Chapter 2 Flashcards
What is the Age of the Universe?
4.567 Billion Years
What is the Age of the Earth?
4.54 Billion Years
What is the oldest mineral age?
4.404 Billion Years
When is Theia crash into earth?
4.48 Billion years ago
What are the three principles that form the basis of all geological mapping?
- Sedimentary rock layers are deposited on top of eachother 2.Layers are lying flat when they are deposited 3.Layers are deposited over large areas
What is the Priciple of Superposition?
Layers of rock below other layers of rock are the younger rocks.
What is the Principle of Original Horizontality?
All sedimentary strata begins by lying flat (horizontal).
What is the principle of Original Laterla Continuity?
Flat lying sedimentary strata begins by lying in all directions ( therefore slanted strata must have experienced some stress to have moved them)
What is an unconformity?
horizons in rock that represent a time break during which erosion of a sequence of rock took place prior to the deposition of a more recent time sequence.
What is an angular unconformity?
An unconformity where horizontally parallel strata are deposited on titled and eroded layers producing an angular discordance with the overlying horizontal layers
What is a disconformity?
An unconformity between parallel layers of sedimentary rocks which represents a period of erosion and non-deposition.
What is a non-conformity?
A non-conformity exists between sedimentary rocks and metamorphic or igneous rocks when the sedimentary rock lies above and was deposited on the pre-existing and eroded metamorphic or igneous rock.
What is the Principle of Cross-Cutting Relationships?
This does three things: 1. A fault is younger than the youngest rock it cuts. 2. the strata above an unconformity are younger than the strata below 3. any feature that cuts across a rock must be younger than the rock it cuts
What is the Principle of Faunal Succession? Who first found the reasons for this principle?
The age of rock layers based on the fossils found in them, which was similar across multiple geographies, found by canal engineer William Smith.
What are “Eras”?
Long intervals of geologic time separated by major extinction events.
Who discovered that atoms of some chemical elements are inherently unstable and breakdown?
Henri Bequerel
What does the atomic number of an element represent?
The number of protons in the nucleus.
What does the Atomic Mass of an element represent?
The number of protons plus the number of neutrons.
What are isotopes?
Atoms of the same element that differ in their number of neutrons in the nucleus?
What are the three described ways in which an isotope can decay?
1.either a proton or a neutron will turn into the other. 2. Two Neutrons and two protons bound tightly together eject from the element (alpha particle) 3. Fission: a neutron CRASHES into a nucleus and make it break into two smaller particles with different weights
What is the parent and daughter in the case of radioactive decay?
Parent = original, daughter = new isotope
What is a half-life?
The period of time in which exactly half of the nuclei of a species of radioactive substance would decay
Describe the process where we date organic matter?
A process called carbon dating where we use Carbon 14 and Carbon 12(the latter does not decay), carbon 14 is radiactive and has a half life of 5730 years, thus allowing us to date organic matter up to 50,000 years back.
