NAME: SECTION: DATE:
EXERCISE 7-1
GeologicTime
PURPOSE
The purpose of this exercise is to help you master creating relative geologictime histories.
For each of the cross section diagrams, determine the relative geologic history and answer
questions about each diagram.
ormaon f Diagram1
olepo
lbreccia C y t a h imestone
ne
c l e po
of
senls
tDne tnie
Fini normal2 depo of,
dipslip
horma
dip slip o o oo o
M) Ihtusve
ock
SAnston
eosion
aemter formHISTORY(TE
EOLoGICAL shoEAT RAND CAS-ONE bpEift
VENT)of shist
14.A - \ava f\ow
13. BtC- dike t S|
normaL dip slup
1M - nor mal dip slip
10. K epDahDn of shale
9. J- dpontion of fossilHerous liMestone
8, I diposihon of shave
7. H- duposathon oi Caitaine lin shone
6.G iposa hon f fne sandstone
s. F- leposition d breccia
4.E-eposiiDn of ourse sandstne
3.L- hon conform1hy
2. Q- wplift of shist
1. D- formaton Gf shist
Exercise 7-1 | Geologic Time 107
, QUESTIONS FOR DIAGRAM 1:
1 What twoprinciples allowed youto determine the relative ages of Iand B?
Answer: Driginas horiLont otht
Answer: Cros3cuttn ruahons
2. The erosional surface labeled Lis a (an):
Answer: non onformit
3. What name best describes the portion of the igneous intrusion Bthat is underneath Earth's surface?
4
Answer: dike
What name best describes the portion of the igneous intrusion Cthat is underneath Earth's surface?
Answer:
S. What is the texture of the rock found inintrusion C?
Answer: phânentic
6. What rock name would you give lava flow Aif it was intermediate in composition?
Answer: andesite
7 What texture would you expect unit Kto have?
Answer: CAQshc.
Draw arrows on the fault planes for fault Mand fault Nand label the hanging wall (HW) and
footwall (FW) for fault Mand fault N.
9 What name best describes fault M?
Answer:
hamad cip sie
10. What plate tectonic boundary would most likely be responsible for formingfault N?
Answer:
dwcrgent
11. Geologists used geochronology to determine that lava flow A is26 million years old and
intrusion Bis 143 million years old. How old is unit J?
Answer: 143 million
12. What metamorphic rock formed right next to intrusion Bwhen unit J was contact
metamorphosed?
Answer: marble
108 Geologic Time Exercise 7-1
EXERCISE 7-1
GeologicTime
PURPOSE
The purpose of this exercise is to help you master creating relative geologictime histories.
For each of the cross section diagrams, determine the relative geologic history and answer
questions about each diagram.
ormaon f Diagram1
olepo
lbreccia C y t a h imestone
ne
c l e po
of
senls
tDne tnie
Fini normal2 depo of,
dipslip
horma
dip slip o o oo o
M) Ihtusve
ock
SAnston
eosion
aemter formHISTORY(TE
EOLoGICAL shoEAT RAND CAS-ONE bpEift
VENT)of shist
14.A - \ava f\ow
13. BtC- dike t S|
normaL dip slup
1M - nor mal dip slip
10. K epDahDn of shale
9. J- dpontion of fossilHerous liMestone
8, I diposihon of shave
7. H- duposathon oi Caitaine lin shone
6.G iposa hon f fne sandstone
s. F- leposition d breccia
4.E-eposiiDn of ourse sandstne
3.L- hon conform1hy
2. Q- wplift of shist
1. D- formaton Gf shist
Exercise 7-1 | Geologic Time 107
, QUESTIONS FOR DIAGRAM 1:
1 What twoprinciples allowed youto determine the relative ages of Iand B?
Answer: Driginas horiLont otht
Answer: Cros3cuttn ruahons
2. The erosional surface labeled Lis a (an):
Answer: non onformit
3. What name best describes the portion of the igneous intrusion Bthat is underneath Earth's surface?
4
Answer: dike
What name best describes the portion of the igneous intrusion Cthat is underneath Earth's surface?
Answer:
S. What is the texture of the rock found inintrusion C?
Answer: phânentic
6. What rock name would you give lava flow Aif it was intermediate in composition?
Answer: andesite
7 What texture would you expect unit Kto have?
Answer: CAQshc.
Draw arrows on the fault planes for fault Mand fault Nand label the hanging wall (HW) and
footwall (FW) for fault Mand fault N.
9 What name best describes fault M?
Answer:
hamad cip sie
10. What plate tectonic boundary would most likely be responsible for formingfault N?
Answer:
dwcrgent
11. Geologists used geochronology to determine that lava flow A is26 million years old and
intrusion Bis 143 million years old. How old is unit J?
Answer: 143 million
12. What metamorphic rock formed right next to intrusion Bwhen unit J was contact
metamorphosed?
Answer: marble
108 Geologic Time Exercise 7-1
