RELATIVE AGE DATING

THE FOUNDERS OF GEOLOGY

A. The Early Greeks and other cultures—volcanoes and earthquakes caused By the wrath of the gods.

Ex. Vulcan—the god of fire; Plato taught that earthquakes were caused

By the collision of hot and cold gases above the mythical lake-

Tartarus-in a huge cave.

1. Herodotus-the Father of History-485 BC, compared fossil shells on

the banks of the Nile to similar living animals in the river.

2. Aristotle-first to describe infiltration to feed limestone springs

3. Aviccena (pronounced-Iba Sina)-first to describe the origin of mtns;

2 types:erosional such as deep cutting of high plateaus &

constructional like volcanoes.

B. The Dark Ages—Archbishop of Ussher—in the 1600’s he decreed that the

Earth was created on 4004 BC, April 15^th, at 9:30 am—Doctrine of

Catastrophism; the Great Flood.

C. Nicolaus Steno--(1638-1687)--Danish physician who worked for the Grand

Duke of Tuscany in Florence, Italy. Came up with first 3 laws of Geology

1. Principle of Superposition

2. Principle of Original Horizontality

3. Principle of Original Lateral Continuity

D. James Hutton—(1726-1796)-- Father of Geology"taught "The Present is the

Key to the Past"—Doctrine of Uniformitarism; wrote the first geology

Textbook, "Theory of the Earth"; Scottish

E. John Playfair—1802—was Hutton’s friend; wrote a more simple and

Widespread version of Hutton’s book entitled, "Illustrations of the

Huttonian Theory of the Earth"

F. Baron Georges Cuvier—(1769-1832)--Actually the man who came up the

"Doctrine of Catastrophism" to explain sudden changes in the fossil

in strata such as great extinctions and missing strata-unconformities.

G. William Smith—Englishman—(1769-1839); canal builder in England.

Correlated strata based on fossils and rock type. The Geological

Society of London produced his geology map of England, Scotland,

And Wales--"Principle of Biological Succession"

G. Charles Lyell—Englishman--(1797-1875)— follower of Hutton and actually

first to use the term "Uniformitarianism". Classic 5 volume work

"Principles of Geology" became the handbooks of all geologists. Came

up with the "Principle of Cross-cutting Relationships"

H. Charles Darwin--(1809-1882)--went on a 5 year, unpaid trip on the HMS

Beagle (1831-1836) to further his study of biology and geology. Came

up with theory of evolution based on natural selection. He was afraid to

publish his theory but told Lyell. Prior to this geologist could not explain

why fossils changed in the strata. Finally, 23 years later, Lyell convinced

him to publish his book, "Origin of Species"

I. Jean Louis Agassiz—1840—A Swiss engineer who came up with the concept of the Ice Ages—began studies in the USA, as well.

J. Major John Wesley Powell—1869—First explored and described the origin of the Grand Canyon; became the first head of the US Geological Survey in 1877.

GEOLOGIC TIME

GEOLOGIC TIME—The Earth is at least 4.5 billion years old; the rocks beneath MTSU are only about 450 million years old.

The Geologic Time Scale is divided into:

1) Eons; Precambrian represents 85% of the Earth’s history; 4.5 BY to 570 million years ago. Phanerozoic meaning "visible life" is the Cambrian through the Quaternary and is the last 570 million years

2) Eras; Paleozoic (570 my BP)—"Ancient Life"—most rocks in Tennessee; Mesozoic (245 my BP)—"Middle Life"—mostly missing in Tennessee; Cenozoic (65 my BP)—"Recent Life"—sediments of west Tennessee.

3) Periods; Cambrian through Quaternary

4) Epochs; The Tertiary and Quaternary are divided into Epochs; The first Epoch of the Quaternary is the Pleistocene (The Ice Ages). The Pleistocene began 1.6 million years ago and ended just 10,000 years ago, marking the beginning of the Holocene.

THE THREE ROCK GROUPS

A. Igneous—once molten (magma); examples are basalt and granite.

B. Sedimentary—composed of loose particles (sediments) that have been cemented together; examples are limestone, sandstone, shale.

C. Metamorphic—changed by heat and pressure; examples are marble (from limestone), slate (from shale).

THE ROCK CYCLE

A. All the earth was once molten (magma); crystallization of magma forms igneous rocks; magma reaching the surfaces forms Volcanoes which are then eroded down with time.

B. Weathering and erosion of existing rock produces sediments that are deposited in a basin (usually the ocean bottom) and then Lithified through compaction and cementation to form Sedimentary rocks; then uplift to form mountain ranges.

C. Deep burial causes rocks to be changed from the high heat (but not enough to melt the rock) and pressure to produce metamorphic rocks; Tectonic uplift in orogenic zones results in mountain ranges and the whole process begins again.

PLATE TECTONICS

The outer layer of the Earth is called the Crust which is only 6 to 30 miles thick compared with a radius of the earth of 4000 miles. Below the Crust is the solid Mantle and then the Core of the Earth with is composed of a liquid Outer Core and solid Inner Core.

The Crust and uppermost Mantle are called the Lithosphere which is cool and rigid. Below the Lithosphere in the upper Mantle is the Asthenosphere which is hot, much less rigid and capable of flow. Convection heat cells emanating from the Core are believed to be the driving force which moves rigid plates of Lithosphere over the Asthenosphere.

Continental Crust (granite) is thicker than Oceanic Crust (basalt). The cores of Continental Crusts are called Shields.

There are approximately 12 plates on the Earth moving relative to each other at a rate of about 2 inches per year

There are 3 types of plate boundaries:

1) Divergent Boundaries: spreading centers such as the middle of the Atlantic Ocean called the Mid-Atlantic Rift; major areas of lava outpouring along hugh fissures

2) Convergent Boundaries: where 2 plates collide

There are 2 types of Convergent Plate Collisions

a) Oceanic Plate subducting under a Continental Plate. These boundaries are called Subduction Zones and commonly deep ocean trenches form such as the deepest, the Marianes Trench-35,000". Most of the world’s volcanoes form at these boundaries. Example include the Juan de Fuca Plate colliding with the North American Plate causing the volcanoes of the Cascade Mts (Mt. St. Helens)

b) Two Continental Plates colliding—no subduction but rapid uplift of land masses. The India plate is colliding with the Asian Plate causing the formation and rise of the Himalayas.

3) Transform Plate Boundaries are where one plate is sliding by another without subduction or collision

An example of this is where the Pacific Plate is sliding by the N. American Plate along the San Andreas Fault.

Late Precambrian (600 my ago)--One supercontinent existed called Rodinia--By Late Cambrian (550 my ago), most of the continents were in the tropics (no green plants yet).

By the Pennsylvanian (300 my ago), the continents were one and called Pangea; Tennessee was at the equator.

BREAKUP OF PANGEA-THE SUPERCONTINENT

1) Late Jurassic (180 my BP) Europe and N. America (Laurasia) began to split from Gondwanaland.

2) Africa than began to break away from South America about 135 my BP during the early Cretaceous.

3) Then India began to move toward Asia about 80 my years BP during the late Cretaceous.

4) Finally Australia and Antartica broke apart about 40 my years BP during the Eocene Epoch of the Tertiary. From that time to recently, Antartica slowly moved to its present position at the South Pole.

Evidence for Plate Tectonics includes: 1)matching mountain chains, 2) matching fossil records, 3) matching of coasts, 4) magnetic reversals on each side of the Mid-Atlantic Rift

5) matching of glacial record, 6) matching of rock types

ATOMS, ELEMENTS, IONS, MINERALS, & ROCKS

The atom is composed of electrons of negative charge that spin around a nucleus composed of positively charged protons and neutrons of no charge.

Elements represent a unique number of protons and electrons which the number of each being the same so that the atom of the element has no charge.

Elements you need to know for this course are:

Na—Sodium Cl—Chloride

Ca—Calcium C—Carbon

O—Oxygen Si—Silica

S—Sulfur Fe—Iron

Mg—Magnesium Mn---Manganese

Minerals are a unique combination of elements. Mineral formulas you need to know for this course are:

NaCl—Halite "salt" CaCO3—Calcite

SiO2—Quartz FeS2—Pyrite "fools gold"

CaCO4—Gypsum

An ion is a charged particle formed by a chemical reaction such as the dissolving of salt in water

Isotopes of an element differ in the number of neutrons:

A mineral is a unique combination of elements and most

Be naturally occurring to qualify as a mineral

A rock is a combination of 1 or more minerals.

RELATIVE AGE DATING

1. LAW OF SUPERPOSITION--top layer is younger than beds below

2. LAW OF ORIGINAL HORIZONTALITY—sediments are originally deposited as horizontal layers.

3. LAW OF CROSS-CUTTING RELATIONSHIPS

a) Faults younger than the beds

b) Intrusions they cut

Structural Geologic Terms

1. Joints—fractures in rock layers; no displacement of beds; all rocks have them due to uplifting of rocks

2. Faults—break in rock layers

a) Reverse Fault due to compression—collison of plates (Convergent Plate Boundary-ex. Is Cascade Mtns-Mt. St. Helen) A thrust fault is a low angle reverse fault—this is the most Common type in East Tenn.—Valley & Ridge Province

b) Normal Fault due to tension (extension-"pull apart"- Divergent Plate Boundary-ex. Is Mid-Atlantic Ridge. Common in the Basin & Range Province (Nevada)

c) Strike-Slip Fault—plates sliding by one another-Transform Plate Boundary; ex. San Andreas Fault of CA

3. Folds

a) anticline—linear "upbending of rocks". If it is symmetrical (round), it’s called a dome). Ex.—Murfreesboro is in the Nashville Dome although it is the Central Basin Physiographic Province (Inversion of Topography)

b) syncline—linear "downbending of rocks". If it is symmetrical it is called a basin, not to be confused with the physio-graphic term

1. Dip of Rock Beds—the degree of tilting

0º is horizontal layers like around Murfreesboro; 90º represents beds that are vertical

2. Strike of the Rocks—the compass direction that the rocks run as displayed on a geologic map

STANDARD GEOLOGIC SYMBOLS

SHALE SANDSTONE

LIMESTONE IGNEOUS

METAMOR.

RELATIVE AGE DATING (continued)

4. Types of Unconformities—an unconformity represents a time of erosion or non-deposition

a) Angular Unconformity

b) Disconformity—most common but less conspicuous;layers on either side are parallel

c) Nonconformity—the time break separates older igneous or metamorphic rocks from overlying sedimentary rocks

4. Principle of Strata Correlation

a) Matching of rock layers of similar age and type from different areas

5. Principle of Faunal Succession-matching of rock layers by the type of fossils found

a) Index Fossils—evolution of life

b) Fossils come as molds or casts

RADIOACTIVE AGE DATING

1. Based on the decay rate (half-life) of radioactive isotopes

2. First applied to rocks in 1905

3. Not all rocks can be age-dated; igneous are the best

SEDIMENTARY ROCKS

I. Products of weathering (sand, silt, clay, gravel) are deposited as sediments; than lithified to become rock

A) Lithification occurs through compaction and cementation

II. Classification

A) Detrital Sedimentary Rocks

1. Gravel—conglomerate

2. Sand—sandstone

3. Silt—siltstone

4. Clay—shale

B) Chemical Sedimentary Rocks

1. Biochemical—limestone (CaCO3-calcite), chalk, coquina, coal, chert (SiO2-quartz)

coal begins as peat and then upon compactions becomes lignite, than bituminous coal, and then if

metamorphosed becomes anthracite coal

2. Inorganic—travertine (calcite); cave formations

3. Evaporites

a) rock salt (halite) NaCl

b) rock gypsum (CaSO4)

SEDIMENTARY ENVIRONMENTS

I. Types of Environments

A) Deltas—Facies Changes-clay, silt, peat, sand

1) A facies is a contemporaneous but lithologically distinct sediment from the same region

2) Facies changes are due to geographic coastline shifts of the depositional environments

a) Transgression—sea invades the land (onlap) due to ocean bottom uplift or land subsidence

b) Regression—sea retreats (offlap) due to ocean bottom subsidence or mountain building forces on land

B) Alluvial Fans—Desert regions of Nevada-course gravels and sand

C) Eolian—Sand dunes and windblown silt (loess)

D) Carbonate—Florida Keys, Bahamas; reef and assorted deposits of Limestone

E) Lakes—Varved Clays

TYPES OF BEDFORMS

I. Bedforms are surface features on strata that give a clue as to the deposional Environment in which the beds were formed

A. Ripple Marks

1) Current Ripple Marks—water moved one way such as in a river

2) Oscillation Ripple Marks—water moved back and forth like on a beach

B. Mudcracks—wetting and drying cycles—areas influenced by the tides

C. Cross-beds-moving sand dunes or submarine sand bars

D. Scour or Sole Marks—from submarine landslide

E. Animal Footprints

GEOLOGY OF TENNESSEE

I. There are 6 major physiographic provinces; from east

To west these are:

A. Blue Ridge (Unaka Mtns)—PreCambrian gneiss,

Schists, slates, and granite.

B. Valley and Ridge—primarily Cambrian and

Ordovician limestones, dolomites, sandstones,

And shales; the valleys are usually limestone

And dolomite or shale; the ridges are usually

Sandstone or sandy dolomite. The rocks are

Folded and faulted; thrust faults are most

Common. Knox Group (3000’ thick)

C. Cumberland Plateau—Pennsylvanian-aged coal,

Conglomerates (Sewannee), sandstones, and

shale

D. Eastern and Western Highland Rim—Mississipp

Ian-aged rocks; primarily limestone.

E. Central Basin—Ordovician-aged limestones

MTSU is underlain by Ridley Limestone.

Beneath that is the Pierce Limestone

(shaly), and beneath that is the

Murfreesboro Limestone (main aquifer).

F. Coastal Plain—Cretaceous, Tertiary, and

Quaternary (recent) unconsolidated sands with

Some clays. Memphis sand aquifer

DESCRIBING IGNEOUS ROCKS

Igneous rocks form from the crystallization of molten rock called magma

If the magma is extruded to the earth’s surface (volcano), the rocks have a fined-grained texture and are called Extrusive Igneous Rocks

The most common types of extrusive rocks are basalt(black) and rhyolite (red)

If the magma cools inside of the earth, a pluton is formed and the rocks are called Intrusive Igneous Rocks; they have a coarse texture and you can

see individual crystals; granite is an example

Magma is composed primarily of Silica (Si), Oxygen (O), Aluminum (Al), Sodium (Na), Potassium (K), Calcium (Ca), Iron (Fe), Magnesium (Mg), Volatiles (gases) and trace elements (gold, silver, platinum, etc)

I. Igneous Texture—size and arrangement of interlocking crystals

A) Apanitic—fine-grained; crystals too small to see-basalt

Vesicles—voids left by escaping gases as the magma cools

B) Phaneritic—crystals can be seen and are about the same size-granite

C) Porphyritic Texture—mixture of larger crystals called phenocrysts in a matrix of smaller crystals called ground mass

D) Glassy Texture—rapid cooling; commonly from lava pouring in the ocean or a submarine eruption---Obsidian—volcanic glass

E) Pyroclastic Texture—combination of textures with various amounts of ash, cinder, molten blobs, and/or large angular blocks from a violent eruption

II. Types of Lava Flows

A) Pahoehoe-very fluid, fast-moving; have a ropey appearance when cooled; composed of little quartz and called Mafic—Basalt

Mafic—ferromagnesian—dark colored; little quartz

Felsic—non-ferromagnesian-light colored; lots of quartz

B) Aa—viscous, slow moving flows; cools to form jagged surface with sharp spines

III. Ash Flows: combination of fine silica rich particles and gases

A) Nuees Ardentes—a particularly fast moving destructive glowing cloud of white hot fragments and gases

Ex. St. Pierre, Martinique and Mt. St. Helens

IV. Pyroclastic Material: material ejected solid from a volcano; also called Tephra

A) Ash—the smallest size; less than ¼ inch in size

B) Cinder- between ¼" and 1¼" in size

C) Blocks—greater than 1¼" in size

D) Bombs—same size as blocks but thrown out molten

VOLCANOES

I. Types of Volcanoes

A. Shield Volcanoes—all lava flows; the largest in size; very broad with shallow slopes of less than 10%

Ex.—Kilauea, Hawaii

B. Cinder Cone—all pyroclastic material; greater than 30% slopes; steep sides but these are the smallest types; there are literally hundreds throughout the west

Ex.—Sunset Crater, Arizona

C. Composite or Strato- Volcano—alternating lava flows with pyroclastic flows or eruptions

Ex. Mt. St. Helens, Oregon; Mt. Rainer, WA

D. Plug Domes--Mono Craters; Mammoth Lake

II. Fissure Eruptions—massive outpourings of lava along a fissure or fault

A. Forms Basalt Plateaus in many cases

1. The Deccan Plateau of India—likely killed the dinosaurs and 70% of life; eruptions in Brazil at the same time; evidence:

a. Great CO2; 3 million years

b. Iridium found throughout up to 5’ofclay

c. Antimony and Arsenic also found clays

(found in volcanic ash, not meteorites

2.The Traps of Russia; end of Permian; 90% of life became extinct

3. The Snake Plains of southern Idaho

The Columbia Plateau of Idaho, Oregon, & WA

B. Asteroid Theory on Dinosaur Extinction

1. Iridium present in meteorites; rare in crust 2. Tektites found in the clay

3. Soot on top of clay from widespread fires

4. 100 mi. wide crater known in Yucatan(bur.)

C. Planet X-10^th planet that would explain orbits of

Neptune and Uranus; 56 my orbit around sun

1. Twice (every 28 my) it would pass through a

cloud of comets (Oort Cloud); deflecting

comets toward earth.

2. Extinctions to some degree appear to

regularly occur every 26 my or so

III. Examples of Eruptions

A. Hawaii-Mauna Loa-quiet, pahoehoe flows of basalt; on-going; shield volcano; over a hot spot

B. Mt. St. Helens-1980, Washington; violent pyroclastic eruption; nuees ardente, pyroclastic flows, and mudflows

C. Paricutin, Mexico—1943—small cinder cone

D. Krakatoa—1882—violent pyroclastic eruption; tsunami killed 36,000; Indonesia area

E. Mt. Pelee, Martinique Island—Caribbean-1902—deadly nuees ardente

F. Laki, Iceland—1783—layer of dust worldwide that cooled down the Earth producing a severe winter; Iceland is on the Mid-Atlantic Rift

G. Santorini—1500 BC—believed to be the Lost Continent of Atlantis

There was once 1 large island but now only 5 small islands. The age-dating of the eruption corresponds with the time Plato said Atlantis was "lost"; The people of Atlantis are believed to have been the Minoan civilization

Up to 180 feet of ash and cinder fell and the tsunami wiped out everyone else along the shores of Crete and Greece; A caldera 10 miles across was formed that now ocean liners take tourists through

IV. Craters and Calderas

A. Craters are of 2 types: Explosion and Collapse

If the "hole" is less than about 1 mile across, it is called a crater

B. Caldera—the size of the "hole" is greater than 1 mile across. These form primarily from subsidence, but can be from hugh explosions like Santorini

V. Fumaroles—the vent issues hot gases for long periods of time;Mt. Fuji,

VI. Geographic Distribution of Volcanoes

A. Most volcanoes are located on Convergent Plate boundaries ("Ring of Fire"); most fissure eruptions

Occur along Divergent Plate boundaries such as the

Mid-Atlantic Rift

B. Some volcanoes are referred to as Intraplate Eruptions believed due to plates moving over stationary Hot Spots in the Earth

1. Evidence from Hawaii

2. Evidence from Idaho and Yellowstone (Yellowstone has had 3 feet of uplift in the last 50 years)

VII. Predicting Volcanic Eruptions

A. More tremors B. Ground temperature

C. Tilt of Cone (bulging of earth)

D. > temperature of fumarole gases

E. Greater levels of carbon dioxide

F. Loss of magmatic magnetism

G. Geologists leave town

VIII. Hot Springs and Geysers

IX. Geothermal Energy—Boise, Idaho; Iceland; The Geysers, CA

INTRUSIVE IGNEOUS BODIES

I. Pluton—any body of intrusive igneous rock—usually granite; Named for the Roman god of the underworld

II. Heat Sources for Magma

A) Original heat of formation of the Earth

Geothermal Gradient is 1 degree per 100 feet

B) Radioactive decay

C) Pressure release-friction from faulting—Plate boundaries

III. Discordant versus Concordant

A) Discordant—pluton cuts across existing rock; layers if sedimentary

B) Concordant—pluton does not cut across the pre-existing rock

IV. Lenticular, Tabular, and Massive

A) Lenticular—lense shaped—concordant

B) Tabular—"table top" shaped—concordant

C) Massive—large irregular shape—discordant

V. Types of Plutons

A) Dike—tabular and discordant

B) Sill—tabular and concordant

C) Laccolith—lenticular and concordant

D) Stock—massive and discordant; <100 km² exposed

E) Batholith—massive and discordant; > 100 km² exposed

1) Ex.-- Idaho Batholith and Sierra Nevada Batholith, CA

VI. Dating of Plutons

A) Relative Dating

B) Absolute Dating

WEATHERING

WEATHERING is defined as the Disintegration and Decomposition of Rock In Place

Weathering is the first step in the process of erosion and transportation of sediment, as well as, the formation of soil.

A. Factors affecting Weathering

1. Rock structures—joints

2. Climate—type of weathering and rate of weathering

3. Topography—relief

4. Vegetation—physical and biological forces

5. Organisms—primarily physical

B. Types of Weathering

1. Physical—Disintegration

2. Chemical—Decomposition

C. Physical Weathering Processes

1. Crystal Growth

a. Ice—frost heaving (congeliturbation)—stirring of soil frost wedging (congelitafaction)—formation of talus

slopes at the base of cliffs

needle ice—called pipkraka

b. Salts—halite and gypsum

c. Spring sapping—forms shelter caves out west

2. Expansion due to Unloading—called exfoliation and forms granite domes; symmetrical breaking of rock along sheet joints due to the reduction of lithostatic pressure as cover is removed

3. Thermal Expansion—causes granular disintegration particularly of granitic rocks composed of different crystal types—differential

expansion and contraction of crystals—forms Grus

particularly effective in deserts of high elevation

a) Grus is a type of poor soil formed on granite and composed primarily of the crystals that make up granite

4. Organisms—tree roots, burrowing animals, decay products of dead organisms

1) Humans—growth and digging

D. Chemical Weathering

1. Oxidation—rusting of iron; addition of oxygen to another element

2. Hydrolysis—chemical combination of water and silicates to form clay minerals such as kaolinite

3. Hydration—the physical bonding of water to a mineral; this causes clays like montmorrilinite to expand-sheet minerals; also transforms anhydrite to gypsum

4. Dissolution—the dissolving of a mineral; ions removed from the minerals are put into solution; this process forms caves

E. Rates of Weathering

1. Depends primarily on what minerals (rock) types are present, the amount of rainfall, and the number of joints and bedding planes

ex. Limestone (calcite) dissolves very fast; Central Basin—6 to 10 million years to form from former flat surface

Shales are thin-bedded and easily break

Sandstones (quartz) is very hard and resistant to weathering;

As a result, in East TN (Valley and Ridge) sandstone usually caps the mountains and limestone and shale are found in the Valleys

Granite is very resistant to weathering and forms the core of many Mountain ranges such as in Colorado, Idaho, and N. Carolina.

Basalt (lava) Flows are resistant and cap many hills (Mesa’s) out West.

F. Depth of Weathering

1. Depends on the depth to the watertable and the amount of rainfall

a) the deeper to the watertable the deeper weathering will occur due to oxygen and carbon dioxide (carbonic acid)

G. Differential Weathering—the reason we have differences in topography

SOILS

I. Regolith—layer of broken up rock and mineral fragments above the bedrock

The uppermost part of the regolith is commonly referred to as the soil.

Humus is the decayed remains of animals and plant life

II. Soil Texture—Distribution of grain sizes; clay, silt, and sand; Loam is a nearly equal mixture of grain sizes

A) Soil Peds—natural shapes in which soil break apart

B) Soil Structure—the form of the peds

1) Platy, Prismatic, Blocky, Spheroidal

III. Controls on Soil Formation

A) Parent Material: Residual Soils-most common

Transported Soils

B) Time

C) Climate

D) Plants and Animals

E) Slope

IV. Soil Horizons—layers in the soil that have developed through time by physical, chemical, and biological processes.

O—partially decayed plant & animal material-

humus; very thin

A—the "top soil"—zone of maximum leaching (chemical) and eluviation (physical) "washing" downward of the fine-grained material

B—the "subsoil"—zone of maximum accumulation

Soil Pans—hard layers in the soil

Laterite—aluminum and iron rich

Fragipan—clay rich

Caliche—calcite and/or quartz rich

C—weathered bedrock

D—bedrock

V. General Soil Types

1. Pedalfers—wet, moist areas of the country;east of the Miss.; fragipans common

2. Pedocals—dry climate soils of the west;caliche common

3. Latisols—tropical soils; severely leached;

few minerals; poor soils, laterite (bauxite) pans

4. Permafrost soils—tundra, dark boggy soils

5. Buried Soils—volcanic, glacial, alluvial

VI. Soil Erosion

A. Raindrops—set soil in motion

B. Sheetwash—unchannized soil erosion

C. Rillwash—channized soil erosion

D. Dust Bowl—dried up soil blew away; loess

West TN is suffering severe soil erosion due to soil particle size (silt) and continued farming. Sheep and

Goats are the worst animals in regards to soil erosion.

MASS-WASTING (MASS MOVEMENT)

I. Mass Wasting—mass movement of earth and rock material down a slope under the influence of gravity.

A. Controls on mass-wasting.

1. Role of water

a. as a thin film-high surface tension

b. more water—more water

c. more water—more hydrostatic pressure

d. lubrication

e. spontaneous liquifaction—shaking

usually by earthquakes that causes

"liquid-filled" sediment to flow

2. Angle of Repose—critical angle that loose

material can obtain; 25 to 40 degrees.

II. Classification of Mass Wasting

A. Type of material:

1. Rock; ex.-rock slide

2. Earth; ex.-earth flow

3. Debris-mixture of earth and rock; ex.-debris

flow.

B. Style of Motion:

1. Fall, slide, flow, subside (collapse)

III. Rockfalls

A. Talus slopes—freeze thaw

B. Undercutting by streams or ocean

IV. Rockslide/rock avalanches

A. Common where dip slopes have a porous

Material over an impermeable shale

V. Slump

A. Unconsolidated material moving as a unit

Along a curved surface.

B. Common along roads where the "toe" of the

Slump has been cut away. Terracettes

Develop indicating several slumping events

VI. Mudflows

A. Confined to a channel; relatively rapid involving

Flow of earth material containing large volume

Of water. More common in arid areas.

B. Lahar—special type of mudflow caused by

Eruption of volcanic ash on snow and ice on

The sides of the cone.

VII. Earthflows

A. Humid areas; not confined to channels; result

Of excessive rainfall or snowfall; common at

The toe of slumps or sides of pastures

B. Hummocky topography is indicative of these

VIII. Creep

A. Soil and rock creep—imperceptibly slow

Movement of material down a slop due to:

Freeze-thaw, expansion of clays, and organism

1. Takes very little slope to initiate.

B. Causes more monetary damage nationwide than

Other types of mass-wasting.

C. Causes slow damage to buildings

D. Indications of creep: tilted trees or telephone

Poles; tilted or cracked walls

IX. Engineering Solutions to Mass-Wasting

A. Retaining walls; concrete cribbing; stone-

Filled baskets, or driven piles—restores the

Toe of the slope

B. Rock bolts

C. Injection of cement (grout)

D. Vegetation—deep routed

E. "Steps" on the sides of the roads

F. Drainage control

G. Lower the water table

1. horizontal drain pipes

2. cap or cover with impermeable material

RUNNING WATER AND GROUND WATER--CHAPTER 5

I. Hydrology--the study of water

A. Surface water--Civil and Environmental Engineers

B. Ground Water--Hydrogeologists

C. The Hydrologic Cycle--description of the exchange of water on the planet from liquid, gas, and solid

1. Three Reservoirs of Water

a. Ocean- 97.3%

b. Continent-2.7%

c. Atmosphere-0.01%

2. P=ET +R+I The Hydrologic Budget Equation

a. P=precipitation

b. ET=evapotranspiration; transpiration is evaporation from plants;

generally greater than 70% of total P

c. R=runoff; stream flow called discharge; generally about 25% of total P

d. I=infiltration; this is recharge to aquifers; 5% or less of P

II. Uses of Water

A. People; 100 gpd per person or 36,500 gallons/year

B. Industry; 250 billion gallons per day; 90-95% for cooling

examples: 200 tons of water for 1 ton of steel

20 tons of water for 1 ton of gas

2 tons of water for 1 ton of bricks

C. Agriculture--the largest users of water; for IRRIGATION-often polluted with pesticides, herbicides, and nutrients such as nitrate

III. MECHANICS OF STREAMS

A. DISCHARGE; Q= VA; Q IS DISCHARGE IN CUBIC FEET PER SECOND (CFS)

V IS VELOCITY IF FEET PER SEC (FT/SEC)

A IS CROSS-SECTIONAL AREA IN FEET SQUARED (WIDTH X DEPTH)

EX. V= 5 ft/sec Width=20 FT, DEPTH=5 FT

Q= 500 CFS

A STREAM IS FED BY GROUND WATER; THAT IS WHY IT CONTINUES TO FLOW AFTER LONG PERIODS OF NO RAINFALL

B. VELOCITY OF STREAMS; fastest on top, slowest on bottom; slowest on inside of meander, fastest on outside of meander

C. STREAM CHARACTERISTICS

1. GRADIENT-STEEPNESS OF STREAM (FT DROP PER MILE); GREATEST AT HEAD

2. BASE LEVEL; the level to which a stream can erode

OCEAN--UTLIMATE BASE LEVEL

LAKES--TEMPORARY BASE LEVEL

3. DEGRADATING STREAM--one that is eroding its channel

4. AGGRADATING STREAM--one that is not downcutting but is building up stream deposits (alluvium)--ROUNDED SEDIMENT

5. GRADED STREAM--one capable of carrying off its load(sediments washed into stream during storms);

streams in humid areas are usually graded

D. EROSION

1. CORROSION--THE DISSOLVED LOAD

2. CORRASION--THE SEDIMENT LOAD;CLAY, SILT, SAND, AND GRAVEL

a. Suspended Load--clay size

b. Bedload--silt and bigger size

1. Saltation--bouncing & rolling bedload

3. Stream COMPETENCE--largest particle size a stream can carry; depends on velocity

4. Stream CAPACITY--the amount of load a stream can carry.depends on discharge

IV. RIVER VALLEYS

A. DRAINAGE BASIN OR WATERSHED;

Separated by DIVIDES--The Great Divide/Rockies

B. Rivers create valleys by:

1. HEADWARD EROSION—LENGTHENS

RIVERS

2. DOWNCUTTING--Deepens rivers

3. MASS-WASTING/UNDERCUTTING--WIDENS river valleys

C. Processes of Surface Erosion: Raindrop splatter/sheetwash(no channel)/ rillwash(channelized)

D. Rates of Erosion

1) Affected by relief, amount of rainfall, and vegetal cover

2) Can be measured direction--steaks in ground or

indirectly--dissolved load, plus bedload & suspended load at mouth of basin

E. EROSIONAL CYCLES

1). YOUTH-waterfalls, rapids, steep valley walls

2) MATURITY-V-shaped profile, MAXIMUM RELIEF, well developed stream network

3) OLD AGE-flat erosional surface called a PENEPLAIN

MONADNOCK--erosional remnant(hill or mtn) on a peneplain

Believed due to standstills of base level and no uplift of mountains

REJUVENATION--renewed uplift that begins an erosional cycle over

THEORY OF DYNAMIC EQUILIBRIUM--the Earth is too unstable and dynamic to ever have a complete erosional cycle take place.

F. DRAINAGE PATTERNS--Important tool for interpreting the geology and geologic structures

1. TRELLIS--TN Valley and Ridge Province/folded areas

2. RECTANGULAR--strong fracture control-- streams follow joints and fractures

3. RADIAL--Volcano or Granite Dome

4. Centripetal--Sinkhole or Enclosed Basin such as in the Basin and Range Province of Nevada

5. DENDRITIC--MOST COMMON PATTERN or really lack of pattern--like "veins" of a feather/unconsolidated sediments like in West TN or flat lying rocks without predominant fractures (Cumberland Plateau).

6. ANNULAR--Domes with various sedimentary rocks of varying resistance to weathering and erosion.

V. STREAMS AND STREAM DEPOSITS

A. FLOOD-PLAIN RIVERS--most common in humid areas like TN river or Miss River

1. Such streams are graded and can carry off the sediment supplied//they have broad meanders

2. Alluvial Deposits:

a) Natural levees-due to floods over banks

b) Swamps

c)Channel deposits--POINT BAR

3. Meanders

a. Meander Cut-offs; OXBOW LAKES

4. YAZOO STREAMS--parallel main river

5. ENTRENCHED MEANDERS—from rejuvenation

B. BRAIDED RIVERS--SHALLOW

1. Lots of inter-channel bars due to the river not being graded

C. ALLUVIAL FANS--where streams come out of mountains and dump load due to lower gradient

D. STREAM TERRACES--CUT IN ROCK OR BUILT OF SEDIMENT

1. Due to base level standstill and then rejuvenation or change in climate/precipitation

E. DELTAS--SHAPED LIKE A FAN OR A BIRDSFOOT

1. The position of the Miss. River Delta has change drastically over the last several million years and

would like to change position NOW

GROUND WATER

I. INTRODUCTION

Ground water (GW) is 14% of all freshwater
GW is 94% of all freshwater if you exclude the Antarctic and Greenland icecaps & other glaciers
GW exits in porous and permeable geologic units called aquifers.
"STREAMS" VS REALITY

Nearly all wells obtain water from tiny interconnected pores and fractures not underground streams.
Only in KARST areas (limestone and dolomite) do a few wells actually hit a cave stream.

TYPES OF GROUND WATER

METEORIC—infiltrated rainwater that has recharged aquifers—potable(drinkable)
CONNATE/BRINES—original water of depostion; usually ocean water and very salty
JUVENILE---water from volcanic expulsion

UNCONFINED AQUIFERS-the water is not held under pressure; generally the shallow ground water

CONFINED AQUIFERS(ARTESIAN)-the water is held beneath a confining layer called an aquiclude (ex. Shale/clay)

What type of earth materials make good aquifers?

Those with good porosity and permeability such as unconsolidated sands, sandstones, or limestones with solution enlarged fractures and caves

Porosity= volume of voids

Volume of material usually 5 to 30%

Types of Porosity

INTERGRANULAR—unconsolidated sands & gravels.
FRACTURE—most rock types
CAVITY OR SOLUTION—limestone & dolomite
BEDDING PLANE—most sedimentary rocks

PERMEABILITY—a measure of the rate of ground water flow in ft/day or ft/year and is related to the amount of the interconnectedness of pores or fractures.

Most GW moves very slow (less than 1000 ft/year.
Most GW is very old, particularly in confined aquifers. Much GW is thousands and some a few million years old. The older, the safer to drink.

Very few well casings are "secure"; therefore surface waters commonly leak down along the side of the casing and pollute the aquifer water below.

II. THE WATER TABLE—UNCONFINED AQUIFERS

A. Zone of Aeration (Vadose Zone) above the water table

B. Then the Capillary Fringe—thin layer of water pulled

Up from the water table against gravity by surface

Tension (capillary forces)—from inches to a couple

Feet.

C. Zone of Saturation (Phreatic Zone)—all pores and

Fractures are filled with water.

D. Most streams are fed by ground water and are the

Surface reflection of the water table—these streams

Are called effluent streams.

1. Influent streams—losing or sinking streams;

common in karst and desert areas

III. CONFINED AQUIFERS

A. Many aquifers are confined; that is the water is held

Under pressure by a confining, impermeable unit

Called an AQUICLUDE; these are commonly shale

Or clay; this ground water is usually very old.

B. Confined aquifers are called artesian because the

Water rises in the well from where it is intersected;

Rarely does the water reach the surface.

1. Pumping of a well causes temporary lowering of

the water table around the well forming a cone

shape thus called the CONE OF DEPRESSION

The amount of lowering in feet is called the

DRAWDOWN

C. RATE OF GROUND WATER MOVEMENT AND

WATER TABLE MAPS

1. HYDRAULIC GRADIENT—the slope of the

water table; this drop in the water table is

measured as feet drop over the horizontal

distance in feet; no units; no units; water tables

are VERY flat thus contaminants move very

slowly in the order of a few feet per year—

except in karst.

GROUND WATER POLLUTION

Water Pollution Control began when Nixon signed EPA into law in 1970.

TDEC-TN Dept. of Environment and Conservation: composed of Divisions like Superfund, RCRA, Water Pollution Control, and Water Supply. Within divisions there are sections like Ground Water Management

Laws protecting GW are relatively recent. Love Canal (1976) caused Jimmy Carter to Pass the Superfund and RCRA (Resource Conservation and Recovery Act) to deal with hazardous waste dump sites

SUPERFUND (CERCLA)—Emergency response to newly discovered dump sites with the pollutors are unknown; now this program also responds to highway and railroad tanker spills of hazardous substances; use to be paid for by a tax on petrochemical industrials, but now the costs by former collections from industry and our tax dollars as well as the companies that caused the problem if still in business.

RCRA—this State and EPA program has 3 divisions

Solid Waste (non-hazardous) landfills
Hazardous Waste – generators and treaters of hazardous waste—RCRA requires a MANIFEST which is a "cradle to grave" tracking of hazardous waste. One of the most common industrial contaminants is TCE-Tricloroethylene, which is a degreasers (solvent).
Underground Storage Tank (UST) Program—gas stations; most of the cleanup costs come from a tax on gasoline (UST Trust Fund).
Underground Injection Control (UIC) Program-injection of waste/common of brines associated with pumping oil out of the ground/ includes sinkholes modified to accept stormwater

TODAY’S LANDFILL VS YESTERDAY’S DUMPS/The NIMBY Principle (Not in My Backyard)

Todays landfills are required a double liner, a leachate collection system, and a monitoring well system to detect contaminants if the liner leaks.
Leachate is the "nasty" liquid usually rich in metals that can emerge from the toe of a landfill
Incineration vs landfilling
Ocean disposal vs landfilling; there is a greater dilution ability of the ocean and air than ground water

OTHER POSSIBLE GROUND WATER POLLUTION SOURCES.

POINT SOURCE VS NON-POINT SOURCE POLLUTION

Waste Lagoons—survey showed 180,000 exits and only about 5% have monitoring wells
Septic tanks-bacteria, nitrate, viruses, GIARDIA AND CRYPTOSPORIDIUM. Generally septic tanks are okay if there is thick soil and its far from a well; FECAL COLIFORM BACTERIA is the indicator parameter for pollution from solid waste of humans or animals
Broken Sewer Lines; COMMON UNSEEN PROBLEM
Recycling: Recycling of aluminum has caused chloride pollution in many states.
Trash in Sinkholes causes pollution of karst springs.
Waste oil dumps at homes; please recycle—don’t be stupid!
FARMS AND GOLF COURSES—PESTICIDES,HERBICIDES, NITRATES—Non-point source pollution as well as is runoff from parking lots; Too much nitrate causes methanamoglobenimea—"Blue Babies Disease"
Chlorinated water;chlorine forms Trihalomethanes (THM’s) which chloroform is one; and estimated 12,000 deaths occur in the US each year due to bladder and rectal cancer from chlorine///this is more cancer deaths than can be attributed to ALL OTHER CARCINOGENS consumed in water supplies;

9. New medical research suggests that a majority of cancers are now believed to be genetic as are allergies versus exposure to chemicals in water or air. One significant exception is RADON which causes lung cancer and is at the top of the EPA list of carcinogens.