Geologic Time abbrev

Geologic Time abbrev - Exam #2 Thursday, February 25 Topics...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Exam #2 Thursday, February 25 Topics 1-10
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Geologic Time
Background image of page 2
Changing Concepts of Time 1. 1654 – Archbishop Ussher estimated that the Earth is ~6,000 years old based on biblical genealogies. 2. 1800 – John Joly (Irish geologist) estimated the Earth to be 90 million years old based on the salt content of the ocean 3. 1866 – Lord Kelvin (English physicist) calculated that the Earth is 100 million years old based on cooling rates 4. 1950 – Development of radiometric dating; estimate Earth to be 4.6 billion years old based on dating of meteorites and lunar rocks.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Major Events in Earth History 1. 4.6 BYA – Earth forms Primitive atmosphere produced through degassing (CO 2 , H 2 O and N) Early atmosphere had no free oxygen 2. 3.2 BYA – photosynthetic plants first evolve 6H 2 O + 6CO 2 C 6 H 12 O 6 + 6O 2 3. 1.8 BYA – aerobic organisms evolve
Background image of page 4
Degassing of the Earth’s Interior
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Geologic Time Scale
Background image of page 6
Approaches to Geologic Time 1. Relative Time : place rocks or geologic events in their proper chronologic sequence of formation Example: The recent eruption of Mt. St. Helens occurred after the eruption of Mt.
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 42

Geologic Time abbrev - Exam #2 Thursday, February 25 Topics...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online