1. Geological history of the earth
Fossils
Rock and Fossil Formation
Dating the Past
Geological Time
Geological history of the earth

2. Where are fossils formed? What can become a fossil?
Formed in ________________
___________________________
Can be bone, _____, pollen grain, ________, or ________________

3. What are the types of fossils?
______________________- minerals turn the bone or shell to stone.
Mold- ____________________ left by soft tissue dissolving away.
Cast: A mold filled in with _________________.
____________________: The impression, like a __________________, left in soft sediment that hardens into rock over time.

4. Petrification
Minerals turn the ________________________.

5. Molds
_______________________________ dissolving away.

6. Casts
A mold filled in with ______________________.

7. Trace fossils/imprints
The impression, ___________________, left in soft sediment that hardens into rock over time

8. How do entire organisms get preserved?
__________- A mastodon was found in Canada

9. How do entire organisms get preserved?
Amber- _______________________________, which hardens into the mineral Amber.

10. How do entire organisms get preserved?
_____________________- Capture animals that come to feed on other captured animals

11. How do we interpret fossils?
Law of Superposition- __________________ are usually ____________________________. (Like the clothes on the floor of your room).

12. How do we interpret fossils?
______ fossils- come from _________________ or periods. Used to piece together the geological record.

13. How do we interpret fossils?
Unconformity- a _____________________ sequence indicating interruption of sedimentation, commonly accompanied by ___________________ below the break.

14. How do we interpret fossils?
Faults- ___________ than the rock layers that contain them.

15. How do interpret fossils?
_________________- magma forces its way into layers of rock. Intrusions are _________________ than the rocks they intrude into.

16. How do we interpret fossils?
__________________- If magma reaches the surface of the earth, it forms an “extrusion”, a pool which hardens into igneous rock. The extrusion is _________ than the rock it overlays.

17. How do we date the past?
The _____________________, some containing fossils, determine which were deposited first.

18. What are the theories for dating rocks?
First theory- sediment is deposited at _________ ______can determine the age of any unmetamorphised sedimentary rock layer and fossils it contains.
Problem- sediment is NOT deposited at a steady rate…

19. How do we date rocks? ____________________________:
1. Atom of radioactive elements decays at a __________________________
2. Atoms form different, more stable elements, called _____________________.
3. the time it takes for a radioactive element to decay to half of the original amount is its __________________.

20. How do we date rocks?
4. Half-life of elements can be fractions of a second to _______________________.
5. Since we know the half-life’s of most elements, we can date many rocks by _________________________.

21. What is carbon dating?
_________ isotope Carbon-14 is used to date relatively __________________
Works well for dating ancient _______________ remains
Page 603 has list of elements and their half-lives

22. What is varve?
Varve- sediment layers laid down each year or season in __________________

23. How old are the oldest rocks on earth?
The oldest rocks found on the Earth are in__________ __________ and are over 4 billion years old
Moon rocks are even older, and scientists accept that the Earth is the same age as the Moon because they formed at the __________.

24. What are the eras of geological time?
Precambrian Era- ______ form, ____________ increases in the ______________. Life is simple; bacteria, algae, jellyfish, clams, coral –___________________
The landmasses are low and flat and large, a with low ____________ quite abundant.

25. What are the eras of geological time?
___________________________ seas increase in size, encroach on land
________________ thrive; ________, sponges, snails, worms, and other ___________ critters.

26. What are the eras of geological time?
Ordovician- life in seas; ___________________, invertebrates advance; lots of ______________ critters
On land, mountains and ____________________ continue

27. What are the eras of geological time?
Silurian- first __________________, air breathing arachnids, and __________________
Shallow seas dominate, _____________ climate and topography are abundant.
_______________
occurring

28. What are the eras of geological time?
Devonian- swampy forests grow; _______________ arrive, as do sharks and insects
___________________ appear
Uplift and erosion continue. Still quite _____________ and ________________.

29. What are the eras of geological time?
Carboniferous- swamps abound in the lowlands. First ____________, reptiles, and flying insects. Seed-bearing _____________ grow.
Mountain building going on. ______________ much of the planet, swamps still in lowland areas. ___________.

30. What are the eras of geological time?
Permian- first ______ bearing plants. Ferns, fish, amphibians, and _____________ thrive. Big die-out of sea life
___________ building continues. Climate dries out, forests thrive.

31. What are the eras of geological time?
Triassic- first ____________________________, modern coral, fish, and ____________ develop.
____________ still thrive, but plains to emerge.

32. What are the eras of geological time?
Jurassic- fist _______, trees thrive, mammals continue to develop
__________________ grow, volcanoes are active

33. What are the eras of geological time?
Cretaceous- first _________ plants, first placental mammals develop. Dinos die out, and so do many sea living _______________.
Volcanic time. ___________ layer found in rocks of this period. Often comes from ___________, seldom found anywhere else.

34. What are the eras of geological time?
Tertiary- first ___________, primates, humanoids develop. Mammals look modern.
Tropical climate; lots of ___________________.

35. What are the eras of geological time?
Quaternary- first _______ beings appear, Wooly Mammoth die out, human culture develops.
________________ dominate. We are still in an ice age that is __________________.

36. How does life change on earth?
_________________- change over time
Occurs due to environmental ___________________
Supported by the _________________ record.