Guided Notes

Geologic History

Relative Age Sequence of Events

Correlation Techniques Volcanic Ash Markers

Index Fossils Geologic Time Scale

Evolution Radioactive Dating

8. What are major events that have occurred on Earth?

▪ Earth formed about 4.6 billion years ago.

▪ Geologic time scale: geologists have subdivided geologic time into units based on fossil evidence.

o Fossil: any evidence of former life

▪ See ESRT pages 8-9 for specific geologic history of New York State!

Units of Time: Largest to SmallestTime scale in

millions of years

Formation of Earth

TodaySplit into 3 eras. Note that each is

magnified to show all of the things that happened.

8. What are major events that have occurred on Earth?

Four Major Divisions of Time: 1. Precambrian Eon: represents the first 88%

of Earth history.

• No fossils because organisms were small and soft & because most rocks were not sedimentary.

Precambrian Eon

8. What are major events that have occurred on Earth?

2. Paleozoic Era: 7% of Earth’s history

• Invertebrates, fishes, amphibians, vertebrate, land plants, and land animals all appear.

Paleozoic Era

8. What are major events that have occurred on Earth?

3. Mesozoic Era: 4% of Earth history.

• Evidence of dinosaurs, early birds, and early mammals

Mesozoic Era

8. What are major events that have occurred on Earth?

4. Cenozoic Era: Most recent 1% of Earth history.

• Fossils of modern plants and mammals

• Humans: Humanoids showed up late in the Cenozoic era and have existed for about 0.04% of Earth’s history.

Cenozoic Era

8. What are major events that have occurred on Earth?

Summary:

1. Life has not existed for most of Earth’s history. 2. Fossils provide evidence of evolution. 3. Humans are very “new” to Earth.

8. What are major events that have occurred on Earth?

Precambrian

PaleozoicM

esozoic

CenozoicComplete the pie graph to show the amount of Earth’s history each time unit took.

Units of Time: Largest to Smallest Information about species living at different times.

If there is no line, there is no rock record from that time in New York.

Time scale in millions of years

Index fossils that are found in New

York State

Bars have organism group names. The beginning of the bar shows when the group came into existence. The end of the bar is when the group went extinct. The letters on the bars represent the time of the index fossils at the bottom of the page.

Mountain building (orogeny) and rock forming events.

How the continents have moved

Use both pages together to determine when different events occurred.

✓ Checkpoint – Geologic History & the ESRT: Use your knowledge of Earth Science and the Earth Science Reference Tables (pages 8/9, 2, and 3) to answer the questions below. Use your ESRT to fill in the table below for the three index fossils pictured.

Identification Letter

Fossil Name

Organism Group

Eon

Era

Period

Epoch

Important Geologic Event at this Time

NYS Landscape Region They May Be Found

! ! !

Use both pages together to determine when different events occurred.

© K. Coder 2015

© K. Coder 2015

✓ Checkpoint – Geologic History & the ESRT: Use your knowledge of Earth Science and the Earth Science Reference Tables (pages 8/9, 2, and 3) to answer the questions below. Use your ESRT to fill in the table below for the three index fossils pictured.

Identification Letter

Fossil Name

Organism Group

Eon

Era

Period

Epoch

Important Geologic Event at this Time

NYS Landscape Region They May Be Found

! ! !

L

Coelphysis

Dinosaurs

Phanerozoic

Mesozoic

Triassic

LatePangaea begins to

break up

Newark Lowlands

✓ Checkpoint – Geologic History & the ESRT

2) What are two characteristics of index fossils that make it important in determining the age of rocks?

✓ Checkpoint – Geologic History & the ESRT

3) What was another method discussed (very similar to index fossils) that helps geologists determine the age of rocks?