GC77HFH BRP 424.4 Herrin Knob Overlook (Earthcache) in North Carolina, United States created by rainbowtree

This cache has been archived.

rainbowtree: DO NOT post a log to this cache, even backdated. Your log will be immediately deleted.
Location and content gifted to a special cacher for development of a new earthcache,

GC77HFH ▼

A cache by rainbowtree Message this owner

Hidden : 6/1/2017

Difficulty:

Terrain:

Size: Size: other (other)

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Geocache Description:

BLUE RIDGE PARKWAY OVERLOOKS GEOLOGY TOUR
There are countless wonders to behold along your journey.
Posted coordinates are for parking. - Outcrops are within 100 feet.

EARTHCACHE REQUIREMENTS
Each cacher must send his/her own answers BEFORE logging a find. Enjoy the journey (learning adventure) as well as the destination (smiley earned). Remember to take only pictures and leave only footprints. To get credit for this Earthcache, complete the following tasks:

1. MESSAGE …. Observe the mica gneiss and the trondhjemite dike. Give two ways that differentiate the two.

2. MESSAGE …. Observe the igneous trondhjemite dike that cross-cuts across the mica gneiss. Which direction does the dike strike?

3. MESSAGE …. Observe the igneous trondhjemite dike that cross-cuts across the mica gneiss. Which direction does the dike dip?

4. LOG …. Post a picture at or near the coordinates. This picture is your log signature.

OPTIONAL - Please respect the time and effort involved in finding and creating this earthcache by adding A and B to your log.

A. JOURNEY OF THE MIND ... Science explains what we observe. Relate (in your own words) something you found interesting in the reading. This adds to your learning adventure and your log.

B. JOURNEY OF THE HEART ... Art shares our personal experience of what we see. Share something special you found on site, and why it is special to you. This is a memorable addition to your log and will make other hearts smile.

THANK YOU Mark W. Carter for permission to use your book for this earthcache.
THANK YOU Lillian for permission to place this earthcache along the Blue Ridge Parkway.

HERRIN KNOB OUTCROP
The migmatitic (mixture of metamorphic rock and igneous rock) mica gneiss is cross-cut by a thick dike of a light-gray, medium-grained igneous trondhjemite (light-colored intrusive igneous rock in which the dominant feldspar is plagioclase). The dike strikes __________ and dips __________. This dike is younger than the gneiss around it because it cuts across the foliation. This nicely illustrates the Law of Cross-Cutting, which states a rock mass that intrudes or cuts across another must be the younger of the two.

DIP AND STRIKE
DIP is the acute angle that a rock surface makes with a horizontal plane.
STRIKE is the direction of the line formed by the intersection of a rock surface with a horizontal plane.