ASBOG - General and Field Geology (20%)
(28 Questions And Answers )
Younger layers of rock sit
atop older layers
Law of Superposition
Layers of sedimentary
rock are initially deposited
Law of Initial Horizontality flat in layers.
the fossil assemblage ex-
isting within a rock speci-
men can be used to deter-
relative age dating
mine upper and lower pos-
sible age. Gives age range.
Example: 100 to 200 mya.
the process of measuring
the absolute age of geo-
logic material by measur-
radiometric dating ing the concentrations of
radioactive isotopes and
their decay products. Can
give exact date.
, ASBOG - General and Field Geology (20%)
(28 Questions And Answers )
A method for determining
the age of rocks based
on properties relating to
paleomagnetic dating
changes in the patterns
of Earth's magnetism over
time.
Carbon-14 or radiocarbon dates up to 60,000 years.
Potassium-argon isotope greater than 100,000
dating years old
date carbonate materials
Uranium-thorium dating that are younger than
about 500,000 years
Rubidium-Strontium iso- igneous materials over 10
tope dating million years old
date between 1 million and
Uranium-lead isotopes
4.5 billion years old
geologic time scale
, first appearance of inverte-
brates
Paleozoic
appearance of reptiles
Mesozoic Era
Appearance of mammals
and man
Cenozoic Era
Geologic formation named
based on the specific loca-
Type section
tion or area where the for-
mation is best exposed or
(28 Questions And Answers )
Younger layers of rock sit
atop older layers
Law of Superposition
Layers of sedimentary
rock are initially deposited
Law of Initial Horizontality flat in layers.
the fossil assemblage ex-
isting within a rock speci-
men can be used to deter-
relative age dating
mine upper and lower pos-
sible age. Gives age range.
Example: 100 to 200 mya.
the process of measuring
the absolute age of geo-
logic material by measur-
radiometric dating ing the concentrations of
radioactive isotopes and
their decay products. Can
give exact date.
, ASBOG - General and Field Geology (20%)
(28 Questions And Answers )
A method for determining
the age of rocks based
on properties relating to
paleomagnetic dating
changes in the patterns
of Earth's magnetism over
time.
Carbon-14 or radiocarbon dates up to 60,000 years.
Potassium-argon isotope greater than 100,000
dating years old
date carbonate materials
Uranium-thorium dating that are younger than
about 500,000 years
Rubidium-Strontium iso- igneous materials over 10
tope dating million years old
date between 1 million and
Uranium-lead isotopes
4.5 billion years old
geologic time scale
, first appearance of inverte-
brates
Paleozoic
appearance of reptiles
Mesozoic Era
Appearance of mammals
and man
Cenozoic Era
Geologic formation named
based on the specific loca-
Type section
tion or area where the for-
mation is best exposed or
