In this assignment you are going to reconstruct the geologic history of the Halifax area. But to addsomething new you are also going to complete a block model showing the underlying geology.1. Cut out the model showing the geology of Halifax, Dartmouth, and Bedford Basin.2. The top of the model shows the geology as mapped on the ground. To help with visualization,try to imagine what you would see if the water were drained out of the area; the geological unitswould extend across the floor of the Basin and Halifax Harbour. Try to connect the geologicalboundaries across these areas and shade them according to the rock unit probably present.
3. The four sides of the block are cross-sections. Complete the sides of the block using theevidence from the map. To help you are provided with a cross-section that shows the structurethat would be seen if the model were sliced along line A-B. Where you do not have clearevidence for the structure, you should make reasonable assumptions. For example, the mapdoes not tell you the orientation of the boundary of the granite; assume it is irregular but roughlyvertical.4. Complete the assembly of the model, but don’t tape it too firmly because you will need to scanor photograph your completed model as part of your assignment5. Use your model to deduce the geological history of the Halifax area. The following is
Geol 1202 Planet Earth
Assignment: Geologic History of Halifax
In this assignment you are going to reconstruct the geologic history of the Halifax area. But to add
something new you are also going to complete a block model showing the underlying geology.
1. Cut out the model showing the geology of Halifax, Dartmouth, and Bedford Basin.
2. The top of the model shows the geology as mapped on the ground. To help with visualization,
try to imagine what you would see if the water were drained out of the area; the geological units
would extend across the floor of the Basin and Halifax Harbour. Try to connect the geological
boundaries across these areas and shade them according to the rock unit probably present.
3. The four sides of the block are cross-sections. Complete the sides of the block using the
evidence from the map. To help you are provided with a cross-section that shows the structure
that would be seen if the model were sliced along line A-B. Where you do not have clear
evidence for the structure, you should make reasonable assumptions. For example, the map
does not tell you the orientation of the boundary of the granite; assume it is irregular but roughly
vertical.
4. Complete the assembly of the model, but don’t tape it too firmly because you will need to scan
or photograph your completed model as part of your assignment
5. Use your model to deduce the geological history of the Halifax area. The following is a jumbled
list of events in the history of the Halifax area. List these events (A-I) in order using evidence
from the map.
Make sure you indicate which is the oldest and which is the youngest in your list.
a.
b.
c.
d.
e.
f.
Metamorphism of surrounding rocks, producing hornfels, by heat from the granite magma.
Lithification of sediments of the Halifax and Goldenville Formations.
Erosion of the overlying units to expose folded rocks and granite.
Deposition of muds and silts of the Halifax Formation.
Intrusion of granitic magma in the area west of Halifax.
Deformation of the Halifax and Goldenville Formations producing folds and cleavage, during
building of the Appalachian orogen.
g. Flooding of Halifax Harbour and Bedford Basin.
h. Deposition of glacial till in the form of drumlins.
i. Deposition of Goldenville Formation sands by turbidity currents.
Submit your completed block diagram and geological history to the Assignment Seven dropbox.
Name:
Student Number:
20
30
N
29
B
36
74
64
40
70
70
60
60
25
A
10
Legend to block diagram of Halifax-Dartmouth
PLEISTOCENE
Drumlin
DEVONIAN
DC G
Granite
CAMBRAN TO ORDOVICIAN
MEGUMA GROUP
HALIFAX FORMATION
CO H
Slate, Siltstone
GOLDENVILLE FORMATION
CO G
Sandstone, slate
Cross-section A-B
0
A
Km
3
B
0
Metres
-1525