Chapter 9: View of Earth’s Past Megan Darvish June 1.
-
Upload
bartholomew-washington -
Category
Documents
-
view
215 -
download
0
Transcript of Chapter 9: View of Earth’s Past Megan Darvish June 1.
Chapter 9:View of Earth’s Past
Megan Darvish June 1
Geologic Column
• Represents a timeline of Earth’s history• Invented in the 19th century• Oldest rock at top bottom• Newest rock at the top• Distinguished by the type of rock and kinds of
fossils• Fossils in more recent layers are modern day
plants/animals
Using a Geologic Column
• Uses ages of rock layers• Radiometric dating• Compare two similar rocks together; if
matched, probably from same time period
Divisions of Time
• Marked by climate, Earth’s surface, and types of organisms
• So long scientists use abbreviations • Separated into periods/eras
Major Elements of Column
• Precambrian Tertiary• Mesozoic Permian• Cenozoic Carboniferous • Paleozoic Devonian• Cretaceous Silurian• Jurassic Ordovician• Triassic Cambrian • Quatemary
Law of Superposition
• States that older rock layers will sink to the bottom of the strata due to age.
• Intrusions are youngest, most often.
Eon
• Period in time marked by major events• Precambrian Eon• Lasted approx. 4,058 million years• Cambrian Eon• From when the Precambrian Eon ended until
present day
Era
• Important time periods within an eon• Paleozoic• Lasted 251 million years• Mesozoic• Lasted 65.5 million years• Cenozoic• Present day
Period
• Cambrian- 542 million years• Ordovician- 488 million years• Silurian- 444 million years• Devonian- 416 million years• Carboniferous (includes Pennsylvanian and
Mississippian)- 677 million years• Permian- 299 million years• Triassic- 251 million years
Period
• Jurassic- 200 million years• Cretaceous- 146 million years• Tertiary- 183.5 million years• Quaternary- approx. 1.8 million years
Epoch
• Only in the Cenozoic Era• Longer than an age; shorter than a period• Divided into ages- events of distinct fossils in
the fossil record• 7 total• 5 in the Tertiary Period• 2 in the Quaternary Period
Epoch
• Tertiary:• Paleocene- 65.5 million years• Eocene- 55.8 million years• Oligocene- 33.9 million years• Miocene- 23 million years• Pliocene- 5.3 million years
Epoch
• Quaternary:• Pleistocene- 1.8 million years• Holocene- .0115 million years
When do I live?
• Cenozoic Era• Quaternary Period