Topic/Objective:_______________
Full Name: _______________________________
_____________________________
Class: ___________________
_____________________________
Date: _________________
Tutor Use
Only:
Period: _____
Essential Question:
Geologic Time
Determining geological ages:
 Relative dating – places rocks and geologic events in their proper
____________________, _________________ to ____________________.

Absolute dating – the actual ______________________ age of a particular
geologic event. Example: large dinosaurs died out 65 mya.
Relative age dating assigns a ___________________________ age to a rock, rock
layer or fossil based on its ___________________ in the strata relative to other
rocks, rock layers or fossils. There are laws/principles that help determine the relative
age.
Laws/Principles of Relative dating:
 Law of Uniformitarianism: The ____________________,
__________________, and ______________________ laws that govern
___________________ today have remained constant throughout time.
Summary:

Principle of original horizontality: Layers of _____________________ are
originally deposited _____________________ (flat strata that have not been
disturbed by folding or faulting)

Law of Superposition: in an undeformed
___________________ or sedimentary
or volcanic rocks the __________________
are on the bottom and the
____________________ are on top.

Law of Cross-Cutting Relationships:
An __________________ rock is always
_________________ than the rock layer
than the rock layer that it has
_________________ or
_____________ across. (Note erosional
Features and faults that cut across rock
Layers are always younger.)
Essential Question:

Law of Inclusions (embedded fragments):
States that rocks that are _________________
in another rock must be _________________
than the rock in which it is found.

Law of Unconformities: is a break in the rock record produced by
erosion and/or nondeposition.
o Non conformity: sedimentary
rocks deposited abouve
metamorphic or igneous rocks
indicates time lost.
o Angular unconformity: tilted
rocks overlain by flat-lying
rocks.
o
Disconformity: strata on either side
of the unconformity are parallel but
time is lost.
Rock Layer Correlation:
Correlation is the _____________________ of rock layers from one location to
another.
 Matching rocks in different locations due to their ____________________
characteristics
 _____________ Beds: a distinct layer of rock.
 Stratigraphic Matching
 Index Fossils: __________________ that lived and died in one particular
geologic time.
Summary:
Essential Question:
Index Fossil Requirements:




Be easy to __________________
Have been very ___________________
Have lived in a wide ________________________ area
Have existed for a short __________________ time.
Absolute Age Dating: determining the age of a rock by radio active decay of
certain elements. This provided an actual numerical age for rocks and
particular geological events.
 Half Life:
o Original isotope is called the _________________
o New isotope is known as the _________________ isotope.
 Produced by _______________ decay
 All parent isotopes decay to their daughter isotope at a
specific and unique ____________.
 Based on decay rate, it takes a specific amount of
___________ for one half of the parent isotope to
decay to its daughter.
 Half-live: the time it takes for half of the atoms in the
isotope to decay.
Examples of radiometric dating:
Radiocarbon Dating:
o Useful for dating things that were once living up to
_____________ years ago.
 Tree Ring: Tree rings determine the age of a tree, they also indicate
droughts and excess precipitation and even events like fires.
 Varve: is like tree rings in such that in lakes the amount of fine
sediments deposited correspond to seasons of a year and can be
counted to indicated how many years ago it was deposited.
Summary:
Essential Question:
Summary: