For each geologic map shown below, complete the tasks listed. 1 a. Draw a strike

Question

For each geologic map shown below, complete the tasks listed.
1 a. Draw a strike and dip symbol on the map indicating the approximate bedding orientation in the sedimentary rocks.
b. Sketch a vertical profile(cross section) along the line indicated in the space provided below: (i) Locate the contacts on the topographic profile based on where they cross the profile line on the map; then (ii) sketch the approximate dips of the contacts. Note that the topographic contours are in meters.

c. What type(s) of contact might be present between the granite and the sedimentary rocks? List the possibilities permitted by the rock types and map relationships.

d. Identify two pieces of additional geologic information that could resolve uncertainty in the type of contact that bounds the granite, AND briefly explain HOW that information applies to this example.

Please expain how you worked out this problem. My professor and the book do not go over many examples so I am struggling on figuring this out. I would like to be able to do this on my own! So the more detail that better. Thanks.

Explanation / Answer

(a) in order to draw a strike line we need at least two points on a lithological contact boundary(between two different rock types) where the same contour line (known value) intersects. draw a straight line joining two such points to get the strike of that bedding plane. in order to draw the dip direction and amount of dip, we need two or more strike lines and known contour intervals. between two strikes the direction of dip is determined by the direction in which contour values decrease. and the amount of dip is calcualted by simple geometry.

(b) to draw the vertical profile, draw the lithologies along the contour lines of given altitude (Y-axis in the section) and the lithocontact boundaries along the section line . then draw the bedding plene dips according to the dip directions and amount calculated from the previous question.

(c) between granite and sedimentary rock there can be unconformity (Nonconformity), or a baked and chilled margin of the granitic body is a late intrusive body.

(d)

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