GEOL Test 3

cryptocrystalline quartz

"crypto" is Greek for "hidden". quartz (SiO2) grains that are too small to be seen without extreme magnification of an electron microscope (can't see the crystals)

Carbonate Factory - conditions required for coral reefs

- Warm (tropical and subtropical) - Normal salinity marine water - wave agitated - oxygenated - shallow - clear Calcite sand > Calcite mud > Calcite sand > Reef + Reef buildup > Broken fragments of reef

Latitude tropical

0-30

How big are fine grains

0.062-0.0039 mm

Grain shapes - list

1 - Angular quartz grains 2 - rounded quartz grains 3 - well-rounded quartz grains

Classification of Sedimentary rocks - Longer

1 - Clastic or Detrital sedimentary rocks - consists of cemented-together detritus (solid fragments and grains) derived from preexisting rocks 2 - Chemical sedimentary rocks - made up of minerals that precipitate from water solutions 3 - Biochemical sedimentary rocks - made up of the shells of organisms 4 - Organic sedimentary rocks - consist of carbon-rich relics of plants

2 Types of Lithification

1 - Compaction 2 - Cementation

Continental Environments

1 - Lake 2 - Alluvial 3 - Desert 4 -Glacial

Types of Physical (mechanical) weathering

1 - Natural zones of weakness (joints, fractures) 2 - Exfoliation and spheroidal weathering 3 - Root wedging 4 - Frost wedging 5 - Salt wedging 6 - Differential thermal expansion of minerals creates stress in rocks (deserts) 7 - other forces: rivers, glaciers, waves, burrowing creatures (earthworms, gophers, humans)

Grain arrangements - list

1 - Poorly sorted 2 - moderately sorted 3 - well sorted

3 Processes taking place at or just below Earth's surface that contribute to soil formation

1 - animals, plants, microbes, and fungi interact with sediment, absorbing nutrients, and leaving behind their waste and remains 2 - rainwater enters sediments and percolates downward (zone of leaching, zone of accumulation) 3- burrowing organisms like ants, worms, gophers churn the soil so its fabric becomes different from that of the original sediment, and organic material from the ground surface gets mixed in

Chemical effects of chemical weathering on silicates:

1 - it leaches, dissolves away, cations and silicates 2 - it hydrates, or adds water to, the minerals 3 - makes the solutions less acidic

Factors of Soil Makeup - List

1 - substrate composition and resistance 2 - climate 3 - slope steepness 4 - duration of soil formation 5 - vegetation type

which horizons make up the one of accumulation

B-horizon

Evaporites - Example

Bonneville Salt Flats, near Great Salt Lake, Utah streams bringing water, carrying trace amounts of dissolved ions, from Utah's Wasatch Mountains into the Salt Lake Basin

Dolostone

CaMg[CO3]^2 differs from limestone in that it contains the mineral dolomite

Common Minerals - Biochemically precipitated sediments

Calcite (CaCO3) Aragonite (CaCO3) Chert - Quartz (SiO4)

2 Types of Weathering

Chemical Physical (mechanical) they help and reinforce each other how these are classified but really there is no clear cut boundary between the 2 types

2 Types of Chert

Chert (rock) made of Cryptocrystalline Quartz (mineral) 1 - Chemical a. Flint b. Jasper c. Petrified Wood d. Agate 2 - Biochemical - from radiolaria

Coarse Particle Size: to Sediment and Rock

Coarse > Gravel - boulder, cobble, pebble (sediment) > Conglomerate (glued) (rock)

Bicarbonate ions cause....

Dissolution and Hydrolysis

The Dust Bowl of the 1930s

During WWI, farmers in the Midwest grew what on land normally used for grazing animals. This intensive farming destroyed the protective cover of vegetation and the hot dry summers began to turn the soil into dust. High winds in 1934 turned an area of some 50 million acres into a giant dust bowl

Chemical Weathering of Silicates - Equation

Equation (written): Feldspar + carbonic acid + water >>>> Kaolinite (clay) + dissolved silica + dissolved potassium + dissolved bicarbonate ion (acidic) Equation (chem): 2 KAlSi3O8 + 2 H2CO3 + H20 >>>>> Al2Si2O5(OH)4 + 4 SiO2 + 2 K+ + 2 HCO3- (acidic)

Iron Types

Fe II (Fe++) = ferrous iron Fe III (Fe+++) = ferric iron

Fine Particle Size: to Sediment and Rock

Fine > Mud - silt (sediment) > Siltstone (rock)

Different Kinds of Chert

Flint Jasper Petrified Wood Agate

where did farmers affected by the dust bowl go

From Oklahoma through New Mexico and Arizona to California From Nebraska through Wyoming and Idaho to Washington

Weathering factors - 1. parent rock properties

From Slow > Fast Weathering Rate: Mineral Solubility: low ie. quartz (slow) > moderate ie. pyroxene, feldspar > high ie. calcite (fast) Rock structure: massive ie. (slow) > some zones of weakness > very fractured or thinly bedded

Weathering factors - 2. climate

From Slow > Fast Weathering Rate: Rainfall: low (slow) > moderate > heavy (fast) Temperature: cold (slow) > temperate > hot (fast)

Weathering factors - 3. Presence or absence of soil and vegetation

From Slow > Fast Weathering Rate: Thickness of soil layer: none-bare rock (slow) > thin to moderate > thick (fast) Organic activity: sparse (slow) > moderate > abundant (fast

Weathering factors - 4. length of exposure

From Slow > Fast Weathering Rate: short (slow) > moderate > long (fast)

Natural zone of weakness

Joints Fractures gives access to water and other degrading agents

where was the heart of the dust bowl

Kansas Oklahoma Colorado Nebraska some Texas and New Mexico

Are minerals that form early in Bowens reaction series more or less stable

Less stable

2 Types of Limestone

Limestone (rock) made of Calcite (mineral) 1 - Chemical - Travertine 2 - Biochemical - fossiliferous a. chalk (foraminifera) b. micrite

What happened to Earth after 1 bil years

Mars lost its atmosphere - without water, there is no life

Surface to Zone of leaching

Rain enters the ground Tree drops leaves Worms churn Roots dissolve minerals Microbes metabolize soil

Examples of Oxidation

Red and brown iron oxides color weathering in rocks in Monument Valley, Arizona (goes brown to yellow) Mars red surface

Pluvial lakes

presence of ancient pluvial lake or remnants represents period where world's climate was very different from the present-day. Arid areas were extremely wet, and various weather patterns were shown to be important.

What if life on Mars went subsurface?

To answer this question, scientists went to Earth's extreme conditions where they thought life couldn't exist - and they did find life, like bacteria Ex: 5 miles deep in the ocean (dark, no O2, radioactive) Antarctica South African mines

Lake Environment

Transport Agent: lake currents, waves Sediments: sand and mud, saline precipitates in arid climates Climate: arid to humid Organic Processes: freshwater organisms and precipitates

Glacial Environment

Transport Agents: ice, meltwater Sediments: sand, mud, and gravel Climate: cold Organic Processes: little organic activity

Continental Margin Environment

Transport Agents: ocean currents and waves Sediments: mud and sand Organic Processes: deposition of remains of organisms

Deep Sea Environment

Transport Agents: ocean currents, turbidity currents Sediments: mud and sand Organic Processes: depositions of remains of organisms

Alluvial Environment

Transport Agents: river currents Sediments: sand, mud, and gravel Climate: arid to humid Organic Processes: organic matter in muddy flood deposits

Delta Environment

Transport Agents: river currents, waves Sediments: sand and mud Climate: arid to humid Organic Processes: burial of plant debris

Tidal flats Environment

Transport Agents: tidal currents Sediments: sand and mud Climate: arid to humid Organic Processes: organisms mix sediments

Organic Reef Environment

Transport Agents: waves and tides Sediments: calcified organisms Organic Processes: secretion of carbonates by corals and other organisms

Continental Shelf Environment

Transport Agents: waves and tides Sediments: sand and mud Organic Processes: deposition of remains of organisms

Beach Environment

Transport Agents: waves, tidal currents Sediments: sand and gravel Climate: arid to humid Organic Processes: little organic activity

Desert Environment

Transport Agents: wind Sediments: sand and dust Climate: arid Organic Processes: little organic activity

Common Minerals - Clastic Sediments

quartz feldspar clay minerals

residual soil - example

rainforest of Brazil - formed on deeply weathered Precambrian rock

where are the most famous of today's pluvial lakes?

United States Great Basin Area: Bonneville - once covered all of Utah and portions of Idaho and Nevada - formed about 32,000 yrs ago and lasted until around 16,800 years ago Lahontan

Very Fine Particle Size: to Sediment and Rock

Very Fine > Clay (sediment) > Mudstone (blocky fracture), Shale (breaks along bedding), Claystone, Sheets (rock)

Sediments transport agents

Water + wind > currents waves lake currents river currents wind ice meltwater ocean currents turbidity currents tidal currents tides

The process by which feldspar decays is analogous to the brewing of coffee

Water dissolves some of the solid, leaving behind an altered material, and produces a solution containing substances drawn from the original solid. Before: Hot water (input) into fresh ground coffee beans vs. Carbonic acid (input) into the mineral feldspar present in rocks After: spent ground coffee beans and liquid containing caffeine and other substances vs. kaolinite and dissolved silica and potassium and bicarbonate ion

Why is weathering important?

Weathering produces: 1) all the clays of the world 2) all the soils of the world 3) the dissolved substances that are carried by rivers to the ocean

soluble

able to be dissolved, especially in water

Physical weathering ____ to chemical weathering

accelerates

What kind of environment do soil organisms create

acidic environment (combines with moisture for chemical weathering)

spodosol

acidic, low in plant nutrients, ashy, has accumulations of iron and aluminum. forms in humid forests

When are sediments compacted and cemented?

after burial, under additional layers of sediments

Caliche

aka calcrete. accumulated calcite a light-colored mineral deposit of gravel, sand, and nitrates, found especially in dry areas of South America. an area of calcium carbonate formed in the soils of semiarid regions.

What is pedalfer also known as

alfisol

Why are forams important in studying climate

because different species have different ages and conditions, can tell the age through identifying and dating

Lithification

becoming stone. the transformation of loose sediment into solid rock.

Flint

black chert - used for tools and arrowheads (obsidian or flint)

Boulder to 8 fragments example

boulder 1m each side (1m^2 volume // 6m^2 sa) >>>> 8 fragments .5m each side (.5^3) x 8 = 1m^2 volume // 12 m^2 sa) 6m^2 > 12m^2 > 60m^2

what does weathering do to rocks that turns them into sediment?

break up and corrode solid rock

Soil

broken down rock but not moving, it rests on top of rock - soils consist of rock and sediment that have been modified by physical and chemical interaction with organic material and rainwater, over time, to produce a substrate that can support the growth of plants

limestone is made of...

calcite

Common Minerals - Chemically precipitated sediments

calcite (CaCO3) aragonite (CaCO3) Dolomite (CaMg(CO3)^2) Gypsum (CaSO4) Halite (NaCl)

Pedocal - drawing

calcite accumulates unweathered bedrock

What do organisms construct their shells out of

calcium and carbonate ions, merged to make calcite or aragonite. becomes sediment when the organisms die.

What are organic sedimentary rocks made up of?

carbon-rich relicts of plants

From the potassium feldspar weathering example: a small proportion of carbon dioxide gas molecules (CO2) in air dissolves in rain droplets to form....

carbonic acid molecules (H2CO3) Equation: CO2 + H2O = H2CO3 (carbon dioxide + water = carbonic acid)

Rivers

carrying stones that scrape bottom/side of channel > widens and deepens channels - moving sand and silt acts like sandpaper on the larger rocks in the river bed and each other the energy of the river directly affects what is being moved rivers in flood stage have greater energy, can move larger pieces with greater force. potential for mechanical weathering is great Rocks hitting other rocks can break, making smaller pieces which can then become part of the suspended load

Stalactites

ceiling drip - travertine

What are clastic sedimentary rocks made up of?

cemented-together detritus (solid fragments and grains) derived from preexisting rocks

Travertine

chemical limestone. terraces (steps, rock layers) accumulates around hot springs and places where hot-water solutions spill out of the Earth. buildup develops because hot water reaching surface degases, less calcite can be dissolved and it precipitates to form rock

what do areas with small amounts of rainfall have

chemical weathering rates are low, soils can retain unweathered minerals and soluble components

what type of maturity are grains with presence of feldspar

chemically immature

what type of maturity are grains with presence of clay

chemically mature

Petrified Wood

chert made when ash from volcanic eruption (hot fire) buries a forest (can be a whole forest) - ash contains silica which dissolves in groundwater that passed into trees - the dissolved silica precipitates as cryptocrystalline quartz within wood, gradually replacing the wood's cellulose (carbon). The chert retains the shape of the wood and even its growth rings (all cells preserved)

Agate

chert that grows in concentric rings (layers) inside hollows in rocks and ends up with a striped appearance, caused by variations in the content of impurities while precipitation took place

Mudstone

clay, does not split into thin sheets - very fine grained

vertisol

clay-rich soils capable of swelling when wet, and shrinking and cracking when dry

zone of leaching

closer to the surface, this water dissolves ions and picks p very fine clay

As sedimentary rocks move from Closer > Farther from source - grain size

coarse to fine grained

how do soils mainly differ from one another

composition thickness

Biochemical Limestone

consist of shells and shell debris. interactions between living organisms and physical planet - some organisms have developed the ability to extract dissolved ions from seawater to make solid shells. Shells are constructed out of calcium (CA^2+) and carbonate (CO3^2-), merged to make calcite (CaCO3). When the organism dies, the solid material sinks to ocean floor, accumulating continuously, turning into sediment that becomes biochemical sedimentary rock.

O-horizon

consists almost entirely of humus

Sediment

consists of loose (unconsolidated): 1) rock fragments and or grains of minerals broken down from once-intact rock 2) mineral crystals that precipitate directly out of water 3) shells -forms when organisms extract ions of water

what part of the earth do sedimentary rocks cover

cover much of the Earth's land surface and sea floor 80% of Earth's surface only 1% of Earth's mass

Lake Bonneville - coverage

covered nearly all of Utah and portions of Idaho and Nevada

Is oil a rock?

debate - its a hydrocarbon

Micrite

dense, fine-grained carbonate mud or rocks composed of mud that forms by erosion of larger carbonate grains, organic precipitation (like algae) or inorganic precipitation - the grains in micrite are generally less than 4 microns in size

Where do mineral eating bacteria live

depths up to a few kms in the Earths crust people wonder if they can life below the surface of mars

What is another name for clastic rocks?

detrital

soil factors - vegetation type

different kinds of plants extract and add different nutrients and quantities of organic matter to a soil. some plants have deeper root systems than others, and more effectively prevent soil from washing away

how do carbonate minerals and salts weather?

dissolution Example: halite, calcite

How sedimentary rocks are formed

formed at or near the surface of the Earth by: 1) cementing together of loose rocks fragments or grains of minerals 2) cementing together of shell fragments 3) precipitation of minerals from water solutions

how do most felsic minerals weather?

hydrolysis Example: muscovite, orthoclase, plagioclase

What is a soil profile

idealized soil profile, from top to bottom,

Column (travertine)

if stalactites + stalagmites combine

basement - which type of rock

igneous

what type of rock make up the main volume of Earth's crust

igneous and metamorphic - underneath sedimentary rocks

institu

in place, not moving

What are chemical sedimentary rocks made up of?

minerals that precipitate from water solutions, without the life activity of organisms

inceptisol

moist, has poorly developed horizons. formed recently

What do mineral eating bacteria eat and why?

molecules from minerals - use energy from chemical bonds

what soil forms in subhumid to subarid grasslands

mollisol

are felsic minerals more or less stable?

more stable - less easy to weather Example: quartz, muscovite, orthoclase

soil factors - climate

mostly amount of rainfall

hydrolysis works faster in ____ water

slightly acidic

Burrowing

small-scale sedimentary rocks and soils - animals burrowing

mollisol

soft, black, and rich in nutrients. forms in subhumid to subarid grasslands

What is one type of regolith

soil

alfisol - lookup

soil comprising leached basic or slightly acid soils with a clay-enriched B horizon

what is the most important resource of civilization and why

soils - allows us to grow our food

soil factors - substrate composition and resistance

soils form on different substrates (basalt, granite, ash), so the soiils on top of them have different chemical compositions

what does water transport - weathering

solid particles and ions (ions in solution) - enter into sea and deposited

What color is the B-horizon

somewhat red

what is a series of beds referred to as?

strata. meaning they occur in layers

ultisol

very mature, strongly weathered soils, low in plant nutrients

As sedimentary rocks move from Closer > Farther from source - sorting

very poorly sorted to very well sorted - sorting according to size

histosol

very rich in organic debris - forms in swamps and marshes

what is lime mud

very tiny grain of calcite

oxisol

very weathered, rich in al and iron oxide, low in plant nutrients. forms in tropical regions

chemical weathering occurs more quickly in what climate conditions?

warm, wet conditions (faster) - the tropics (vs. deserts of the poles)

Hyrdrolysis

water chemically reacts with minerals and breaks them down. Potassium feldspar, a common mineral in granite, reacts with acidic water to produce kaolinite and other dissolved ions. Hydrolysis reactions break down not only feldspars but many other silicate minerals as well, amphiboles, pyroxenes, micas, and olivines.

Travertine in Caves

water seeping through cracks in a cave's surrounding bedrock may dissolve certain compounds, usually calcite and aragonite (calcium carbonate) or gypsum (calcium sulfate). the rate depends on the amount of CO2 held in solution, on temperature, and other factors. When the solution reaches an air-filled cave, a discharge of CO2 may alter the water's ability to hold these minerals in solution, causing its solutes to precipitate. Over time, tens of Ks of years, the accumulation of these precipitates may form speleothems

What is hard water

water that has high mineral content. forms when water percolates through deposits of limestone and chalk which are largely made up of ion-rich calcium and magnesium carbonates (from dolostone)

How does carbonic acid form

when CO2 and H20 molecules combine in rainwater (to form H2CO3)

How is chemical/replacement chert formed

when cryptocrystalline quartz gradually replace calcite crystals within a body of limestone (black, white, red, brown, green, gray)

what is replacement? what does it look like

when silica replaces calcium in limestone. looks like a black line. in petrified wood, it's a very gentle, gradual process (atom by atom) replacement

B-horizon

where the ions precipitate to form new minerals (such as iron oxides) and clay collects.

is coal a rock?

yes, because it is made up of detritus of plants deposited in layers, deeply buried and compacted by pressure and heat to drive off volatiles leaving a carbon concentration

soil factors - duration of soil formation

young soils tend to be thinner and less evolved

How does soil act as geologic agent

1 - the soil retains rainwater 2 - soil hosts a variety of vegetation, bacteria, and other organisms that create an acidic environment that, in combination with moisture, promotes chemical weathering, which alters or dissolves minerals 3 - plant roots and organisms tunneling through the soil aid physical weathering by helping create fractures this weathering in turn leads to the production of more soil

Grand Canyon

1 bil years of sedimentary rocks

Sedimentary rocks are what % of Earth's mass

1%

1930s Dust Bowl - why was the soil turned to dust?

1) intensive farming destroyed the vegetation's protective cover for the soil - poor farming practices 2) natural drought and wind (1934)

What 2 things does weathering transport

1) solid materials 2) dissolved ions

Soil Profile: top to bottom

1- O-Horizon (thin) 2- A1-Horizon 3- A2-Horizon 4- B-Horizon 5- C-Horizon

how fast do glaciers move

1-2 inches per year

Classification of Sedimentary rocks - Short

1. Clastic or Detrital sedimentary rocks 2. Chemical sedimentary rocks 3. Biochemical sedimentary rocks 4. Organic sedimentary rocks

Most Important Components of Soils

1. Clay minerals formed by the alteration of bedrock minerals 2. Mineral Fragments - fragments of bedrock 3. Organic materials (algae, microbes) produced by the organisms that live in it

Common reactions in chemical weathering

1. Dissolution (dissolve) 2. Hydrolysis 3. Oxidation 4. Hydration 5. Chemical weathering produced by organisms

Factors that interact to create sedimentary environments

1. Geographic location and plate tectonic setting 2. Transport agent and medium 3. Organic processes and organisms that modify sediments 4. Climate lead to sedimentary environment lead to sediments deposited

3 factors Classifying Clastic sedimentary rocks

1. Grain size 2. Grain shape 3. Mineral content Also how far from the source

From the potassium feldspar weathering example: what 3 things run off into rivers and soil

1. dissolved silica 2. potassium ions (K+) 3. bicarbonate ions (HCO3-)

factors that control the weathering of rocks

1. the properties of the parent rock 2. the climate 3. the presence or absence of soil (more covered > faster weathering (bc bacteria worms etc secrete organic acid) 4. the length of exposure

How long does it take to make mature and usable soil

10k years 10,000 years

?????

11:59.20 second of 12 hr geologic time scale

How big are medium grains

2-0.062 mm

Latitude temperate

30-60

Oxidation Chemical Equation

4 FeSiO3 + O2 = 2 Fe2SiO3 + 4 SiO2 (iron pyroxene + oxygen = hematite + dissolved silica)

Shoreline Environments

5 - Delta 6 - Beach 7 - Tidal Flats

Compaction

50-60% water >> 10-20%

Marine Environments

8 - Deep sea 9 - Continental Shelf 10 - Organic Reef 11 - Continental Margin

Lake Lahontan - peak coverage

8,500 square miles 22,000 square kms

Sedimentary rocks are what % of Earth's surface

80%

How much does water expand when freezing

9% expanded

Oxidation

An oxidation reaction is a reaction in which an element loses electrons - such a loss commonly happens when elements combine with oxygen . Example: oxidation, rusting of iron

Latitude arid

?

Fast to Slow

????

As sedimentary rocks move from Closer > Farther from source - summary

Grain size: coarse to fine grained Angularity: angular to well-rounded Sorting: very poorly sorted to very well sorted Maturity: less mature to more mature

Grain Sizes - LIst

Gravel-sized Sand-sized Silt-sized Clay-sized Microcrystalline Crysalline

Grain sizes - decription

Gravel-sized - grains visible; larger than sand Sand-sized - grains visible; like in a sandbox Silt-sized - grains barely visible; feels gritty Clay-sized - grains not visible; feels smooth; dull luster on freshly broken surface Microcrystalline - crystals not visible; feels smooth; shiny luster on freshly broken surface Crystalline - aggregate of visible crystals

What are the two major salts/evaporites

Gypsum (CaSO4) Halite (NaCl)

what volatiles are driven from coal's plant materials

H H2O CO2 ammonia

Exfoliation and spheroidal weathering Example

Half Dome, Yosemite National Park, California Exfoliation joints in the Sierra Nevadas

Least Stable to Most Stable

Halite Calcite Olivine Ca-plagioclase Pyroxene Amphibole Na-plagioclase Biotite Orthoclase (k feldspar) Muscovite Clay Quartz Gibbsite Hematite

Fastest to Slowest Weathering

Halite (mafic) Calcite Olivine Ca-plagioclase Pyroxene Amphibole Na-plagioclase Biotite Orthoclase (k feldspar) Muscovite *below don't change Clay (various types) Quartz (felsic) Gibbsite (aluminum hydroxide) Hematite (iron oxide)

What does oxidation transform iron-bearing minerals into?

Hematite and goethite rusty-brown mixture of iron-oxide/iron-hydroxide minerals

Pedalfer - drawing

Humus and leached soil Iron oxide and Al oxide accumulate + calcite is leached

Bicarbonate ions with Dissolution vs. Hydrolysis

Hydrolysis: Bicarbonate ions react with feldspar, weathering it to kaolinite clay and silicate and releasing bicarbonate and potassium ions Dissolution: Carbonic acid also reacts with calcite in limestone to produce bicarbonate and calcium ions

Medium Particle Size: to Sediment and Rock

Medium > Sand (sediment) > Sandstone (rock)

Are minerals that are the products of weathering reactions more or less stable

More stable

are salty lakes originally salty?

No

Does the Great Salt Lake have an outlet?

No - water only escapes by evaporating

which horizons make up the zone of leaching

O + A horizons

which horizons make up the nutrient-rich topsoil

O + A1-horizons

Famous Petrified Wood example

Petrified Forest, National Park, The Painted Desert, Arizona] all different colors

Natural zone of weakness Example

Point Lobos State Reserve, California - weathered enlarged joint patterns developed in two directions Brazil - Vertical joints in sedimentary rocks

How does organic matter become oil or coal?

Pressure Heat: 90-120 deg C

Chemical Weathering of Silicates - Examples

Quartz: very stable Feldspars: form clay minerals Mafic minerals: decompose to oxides

White Cliffs of Dover

Southeastern England. natural chalk, foraminifera layers that formed under the ocean and then it rose up as a cliff

Frost wedging - example

Taylor Valley, Victoria Land, Antarctica - a boulder, 3m high, fractured by frost action

Largest remaining portion of Lake Bonneville today

The Great Salt Lake The Bonneville Salt Flats

Salt wedging - example

Whitby, England - salt erosion led to disintegration of gravestones

Foraminifera - Example

White Cliffs of Dover

Travertine - Example

Yellowstone - near volcano all hotsprings (fume of CO2 gas) Mammoth Hot Springs in Yellowstone National Park, Wyoming

Soil Zones: top to bottom

Zone of leaching Zone of accumulation Zone of weathering

what is a series of strata that is sufficiently unique to be recognized on a regional scale called?

a Formation

How does most dolomite form?

a chemical reaction between limestone (solid calcite (CaCO3)) and magnesium-bearing groundwater

What do Mars and Earth share

a history for the 1st billion years they both had lakes, rivers

What does chemical weathering in warm wet climates produce?

a layer of rotten rock, called saprolite, over 100m thick

Graywacke

a mixture of different clast sizes; contain lithic clasts - medium grained

Laterite

a reddish clayey material, hard when dry, forming a topsoil in some tropical or subtropical regions. a clayey soil horizon rich in iron and aluminum oxides, formed by weathering of igneous rocks in moist warm climates.

oxisol - lookup

a soil of an order comprising stable, highly weathered, tropical mineral soils with highly oxidized subsurface horizons.

what are precipitates

a substance that was deposited in solid form from a solution

what is cover?

a surface veneer - upper part of the crust

Pedalfer

alfisol temperate climate substrate contains Fe + Al Well-defined horizons Organic rich A horizon Soil that is characterized by an abundance of aluminum and iron oxides. Pedalfers are common in humid regions and are deposited in the B horizon of ABC soils, through leaching.

Soils' Cute Names - List

alfisol andisol aridisol entisol gelisol histosol inceptisol mollisol oxisol spodosol ultisol vertisol

what soils are abundant in plant nutrients

alfisol histosol mollisol

what soil forms in humid forests

alfisol spodosol

why do some rocks weather more rapidly than others?

all rocks weather, but the manner and rate of their weathering vary

Sandstone

almost pure quartz sand; other compositions are possible - - grains visible like sandbox - medium grained -

Oil Shale

altered organic matter - the living part inside the shell - hydrocarbon organic chemicals derived from fats and proteins (plankton flesh) that commonly mix with mud and incorporated into shale - gradually transforms into oil oil shale when over 50% organic matter

Coal

altered remains of fossil vegetation. accumulates in lush tropical wetlands. requires deposition in the absence of oxygen - plant remains that fossilized 50%+ carbon - either pure carbon or as element in organic chemicals (not in minerals) a black, combustible rock made up of detritus of plants deposited in layers, deeply buried and compacted by pressure and heat to drive off volatiles (H, H2O, CO2, ammonia) leaving a carbon concentration

Talus

an apron-shaped pile of fragmental rock accumulated near the base of cliffs near Mt. Snowdon, Wales

what would result if seawater is evaporated entirely?

an evaporite with 80% halite and 13% gypsum, 7% other salts and carbonates

what soil forms in volcanic ash

andisol

As sedimentary rocks move from Closer > Farther from source - angularity

angular to well-rounded

Regolith

any kind of unconsolidated debris that covers bedrock

Weathering into dissolved ions:

are carried to the sea in streams or transported underground in groundwater. Eventually, the ions precipitate as new minerals in the sea or as new minerals filling open spaces between grains underground

what is pedocal also known as

aridisol

what soil forms in arid environments

aridisol

Pedocal

aridisol arid climates tend to be thin no O horizon A horizon contains: unweathered minerals, rock fragments, calcile very little organic matter B horixon contains caliche or calcrete a soil which forms in semiarid and arid regions. It is rich in calcium carbonate and has low soil organic matter.

what soils are low in plant nutrients

aridisol oxisol spodosol ultisol

Compaction

as grains are squeezed together by the weight of overlying sediment into a mass denser than the original

Cementation

as minerals precipitate around deposited particles and bind them together

soil factors - slope steepness

as the slope angle decreases, soil thickness increases as the slope angle increases, soil thickness decreases

C-horizon

at the base of a soil profile. consists of material derived from the substrate base that's been chemically weathered and broken apart

bedding is formed where?

at the bottom of the sea, river, or land surface

bedrock

basement, base rock - igneous

Dissolution

dissolve. slow but significant process over millions of years. caused by carbonic acid, a weak but important acid. Equation 1: CO2 + H20 = H2CO3 (carbon dioxide + water = carbonic acid) Equation 2: CaCO3 + H2CO3 = Ca (2+) + 2HCO3 (-) (calcite + carbonic acid = calcium cation + bicarbonate anion)

what does weathering yield in addition to solid materials?

dissolved ions Example: Na and K+ carried to the oceans - this sustains life)

How has the Great Lake changed over time?

during the Pleistocene (the ice age), the rainy season, lots of rain accumulated 13-11k years ago. it has shrank since the Pleistocene

what soil formed very recently

entisol incepisol

what soils have no or poorly developed horizons

entisol inceptisol

Exfoliation and spheroidal weathering

exfoliates like layers - exposes inner layers to elements

what is an outcrop

exposed rock - where rock section is exposed

what is mixed with mud to make oil shale

fats and proteins of plankton flesh

Siltstone

fine sand - fine grained

How big are very fine grains

finer than 0.0039 mm - rounded

Stalagmites

floor rise - travertine

what is the fundamental geologic mapping unit

formation

Lake Bonneville - dates formed

formed about 32,000 yrs ago lasted until 16,800 yrs ago

Sedimentary rocks - Intro

formed by surface processes sediments and sedimentary rocks are characterized by bedding sedimentary rocks - form the earth - igneous rocks are destroyed and when the product is moved somewhere else > becomes sedimentary rock most rocks at Earth's surface are sedimentary, but form only a thin layer atop the igneous and metamorphic rocks that make up the main volume of the crust

Pluvial lakes - misconception

formerly large lake created by excessive rain + little evaporation

transported soil

forms from sediment that has been carried in from elsewhere - include those formed from deposits left by rivers, glaciers, or wind.

residual soil

forms in place, 99% of soils, forms directly from underlying bedrock, deeply weathered

Andisol

forms in volcanic ash

Frost wedging

freezing and thawing, rocks are broken in place after moved as 1 whole block (carried by ice) occurs in Antarctica only

What happens in most lakes with an outlet?

fresh water coming in constantly flushes out through an outlet and the ion concentration stays low

"clastic"

from the Greek Klastos, meaning "broken"

zone of accumulation

further down, where new minerals precipitate out of the water, and the water leaves behind its load of fine clay

what soil is underlaid with permanently frozen ground

gelisol

Weathering

general process by which rocks are broken down at Earth's surface

Weathering into solid materials

gets picked up and moved to a new location by wind, water, ice, until eventually settling out. they then either become incorporated in soil or become buried deeply

Glaciers

glaciers break down rocks - carries broken pieces and takes the broken pieces within itself a glacier is nothing more than a frozen river still moving (1-2 ins per year). ice erodes the ground and rock below faster and more aggressively than if it was just water more aggressive because glaciers pick up and move the rocks that they run over and this gravel (chunks of rocks) can carve mountains down and cute valleys mikes deep

Lake Lahontan - demise

gradually began to evaporate, resulting in a drop of lake level over time

Alfisol

gray/brown, has subsurface clay accumulation

why is travertine formed?

groundwater saturated with CO2 (carrying a lot of Ca +CO3 as a solution (dissolved carbonic acid), thus can't be deposited). when it comes to surface, the CO2 gas escapes and the CaCO3 combines and is deposited as limestone

when 80% of the water evaporates, what forms?

gypsum

when 90% of the water evaporates, what forms?

halite

Soil > resistance to weathering

hardest rock = no soil / bedrock harder rock = thinner soil (fields above) weaker rock =thicker soil

entisol

has no horizons. formed very recently

transported soil - example

heavily farmed American Midwest soil is transported soil - developed at the end of the ice age on thick accumulation of fine silt deposited by strong winds

what soil forms in swamps and marches

histosol

A1-horizon

humus has decayed further and has mixed together with mineral grains (clay, silt and sand)

What does carbonic acid ionize to form

hydrogen ions (H+) and bicarbonate ions (HCO3-)

Zone of leaching to zone of accumulation

ions are carried down with percolating water Ions and fine clay accumulate

Laterite - drawing

iron oxide and Al oxide residue iron-rich cla; Al hydroxide weathered bedrock unweathered bedrock

what does it mean if soil is black

it is carbon-rich from secretions from organic materials

what amt of rainfall accelerates chemical weathering, why

large amts of rainfall - leaches most of the soluble minerals

Breccia

large angular fragments - made mostly of angular gravel - coarse grained

How big are coarse grains

larger than 256 mm - most angular 256-64 mm 64-2 mm

Wet Climate - Soil

laterite Humus: thin or absent Thick masses of insolute iron and aluminum oxides - occasional quartz iron-rich clays and aluminum hydroxides thin leached zone mafic igneous rock

"pluvial"

latin word for rain

As sedimentary rocks move from Closer > Farther from source -maturity

less mature to more mature - mature physically (angular vs. well-rounded) and chemically (feldspar vs. clay) Alluvian fan > River > Beach

what kind of underlying rocks lead to thicker soil

less resistant underlying rocks

are mafic minerals more or less stable?

less stable - easier to weather Example: olivine, pyroxene, amphibole

Examples of dissolution

limestone. 2500-yr old Greek ruins at Segesta, Italy Limestone outcrop, ireland

Aridisol

low in organic matter, has carbonate horizons. forms in arid environments

where does coal accumulate

lush tropical wetlands

Shale

made from clay or mud; splits into thin sheets - grains not visible, feels smooth, dull luster on freshly broken surface - very fine grained

Organic Sedimentary Rocks

made from organic carbon Coil Oil

Dolomite is produced from a reaction between limestone and what?

magnesium-bearing groundwater

Foraminifera (forams)

microscopic animals - plankton shells - made up of different species with different ages and conditions

Radiolaria

microscopic plankton with silica shells which accumulate to form an ooze, a gel at the floor of the deep ocean shaped like a beehive - chambers at different layers empties chambers - allowing it to move (empties to rise and fills with water to sink)

CaCO3

mineral calcite polymorph aragonite or dissolved silica

sedimentary environments (11)

multiple factors interact to create sedimentary environments. different products come from different environments. 1 - Lake 2 - Rivers 3 -Desert Lake 4 - Glacier 5 -Delta 6 - Beach 7 - Tidal flat (where water is covered/uncovered) 8 - Deep sea (turbidity currents occur between continental shelf and deep sea) 9 - Continental shelf 10 - Organic reef 11 - Continental margin (range from delta/beach/continental shelf/organic reef to deep sea)

Do crops grow well in all soils?

no

is petrified wood wood?

no - it's stone

Terminal lakes

no outlet. Great Basin of the Intermountain West. Through the process of continued evaporation (increased temp), minerals and salts that flow into these water bodies are retained and concentrated over time water coming is fresh - gypsum CaSO4 halite NaCl - concentrated salt

what is the cover (range) of Earth's sedimentary rocks

nonexistent (bare basement rock) to almost 20km thick beneath continental shelves

Radiolaria - Example

north end of the Golden Gate Bridge, SF - main columns anchored in biochemical chert

what is stored in igneous rocks?

nothing

important stuff stored in sedimentary rock

oil petroleum natural gas ground water

where else does calcite precipitation also occur?

on the walls of caves, where groundwater seeps out

remaining portion of Lake Lahontan today

only remaining lakes are Pyramid Lake and Walter Lake, both are in Nevada. the rest of the remnants are dry playas and rock formations where the ancient shoreline was

Chemical weathering produced by organisms

organisms play a major role. (ex: roots of plants, fungi, lichens) they secrete acids that help dissolve minerals in rocks; the organisms extract nutrients from the minerals microbes like bacteria eat minerals. They metabolize many compounds, depending on their environment. They pluck off molecules from minerals and use the energy from the chemical bonds to supply their own life force.

how do most mafic minerals weather?

oxidation Example: olivine, pyroxene, amphibole

what is laterite also known as

oxisol

Laterite

oxisol tropical regions so much water, almost all mineral components leached - only insoluble Fe/Al oxide remain so much water passes through soil that accumulation cannot take place at depth, iron rich clays collect have 4-5 years use

Another name for pluvial lakes

paleolakes

bedding is what kind of layers?

parallel

humus

partially decayed organic matter

Lake Lahontan - peak date

peaked at 12,700 years ago

Temperate Climate - Soil

pedalfer humus: thicker later and leached soil (with quartz and clay minerals) Some iron and aluminum oxides precipitated - all soluble materials, like carbonates, are leached away granite bedrock

Dry Climate - Soil

pedocal humus: thin layer and leached soil Calcium carbonate pellets and nodules precipitated Sandstone, shale, and limestone bedrock

what type of maturity are angular grains

physically immature

What type of maturity are rounded grains

physically mature

Current solution to dust bowl

planting buffalo grass because it is deeply rooted - government took back the land to restabilize

Lake Lahontan - coverage

pluvial lake that covered nearly all of northwestern Nevada as well as parts of northeastern California and southern Oregon at peak (12,700 yrs ago), covered approx 8,500 square miles (22,000 square kms)

what kind of feedback process is soil production

positive feedback process - the product of the process advances the process itself -more physical weathering leads to more chemical weathering, more chemical weathering leads to more physical weathering

From the potassium feldspar weathering example: the slightly acidic water dissolves ___ ions and ___ from feldspar, transforming it into ___. ____ are retained in the water of the clay

potassium / silica / kaolinite (clay) / hydrogen ions

what are potassium(k)-bearing salts from evaporating flats processed into

potassium-sulfate, a mineral fertilizer

Oxidation reactions in rocks

reactions (destructive) in rocks transform iron-bearing minerals (ex: biotite, pyrite, olivine, amphibole, pyroxene) into rusty-brown mixture of various iron-oxide and iron-hydroxide minerals (ex: hematite and goethite) Process: iron pyroxene dissolves to release silica and ferrous iron to solution. Ferrous iron is oxidized by oxygen molecules to form ferric iron. Ferric iron combines with water to precipitate a solid, iron oxide, from solution Example: why Mars surface is Red

Jasper

red chert - can be yellow/red/orange - used for jewelry - sooth and polished appearance

Lake Bonneville - demise

reduced precipitation and evaporation, but most water was lost overflowing through Red Rock Pass in Idaho after the Bear River was diverted to Lake Bonneville following lava flows in the area. And continued to shrink over time, as little rain fell into the lake.

Chemical Weathering

refers to the chemical reactions that alter or destroy minerals when rock comes in contact with water solutions or air

Chert (chemical)

replacement chert - nonbiogenic in origin

Chemical weathering as it relates to bowens reaction series and stability

reverse of reaction series. the earlier they form, the less stable they are. the faster they weather, the less stable. the faster the crystallization time, the easier to weather

what is a characteristic of soil formed on basalt, vs. on granite

richer in Fe, because basalt is Mafic - granite is felsic

when do rivers have greater energy

rivers in flood stage (can move larger rock pieces)

Conglomerate

rounded clasts - made mostly of rounded gravel and sand grains (usually quartz grains) - coarse grained

Example of weak ionic bond

salt and water

salt wedging

salt wedging most affects buildings and rocks along the ocean front - stress cracks

Sediments - Examples

sand mud gravel dust calcified organisms (shells) saline precipitates (salt)

Arkose

sand sized quartz plus feldspar grains - grains visible like sandbox - medium grained

what type of rock are most rocks at Earth's surface

sedimentary - but only form a thin layer - only form upper part of the crust

cover - which type of rock

sedimentary and sediments

Erosion

set of processes that loosen and move soil and rock downhill or downwind (broken down rocks to dust - forms new rocks)

what is bedding made up of when formed?

settling of particles a bedrock of igneous rock thin top layers of sedimentary rocks

Biochemical Chert

shells made out of dissolved silica, made from cryptocrystalline quartz - formed from silica shells of plankton called radiolaria accumulate to form an ooze, or gel, at the deep ocean floor. gradually, after deep burial, the shells dissolve, forming a silica rich solution - chert then precipitates from this solution very tough - even sledgehammer can't break

What are biochemical sedimentary rocks made up of?

shells of organisms

where does fresh water inflow come from

surrounding mountains - snow melt

Examples of increasing SA > more chemical weathering

table salt sugar ground black pepper ground coffee bean chew your food

Physical (mechanical) weathering - short

takes place when solid rock becomes fragmented by physical processes that do not change its chemical composition

Chemical weathering - short

takes place when the minerals in a rock are chemically altered or dissolved

A2-horizon

tends to be lighter-colored and contain less organic matter than the overlying topsoil

what does coal deposition require

the absence of oxygen

Hydration

the absorption of water into the crystal structure of minerals, causes some minerals, such as certain types of clay, to expand ground moves - can store or lose water and nutrients

what does the specific type of evaporite depend on?

the amount of evaporation

how do deep root systems affect soil

the deeper the roots, the more effectively preventing soil from washing away

Bedding

the formation of parallel layers by the settling of particles to the bottom of the sea, a river, or a land surface

the smaller the pieces....

the greater the surface area available for chemical weathering

Temperature and weathering

the hotter the melting temperature (1400 C), the easiest to weather (mafic) the colder the melting temperature (800 C), the harder to weather

What does the kind of limestone formed depend on?

the material from which they formed 1 - some retain the internal structure of coral colonies 2 - some consist of large, angular shell fragments 3 - some are made up of rounded grains of calcite that rolled about in the surf 4 - some consist of lime mud (very tiny grains of calcite) 5 - some consist of shells from plankton (microscopic animals, foraminifera)

Evaporites

the product of saltwater evaporation evaporation just removes the water, leaving dissolved ions behind. Over time, the lake water has become a concentrated solution of dissolved ions - very salty occurs when its very hot - and also when no outlet

From the potassium feldspar weathering example: a small proportion of carbonic acid molecules ionizes to form hydrogen ions (H+) and bicarbonate ions (HCO3-), making...

the water droplets slightly acidic Equation: H2CO3 = H2 + HCO3- (carbonic acid = hydrogen cation + bicarbonate anion)

The faster the chemical decay...

the weaker the pieces and the more susceptible to breakage (physical weathering)

What does chert (silica from volcanic ash) replace in petrified wood

the wood's cellulose (carbon)

what is characteristic about salt flats

they are the flattest surface of Earth

why are sedimentary rocks a uniquely important rock type?

they contain the bulk of our energy resources (coal, petroleum, natural gas) and our groundwater

how do oxide minerals weather?

they don't weather at all Example: Gibbsite, Hematite

Soil Groups: top to bottom

topsoil transition subsoil weathering soil unweathered bedrock

Speleotherms

travertine that grows on walls of caves where groundwater seeps out - form from accumulation over thousands of years stalactites + stalagmites

Root wedging

tree roots invade fractured rock, widening cracks promoting further chemical and physical weathering open fracture and put stress on the sides important for bridges

soil itself works as a geologic agent: true/false

true

what is kaolinite

type of clay produced by reactions between potassium feldspar and acidic water

Bedrock

unaltered rock of any kind

on what material do soils develop faster

unconsolidated material - ash or sediment, much slower on bedrock

gelisol

underlaid with permanently frozen ground

nutrient-rich topsoil

usually dark in color, which is the farmers till for planting crops - topsoil contains diverse life, such as bacteria, fungi, insects, and rodents