| West Virginia Master Naturalist Class Description
| Title: |
ROCKS AND MINERALS |
| Objectives: |
Introduce the student to rocks, minerals, and fossils, especially
those most likely to be encountered in West Virginia, and their interpretation
in the light of geological history |
| Class type: |
Elective |
| Time: |
1 to 3 hours |
| Optimal season: |
Spring, summer, fall |
| Materials: |
Rock and mineral samples, dilute hydrochloric (muriatic) acid, hand
lens. |
| Expected outcomes: |
The student will gain a basic understanding of
- the geological history of West Virginia
- the three major rock types and some common minerals.
- using clues such as particle size, shape, and color and fossils
to determine the environment in which sedimentary rocks were deposited.
- how specific rock layers are named.
- how erosion occurs and how it shapes landscapes.
- some common West Virginia fossils and how they were formed.
|
West Virginia Master Naturalist Class Outline
| Title: |
ROCKS AND MINERALS |
| Time: |
1 to 3 hours |
- Introduction.
- Observations of deposits in today's environments is the key
to deciphering the state's ancient geologic history
- Effect of plate tectonics on West Virginia (use West Virginia shaded
relief map)
- North America part of Pangaea, with West Virginia near equator for
millions of years
- Collision of North America and Africa caused folding of rock layers
- Anticlines
- Synclines
- Joints and faults
- Stream erosion created the Mountain State
- Erosion of flat-lying rock layers
- Erosion of folds
- Minerals make up rocks (use mineral samples)
- Two common minerals compared
- Calcite: rhombohedral crystal, hardness 3, fizzes with weak hydrochloric
acid, in limestone
- Quartz: hexagonal crystal, hardness 7, does not react with hydrochloric
acid, in sandstone, shale and conglomerates
- Sedimentary rocks
- 99% of WV rocks are sedimentary
- Sediment (particles) are compressed or naturally cemented together
- Mostly deposited by water in layers, oldest on bottom
- Rocks are named for their particle size and shape
- Shale: mud-sized
- Sandstone: sand-sized
- Conglomerate: mix of mud- to gravel-sized, gravel particles rounded
in shape
- Limestone: calcite precipitated in seas or lakes, or animal or
plant parts
- Coal: from compressed plant materials
- Clues to environment of deposition (where sediments were originally
deposited)
- Particle size indicates speed of water
- Shale: quiet water where tiny particles can settle out
- Sandstone: moderately fast-moving water
- Conglomerate: very fast-moving water
- Particle shape
- Rounded: corners knocked off by abrasion in moving water
- Angular: gravity (landslide) deposit without water flow
- Color
- Red, pink, brown, tan: rusted (oxidized) iron
- Green: iron not exposed to air
- Purple: manganese exposed to air
- Black: carbon-rich (organic)
- Limestone: lake or ocean, thick limestones are tropical ocean reef
deposits
- Coal: tropical swamp with rapid plant growth, no tree rings
- Fossils: most definitive clue, evidence of plants or animals, each
of which lived in a specific environment
- Shells
- Bones
- Plants
- Trace fossils (traces of an organism's activity: burrows, trails,
tracks, borings)
- Interpreting ancient environments
- 300 million year old landscape (birds-eye view)
- From the Piedmont to the deep ocean (horizontal view) Sea level
rise or fall
- Erosion
- Resistance to erosion
- Cement: silica is strongest, iron oxide next, calcite weakest
(soluble)
- Thickness of layers (beds): thicker layers harder to erode
- Rock type
- Sandstone and conglomerate resist erosion, form cliffs
- Shale easily eroded, makes slopes and valleys
- Limestone slowly dissolves in naturally acidic rainwater, makes
valleys
- Naming rock layers (named after the place where they were first studied)
- Period: geologic period, see geologic column and time chart
- Series: 2 or more Groups
- Group: 2 or more Formations
- Formation: can include more than one rock type, has distinctive
easily identifiable features like color or fossils, thick enough to
be mapped on 7.5 minute topographic map
*** DNR *** |
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