Mining, Minerals and More in the Western Ouachita Mountains
Mining, Minerals and More in the Western Ouachita Mountains Mining, Minerals and More in the Western Ouachita Mountains
The active portion of the quarry is located in the fine-grained gray tuff (Fig. 18). Look formineralization (pyrite, calcite or quartz) along bedding planes as well as sedimentary structures.Notice the thickness of the beds and fine-grained character of the rock.The mine manager has collected samples of tuff that have the large green lapilli (Fig. 18).Compare the two rocks. Look for shale rip-up fragments.Figure 18. Fine-grained gray tuff displaying small scale cross-bedding (left). Large (1-2cm) green lapilli ina fine-grained matrix (right).We will also look at the northern section of the quarry where the Arkansas Novaculite ispresent. At various times the novaculite has been mined as well. Look for manganesedendrites (Fig. 19). Notice the red chert nodules in the novaculite. What other rock types canyou find?Figure 19. Manganese dendrites on novaculite (left). Red chert nodules in novaculite (right).16
Day 2 – AfternoonStop 4 - Cossatot River Visitor Center and Cossatot FallsAfter a visit to the new Cossatot River Visitor Center we will walk along the trail past the shalepit and glade to Baker Creek (Fig. 20). This is a good opportunity to look at shale and sandstonein the Stanley Formation.Figure 20. Shale glade near the Visitor’s Center (left) and sandstone along Baker Creek (right).Next we will travel to Cossatot Falls Natural Area. This area is a rugged and rocky canyon thathas ledges of sandstone in the Stanley Shale over which the river drops 33 feet in elevation in1/3 of a mile (Fig. 21). Notice the inclination of the sandstone beds. At this location we willtake a strike and dip reading.1. Which direction are the beds dipping?_____________________________________2. How many degrees from horizontal are the ledges inclined?_________________________________3. List sedimentary features that are here____________________________________4. Find load features in the sandstone (Fig. 21). Which surface is the top of the bed?_____________5. Why are the beds inclined?______________________________________________17
- Page 3 and 4: STATE OF ARKANSASARKANSAS GEOLOGICA
- Page 5 and 6: Table of ContentsGeologic Setting..
- Page 7: Educational Workshop Series 06 -
- Page 10 and 11: Figure 2. Digital ortho-photograph
- Page 12 and 13: This workshop focuses on the Stanle
- Page 14 and 15: Studies of paleocurrent, grain size
- Page 16 and 17: LaurasiaFigure 9. Late Mississippia
- Page 18 and 19: Varying stream patterns develop acc
- Page 20 and 21: Figure 13. Map showing location of
- Page 22 and 23: This area is rich in plant fossils.
- Page 26 and 27: Figure 21. Load features on sandsto
- Page 28 and 29: References:Clardy, B.F., and Bush,
- Page 30 and 31: Sigillaria, an extinct coal-age tre
Day 2 – AfternoonStop 4 - Cossatot River Visitor Center <strong>and</strong> Cossatot FallsAfter a visit to <strong>the</strong> new Cossatot River Visitor Center we will walk along <strong>the</strong> trail past <strong>the</strong> shalepit <strong>and</strong> glade to Baker Creek (Fig. 20). This is a good opportunity to look at shale <strong>and</strong> s<strong>and</strong>stone<strong>in</strong> <strong>the</strong> Stanley Formation.Figure 20. Shale glade near <strong>the</strong> Visitor’s Center (left) <strong>and</strong> s<strong>and</strong>stone along Baker Creek (right).Next we will travel to Cossatot Falls Natural Area. This area is a rugged <strong>and</strong> rocky canyon thathas ledges of s<strong>and</strong>stone <strong>in</strong> <strong>the</strong> Stanley Shale over which <strong>the</strong> river drops 33 feet <strong>in</strong> elevation <strong>in</strong>1/3 of a mile (Fig. 21). Notice <strong>the</strong> <strong>in</strong>cl<strong>in</strong>ation of <strong>the</strong> s<strong>and</strong>stone beds. At this location we willtake a strike <strong>and</strong> dip read<strong>in</strong>g.1. Which direction are <strong>the</strong> beds dipp<strong>in</strong>g?_____________________________________2. How many degrees from horizontal are <strong>the</strong> ledges <strong>in</strong>cl<strong>in</strong>ed?_________________________________3. List sedimentary features that are here____________________________________4. F<strong>in</strong>d load features <strong>in</strong> <strong>the</strong> s<strong>and</strong>stone (Fig. 21). Which surface is <strong>the</strong> top of <strong>the</strong> bed?_____________5. Why are <strong>the</strong> beds <strong>in</strong>cl<strong>in</strong>ed?______________________________________________17
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