Exam 4 Geological Oceanography

Front 1

What is a tide?

Back 1

Changes in elevation of the ocean surfaces

Front 2

What causes the tides to change?

Back 2

Caused by the gravitational forces exerted upon the Earth by the Moon and to a lesser extent the sun

Front 3

What are the two principle factors that produce tides?

Back 3

1.) Gravitational attraction
2.) Centrifugal force (Inertial force)

Front 4

Gravitational attraction?

Back 4

F=G(M1M2/r2), this force is different on different locations due to distance

Front 5

Centrifugal force?

Back 5

Inertial force, this force is always the same and always parallel

Front 6

Barycenter?

Back 6

The center of mass in the Earth-moon system

Front 7

Balance between gravitation attraction and centrifugal force creates?

Back 7

Balance between these forces creates tidal bulges

Front 8

What are assumed in the equilibrium theory of tides? (3)

Back 8

1.) Earth is completely covered by water
2.) Water is in equilibrium with tide producing forces
3.) Earth turns beneath these tidal bulges freely

Front 9

Lunar tides...(4)

Back 9

1.) Moon and Earth
2.) Tidal day = 24 hours 50 mins
3.) Moon moves from 28.5 N to 28.5 S (Latitude) in course of month
4.) Tidal bulge follows moon

Front 10

Solar tides...(3)

Back 10

1.) Sun and Earth
2.) Accounts for 46 degrees W of moon tidal force
3.) Moves 23.5 N and S of equator in course of year

Front 11

The sun and moon together create...(6)

Back 11

1.) Spring tides
2.) Neap tides
3.) Perigee
4.) Apogee
5.) Perihelion
6.) Aphelion

Front 12

Spring tides?

Back 12

When earth, sun, and moon are in line or syzygy

Front 13

Neap tides?

Back 13

When the sun and moon at right angles to Earth or quadrature

Front 14

Perigee?

Back 14

Moon is closet to Earth

Front 15

Apogee?

Back 15

Moon is farthest from Earth

Front 16

Perihelion?

Back 16

Sun is closet to Earth

Front 17

Aphelion?

Back 17

Sun is farthest from Earth

Front 18

What is syzygy?

Back 18

When Earth, sun, and moon are all in line

Front 19

What is quadrature?

Back 19

When the sun and moon are at right angles to Earth

Front 20

Monthly tidal cycles include?

Back 20

1.) Spring tides
2.) Neap tides

Front 21

Spring tides...(4)

Back 21

1.) During the new and full moons
2.) Gravitational forces added together
3.) Especially high and low tides
4.) Large daily tides

Front 22

Neap tides...(3)

Back 22

1.) First and third quarters of the moon
2.) Gravitational forces are offset
3.) Daily tidal range is least

Front 23

The factors that influences the tides? (3)

Back 23

1.) Shape of coastline
2.) Configuration of the ocean basin
3.) Water depth

Front 24

What is the largest tidal zone?

Back 24

Bay of Fundy on Nova Scotia coast

Front 25

What is the tidal range of Tampa Bay?

Back 25

1m or less tidal range

Front 26

What are the main tidal patterns? (3)

Back 26

1.) Diurnal tidal pattern
2.) Semidiurnal tidal pattern
3.) Mixed tidal pattern

Front 27

Diurnal tidal pattern...

Back 27

1.) A single high and low tide each tidal day
2.) Occurs along the northern shore of the Gulf of Mexico

Front 28

Semidiurnal tidal pattern...(3)

Back 28

1.) Two high and two low tides each tidal day
2.) Little difference in the high and low water height
3.) Common along the Atlantic coast of the U.S.

Front 29

Mixed tidal pattern...(3)

Back 29

1.) Two high and two low tides each tidal day
2.) Large inequality in high water heights, low water heights, or both
3.) Prevalent along the Pacific coast of the U.S.

Front 30

What are the tidal currents? (3)

Back 30

1.) Ebb tide (current)
2.) Flood tide (current)
3.) Slack water

Front 31

Ebb tides (currents)?

Back 31

Water rushing out because of fall in sea level

Front 32

Flood tides (currents)?

Back 32

Water rushing in because of rise in sea level

Front 33

Slack water?

Back 33

Occurs during high or low tide, no water movement

Front 34

Tidal features? (3)

Back 34

1.) Flood tidal delta
2.) Ebb tidal delta
3.) Tidal bore

Front 35

Ebb tidal delta?

Back 35

Outgoing tide deposits sediment (Egmont Key)

Front 36

Flood tidal delta?

Back 36

Incoming tide deposits sediment into lagoon

Front 37

Tidal bore? (4)

Back 37

1.) A wall of water that surges up river
2.) Must have: Large tidal range >5m
3.) Tapering basin geometry
4.) Decreasing water depth up river
(5m high bore in Amazon River)

Front 38

Tide prediction? (3)

Back 38

1.) At least 140 tidal variables that must be considerable
2.) NOAA develops tide tables
3.) Can be predicted for into the future

Front 39

Marine geology? (3)

Back 39

1.) It is a young science
2.) Began by scientists going to sea to determine processes that formed rocks they see on land
3.) 1960's plate tectonics revolution and ocean chilling has led to great interest

Front 40

What are the two types of investigative methods in marine geology?

Back 40

1.) Direct methods
2.) Indirect methods
(Of obtaining sediments)

Front 41

Direct methods?

Back 41

1.) Shallow water sampling, SCUBA
2.) Bottom sampling using grab

Front 42

Bottom sampling using grab...(6)

Back 42

1.) Ekman grab
2.) Box-core
3.) Dredge
4.) Coring
5.) Vibracore
6.) Piston core

Front 43

Ekman grab?

Back 43

Spring loaded takes general sample

Front 44

Box-core?

Back 44

Spring loaded upper couple inches of sediment (Doesn't disturb sediments)

Front 45

Dredge?

Back 45

Usually deep water, throw over side, brute force will pick up anything

Front 46

Coring?

Back 46

Allows for time series of sediments

Front 47

Vibracore? (3)

Back 47

1.) Used in shallow water
2.) Only works well with fine-grained sediments
3.) Core apparatus is heavy

Front 48

Piston core? (4)

Back 48

1.) Used in deep water
2.) Average 5-10 m long
3.) Useful for deep sea oozes
4.) Invented by Kullenberg and first in 1947

Front 49

What is the 2nd most expensive program of the National Science Foundation?

Back 49

Ocean Drilling Program

Front 50

The Deep Sea Drilling Project? (4)

Back 50

1.) 1968-1983
2.) Glomar Challenger (ship)
3.) Sampling of deep sea sediments, rocks
4.) Helped to support plate tectonics

Front 51

The Ocean Drilling Program? (5)

Back 51

1.) 1983-2003
2.) Joides Resolution - from BP
3.) Two month long cruises
4.) Largest funded scientific program in the U.S.
5.) 8,200 m depth max

Front 52

The Integrated Ocean Drilling Program? (3)

Back 52

1.) A new international scientific research program beginning October 2003
2.) U.S., Japan, and Europe
3.) Will have multiple patterns for scientific drilling

Front 53

What kind of ship did the U.S. provide?

Back 53

Riserless drillership

Front 54

Riserless drillership - U.S. provides...(3)

Back 54

1.) Currently used in ODP (Ocean Drilling Program) - Joides resolution
2.) NSF (National Science Foundation) request for proposals
3.) Operatives begin summer 2004

Front 55

What kind of ship did Japan provide?

Back 55

Chikyu riser drillership

Front 56

Chikyu riser drillship - Japan provides...(3)

Back 56

1.) Launched January 18, 2002
2.) 12 km drill string
3.) 2.5 km to 4m water depth

Front 57

What kind of ship did the Europe provide?

Back 57

Mission specific platforms

Front 58

Mission specific platforms - Europe provides...(3)

Back 58

1.) Areas unexcessable to riserless and riser ships
2.) Necessary to accomplish goals of science plan
3.) Case-by-case basis

Front 59

Indirect methods? (4)

Back 59

1.) PDR - Precision depth recorder
2.) Seismic profiling
3.) Side-scan sonar
4.) ROV and video imaging (Remote operated vehicle)

Front 60

Seismic profiling? (3)

Back 60

1.) D = V x T/2
2.) Multiple types, many uses for sub bottom
3.) Chrip system at Eckerd

Front 61

Side scan sonar?

Back 61

Allows swath of sea floor tube image

Front 62

Global sea level change is?

Back 62

Eustatic

Front 63

What is eustatic?

Back 63

A change in sea level experienced worldwide due to changes in seawater volume or ocean basin capacity. (Size of ocean basins)

Front 64

Regional or local sea level change? (3)

Back 64

1.) Uplifting and subsidence (sinking) of land
2.) Tidal storms
3.) Erosion, deposition

Front 65

Water held in ice on land or on the ocean...

Back 65

Can melt and make the sea level rise

Front 66

What is the importance of sea level? (4)

Back 66

1.) Controls coastal morphology
2.) Affects climate and paleoclimatic reconstructions
3.) Economic geology
4.) Evolution of shelf

Front 67

Coastal morphology consists of?

Back 67

Barrier islands, estuaries, marshes, ect...

Front 68

Affect on climate and paleoclimatic reconstructions?

Back 68

High level, less weathering, more CO2 in atmosphere, greenhouse

Front 69

Economic geology?

Back 69

1.) Coal deposits tied to swamps (Or marshes)
2.) Oil in old delta deposits

Front 70

Main sea level indicator?

Back 70

Wave-cut terraces

Front 71

Wave-cut terraces?

Back 71

1.) Indicate sea level still stand or slowing
2.) Can form notches in conjunction with bioerosion

Front 72

Intertidal indicator? (5)

Back 72

1.) Dessication cracks
2.) Sediment bedding
3.) Mangrove peats
4.) Marsh deposits
5.) Stromatolites

Front 73

Dessication cracks?

Back 73

Periodically flooded then dried areas, that form these cracked patterns

Front 74

Sediment bedding?

Back 74

Herringbone, flaser, lenticular bedding in tidal

Front 75

Herringbone?

Back 75

Bedding deposited alternately facing one way and then another

Front 76

Flaser?

Back 76

Mud deposited on top of sand, comprised mostly of sand

Front 77

Lenticular?

Back 77

Mud suspended on top is deposited on a small bed of sand, comprised mostly of mud

Front 78

Other sea level indicators?

Back 78

1.) Coral reefs
2.) Beach rock

Front 79

Coral reefs? (4)

Back 79

1.) Only building reefs
2.) Reefs may grow at or near sea level
3.) May be used to determine higher sea level then present (Ex. Florida Keys, Roatan)
4.) Have been used to document recent sea level rise

Front 80

Coral reefs have been used to document sea level rise...

Back 80

Fairbanks curve - sea level change 20,000 years ago to today

Front 81

Beach rock?

Back 81

Sediment cemented together from CaCO3

Front 82

Beach rock...(3)

Back 82

1.) Forms in swash zones
2.) Distinction bedding characteristics
3.) Can be very young (Less than 100 years old)

Front 83

Recent sea level rise?

Back 83

18,000 years ago to present

Front 84

Recent sea level rise...(5)

Back 84

1.) Due to melting of continental ice sheets
2.) ɗ 18^O (del ratio of O-16 isotope + O-18)
3.) Barbados submerged reefs (Fairbanks)
4.) Submerged shorelines of South Florida (locker)
5.) May have implication for future sea level rise

Front 85

Ice floating on ocean...

Back 85

Displaces the same amount of water from frozen to melted.

Front 86

At about about time did sea level reach a high?

Back 86

120,000 years ago

Front 87

What can prove this sea level high?

Back 87

1.) Oxygen isotopes
2.) New Guinea sea level curve - New Guinea is getting pushed up tectonically

Front 88

Ice driven fluctuations?

Back 88

Pleistocene Ice Ages, about the last 2 million years ago

Front 89

How do we know the Pleistocene had ice driven fluctuations?

Back 89

More evidence comes from deep sea sediment cores

Front 90

Tectonic sea level change?

Back 90

550 million years of sea level change

Front 91

Tectonic sea level changes...(4)

Back 91

1.) Size of ocean basins change
2.) Related to spreading rates
3.) Also related to high volcanism, high CO2
4.) Cretaceous Greenhouse Planet

Front 92

Cretaceous Greenhouse Planet?

Back 92

1.) Sea level as much as 300 m higher than today
2.) No ice sheets on planet

Front 93

Reconstructing ancient sea level from continental margins?

Back 93

1.) Seismic profiling
2.) Interpretation of patterns of coastal onlap
3.) Development of the Exxon-Vail sea level curve

Front 94

The interpretations of patterns of coastal onlap is also called?

Back 94

Sequence stratigraphy

Front 95

Sequence stratigraph?

Back 95

1.) Using seismic profile from a number of passive continental margins, sequences are identified, ages assigned based on cores, and they can then be plotted on a time axis
2.) The Slug diagram (Coastal onlap curve)

Front 96

Exxon-Vail curve? (3)

Back 96

1.) Vail and his colleagues recognized large scale unconformities on passive margins around world occurring at the same time
2.) Therefore, they developed a global sea level curve (Or eustatic) to account for these transgressions and regressions
3.) Very controversial when was released (1977)

Front 97

Transgression?

Back 97

Rise of sea level or upcoast line (More with seismic data)

Front 98

Regression?

Back 98

Falling of sea level

Front 99

Why was the Exxon-Vail curve controversial when it was first released?

Back 99

Didn't release all the data, there was prioritory data

Front 100

Prioritory data?

Back 100

Had locations of oil on it so didn't want to release information on it

Front 101

Seismic profiling was developed in?

Back 101

70's

Front 102

Paleoceanography? (3)

Back 102

1.) The study of ocean history
2.) Many sub disciplines
3.) Requires indirect or direct sampling

Front 103

Studies of ocean sediments and what they tell us...

Back 103

1.) Began in 1930's and 40's (Study of paleoceanography)
2.) Kullenberg invented piston cores which allowed longer sediment records, first used in 1947

Front 104

Information contained in sediment...(3)

Back 104

1.) Changes in type of sediment (terrestrial, biogenic, ect...)
2.) Changes in species of planktonic and bethic organisms through time
3.) Change in geochemistry of shells of organisms

Front 105

Paleotemperature?

Back 105

1.) Many marine organisms have a narrow temperature range (Ex. Coral can't live in north)
2.)Transfer function analysis helps explain this history of temperature change

Front 106

Many marine organisms have a narrow temperature range...(4)

Back 106

1.) Most widespread deposits on seafloor are carbonate ooze
2.) Mostly composed of foraminifera tests
3.) Climate indicators par excellence (Good climate indicators)
4.) Good agreement between faunal and climatic zonation (Only get species that live in those climate zones)

Front 107

Transfer function analysis? (4)

Back 107

1.) Simple methodology
2.) A temperature estimate is given based on assemblage of forams present in sample
3.) Califiration set is used consisting of modern sea floor assemblages versus surface temperature
4.) Most abundant + next most + next ect... With given T optimum for each species

Front 108

What is a califiration set?

Back 108

Set of forams that you know temperature they lived in today

Front 109

Application of transfer function analysis?

Back 109

1.) CLIMAP (Climate long-range investigation, mapping, and prediction) group used complicated TFA (Transfer function analysis) to estimate SST (Sea surface temperature) for last glacial maximum
2.) Looked at core data for 18,000 years ago

Front 110

How did we look at core data from 18,000 years ago?

Back 110

Oxygen isotope stratigraphy

Front 111

From this oxygen isotope stratigraphy...

Back 111

Polar front extended from New York to Iberian peninsula, today south of Greenland

Front 112

Uses and limitations of transfer function analysis? (5)

Back 112

1.) Method may be used for any variable that show correlation with plankton abundance
2.) Salinity shows no correlation
3.) Calibration set based on surface samples, average of last 2,000-3,000 years
4.) Differential dissolution and selective preservation, delicate species gone
5.) Old samples, evolutionary changes in T optima

Front 113

Using oxygen isotopes was first found by?

Back 113

Harold Urey 1947

Front 114

What is the most common oxygen isotope?

Back 114

Oxygen 16

Front 115

Harold Urey with oxygen isotopes?

Back 115

Determined that oxygen isotopes in a shell may be used to calculate the optimum T of the water it precipitated

Front 116

Harold Urey?

Back 116

Won the noble prize in chemistry

Front 117

Epstein...

Back 117

In 1953 developed the formula

Front 118

What is this formula?

Back 118

T = 16.5 -4.3 (ɗs - ɗw) + 0.14(ɗs - ɗw)²

Front 119

ɗs is?

Back 119

del of sample

Front 120

ɗw is?

Back 120

del of water

Front 121

This formula is?

Back 121

Finding O-16 and O-18 ratio in shell or water

Front 122

This is a...

Back 122

Function of T° and isotopic ratio in the water

Front 123

What is the delta ratio?

Back 123

ɗ(x) = (Rx - Rstd)/Rstd x 10³

Front 124

x stands for?

Back 124

The sample

Front 125

std is?

Back 125

Standard

Front 126

R is?

Back 126

R = 18^O/16^O

Front 127

SMOW?

Back 127

The standard mean ocean water,
ratio of 16^O/18^O in water

Front 128

PDB?

Back 128

Pee Dee Belemnite, Cretaceous from South Carolina, ratio of 16^O/18^O in sediment

Front 129

Oxygen isotopes and deep sea sediments...(3)

Back 129

1.) Record the temperature and sea water chemistry in their shells (Usually forams)
2.) Accumulate slowly over time
3.) Shell chemistry may be used as proxy for past climates

Front 130

Proxy?

Back 130

A measurement of one thing that is an indicator of another thing

Front 131

Emiliani...

Back 131

1955, collected piston cores in the Caribbean and North Atlantic and looked at the oxygen isotopic composition of forams

Front 132

Emiliani also...

Back 132

1.) Wrote paper in the Journal of Geology, Pleistocene Temperatures
2.) He thought that the change was all temperature due to glacial/interglacial episodes

Front 133

What was the problem with the formula developed and Emiliani's hypothesis?

Back 133

1.) The problem is, the ratio in the shells reflect T° and the ratio of sea water

Front 134

This problem is also called?

Back 134

The curse of Harold Urey

Front 135

How might the ratio of sea water change?

Back 135

Isotopic fractionation

Front 136

Isotopic fractionation?

Back 136

Partitioning of isotopes between two substances with different isotopic ratios

Front 137

When will this occur?

Back 137

May occur during phase change (Liquid to water vapor)

Front 138

Isotopic fractionation...

Back 138

1.) Preferentially incorporate the lighter isotope
2.) O-16 will evaporate first before O-18 because its lighter

Front 139

Fractionation?

Back 139

Is a temperature dependent process

Front 140

At lower temperatures...

Back 140

Higher fractionation

Front 141

Biological mediation...

Back 141

Can alter thermodynamic fractionation, organism can choose to incorporate O-16 or O-18

Front 142

Evaporation of sea water...

Back 142

Preferentially takes lighter isotopes

Front 143

This leaves the ocean....

Back 143

Relatively heavier

Front 144

Today, most water...

Back 144

Runs back into the ocean, so the ratio stays relatively constant

Front 145

During glacial times...

Back 145

The rain is stored on land as ice

Front 146

Shackleton...

Back 146

1967, argued the record was all ice volume based on his use of benthic forams

Front 147

How can we separate the temperature signal from sea water ratio change?

Back 147

1.) Looked at benthic forams, planktonic forams, and compound ratios
2.) In fact, it is about 2/3 ice volume, 1/3 temperature change in the deep sea isotopic record

Front 148

This can be...

Back 148

Used to see if core was in interglacial or glacial

Front 149

There are about...

Back 149

20 ice ages through history

Front 150

Oxygen isotopes...

Back 150

In forams record glacial and interglacial cycles or ice ages through time

Front 151

What causes these cycles?

Back 151

Orbital variations

Front 152

James Croll?

Back 152

Scottish geologist developed a astronomical theory of glaciations (1864-1867)

Front 153

Mitotin Milankovitch?

Back 153

Serbian astromer/mathematician calculated all planetary perturbations and how they affect incoming solar radiation

Front 154

These planetary cycles are often called?

Back 154

Milankovitch cycles or Croll-Milankovitch cycles

Front 155

Since these variations affect the amount of solar radiation reaching the Earth...

Back 155

They therefore play a role in climate

Front 156

What are the three main types of orbital variations?

Back 156

1.) Eccentricity
2.) Obliquity
3.) Precession of the Equinoxes

Front 157

Eccentricity?

Back 157

Change of shape of Earth's orbit from oval to more circular

Front 158

How often does eccentricity occur?

Back 158

Occurs on a 100,000 year cycle

Front 159

Eccentricity also?

Back 159

Affects the average solar energy reaching Earth

Front 160

Obliquity?

Back 160

Axial tilt changes from about 22 to 25 degrees

Front 161

How often does obliquity occur?

Back 161

Cycle of about 41,000 years

Front 162

Obliquity also?

Back 162

Affects the amount of heat each hemisphere receives at high latitudes

Front 163

How can we tell the degree of tilt of the Earth?

Back 163

Wherever the tropic of Capricorn and the tropic of Cancer are that is the degree of tilt

Front 164

Precession of the Equinoxes?

Back 164

Alters where the Earth is at in its orbit, at certain times of the year with respect to the sun

Front 165

Why does the Precession of the Equinoxes occur?

Back 165

Occurs because of wobbles in the Earth's rotation and changes in ellipse

Front 166

How often does the Precession of the Equinoxes occur?

Back 166

Has a cycle between 23,000 and 19,000 years

Front 167

The Precession of the Equinoxes also?

Back 167

Shifts the dates of the winter solstice and summer solstice clockwise around the orbit

Front 168

Precession of the Equinoxes?

Back 168

Doesn't change time of seasons just the distance of the sun

Front 169

Testing this idea that ice ages are controlled by orbital variation...

Back 169

Matching orbital variations to the continuing deep sea record of ɗ18^O

Front 170

Who did this?

Back 170

Hays, Imbrie, and Shackleton published scientific paper Variations in Earth's Orbit: Pacemaker of the Ice Ages

Front 171

How did they do this test?

Back 171

Using spectral analysis to match the ice age cycles to the Milankovitch cycles

Front 172

The first 14 ice ages...

Back 172

Were 3 million years ago

Front 173

What were the questions/problems with the ice ages matching up with the orbital variations?

Back 173

Orbitals variations extend into past, but glacial/interglacial cycles occur at certain times in Earth history

Front 174

More questions/problems with the ice ages matching up with the orbital variations?

Back 174

The 100,000 year signal appears the strongest in record, but the change in solar radiation is the weakest

Front 175

Rapid climate change?

Back 175

Ice core data indicates changes in climate can be much more rapid than Milankovitch cycles (Ex. Younger Dryas)

Front 176

How does ice core data work? (5)

Back 176

1.) Gases are trapped in ice. (CO2, methane, ect...)
2.) The ice accumulates in layers that may be counted back in time
3.) Measures of atom concentrations may be obtained
4.) Geochemistry of ice tells us temperature
5.) Much higher resolution than deep sea sediment cores

Front 177

About 10,000 years ago...

Back 177

Climate began to become stable , which is when the first settling civilizations popped up

Front 178

Younger Dryas?

Back 178

Rapid temperature change

Front 179

Younger Dryas is...

Back 179

The name of an arctic plant

Front 180

When was the most recent Younger Dryas?

Back 180

10,000 years ago

Front 181

Younger Dryas event?

Back 181

Evidence indicates rapid shift back to a more glacial climate during a time when climate should be warming

Front 182

What could cause this?

Back 182

Meltwater events

Front 183

Meltwater events?

Back 183

Melting ice flowed into dammed lakes, once dam breaks the water rushes all at once to join the ocean

Front 184

Meltwater events...

Back 184

Evidence from deep sea sediments indicates meltwater pulses occurring during the glacial retreat

Front 185

How does this cause Younger Dryas cooling?

Back 185

Ocean plays a role in this

Front 186

How does the ocean play a role in the Younger Dryas cooling?

Back 186

1.) Temperature and salinity of water drive thermohaline circulation (Conveyor system)
2.) Meltwater pulses disrupt the conveyor system (No warm water circulates north)
3.) Climate becomes colder (Younger Dryas event)

Front 187

Younger Dryas cooling...

Back 187

North Atlantic deep water that circulates to the Pacific which then returns as a warmer surface current is disrupted, stopping the circulation of warm waters

Front 188

After this Younger Dryas event?

Back 188

Arctic warming after event was 7 degrees in 50 years, this was once the fresh water of the lakes started to get incorporated