Geology 101 notes

What follows are my lecture notes from Mickey Gunther’s Geology 101 course. As these are personal notes, please don’t expect them to be complete in any way, shape, or form. They’re here as an illustrative example of several salient points that will eventually be elaborated on when I find the time.

Actually, they’re here because I want them to be. Just like I’ve always wanted to use the word ‘salient’ in a sentence.

25 August 2004

• Part 1: Overview (2 lectures)
• Part 2: Minerals (2-3 lectures)
• Part 3: Rocks (10 lectures)
• Part 4: Time (1 lecture)
• Part 5: Landforms (10 lectures)
• Part 6: Plates (10 lectures)
• Part 7: Environment (6 lectures)

Objectives

• Introduce the science of geology
• Define minerals and rocks and learn how they’re formed and classified
• Introduce forces that shape the Earth
• Understand how processes on or near the Earth’s surface affect us
• Examine the relationship between geological resources and the environment

27 August 2004

“If you can’t grow it, you have to mine it.”

Part 1: Overview

1. Define geology and it’s subdisciplines
2. The Earth: The BIG Picture

Geology

The study of the planet Earth - the materials of which it is made, the processes that act on those materials, the products that are formed, and the history of the planet and its life forms since its origin.

Physical geology vs. historical geology

• Minerology - the study of minerals
• Petrology - study of rocks
• Geomorphology - study of Earth’s landforms
• Structural - forces that act on rocks
• Paleontology - old life (fossils, no backbones)
• Stratigraphy - layers of rocks

Geology can tie into other disciplines.

• Geo-chemistry
• Geo-physics
• Geo-mathematics
• Geo-biology
• Geo-medicine

[diagram showing how the geological disciplines relate]

[diagram showing the rock cycle]

The Earth: The BIG Picture

People started measuring earthquakes in the ‘40s and '50s and figured out the shape and motion of plates on the Earth.

30 August 2004

Part 2: Minerals

• labs start this week
• take lab books and read chp. 1
• read chp. 3 in text please

1. Motivation: Why bother?
2. Chemistry review
3. Physical properties of minerals and crystal structures
4. Mineral classification and formation

A. Motivation

What do the following have in common?

• sandpaper - (sand sized stuff) made of quartz. Quartz is the most common mineral in the Earth’s crust and a class 1 carcenogen. Now we use garnets.
• brakepads - used to be made of asbestos. Litigation on it = $70 billion per year
• teeth / kidney stones - apatite (cabbage creates kidney stones) bonds with calcium
• money - gold, silver, copper
• quartz watch - squeeze and electricute a chunk of crystal and it will vibrate
• barium milk shakes - x-ray of the stomach and colon
• fertilizer - SE part of Idaho mines apatite to produce phosphates. Phosphate mining is a $1 billion industry.
• water purification / winning WW2 - zealite fills in hard water, removes lead and radioactive elements. Turn oil into gasoline. We developed high octane gasolline before the Germans.
• makeup / paint - clay minerals + coloring (dirt) like what you’d find in a farm field
• engagment rings / lead pencils - carbon, graphite, diamond
• color TV - sphalerite + copper (blue) + cadnium (red) + silver (green)

Good mineral, bad mineral?

• goiter - Where the thyroid gland swells due to lack of iodine (so they added it to table salt) 25% of the world’s population is at risk

Mineral: A naturally occuring homogenous solid with a definite, but not fixed, chemical composition, and a highly ordered atomic arrangment, generally formed by inorganic processes.

1. naturally occuring
2. chemical composition
3. atomic arangment
4. inorganic

Au - gold

NaCl - halite (table salt) p.86

The arangment of atoms defines the shape of the mineral.

muscavite - KAl₂(AlSi₃O₁₀)(OH)₂

Shine x-rays on minerals to see their atomic shape. Inverse finite transform produces the atomic shape (of the x-ray picture).

1 November 2004

Caves and ground water

1. Caves = fun
2. Ground water = $$ and importance

Cave development

1. Cave formation: How do caves form?

   • Mechanical and chemical weathering of carbonates -> limestone, calcite
   • Cracks fill with water and a chemical reaction takes place
   • H₂O + CO₂ + CaCO₃ -> Ca³⁺ + 2HCO^3-
   • The right part of the equation above is acidic

2. Cave formations: How do they form?

   • Percipitation of minerals in the cave (deposition)
   • Stalactites - hang from the ceiling
   • Stalagmites - grow from the floor
   • Columns - when a stalactite and a stalagmite meet
   • Gypsum flowers, hair, needles - form in dryer caves
   • Formations occur due to CO² changes
   • Temperature in a cave is the average yearly temperature in that area
   • Caves are almost 100% humid