomerates and breccias.
Sandstone is a sedimentary rock composed mainly of sand-size mineral or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow, red, gray and white. Since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions.
Sandstones are formed from cemented grains that may either be fragments of a pre-existing rock or be mono-minerallic crystals. The cements binding these grains together are typically calcite, clays and silica.
The formation of sandstone involves two principal stages. First, a layer or layers of sand accumulates as the result of sedimentation, either from water or from air. Typically, sedimentation occurs by the sand settling out from suspension; i.e., ceasing to be rolled or bounced along the bottom of a body of water or ground surface. Once it has accumulated, the sand becomes sandstone when it is compacted by pressure of overlying deposits and cemented by the precipitation of minerals within the pore spaces between sand grains.
Shale is a fine-grained, clastic sedimentary rock composed of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by thin laminae or parallel layering or bedding less than one centimeter in thickness.
The process which forms shale is compaction. The fine particles that compose shale can remain suspended in water long after the larger and denser particles of sand have deposited. Shales are typically deposited in very slow moving water and are often found in lakes and lagoonal deposits, in river deltas, on floodplains and offshore from beach sands.
Shales are typically composed of variable amounts of clay minerals and quartz grains and the typical color is gray. Addition of variable amounts of minor constituents alters the color of the rock. Black shale results from the presence of greater than one percent carbonaceous material and indicates a reducing environment. Red, brown and green colors are indicative of ferric oxide (hematite - reds), iron hydroxide (goethite - browns and limonite - yellow), or micaceous minerals (chlorite, biotite and illite – greens).
To claim this Earthache; you must post a picture of yourself at the spillway, and then email the answers to the following. Do not post answers in your log.
1. What type of spillway is this; Controlled or Uncontrolled?
2. What types of Clastic formations are present?
3. Does the color of the layers change? If so, what are some of the colors present?
Placed with Illinois Dept. of Natural Resources permission. Thank you Jim Carter
1. Geocache is placed on Department managed property with permission.
2. Do not place the following items in the Geocache: Food items, inappropriate, offensive, or hazardous materials.
3. It is the visitors’ responsibility to orient themselves with policies and rules pertaining to this Department managed site.
WARNING: DO NOT ATTEMPT THIS CACHE AFTER A HEAVY RAIN.
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