Answer the following questions regarding features on the geologic map shown in F

Question

Answer the following questions regarding features

on the geologic map shown in Figure G-25 (Appen-
dix G). Use the spaces provided on Fig. G-25. This

exercise will require you to integrate information
from previous chapters as well as this one.
1 For each fault (A, B, C, D, and E) determine the
type of faulting that has occurred and bracket
the age of faulting as precisely as possible.

2 Identify the following features indicated by cir-
cled, lower-case letters on the map.

(a) Type of contacts at localities a, b, c, and d.

(b) Specific geologic structure present at local-
ities e, f, g, and h.

3 The strike and dip directions that are shown are
correct; however, three of the dips are actually
overturned. Correct these directly on the map by
substituting the correct symbol for overturned
beds.
4 Isthe unit onthe east side ofthe map labeled ‘‘Tm’’
older or younger than the other Miocene rocks on
the map? Give a reason for your answer.

5 Determine the minimum amount of displace-
ment on fault C.

6 Write a one-paragraph geologic history of the
map area. Include all episodes of deposition,

erosion, and plutonism. Also indicate when spe-
cific deformational styles (folding and faulting)

occurred.

Explanation / Answer

1. The faults oberserved on the given map are as follows:

A : High angle thrust fault because the dip of the beds are opposite to the dip pf fault plane. Age of faulting- Miocene.

B : High angle normal fault. Age- Silurian.

C : Low angle strike-slip fault. Age- Pennsylvanium.

D : Listric fault as the fault line is curved. Age- Middle Miocene.

E : Low angle nornal fault. Age- Ordovician.

2.a) Type of contacts present on the map are:

a: the contact at this point is unconformity or erosional surface.

b: contact between intrusion and bedding.

c: intrusion contact.

d: bedding contact.

The geological structures present are as follows :

e : core of a synform as the beddings on the both sides converge towards each other.

f : May be the window structure due to erosion on the thrust sheet.

g : outlier structure as younger bed is surrounded by older rocks.

h : Thrust sheet as cambrian rock is bounded by silurian on either sides.

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