Geology of Table Rock - 8th - On-site Activity/Interpreter Led

Grade Level: 8
Content Area: Science
Time to Complete: 75 minutes
Title of Program: Green Creek Hike

South Carolina State Standards Addressed:

Students will hike a section of the trail that parallels Green Creek at Table Rock State Park. They will observe and classify rocks and minerals, estimate stream bend angles and observe folds and igneous intrusions.

Focus Questions for Students:

Culminating Assessment:

Materials/Equipment/Resources:

Teacher Preparation:

Background Information:

   The Carrick Creek Trail is a lasso-shaped, park maintained trail, which starts near the parking lot at Pinnacle Lake and winds up and down as it crisscrosses Carrick Creek. The trail to the top of Table Rock follows Green Creek which joins Carrick Creek from the east. Multiple examples of metamorphic rocks and their associated minerals, near-right angle stream bends, and soil color changes occur along this trail. The rocks in this area consist of two main types, a resistant granitic gneiss and a less resistant amphibolite gneiss.
   For further information, read the background information from the SC MAPS Teaching Manual, 2000 Edition, Characteristic Landforms of the Blue Ridge (page 2-2), Rationale (page 2A-1) and Introduction (page 2A-2).

Procedures:

Inform students about safety precautions for hiking the trail.

Stops

1	Large Rock by the lake channel • Example of a metamorphic rock. • These rocks are formed by heat and pressure. • Contact – volcanic activity. • Regional – force, shifting plates. • Rock layered appearance – foliation, peeling is exfoliation. • Talk about rock cycles
2	First few rocks along the road • Two main rock types at TR. • Granite gneiss – lighter, more resistant to weathering, contains quartz & feldspar. • Amphibolite – darker, less resistant to weathering, contains amphibole & iron. • Weathered garnets seen within rock.
3	Last few rocks along the road • Intrusion seen in rock is not parallel with foliation. The intrusion occurred later. • Rock with large crystals of feldspar and quartz. • Feldspar shows cleavage and weathers into clay. • Larger crystals take more time to form.
4	Rock by drinking fountain at the trail head • Shows foliation and exfoliation well. • Smaller rock across from kiosk shows feldspar crystals – largest mineral group.
5	Waterfall and pool • Waterfalls can occur due to less resistant rock being weathered away causing drop offs. • Evidence of rock layers and folding in rocks to right of pool. Folding occurs deep below the surface. • Rock is uplifted to the surface then weathered. • Same process of pressure causes metamorphic rocks to form.
6	Large outcrop in stream • Rock in bank across stream shows flat surfaces where fractured. • 90 degree bends can be seen in stream. • Rock pieces broken off at top shelf of small waterfall is due to water weakening the rock.
7	Upstream about 50 feet • Examples of rocks in and along stream with near 90 degree angles.
8	Footbridge • Rocks here have common linear patterns. • Running water started to wear rock away in crevices and continued until the present day “needle” of rock was formed. • More 90 degree bends in stream are evident by bridge.
9	Log cut out of trail before short bridge • Fallen logs are only removed where the trail tread is so the rest of the log can decompose as it is. • Decomposition of organic matter is much faster that inorganic material. • Rocks produce sand and clay, organic matter produce humus.
10	(Optional) Rock at far end of footbridge at left corner • Example of micaceous schist. • Evidence of gold-like color of mica. This rock is less common at TR. It is less metamorphosed than gneiss so it is less resistant to weathering.
11	Orange colored soil • Very obvious along trail and at bases of uprooted trees right after sharp turn to left. • Evidence of underlying iron-rich amphibolite rock that has weathered into iron oxide clay.
12	Rocks along bank to the right of trail • Near 90 degree fracture angles can be seen. This is due to internal composition of minerals. • Rock shelf to the right shows an example of biomechanical weathering where a tree root applied force to widen a fracture.
13	(Optional) Large white crystals in rocks • Seen in rocks along section of steps. • Good examples of feldspar. • Smaller loose pieces can also be found in the trail.
14	Large rock on right broke in two pieces • Shows fracture with right angled edges. Rock has slid down bank.
15	Soil color change on left • In area where tree has fallen, soil color is more of a tan color now.  This shows a change in underlying rock. • More granite gneiss and less amphibolite.
16	Overhanging rocks on right • Overhanging outcrop provides habitat for mosses, lampshade spiders, green salamanders (endangered species), mud daubers, occasional phoebe nests, crickets, rodents, etc. • Just past the overhang the exposed rocks show 3-D pattern of fractures and some folding near the bottom.
17	Footbridge • Small 90 degree stream bends evident here. Intrusions seen in stream bedrock. • Rusty stains on creek rocks evidence of amphibolite.