Marine Provinces and Marine Sediments Flashcards
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
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
Size and Shape of Particles. Its origins can be:
- Worn rocks
- Living Organisms
- Minerals dissolved in water
- Outer space
Texture
Over time, sediments can become _____ and form what?
Lithified, Sedimentary rock
More than half of rocks exposed on the continents are sedimentary rocks deposited in ancient ocean environments and uplifted onto land by ____?
Plate Tectonics
Mt. Everest (in Himalaya Mountains) consists of ____, which originated in sea floor deposits
Limestone
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
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
Unconsolidated organic and inorganic particles that accumulate on the ocean floor
Sediment
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
Sediments are classified according to its:
- ?
- ?
- Size
- Origin
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
This indicates the energy of the transporting medium.
- more energy needed
- low energy environments
Particle Size
- Larger Grain Size
- Small Particles
Same size, found in area where energy change within narrow limits (ex. deep ocean sediment)
Well-sorted
Multiple sizes, found where energy fluctuates over wide range (ex. rubble at base of cliff, sediments carried by turbidity currents)
Poorly-sorted
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
Indicated by several factors
- decreased silt and clay content
- increased sorting
- increased rounding of grains, as a result of weathering and abrasion
Sediment Maturity
The _____ the time and distance of transportation, the ____ the rounding and the degree of sorting
Longer, Better
Graphs the relationship between particle size and energy for erosion, transportation and deposition. ____ means pick up and move.
Hjulstrom’s Diagram, Erode
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
also called Lithogenous sediments
Terrigenous Sediments
- 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
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
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
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