Historical
Geology R.
Lopez
1)
What
sets geology as a science apart from other sciences?
2)
What
is Deep Time?
3)
How
old is the Earth?
4)
What
is this age based on, in other words, what did we use to date the origin of the
Solar System and planet Earth?
5)
Know
who made the early estimates of the Earth’s age: Archbishop Ussher, John Jolly.
6)
What
is Uniformitarianism? What is
Actualism? What is the modern view of
Uniformitarianism?
7)
Who
was James Hutton and what was his contribution to geology?
8)
Who
was Charles Lyell and what was his contribution to geology?
9)
Who
was Nicolas Steno and what principles did he conceive?
10)
Describe
Neptuism and Catastrophism. What were
the problems with these hypotheses?
11)
Geologists
deal with two types of ages (i.e. time).
What are they and how do they differ?
12)
Discuss
and apply the principles used to determine relative ages as discussed in
lecture (superposition, original horizontality, lateral continuity,
cross-cutting relations, inclusions or xenoliths).
13)
Name
four primary structures in rocks that can be used to determine if beds have
been overturned (three found in sedimentary rocks and one in lavas)?
14)
What
is an unconformity? Definitely be able
define and distinguish between disconformity, nonconformity, and angular
unconformity?
15)
Be
able to work out the relative ages (youngest to oldest) of the rock units,
unconformities, and faults on diagrams like we did in class.
16)
Who
was Lord Kelvin, how old did he calculate earth to be, and what was his
reasoning?
17)
What
was the final blow to Lord Kelvin’s calculation of a young earth?
18)
Know,
be able to use, and arrange in order the following terms from the geological
time scale (see Appendix page 584):
Precambrian, Hadian, Archean, Proterozoic, Phanerozoic, Paleozoic,
Mesozoic, and Cenozoic. Also know the periods of the Paleozoic,
Mesozoic and two periods of the Cenozoic (Tertiary and Quaternary) as well as
the epochs of the Tertiary and the Quaternary.
19)
What
is the geologic column and what is stratigraphy?
20)
Define
fossils, fossil correlation, and fossil succession (Who was William Smith?)
21)
What
are the two major subdivisions of geologic time?
22)
What
was Lord Kelvin’s argument for a young Earth?
23)
What
is absolute dating based on? Be able to
define “atomic number of element” and mass number of an isotope. What is an isotope? Give some examples of isotopes.
24)
Be
able to explain the concept of half-life using the example of some given number
of parent atoms with a specific half-life (e.g. one hour). Be able to calculate the ratio of parent to
daughter atoms after some given amount of time has passed.
25)
Name
examples of parent-daughter pairs used in absolute dating, and know the
approximate half-life of the parent isotope (see your text Table 6-2 page 165).
26)
The
radioactive parent Carbon-14 isotope decays to the stable daughter isotope of
Nitrogen-14. The half-life of this
isotopic system is 5730 years. If you
measured and Parent/Daughter ratio of 25/75 is a piece of charcoal, how many
half lives have elapsed?
27)
What
is the age of this piece of charcoal?
28)
How
many half lives have elapsed if you measure a P/D ratio of 75/25? Use the U-238/Pb-206 isotopic pair with a half-life
of 4.46 Ga. What is the age of the
sample?
29)
What
is stratigraphic correlation?
30)
What
are radioactive isotopes, radiogenic isotopes, protons, and neutrons?
31)
What
is Half-Life?
32)
Using
our decay equation, determine the age of the following rocks using the
235U-207Pb isotopic system (l = 9.8485x10-10/yr): Sample 1 – D = 2722, N = 85; Sample 2 –
D = 998, N = 555; Sample 3 – D = 122, N = 111; Sample 4 – D = 1555, N = 1001.
1)
Relative time simply deals with the order
of events; no information on how long the events lasted or the length of time
between events.
2)
Absolute time assigns absolute age to
events, usually in “years before present”.
1 Ma = one million years before present.
3)
Superposition: in any sequence of strata
not overturned, the order of deposition is bottom to top.
4)
Original horizontality: water-laid sediments are deposited in strata that are horizontal.
(Note: cross beds are within beds or
strata.)
5)
Use
of inclusions: a rock or sediment containing fragments or
other rocks must be younger than the rocks it contains.
6)
Unconformity: a break or gap in the stratigraphic record. Also, a hiatus; i.e. a lapse in time.
7)
The
nucleus of an atom contains protons
(+ charge) and neutrons (no charge, or you can think of a neutron as having
both a + and – charge which balance each other).
8)
Atomic number: an element is defined by its atomic number, that is the number of
protons in the nucleus of the atom. All
atoms of an element have the same atomic number.
9)
Atomic weight (mass number) of an atom is
the sum of its protons and neutrons.
For example, the most common atoms of oxygen contain eight protons and
eight neutrons, and thus have an atomic weight of 16.
10)
Isotopes: atoms of an element that
contain different numbers of neutrons, and consequently, have different atomic
weights or mass numbers.
11)
Radioactive Isotopes: isotopes that spontaneously
transform into either a more stable isotope of the same element or an isotope
of a different element. Parent isotopes
decay to daughter isotopes.
12)
Half life: time needed for the number
of parent atoms to be reduced by one-half.