Geologic Foundations
What is geology the scientific study of?
(3 components)
The study of the Earth's structure, composition and processes.
What is the largest division of geologic time?
An eon.
What is biostratigraphy?
The branch of geology that uses fossils to determine the relative age of rock layers.
What is the difference between relative and absolute dating?
Relative dating is based on observations and provides a vague timeline;
Absolute dating using scientific techniques evaluating various isotopes (like carbon) to provide specific ages and timelines.
What is physical geology compared to historical geology?
Physical geology examines physical composition and dynamic processes.
Historical geology creates a timeline of Earth's past using rock layers, fossils, volcanic ash, dating techniqes and the geologic time scale.
What is the term for the study of the rock layers?
Stratigraphy
Which eon do we live in?
Phanerozoic eon.
What are the fossils that are used to help date and correlate rock layers that were short lived, abundant and widespread?
Index fossils
Who developed carbon dating in the 1940s?
Willard Libby
Which 3 eons make up the PreCambrian?
Hadean eon
Archaen eon
Proterozoic eon
Who was the first to introduce the idea of uniformitarianism?
James Hutton
What percentage of Earth's history does the Precrambrian represent?
90%
This fine-grained deposit that is formed after an eruption is ideal for relative dating because it covers wide regions quickly and can be chemically identified across rock layers.
Volcanic Ash
Of the 3 carbon isotopes which isotope is radioactive?
Carbon 14
Which event marked a rapid and very large diversification of life on Earth?
The Cambrian Explosion
Which concept suggests that slow processes shape Earth over long periods of time?
Uniformitarianism
What are the 4 units of geologic time?
Eon
Era
Period
Epoch
What are the 3 main characteristics of index fossils?
Short lived
Abundant
Widespread
(SAW)
What is the half life of carbon 14?
5,730 years
This event wiped out approximately 90% of species and occurred about 250 million years ago.
Permian Triassic Extinction
Why is geology referred to as the "storyteller of the Earth"?
Because each rock layer records a piece of Earth's 4.6 billion year history like a page in a book.
List the 3 eras within the Phanerozoic eon?
Paleozoic
Mesozoic
Cenozoic
What is teprochronology?
A relative dating technique that uses volcanic ash to create a chronological timeline.
Why is carbon dating not effective on fossils or rocks that are millions of years old?
Carbon dating is only effective up to 50-60,000 years.
What events occurred during the Cretaceous Paleogene boundary?
An asteroid struck Earth and eradicated the dinosaurs.