Modern Soil
Stockton Sandstone
Cambrian
Geologic Time
Quaternary
Triassic
Ledger Dolomite
The Scale of Geologic Time
Nicolaus Steno
(1638-1686)
Relative Age
•Principle of Original Horizontality
•Principle of Superposition
•Principle of Original Continuity
Catastrophism – Large
Large--scale Geologic change is
the result of major catastrophes
Georges Cuvier
1769--1832
1769
Uniformitarianism – The laws of
nature do not change
g with time.
James Hutton
(1726 1797)
(1726-1797)
Age of Enlightenment
C t t
Catastrophism
hi
– Large-scale
L
l Geologic
G l i change
h
is
i
the result of major catastrophes
Relative Age
Principle of Faunal Succession
Relative Age
Principle of Inclusion
Relative Age
Principle of Cross-Cutting Relations
Angular Unconformity
Relative Age
Nonconformity
Disconformity
Geologic Column
Geologic Column
Geologic Column
Periodic Table of the Elements
# of Protons
(
(mass)
)
# of Protons + Neutrons
Isotopes
Two or more substances of different
mass (atomic mass) but occupying
the same place in the periodic table
(atomic number).
Radioactive decay
Processes by which an atom
spontaneously
t
l changes
h
iinto
t
another kind of atom
Parent vs. Daughter
Radiometric Dating
U(92) – Th(90)
Alpha Emission
Rb(37) – Sr(38)
Beta Emission
K(19) – Ar(18)
A (18)
Electron Capture
N(7) – C(6)
Positron Emission
Half - Life
Half – Life Rates & Dating
Mass Spectrometer
Varves – thin layers of clay that show
rhythmic changes in lucustrine environments
Ice Layers – seasonal changes in snowfall
and subsequent snowmelt
- Thickness
- Isotopic composition
Tree Rings
Geologic Ages