1. Sedimentary Rocks
Erosion
Transport
Deposition
Lithification
Clastic Sedimentary Rx – from broken pieces
Chemical Sedimentary RX – from dissolved stuff
Biochemical Sedimentary Rx – from dissolved stuff

2. Clastic Sedimentary Rocks – pieces of mins (quartz, feldspars, mica, etc.) & clay
gravel conglomerate
sands sandstone
silt siltstone
clay shale, mudstone
Sizes sorted by transportation

3. Chemical Sedimentary Rocks
Evaporites – Halite, Gypsum
Biochemical Sedimentary Rocks
Limestone - Calcite
Chalk - Calcite
Chert - Quartz

4. Group PRS
In which group of sedimentary rocks do most of the weathering products of most felsic (rhyolitic) rocks end up?
A. Clastic B. Chemical C. Biochemical

5. Metamorphic Rocks – heat and pressure alters other rx
Heat and pressure can come from burial or contact – cause minerals to grow, recrystallize, or change into new mineral. Name of MM rock depends on texture and minerals in it. Minerals depend on protolith and amount of temp & press
Contact MM – due to igneous contact
Regional MM – burial
Foliation – parallel alignment of minerals due to pressure-
not all minerals will do this (mostly micas, feldspars do)

6. MM Rocks include
Marble – MM limestone
Slate – MM shale
Quartzite – MM sandstone
Schist – usually can’t tell protolith

7. You have found a rock. It appears to be composed
of Quartz, Potassium Feldspar, and a little mica.
The minerals have planar irregular boundaries
that appear to interlock with one another like
pieces of a jigsaw puzzle. There is no obvious alignment of any minerals. What is the rock?
A. Igneous B. Sedimentary C. Metamorphic

8. May form from basaltic magma
Form at the earth’s surface
Have texture
Made of small grains
Granite is an example
Form as a result of melting
May form from rhyolitic magma
May form in presence of water
Exposed at surface only after erosion
Contains minerals
Classified based on density of minerals
Dark colored have low silica content
Contains visible grains
both
volcanic
plutonic
both/neither
neither

9. TIME

10. Relative Time vs. Absolute (Numerical) Time
Bishop Ussher – Earth formed 4004 B.C. –October 23 – using Biblical history
GROUP QUESTION: Think of another way to come up with a minimum age for the earth (do not use radioactivity)

11. Atoms

12. Isotopes 6 protons 6 protons 6 protons
6 neutrons 7 neutrons 8 neutrons

13. PRS
If an atom with 19 protons and 20 neutrons is an isotope of Potassium,
Which of the following is another isotope of Potassium?
20 p, 19 n
20 p, 21 n
19 p, 22 n
20 p, 22 n
18 p, 22 n

14. Radioactivity
Parent Daughter

15. Need to know 4 things
Sample had some parent at start
Sample has been “closed system”
Decay rate of parent-daughter pair
Parent-daughter ratio at start
Need to measure 1 thing
Parent-daughter ratio now

17. Industrial revolution added C12 – diluting the C14
Nuclear Bomb Tests added C14

18. C14 Calibration

19. Why don’t geologists use 14 C to date rocks?
Half life is too long
Rocks aren’t closed systems
Rocks don’t have any Carbon
Rocks don’t get carbon from atmosphere
Rocks have too much 14 C

20. K – Ar dating
HL 1.26 BY
Daughter is noble gas

23. (compiled from Dalrymple, 1991)
Technique
Age Range (billion years)
uranium-lead
3.60±0.05
lead-lead
3.56±0.10
3.74±0.12
3.62±0.13
rubidium-strontium
3.64±0.06
3.62±0.14
3.67±0.09
3.66±0.10
3.61±0.22
3.56±0.14
lutetium-hafnium
3.55±0.22
samarium-neodymium
3.56±0.20
(compiled from Dalrymple, 1991)

24. Geologic Time Scale
Pieced together through correlation
Dates come from radioactivity

25. Correct answer for 8.3
Youngest J E C A G B I D F H
Oldest