Marine Provinces and Marine Sediments Flashcards by Nathanael Kent Rondario

Represent earth’s largest museum with displays of earth history, dating millions of years. It provides clues to history, specifically on:
- Marine Organism Distribution
- Ocean Floor Movements
- Ocean Circulation Patterns
- Climate Change
- Global Extinction Events

Marine Sediments

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Destroyed >75% of species on earth (dinosaurs, many others). After extinction, many groups underwent sudden and prolific divergence into new forms and species (ex mammals diversified into horses, whales, bats, primates). Boundary clay showed high levels of metal _____? which is rare in earth’s crust

K-Pg Extinction Event, Iridium

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Size and Shape of Particles. Its origins can be:
- Worn rocks
- Living Organisms
- Minerals dissolved in water
- Outer space

Texture

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Over time, sediments can become _____ and form what?

Lithified, Sedimentary rock

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More than half of rocks exposed on the continents are sedimentary rocks deposited in ancient ocean environments and uplifted onto land by ____?

Plate Tectonics

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Mt. Everest (in Himalaya Mountains) consists of ____, which originated in sea floor deposits

Limestone

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The study of the history of the oceans in the geologic past. It is the study of how ocean, atmosphere, and land interactions have produced changes in ocean chemistry, circulation, biology, and climate.

Paleoceanography

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As sediments accumulate, they preserve materials and conditions of the environment that existed in the overlying water column; can infer sea surface temp, nutrient supply, abundance of marine life, atmospheric winds, ocean current patterns, volcanic eruptions, major extinctions events, changes in climate, movement of tectonic plates

Sediment Cores

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Unconsolidated organic and inorganic particles that accumulate on the ocean floor

Sediment

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Sediment Load:
- Dissolved chemicals, ions
- Fine-grained particles, carried in water column
- Coarse-grained particles, remain on or near stream bed by rolling, sliding, or jumping

Dissolved Load
Suspended Load
Bed Load

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Sediments are classified according to its:
- ?
- ?

Size
Origin

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Sediments are classified by size according to the ____?. It’s measured on a _____ scale called the “___”, which classified particles by size from “clay” to “boulder”.

Wentworth Scale, Log Base 2 Scale, Phi Scale

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This indicates the energy of the transporting medium.
- more energy needed
- low energy environments

Particle Size
- Larger Grain Size
- Small Particles

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Same size, found in area where energy change within narrow limits (ex. deep ocean sediment)

Well-sorted

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Multiple sizes, found where energy fluctuates over wide range (ex. rubble at base of cliff, sediments carried by turbidity currents)

Poorly-sorted

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The function of energy of the environment – exposure of area to action of waves, tides, currents. Well sorted sediments occur in env where energy fluctuates within narrow limits (ex deep ocean sediments). ____? form in env where energy fluctuates over wide spectrum (ex. rubble at base of cliff, sediments carried by turbidity currents)

Sorting, poorly sorted sediments

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Indicated by several factors
- decreased silt and clay content
- increased sorting
- increased rounding of grains, as a result of weathering and abrasion

Sediment Maturity

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The _____ the time and distance of transportation, the ____ the rounding and the degree of sorting

Longer, Better

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Graphs the relationship between particle size and energy for erosion, transportation and deposition. ____ means pick up and move.

Hjulstrom’s Diagram, Erode

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Sediments Originate from Numerous Sources:
1. Terrigenous
2. Terrigenous
3. Biogenic
4. Autogenic
5. Cosmogenic

Weathering and erosion of the continents
Volcanic eruptions
Biological activity
Chemical processes within the oceanic crust and seawater
Impacts of extra-terrestrial objects

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also called Lithogenous sediments

Terrigenous Sediments

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Eroded rock fragments from land
Also called terrigenous
Reflect composition of rock from which derived
Produced by _____, the breaking of rocks into smaller pieces.

Lithogenous Sediments, Weathering

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Most abundant, derived from weathering of rocks at or above sea level (e.g., continents, islands)
- from erosion, volcanic eruptions,
blown dust
- two distinct chemical compositions
ferromagnesian, or iron-magnesium bearing minerals
- non-ferromagnesian minerals – e.g., quartz, feldspar, micas
- largest deposits on continental margins (less than 40% reach abyssal plains)
transported by water, wind, gravity, and ice
- ____? – most familiar continental igneous rock , source of quartz and clay (2 of the most common component of terrigenous sediments)
- ____ are main source of terrigenous sediments. Lithogenous (lithos = stone) derived from preexisting rock material

Lithogenous/Terrigenous Sediments, Granite, Rivers

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One of the most abundant, chemically stable, and durable minerals in earth’s crust is _____?, composed of silicon and oxygen in the form of SiO2 – same composition as ordinary glass. Because ____ is resistant to abrasion, it can be transported long distances and deposited far from the source area. Majority of lithogenous deposits such as beach sands are composed primarily of _____.

Quartz

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Primary dust source is ____ in Asia and North Africa

Deserts

Dust from ____? is carried downwind across the _____?, hence ships traveling downwind are dusty. Some dust fall in ____? where it has been linked to stress and disease among corals.

Sahara Desert, Atlantic, Caribbean

Slow moving mass of ice formed by accumulation of snow on mountains or near poles. Boulder to clay size particles also eroded and transported to oceans via glacial ice

Glaciers

A large floating mass of ice detached from a glacier or ice sheet and carried out to sea.

Iceberg

Cloudiness or haziness of water. Sediment also transported to the open-ocean by gravity-driven ____ currents. Dense 'slurries' of suspended sediment moved as ______ underflows - Means for deep water ventilation of the Sulu Sea

Turbidity / Turbidity Currents

Cut some of TransAtlantic telegraph cable south of Newfoundland. Cables close to earthquake broke simultaneously with earthquake, but cables that crossed the slope and deeper ocean floor at greater distances from the earthquake were broken progressively later.

1929 Grand Banks Earthquake

Typically consists of rock fragments and silicate materials. _____ means formed by rock breakdown. _____ means volcanic rock.

Rock-clastic sediments, Clastic, Pumice

Begins as the hard parts (shells, bones, teeth) of living organisms ranging from minute algae and protozoans to fish and whales. What are the two most common chemical compounds in biogenous sediments?

Biogenous Sediments, Calcite, Silica

Biogenous sediments classified into: - Large enough to be seen without microscope; ex. shells, bones, teeth - Accumulate in deep-ocean floor; ex. tiny shells called tests

- Macroscopic - Microscopic

_____ are 10-100x smaller than most diatoms, hence they are called _____

Cocolithophores, Nanoplanktons

Calcareous or siliceous 'oozes' if biogenic component greater than ____. Median grain size typically less than _____ (i.e., silt or clay size particles)

30%, 0.005mm

_____ (primarily diatom oozes) cover __%? of the ocean floor

Siliceous Oozes, 15%

Tests are perforated with small holes in intricate patterns to allow nutrients to pass in and waste products to pass out. Two parts of the _____'s test fit together

Diatom

Have long spikes or rays of silica protruding from their siliceous shells, they display well-developed symmetry hence they are described as the living snowflakes of the sea. _____ oozes are more commonly found in the ____? regions.

Radiolarians, Equatorial

____? (foraminifera, coccolithophores) cover ____? of the ocean floor. Distribution controlled largely by _____? processes

Calcareous Oozes, 50%, Dissolution

Affected by temperature, pressure, CO2 solubility of CaCO3 increases in colder water and at greater pressures

Dissolution

Photosynthetic Algae, _____ are individual plates from dead organism. _____ are lithified coccolith-rich ones.

Coccolithophores, Coccoliths, Rock Chalk

- Depth where dissolution begins - Depth where calcium carbonate has dissolved

- Lysocline - Carbonate Compensation Depth or CCD

- Calcareous hard parts of invertebrates - Thanatocoenosis - Ease of identification depends on _____

Carbonate Sand Grains, Degree of Damage

_____ is a genus of green macroalgae. The algal body (thallus) is composed of calcified green segments. _____ is deposited in its tissues, making it inedible to most herbivores.

Halimeda, Calcium Carbonate

- Coral Fragments - Coral reef-associated algae such as Halimeda, Mollusks, some Echinoderms and Foraminifera

Coral Reef-Derived Beach Sediments

Minerals ____? daily from seawater. - Manganese Nodules - Phosphates - Carbonates - Metal Sulfides Small proportion of marine sediments and is distributed in diverse environments.

Hydrogenous Marine Sediments

- Produced by chemical processes in seawater (due to change in temperature, pressure or addition of chemically active fluids - Essentially solid chemical precipitates of several common forms

Hydrogenous (or Authigenic) Sediments

Form in surface waters supersaturated with calcium carbonate (ex. short aragonite crystals and oolites)

Non-biogenous Carbonates

- Phosphate crusts (containing greater than 30% P2O5) occurring as nodules - Formed as large quantities of organic phosphorus settle to the ocean floor - Unoxidized material is transformed to phosphorite deposits - Found on continental shelf and upper slope in regions of high productivity

Phosphorites

Occur abundantly as coatings on rocks and as nodules on the continental shelf and on banks at depth shallower than 1000m. Conc of _____ in such deposits commonly reach 30% by weight and indicate abundant biological activity in surface water where they accumulate.

Phosphates

- Surficial deposits of manganese, iron, copper, cobalt, and nickel - Accumulate only in areas of low sedimentation rate (e.g., the Pacific) - Develop extremely slowly (1 to 10 mm/million years)

Manganese Nodules

____ object may be a piece of lithogenous sediment, coral, volcanic rock, fish bone, shark’s tooth

Nucleation

_____ contain: - Important for making high-strength steel alloys - Used in electrical wiring, in pipes, and to make brass and bronze - Used to make stainless steel - Used as an alloy with iron to make strong magnets and steel tools

Nodules, - Manganese - Copper - Nickel - Cobalt

- Form where there is restricted open ocean circulation and where evaporation rates are high (ex Mediterranean Sea). - Composed dominantly of varying proportions of halite (rock salt) (NaCl), anhydrite (CaSO4) and gypsum (CaSO4-2H2O. - May be classified as chlorides, sulfates or carbonates on the basis of their chemical composition

Evaporites

Surrounded by land except for shallow connection to Atlantic Ocean through the Strait of Gibraltar which is 14 km wide. 6million years ago, drop in sea level cut off Atlantic Ocean. Arid climate resulted in high evaporation rates. Dissolved substances began to precipitate. Salt deposits are 4000m thick. Half million years later, erosion or rise in sea level caused dam at Gibraltar to be breached and Med started to refill.

Mediterranean Sea

- Sediments derived from extraterrestrial materials - Includes micrometeorites and tektites

Cosmogenous Sediments

- Debris from meteors that settle around impact site, composed of silicate rock or iron and nickel. - A small body of matter from outer space that enters the earth's atmosphere, becoming incandescent as a result of friction and appearing as a streak of light.

Meteorites

- Result from extraterrestrial impact events on earth or other planets that eject small molten pieces of crust - Fragments of earth's crust melt and spray outward from impact crater crustal material re-melts as it falls back through the atmosphere - Forms 'glassy' ___

Tektites

In Marine Sediment Collection, early explorations used _____, while modern explorations used: - Hollow steel tubes collect sediment columns - Collects deep ocean sediment cores

Dredges - Cores - Rotary Drilling

Net or wire baskets dragged across the bottom to collect loose bulk material, surface rocks, and shells

Bottom Dredge

Hinged devices that are spring- or weight-loaded to snap shut when sampler strikes the bottom

Grab Sampler

Hollow pipe with sharp cutting end. ______ is forced down into the seafloor by its weight or for longer cores, by a piston device within the core barrel that uses water pressure to help drive the corer into the sediments. Sediments obtained has undisturbed sediment layers

Piston Corer, Free-falling Pipe

- Drive a rectangular metal box into the sediment, with doors that close over the bottom of the box before sample is retrieved. - Used when large and undisturbed surface sediment needed

Box Corer

- Measure carbon flux - Estimates Global carbon cycle - Important for study of Climate change

Sediment Traps

- Originally believed deepest parts of the the ocean were in the _____? - Estimates of depths (soundings) go back centuries, but details of seafloor didn’t arise until the late 19th century with the laying of transatlantic telegraph lines

Seafloor Investigation, Middle

- (bathos = depth, metry = measurement) - Ocean depths and topography of ocean floor (topo = place, graphy = description)

Bathymetry

- Rope/wire with heavy weight - Known length

Sounding

1st recorded attempt to measure ocean’s depth conducted in the Mediterranean Sea in 85BC by Greek named ____?

Posidonius

- Comprehensive scientific expedition - Ship refitted with laboratories, winches, and sounding scope - 3.5 yr voyage; every so often ______ crew stopped and measured the depth and other ocean properties. Found out the deep ocean floor not flat but with had significant relief (variations in elevation)

HMS Challenger

- Reflection of sound signals (pings) - 1925 German ship Meteor - Invented in 1920 - invented in early 1900s. In 1925, Meteor used _____to identify underwater mountain range

Echo Sounder

Depth Formula: What is V (Speed of Sound?):

Depth = V * (T/2) V = 1507 m/s

- 1950s - Focused High-Frequency Sound Beam (Resolution of 1m) - First reliable sea floor maps produced using _____ - Helped confirm sea floor spreading and plate tectonics

Precision Depth Recorder (PDR)

Multiple simultaneous sound frequencies

Multibeam Echo Sounders

- The first multibeam echosounder, made it possible for a survey ship to map the features of the seafloor along a strip up to 60 km wide. - Hull mounted _______emit multiple beams of sound waves, which are reflected off the ocean floor. - From data, can determine the depth, shape, and whether bottom is rock, sand or mud. Can produce detailed image of sea floor bathymetry

Seabeam, Multibeam Instruments

SONAR, makes picture with sound

Sounding Navigation and Ranging

Can be towed behind ship to provide very detailed bathymetric strip map. In deep water where detailed survey is required, _____ can provide enhanced views of the seafloor. (ex: _____ and _____)

Side-scan Sonar - GLORIA (Geological Long Range Inclined Acoustical Instrument) - Sea MARC (Sea Mapping and Remote Characterization)

- Gets close to seafloor so it can image with higher resolution - Trade off is slower, more limited coverage

Deep-Tow Sonar

- Uses Satellite Measurements - Measures sea floor features based on gravitation bulges in sea surface - Indirectly reveals bathymetry - The result is that the ____ roughly reflects the ______

Sea Floor Mapping From Space, Surface, Bottom Topography

- Air Guns - Strong, low frequency sounds - Details ocean structure beneath sea floors

Seismic Reflection Profiles

Good for determining subsurface properties; application in mineral and petroleum exploration

Seismic Profiling

3 Major Ocean Provinces - Shallow-water areas close to shore - Deep-water areas farther from land - Submarine mountain range

- Continental Margins - Deep-ocean Basins - Mid-Ocean Ridge

- Includes: Shelf, Slope and Rise - Make up ____%? of ocean floor

Continental Margins, ~21%

2 major types of Continental Margins: - Relatively little earthquakes/volcanic activities ; facing the edges of diverging plates - Much movement; near the edges of converging plates or where plates are slipping past each other; coincide with plate boundaries

- Passive (e.g. Atlantic) - Active (e.g. Pacific)

Shallow submerged extension of a continent; more similar to the continent than the deep-ocean floor; varying widths depending on proximity to plate boundary (active or passive margin) and currents and sea level

Continental Shelf

Transition between gently descending continental shelf and deep ocean floor; formed of sediments that reach the edge of shelf and transported over the side; at shelf break (~ 140 m)

Continental Slope

Due to underwater “avalanche” triggered by e.g., earthquakes

Submarine Canyons

Along passive margins; base of slope covered by an apron of accumulated sediment (100-1000km width)

Continental Rise

- Make up ______ of Earth’s surface - Includes * Abyssal plains and hills * Volcanic peaks * Trenches

Ocean Basins, More than Half

Majority of ocean trenches are along the margins of the _____, where plates are being subducted. Most of the world’s large earthquakes and active volcanoes occur around the _____.

Pacific Ocean, Pacific Rim / Pacific Ring of Fire

- Very flat depositional surfaces starting from base of continental rise - 4500 – 6000 meters deep - Next to trenches they are the deepest parts of the ocean - Suspension settling of very fine particles - Sediments cover ocean crust irregularities so it looks flat…like snow - Well-developed in Atlantic and Indian oceans

Abyssal Plains

- Poke through sediment cover - Below sea level: * _____ are less than 1 km * _____, _____, ______ at least 1 km above seafloor Above sea level: - _____

Volcanic Peaks Below Sea Level: - Abyssal Hills <1 km - Seamounts, Tablemounts, Guyots >= 1km above seafloor Above Sea Level: - Volcanic Islands

Volcanoes that don’t rise above sea surface;

Seamounts

If they rose above sea level in the past and eroded to a flat top by waves

Guyots

Broad undersea mountain chains; Location of diverging plates; - Oceanic ridge - Oceanic rise Features; - Central rift valley, faults and fissures - Pillow basalts - Hydrothermal vents

Mid-Oceanic Ridges

Volcanic igneous rock that forms when lava of basaltic composition is erupted underwater, rapidly cooled w/ seawater

Pillow Basalts

Solar Energy = Photosynthesis Hydrothermal Energy = _____? Instead of Oxygen, hydrothermal energy uses ____?

Chemosynthesis, Sulphuric Acid

- _____ is a 13-million-hectare underwater plateau located near Aurora. It is larger than Luzon and is considered part of the Philippines' continental shelf. - It is potentially a rich source of natural gas and other resources such as heavy metals. It is about 2,000 to 5,000 meters deep. - In 2012, the United Nations Commission on the Limits of the Contintental Shelf (UNCLOS) confirmed _____ as part of the Philippines' continental shelf. Under the UN Convention on the Law of the Sea (UNCLOS), the continental shelf comprises the seabed and subsoil of the submarine areas 200 nautical miles (NM), or 370 kilometers, from a state's baselines or “edges.” - According to scientific data based on seismic, magnetic, other geological features, the Benham Rise region is an extension of the Philippines’ continental shelf.

Benham Rise

Marine Provinces and Marine Sediments Flashcards

(97 cards)