The document discusses the significance of geological history in understanding the present and future, highlighting the principle that past geological events occurred similarly to today's events. It explains the use of sedimentary rocks and radioactive isotopes to determine the age of objects, detailing the process of radioactive decay and half-lives of various isotopes. Specific examples are given to illustrate how to calculate the age of ancient bones and rocks using isotopic analysis.

2. I believe that the more you know about
the past, the better you are prepared for
the future.

5. The major assumption of Geology
Events of the past occurred the same way that they
are occurring today.

6. Used to determine whether an object or
event is older or younger than other
objects or events.
Tool: Sedimentary
rocks They are formed from the
fragments of other rock types.
New sedimentary rocks are flat.
Fossils are deposited in these
rocks

10. IDEA OF UNCONFORMITIES

11. Idea Of Unconformities

12. Used to measure the absolute age of an
object or event by analyzing isotopes of
radioactive elements.
Tool: Radioactive
IsotopesIsotopes-Atoms of the same element that
have similar # of p+ but different # of n⁰.
Unstable isotopes that break down stable
isotopes and/ or elements-Radioactive Decay

14. Time needed for half of a sample of a radioactive
substance to undergo radioactive decay.

15. PARENT ISOTOPE HALF- LIFE STABLE DAUGHTER
Uranium-235 704 million years Lead-207
Uranium-238 4.5 billion years Lead-206
Potassium-40 1.25 billion years Argon-40
Thorium-232 14.0 billion years Lead-208
Lutetium-176 35.9 billion years Hafnium-176
Rubidium-87 48.8 billion years Strontium-87
Samarium-147 106 billion years Neodymium-143

16. 1. An Ancient bone was
found and analyze. It
contain Potassium-40
that have decayed for
nearly 2 half- lives. How
old is the bone?
2. An igneous rock
contains ½ of its
original amount of
Potassium-40. how old
is the rock?
2.5 billion years 1.25 billion years
3. If Strontium-147 is
cut into pieces,what
would be the half- life
of each piece?