This Earthcache will take you to the front steps of a beautiful building featuring Gothic Revival style of architecture in Ozark, Arkansas.
The medieval towers, parapets, Gothic arches, and the decorative details in this building are, in fact, are part of what placed it on the National Register of Historic Places.
But, let's look closer at the actual building blocks of this structure.
The building blocks in this structure are made from locally quarried limestone. Limestone has been used throughout the ages and is a popular construction material. This natural material adds beauty to many buildings because it is offered in a wide range of finishes such as polished or brushed. The finish applied to the stone can change the color, creating deeper or richer tones.
Limestone is one of the most durable building materials and can withstand the test of time. Limestone is made mostly of calcium deposits from large collections of shell, bone and coral and creates a solid colored stone. Limestone is composed of calcium carbonate. Calcium carbonate often comes from plant and animal skeletons and remnants including the shells of mollusks. The calcium in limestone contributes to its color. Most limestone beds form in marine environments in which big deposits of organisms and carbonate precipitation build up over the years, like an ocean or large lake.
Now, let's go back in time to see how limestone formed in the Arkansas River Valley area.
Millions of years ago in the Cretaceous (66-144 MYBP*) and Jurassic (144 - 208 MYBP) time periods, this part of current day Arkansas, a shallow sea covered the area. In Arkansas, deposition of redbeds, shallow water shales and limestones occurred. Deposition is a process in which materials such as rocks and sediments settle down, giving rise to specific deposits, like limestone. The shallow sea covering southern and eastern Arkansas had limestone reefs near the shoreline, capped by dark marine shale.
(*Millions of years before present)
Limestone can be classified as clastic or non-clastic.
Clastic limestone is rock or sediment composed of clasts which have been transported from their place of origin, as sandstone and shale. Clasts are rock fragments which can be seen, such as those that form mud, sand, and gravel.
Non-clastic limestone has the texture of a sediment or sedimentary rock, is formed chemically or organically and shows no evudents of a derivation from a preexisting rock or mechanical deposition.
Limestone can also be classified by rock type.
1. Chalk limestone forms from calcareous shell remains of microscopic marine organisms such as foraminifera and small marine algae. It’s usually white or light gray and has a very fine texture, so it’s easily crushed or crumbled.
2. Animal shell limestone is made from animal shells of an ancient form of marine life called sea lilies because they resemble flowers.
3. Coral reef limestone is made from skeletons from coral animals that have no backbones. Coral limestone is generally free from mechanical impurities.
4. Travertine limestone is usually light in color and can be extremely porous or cellular. It forms along streams, near waterfalls, and around hot or cold springs.
5. Black limestone rock features this color because it has the organic materials fused within it.
________________________________________________________________________________________________________________
To claim a find on this Earthcache, please send your responses through the email on my profile page OR through the message center using the link found near the top of this cache page. Please do not post your responses in your log, other than your images. Found it logs that are not supported by the required information, will be deleted. (There is not a physical cache to find.) ____________________________________________________________________________________________________________________
1. Name of this Earthcache: "do you ever play with building blocks?" along with the people in your party. (One email with answers will cover all geocachers listed in the email.)
2. Examine the blocks that were used to build this structure. What colors do you see?
3. What is the texture of the blocks?
4. Based on the information on the cache page, do you believe the limestone building blocks are clastic or non-clastic?
5. Based on the information on this cache page and your observation of the structure, what type of limestone rock type do you believe the building blocks are?
6. Add a picture of you or your party or a navigation device or other personal item with the limestone building blocks in the background to your log. ________________________________________________________________________________________________________________ Sources:
https://www.arkansasheritage.com/docs/default-source/national-registry/FR0049-pdf
https://www.sidmartinbio.org/what-building-materials-are-made-from-limestone/
http://rockhoundingar.com/timescale.php
https://www.thefreedictionary.com/clasts
https://geologyscience.com/rocks/sedimentary-rocks/limestone/
https://southlandstone.com/types-of-limestone/
Brown, Bryan J.; Petroleum Geologist, Arkansas Oil and Gas Commission ________________________________________________________________________________________________________________