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Line 10: − • Measure strike and dip of planes+ − • Measure trend and plunge of lines+ − • Measure vertical angles+ − • Measure bearings+ − • Set local declination[3]+ Line 21:
Line 21: − 1. Place the bottom EDGE of the compass flat against the plane of interest. (The direction of sighting armature follow the direction of strike) + − 2. Adjust the compass orientation, making sure the bottom edge is always flat against the plane (Sometimes it is easier to put your field book against the outcrop and then the compass against the book to get a smoother and/or a larger surface), until the air bubble in the "Bull's eye level" is centered. + − 3. Read either end of the compass needle to obtain the value of strike.+ + + + + + + + + + + + + +
How to plot the strike data to the Rosette diagram (view source)
Revision as of 04:16, 1 July 2015
, 04:16, 1 July 2015no edit summary
Brunton Compass can be used for:
Brunton Compass can be used for:
* Measure strike and dip of planes
* Measure trend and plunge of lines
* Measure vertical angles
* Measure bearings
* Set local declination[3]
In determine the direction of strike and dip, there are four quadrants at Brunton Compass such as North East, North West, South East, and South West. Each of them have value 0-90 degree. For example in Figure 3, N40o W mean the direction of strike is 40o from North to West. 45o is amount of dip. The direction of dip always perpendicular with direction of strike, so we know the direction of dip is N50o E.
In determine the direction of strike and dip, there are four quadrants at Brunton Compass such as North East, North West, South East, and South West. Each of them have value 0-90 degree. For example in Figure 3, N40o W mean the direction of strike is 40o from North to West. 45o is amount of dip. The direction of dip always perpendicular with direction of strike, so we know the direction of dip is N50o E.
=How to Measure Strike=
=How to Measure Strike=
To measure strike of rock we can used Brunton Compass. The steps are:
To measure strike of rock we can used Brunton Compass. The steps are:
# Place the bottom EDGE of the compass flat against the plane of interest. (The direction of sighting armature follow the direction of strike)
# Adjust the compass orientation, making sure the bottom edge is always flat against the plane (Sometimes it is easier to put your field book against the outcrop and then the compass against the book to get a smoother and/or a larger surface), until the air bubble in the "Bull's eye level" is centered.
# Read either end of the compass needle to obtain the value of strike.
[[File:Measure strike.png|framed|center|Figure.5 Measure strike with Brunton Compass<ref>http://courses.geo.ucalgary.ca/glgy203/images/sd.htm.<ref/>]]
=Rosette Diagram=
The direction of strike indicate the direction of main force of plat tectonic in there regional. It can be determined with rosette diagram.
[[File:Rosette.png|framed|center|Figure 6. Rosette diagram<ref>www.gigawiz.com<ref/>]]
The radial histogram in rosette diagram (the yellow one on Figure 6) show the direction of strike.
=Case Study=
Indonesia is a country located between three major plates, there are Eurasian Plate, Indo-Australia Plate and Pacific Plate. Eurasian Plate have opposite moving direction with Indo-Australia Plate. Eurasian Plate have moving direction about
Base rock of Java Island is claystone. At Karangrangsambung, Kebumen, Center of Java, there are outcrops of claystone, base rock of Java Island, it is called Karangsambung Formation.
On June 16, 2015 Geophysics of University of Indonesia held Field Trip to Karangsambung, and observed strike of claystone at Kalimandala Karangsambung. The result of the observation is: