During the Permian period, approximately 280 milion years ago, this area was part of an inland sea. We are looking at the erosion of limestone in an area called the Flint Hills. The exposed rock wall area is composed of multiple layers of limestone. Within the limestone there are numerous deposits of chert (see picture).
Chert refers to cryptocrystalline or polycrystalline quartz that forms as nodules in limestone, as you can see here. If the nodules are numerous, they can grow large enough to merge with one another to form a nearly continuous layer of chert within the sediment mass; this is not the case here. Because chert is less soluble than limestone, it is often found in small gravel or rock. The terms flint and chert are used interchangeably, however they do have different properties. Flint is a type of chert, usually black or dark gray as it contains carbon. Chert is often whitish to gray, pink, or pale brown in color. It can also be yellow, reddish, or light green. Sometimes you will be able to see the outline of the chert in the limestone rock and when you feel it the texture is smooth. To further identify it you can try to break it against another rock. The limestone is softer so it will break or crumble easily. Chert breaks with a conchoidal fracture, often producing very sharp edges. Early people took advantage of how chert breaks and used it to fashion cutting tools and weapons.
ROCK FRAGMENTS CONTAINING CHERT
For fossil hunters there are many fossils embedded in the rocks in this area. The coordinates take you next to a flat rock that contains a few small fossils. If you choose to expand the search area you will have the opportunity to find a number of fossils.
When logging this cache please send me the answers to the following questions:
1. How many strata (layers) do you count in the rock outcropping.
2. Do you see any chert or flint in this area? Referring to the description of chert in the text find a piece of rock that contains chert. What color is the chert?
3. What kind of chert do you see here? (Nodules or layers)
4. Please provide a photo of yourself or of a personal object to prove you were here.
You may designate one person in your group to respond but please include their names in your response.
Source of data and pictures: Geology.com, Flint_Hills_Geology, and Wikipedia