WHAT HAVE WE FOUND ON THE CADDO BEND TRAIL? EarthCache
WHAT HAVE WE FOUND ON THE CADDO BEND TRAIL?
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The posted coordinates for this Earthcache are located on the Caddo Bent trail in the Lake Ouachita State Park.
In our world we find minerals which are a naturally formed solid substance with a unique chemical and crystal makeup. Minerals are inorganic – composed of matter not from plants or animals.
We also find rocks which are several types of minerals joined together, forming one mass.
We find three types of rocks:
Igneous rocks are rocks formed by the cooling of molten or melted material. Most of the earth’s crust is formed from igneous rock.
Metamorphic rocks original form and mineral content have been transformed due to changes in temperature, pressure and their chemical environment.
Sedimentary rocks are layered rocks formed by deposited rock and mineral. Sediment is fragments of solid material that are deposited by water or air. It can also be separated where water evaporates.
Ouachita Mountains
Millions of years ago, the South American continental plate moved closer to the North American continent. The deep layers of sediment on the bottom of the ocean were squeezed into a smaller area. Eventually this dense ocean floor was pushed up against the crust of the North American continent. The ocean floor sediments rose up and over the existing crust. That crust is now tens of thousands of feet below the rocks of the Ouachita Mountains. Erosion also affected these sediments. The result is the folded Ouachita Mountains we see today.
Many of the brittle sedimentary rocks in these folded mountains cracked or faulted. Heated fluids deposited quartz veins and crystals into many of the cracks during and soon after the mountain was built. Much later, fluids from molten rocks deep within the earth were injected into the Ouachita Mountains. As these molten rocks cooled and became solid, they formed many small and some larger masses of igneous rock.
The rocks in the Ouachita Mountains consist primarily of Paleozoic sandstones, shales, novaculites and cherts that have been intensely folded and deformed during the late Paleozoic age mountain building process into anticlinal and synclinal forms that trend almost due east and west.
The most prominent hardrock mineral commodity in the Ouachitas is quartz crystal produced from quartz veins in the Paleozoic formations of the forest and adjacent lands, and building stones and aggregate material produced from many of the formations. A belt or zone of quartz crystal bearing veins extends 30 to 40 miles wide for 170 miles.
Sandstone
Sandstone is a clastic sedimentary rock composed of mostly sand-sized minerals or rock grains being made up of quartz and feldspar. It can be any color, but most commonly found in tan, brown, yellow, gray, black, and red. It is created in layers and will have horizontal lines. It forms in 2 stages starting as layers of sand accumulates as a result of sedimentation, either from water or air. After accumulating, stage 2 happens when it is compacted by pressure.
Shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments (silt-sized particles) of other minerals, expecially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering or bedding less than one centimeter in thickness, called fissility.
Novaculite
Novaculite is a form of chert or flint. Novaculite is considered to be highly siliceous sediments and may be a product of the low-grade metamorphism of chert beds. Novaculite is very resistant to erosion. Novaculite is a form of microcrystalline or cryptocrystalline quartz. The color varies from white to grey-black. Novaculite is a very hard dense rock.
Chert
Chert is a fine-grained silica-rich microcrystalline, cryptocrystalline or microfibrous sedimentary rock that may contain small fossils. It varies greatly in color from white to black, but most often manifests as gray, brown, grayish brown and light green to rusty red. Its color is an expression of trace elements present in the rock and both red and green are most often related to traces of iron.
At the listed coordinates you will see a rather large outcropping of rock formations.
In order to claim this Earthcache you must answer the following questions. Please send an email with your answers. Do not post your answers in your online logs. You can post pictures of the area if you like, but do not post pictures that may give the answers away.
1. Which of the rock classifications found in the Ouachita Mountains are these boulders?
2. What color are these boulders?
3. As you move and examine these boulders, do you see any quartz veins in these boulders? What are the size of these veins?
Lake Ouachita State Park Permit # EC28-15-02
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