GY403 Structural Geology Laboratory Lab: Stereographic Projections A Key Problem 1 Problem 1: A bed has an Exercise 3A attitude of 040°, 60°SE. Problem 1 N What is its apparent dip App. dip: 090, 53 angle in a vertical plane trending 090°? 040, 60SE 090, 90 090, 53 Problem 2 Problem 2: The vertical faces Exercise 3A of a quarry trend 270E and Problem 2 Answer: 023, 42NW N 000E respectively. A coal seam 023, 42NW has apparent dip of 20E in the 000, 20 000E wall and 40E in the 090E wall. What is the strike and true dip of the coal seam? 270, 40 Problem 3 Problem 3: Two dikes with orientations of: Exercise 3A Problem 3 Answer: 186, 25 (1) 060E, 30ESE N (2) 350E, 60ESW 350,60SW intersect. What is the bearing and plunge of the line of intersection between these 060,30SE two planar structures? 186, 25 Problem 4 Problem 4: A thin Exercise 3A planar bed (348E, Problem 4 Answers: intersection=231, 32 35ESW) intersects a app. dip vein 270, 54 vein (027E, 57ENW). app. dip bed 270, 34 N Bed:348,35SW If we assume that Vein:027,57NW both structures are essentially planar geometries, what is the plunge and bearing of the line of intersection of the 270, 34 270, 54 two planes? What is 090, 90 E the apparent dip of both the vein and the bed in the 090E 231, 32 direction? Problem 5 Problem 5: A sequence of Exercise 3A formations which strike 050E Problem 5 Answer: true dip = 320, 42 each display an apparent N dip of 35E in the 000E direction. What is the true dip trend and plunge ? 050,42NW 000, 35 340, 42 340,90W Problem 6 Problem 6: A planar coal Exercise 3A Problem 6 seam has an attitude of 065E, Answers: 010, 30 N (1) 35ENW. Find the apparent 340, 35 (2) dips along vertical cuts 270, 17 trending: 010, 30 340, 35 (1) 010E (2) 340E (3) 270E (3) 270, 17 270, 90E 010, 90E 340, 90E Problem 7 Problem 7: Given two apparent Exercise 3A Problem 7 dips (12E, N57EW; 11E, S20EE) for Answers: a pegmatite dike, and two Pegmatite: N38W,33SW Schist: N34E,80SE N apparent dips (78E, N90EE; 13E, Mine shaft: 31,S28W S32EW) for a carbonaceous schist layer, find the orientation of both Pegmatite N38W,33SW planar structures. The presence of Schist N34E,80SE graphite in the schist caused a 12,N57W reaction in the pegmatite that produced Cassiterite (SnO2). Starting at the point where the mineralized zone is exposed, 78,N90E along what bearing and plunge would you instruct your mining engineer to sink a mine shaft to mine this ore? Mine shaft=31,S28W 13,S32W 11,S20W Problem 8 Problem 8: A polydeformed Exercise 3A Problem 8 metamorphic rock contains two Answers: different mineral lineations that lie A. N2E,62SE within the plane of S1 foliation: B1. 16NE B2. 75SW C. 90 N Mineral lineation (1): 14, N10E 16 14,N10E Mineral lineation (2): 58, S58E Find the following: 90 (a) Attitude of the S1 foliation plane containing the two mineral S1: N2E,62SE lineations. W E (b) Rake of each lineation relative to 58,S58E the S1 plane. (c) What is the angle (< 90E) between the two lineations as measured within the S1 plane? 58 S Problem 9 Exercise 3A Problem 9: A planar fault Problem 9 contact contains slickenside Answers: Intersection: N60W,79 N lineations that trend N60EW. Rake: 86NE N10E,80NW The fault contact has an attitude of N10EE,80ENW. Find the following: N60W 86NE (a) What is the plunge of the lineation? (b) What is the rake angle of N60W, 79 the lineation relative to the fault contact? .