Log entry: environmental studies: earth science

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Week 7

ES 101 Laboratory

Week 7 Lab Activities

It’s Not My Fault: Complete Part I and Part III of Faulting Exercise

Complete Parts I and II of Mass Wasting Exercise

My Sediments Exactly: identify the sedimentary rocks in the egg crate using the process and properties described in the lab manual; complete the Sedimentary Rocks Identification Worksheet

Tectonic Landforms

Faults and Fault Landforms

Fault: sharp break in rock with a slippage of the crustal block on one side with respect to the block on the other

Fault lines may extend for many kilometers

Most major faults extend down several kilometers

Fault slippage varies from 1 cm to 15 m

Four main types of faults:

Normal

Transcurrent

Reverse

Overthrust

Tectonic Landforms

Faults and Fault Landforms

Normal faults are produced by crustal extension

Tectonic Landforms

Faults and Fault Landforms

Transcurrent or Strike-slip Faults are produced when tectonic plates move past each other horizontally

Tectonic Landforms

Faults and Fault Landforms

Reverse and overthrust faults are produced by compression in the crust

Tectonic Landforms

Faults and Fault Landforms

Repeated faulting can produce high fault scarps

Landforms are modified by erosion

Mass wasting

Slope stability factors

Mass wasting factors

Parent material (sand, soil, rock, etc.)

Moisture content

Type of strain

Rate of movement

Angle of repose factors

Density

Angularity

Shape

Size

Sedimentary Rock Lab

Sedimentary Rock: rock formed from the accumulation of sediment

Clastic—formed from rock and mineral fragments

Chemically precipitated: formed by chemical precipitation from seawater or salty inland lakes

Organic: formed from organic material

Sediments and Sedimentary Rocks

Rocks and Minerals of the Earth’s Crust

Sediments and Sedimentary Rocks

Sandstone, deposited in layers

Conglomerate

Shale

Chalk, a form of limestone

Rocks and Minerals of the Earth’s Crust

Sediments and Sedimentary Rocks

Coal, a fossil fuel, is an organic sedimentary rock

Fossil Fuels: naturally occurring hydrocarbon compounds produced from remains of organic matter enclosed in rock; examples are coal, petroleum (crude oil), and natural gas

Sedimentary Rock Types

Figure 11.9

Sedimentary rocks – rocks derived from mechanical and chemical external processes … sediments.

Sedimentary Rocks have the following characteristics:

Transported and deposited by wind, water, ice, and gravity, or a combination thereof.

Pressure and cementation consolidates and transfers sediments into sedimentary rocks - Lithification.

Sorted in strata - Stratigraphy.

Particles classified according to

chemical (calcium carbonate

or limestone), mechanical

(shale or sandstone), or organic

formation (coal or chalk).

Making sedimentary rocks

Steps in the process:

Break down rock to make sediments (mechanical, chemical)

Transport the sediments (wind, water)

Deposit the sediments

Lithification

Figure out the rock’s past by looking at its present appearance and characteristics

Sedimentary rock lab

Rock properties and lab activities

Reaction with acid

Hardness (nail scratch)

Size of fragments in rock

Shape of fragments in rock

Size & shape of fragments

Clastic: made up of parts of other rocks

Visible fragments vs. fine-grained (can’t see fragments)

Rock name taken from most abundant size

Sandstone

1.5 mm FOV, PPL

Why bother with sedimentary classification?

Particle size classification

= energy of deposition

Grain type classification

= origin of sediment

Sedimentary rocks come

in more “flavors” than any

other type of rock.

Sorting is a measure of how similar grain sizes are within a sediment or rock and tells us about the relative strength of the current before it dropped (deposited) it cargo.

Sorting:

Roundness & Angularity

Roundness is a rough measure of the distance of transportation

Round is opposite of angular

Diagensis = Sedimentary rock formation

Diagnesis includes

(1) compaction = volume loss (mechanical squeezing) and is accompanied by dewatering (= water loss), by chemical or physical means

(2) changes in mineral composition (chemical process with heat and or fluids)

(3) cementation (physical)

If a sediment eventually becomes a rock we say it is lithified.

Relative abundance of sedimentary and crystalline rocks in the crust and at the surface.

Surface distribution of rock classes in the conterminous United States.

Note that sedimentary rocks dominate the surface (same worldwide).

Remember

To do your Moodle quiz by 11:55 pm on Saturday night

To do your Environmental Events Log by 11:55 pm on Saturday night

To review completed lab exercises for next week’s quiz