# Lab Exercise 7 â€“ Foliation and Lination

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```					Lab Exercise 8 – Foliation and Lineation
Lab Manual: Structural Analysis & Synthesis: A Laboratory Course in Structural
Geology, 3rd Edition

Foliation and lineation; rotation
/10 pts
1. Plot the following lineations (given in plunge, trend) with the  symbol on the
same tracing paper using the stereonet. Label each lineation (e.g., a, b).

a.   32, 087
b.   43, 217
c.   12, N12E
d.   88, 092
e.   86, 270
f.   59, N60E
g.   59, S60E

Is there any pattern? _________________
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/10 pts
2. A polydeformed metamorphic rock contains two mineral lineations that lie on
the same foliation plane. The 1st lineation is oriented 14, N10E, and the 2nd one
is oriented 58, S58E.

Plot the two lineations using the 1 and 2 symbols.

a. What is the attitude of the foliation plane on which these lineations occur?
Foliation: _________________
Show the pole to the foliation with the  symbol.

b. What is the rake (pitch) of each lineation in the foliation plane?

Rake of 1st lineation: ___________ Rake of 2nd lineation: ____________

c. What is the angle between the two lineations as measured in the plane of
foliation?

Angle: ________________
/10 pts
3. A slip lineation on a fault plane has a rake of 68NE.
The fault is oriented N52E, 83SE.

What is the plunge _________ and bearing (trend) ____________ of this lineation?

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/10pts
4. A slickenside surface (fault) is oriented N10E, 80W. Fibrous slickenlines on the
surface trend N60W.

a. What is the plunge of the lineation? _______________________

b. What is the rake ____________ of the lineation on the slickenside surface?

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/10 pts
5. In the Granite Wash Mountains of Arizona, bedding in a flysch sequence is
oriented N47E, 34NW. A spaced cleavage in this unit is oriented N22E, 68SE.
The intersection of bedding with cleavage produces a pronounced lineation that
is visible on bedding-plane surfaces.

What is the attitude of this intersection lineation?
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/10 pts
6. A fault plane displays two different sets of slip lineation. One set is oriented 22,
325, and the other set is oriented 49, 041. What is the orientation of the fault
plane (i.e., slip plane) that contains the two slip lineations?

Fault plane: __________________

/10 pts
7. The limb of a fold strikes 030o and dips 20o SE. On this limb a linear sedimentary
structure (crest of a ripple mark) pitches 42oE. Knowing that the ripples were formed
prior to the formation of the fold about a horizontal axis. Determine the:

A. plunge of the lineation: ____________

B. plunge of the lineation on the steep limb of the fold dipping 53oNW ____________

C. plunge on an overturned limb dipping 49oSE. ____________
______________________________________________________________________________
/20 pts
8. On a plunging overturned fold the upper limb strikes 022o and dips 27oE; the overtuned
limb strikes 090 and dips 58oS. On the upper limb a lineation pitches 27oS, and a
lineation on the middle limb pitches 36oW.

Plot the data using the stereonet, and label all the great circles (i.e., upper limb, middle limb).
Use the following symbols:
        Lineation
       Fold axis
       Pole to bedding in the limbs of the fold.

NOTES:
(1) de-plunge the fold axis. In this activity, you need to rotate the poles to the two limbs, and the
two lineations, the same amount as the plunge of the fold axis, and in the same sense. Put a prime
(‘) mark on the symbols.

(2) Un-dip the overturned limb. This requires you to rotate the pole of the middle limbs, after it
has been rotated during de-plunging, to the center. However, notice that overturned folds have
rotated beyond 90 degrees. So, the correct way is to move the rotated pole of the middle limb first
to the primitive, and then to the center (i.e.,the angle of rotation must be greater than 90).

While you do this, keep track of the lineation on the overturned limb, and get a glass of water.

Questions:
A. Could the lineations represent an original pre-fold structure subsequently folded?
___ yes          ___ no

B.   Why? __________________________________________________________

/10 pts
9. Mineral lineation occurs on the foliation plane of the Lion Den mylonite at Battleship
Peak Arizona. The foliation at this locality is oriented N22W, 73SW. The rake of the
lineation is 20N. The Lion Den mylonite was folded subsequent to the formation of the
foliation. In fact the gneiss is on the limb of a large antiform. Foliation at a locality
(South Ridge) on the other limb is oriented N64W, 48NE. Assume that the lineation
formed while mylonite was horizontal.

A. What was the orientation of the lineation prior to folding?
Hint: Calculate the plunge and bearing of the fold axis first.

Original lineation: _________________________

B. Predict the present orientation __________________ of the lineation at South Ridge

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