LOGGING REQUIREMENTS
For this EarthCache, you will be visiting the Travel Information Center at the I-70 East Bound Rest Area. The building and many of the sign walls are made of Fort Hays Limestone. You can use any of these to make your observations.
In order to log this EarthCache, send me your answers to the following questions either through email or messaging from my profile page.
1: What color is the limestone here?
2: Based on the information below, what gives it this color?
3: Can you find any fossils? If so, describe the quantity, size and origin of the fossil.
4: Post a pic of you or a signature item with the building in the background.
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WHY HERE?
The material used in this building and the sign walls was taken from a quarry in nearby Hays, KS. It is called Fort Hays Limestone. It should give you some insight as to what this area was like around 90 million years ago.
FORT HAYS LIMESTONE
The Fort Hays Limestone is upper Cretaceous (Coniacian) in age (between 90 and 86 million years ago) and occurs in a wide area across the middle United States. It is recognized in the field primarily by its thick, massive bedding and the small amounts of interbedded shale. It is resistant to erosion and forms prominent outcrops, especially where it capes hills or forms valley walls. The Fort Hays Limestone covers approximately 350 square miles in Ellis County, Kansas. The thickness varies from a few feet to over 90 feet with an average thickness of 50 feet.
LIMESTONE
One of the most common rocks in Kansas, limestone is a sedimentary rock composed mainly of the mineral calcite, which is a calcium carbonate. Most limestone layers formed from marine sediment deposited on sea floors, although some formed in freshwater lakes and rivers and even on dry land. Sources for the calcite in limestone include seashells. When shelled animals that use calcium carbonate in water to build their shells die, the remains of their shells accumulate on a sea or lake floor. Under the right conditions, large amounts of shell debris eventually gets buried under other sediment and compressed into rock. Many limestone layers also contain fossils of such animals as corals, brachiopods, clams, bryozoans, crinoids, and one-celled fusulinids that were preserved whole or nearly whole.
COLORS
White
White limestone is one of the most prevalent color variations. It is often associated with high-purity limestone that has minimal impurities. This color is typically seen in limestone formations with a high calcium carbonate content.
Beige or Cream
Beige or cream-colored limestone is another common variation. It often results from the presence of impurities or organic matter, such as clay, silt, or iron oxide, which give the limestone a warmer tone.
Gray or Cream
Gray limestone is widespread and can vary in shades from light gray to dark gray. The presence of organic matter, minerals like graphite or pyrite, or fine-grained sediment can contribute to the gray coloration.
Brown
Some limestones exhibit brown hues, which are often caused by the presence of iron oxide or other minerals. These impurities can create a range of brown shades, from light tan to deeper brown tones.
Yellow
Yellow limestone is less common but can occur in certain geological formations. It is typically attributed to the presence of iron oxide or other minerals that impart a yellow tint to the rock.
Blue
Blue limestone is relatively rare and can be found in specific regions with unique geological conditions. It is often associated with fossil-rich limestone that contains marine organisms, such as shells or coral, contributing to the blue coloration.
references
https://geokansas.ku.edu/limestone
https://zohdytrading.com/
https://scholars.fhsu.edu/
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