My Notes for Unit 4 Flashcards
What are the 3 parts of geological time?
1) Relative Time
2) Absolute Time
3) Geological Time Scale
What is dating?
The procedures we use to:
i. determine when an event took place, and
ii. determine the sequence of events
What is the age of rocks?
the time it was emplaced
What is deep time?
- very old events
- very old rocks
What is relative geological time?
- The sequence of processes that have occurred at some location
- We can see this with the naked eyes – or work it out with fairly simple geological observations.
What is age sequence?
One process took place after another
What is stratigraphic succession?
Shows a superposition of rocks (old below young) –> layers of rock
What is magma?
general name for liquid rock under ground
What is lava
name for liquid rock above ground
What are anticline and syncline a part of?
tilting (deformation and angular unconformity)
What is a normal fault?
Body of rock above fault has gone downwards (bottom side “footwall block”) and body below has gone upwards (topside “hanging-wall block).
What is the opposite of a normal fault?
thrust fault
what is iodine?
syncline and anticline
What is stratigraphic facing?
The upwards movement of young rocks
What does the topographic sequence of unconformity represent?
passing of time
What is metamorphism?
Newer crystals form in roc and metamorphic rock becomes crystallized as well (for nonconformity)
___million years ago life became common.
540
How long has fossil correlation been useful for?
Only for about the last 500 or so million years.
What is fossil range?
timespan an organism exists.
On average, how long does a species exist for?
6 million years
Time ranges___for different species.
overlap
When looking at fossils records in rocks, we find___.
gaps
Fossils have specific geological___.
ranges
___ages are “add ons” and can change (improve) from time to time.
absolute
What is the oldest fossil found on earth?
stromatolites (blue-green algae / cyanobacteria)
When was the birth of stromatolites?
3.5 - 3.8 mya
Stromatolites appeared during the___explosion.
Cambrian
What was the first sexual reproduction between?
stromatolites (blue-green algae)
Up to how high can stromatolites grow to be?
~ 1 m
What are stromatolites composed of?
CaCO3
What are CaCO3 “houses”?
Stromatolites
What is the biggest ice age on Earth known as?
Snowball Earth
What is Greenhouse Earth?
hot
The Earth’s temp bounces back and forth between?
Snowball Earth and Greenhouse Earth
What was the temp when the T-Rex arrived?
+23 degrees C
What is the global average temp?
+17 degrees C
How can we work out the atmospheric temperature?
mainly oxygen isotopes and other isotopic studies
What was the temp during the 300-250 (approx. 251) ice age?
-5 degrees C
When was Snowball Earth?
during the precambrian
When was there glaciation in Canada?
during the precambrian
