Essentials of oceanography 100-200

Flashcards for vocabulary review based on the provided lecture notes.

Mid-Atlantic Ridge

A great sea-gash which separates the continents and extends from the Arctic to the Antarctic.

Bathymetry

The measurement of ocean depths and charting the shape or topography of the ocean floor.

Sounding

A probe of the environment for scientific observation.

Fathom

The standard unit of ocean depth, equal to 1.8 meters (6 feet).

Relief

Variations in elevation.

Echo Sounder/Fathometer

An instrument that sends a sound signal (ping) to measure ocean depth.

Ping

A sound signal used in echo sounding.

Precision Depth Recorder (PDR)

A focused high-frequency sound beam used to measure depths to a resolution of about 1 meter.

Multibeam Echo Sounders

Instruments that use sound to map the sea floor using multiple frequencies simultaneously.

Side-scan Sonar

An instrument that uses sound navigation and ranging to map the sea floor.

Sea MARC/GLORIA

Detailed strip map of ocean floor bathymetry that can be towed behind a survey ship.

Hypsographic Curve

Shows the relationship between the height of the land and the depth of the oceans.

Continental Margins

Areas of shallow water close to continents.

Deep-Ocean Basins

Deep-water areas farther from land.

Mid-Ocean Ridge

Shallower areas near the middle fo an ocean.

Passive Margins

Continental margins lacking proximity to plate boundaries and tectonic activity.

Active Margins

Continental margins associated with plate boundaries and high tectonic activity.

Convergent Active Margins

Margins associated with oceanic-continental convergent plate boundaries.

Transform Active Margins

Margins associated with transform plate boundaries.

Continental Shelf

Flat zone extending from the shore beneath the ocean surface to the shelf break.

Shelf Break

A marked increase in slope angle.

Continental Borderland

Marked by a high degree of relief, islands, shallow banks, and deep basins present along transform active margins.

Continental Slope

Area where the deep-ocean basins begin beyond the shelf break.

Submarine Canyons

Narrow but deep submarine valleys, V-shaped in profile view and have branches or tributaries with steep to overhanging walls.

Turbidity Currents

Underwater avalanches of muddy water mixed with rocks and other debris.

Continental Rise

A transition zone between the continental margin and the deep-ocean floor comprised of a huge submerged pile of debris.

Graded Bedding

Distinctive type of layering that deposits larger pieces first, then progressively smaller pieces that grades in size upward.

Turbidite Deposits

Stacks of graded bedding.

Deep Sea Fans/Submarine Fans

Deposits at the mouths of submarine canyons that are fan, lobate, or apron shaped.

Abyssal Plains

Extending from the base of the continental rise into the deep-ocean basins are flat depositional surfaces with slopes of less than a fraction of a degree that cover extensive portions of the deep-ocean basins.

Seamount

Volcanic peaks that are below seal level but rise more than 1 kilometer above the deep-ocean floor and have a pointy top.

Tablemount/Guyot

A volcano that has a flattened top.

Abyssal Hills/Seaknolls

Volcanic features on the ocean floor that are less than 1000 meters tall.

Abyssal Hill Provinces

Regions dominated by abyssal hills

Ocean Trenches

Deep linear scars in the ocean floor, caused by the collision of two plates along convergent plate margins.

Volcanic Arc

The landward side of the trench that rises as a volcanic arc that may produce islands or a volcanic mountain range along the margin of a continent.

Pacific Ring of Fire

Has the majority of Earth’s active volcanoes and large earthquakes because of the prevalence of convergent plate boundaries along the Pacific Rim.

Mid-Ocean Ridge

A continuous, fractured-looking mountain ridge that extends through all the ocean basins.

Rift Valley

Central downdropped rift valley created by sea floor spreading (rifting) where two plates diverge.

Oceanic Ridges

Segments of the mid-ocean ridge that have a prominent rift valley and steep, rugged slopes.

Oceanic Rises

Segments of the mid-ocean ridge that have slopes that are gentler and less rugged.

Pillow Lavas/Pillow Basalts

Smooth, rounded lobes of rock that resemble a stack of bed pillows.

Hydrothermal Vents

Sea floor hot springs created when cold seawater seeps down along cracks and fractures in the ocean crust and approaches an underground magma chamber.

Warm-Water Vents

Hydrothermal vents that have water temperatures below 30°C.

White Smokers

Hydrothermal vents that have water temperatures from 30° to 350°C and emit water that is white because of the presence of various light colored compounds, including barium sulfide.

Black Smokers

Hydrothermal vents that have water temperatures above 350°C and emit water that is black because of the presence of dark-colored metal sulfides, including iron, nickel, copper, and zinc.

Chemical Precipitate

A formed phenomenon when dissolved materials change from existing in the dissolved state to existing in the solid state.

Archaeons

Microscopic bacteria-like organisms a newly discovered domain of life.

Transform Faults

Oriented perpendicular to the spreading zones, transform faults give the mid-ocean ridge the zigzag appearance.

Transform Fault

Seismically active area that offsets the axis of a mid-ocean ridge.

Fracture Zone

Seismically inactive area that shows evidence of past transform fault activity.

Lithogenous/Terrigenous Sediment

Derived from preexisting rock material that originates on the continents or islands from erosion, volcanic eruptions, or blown dust.

Biogenous/Biogenic Sediment

Derived from the remains of hard parts of once-living organisms.

Hydrogenous Sediment

Derived from the dissolved material in water.

Cosmogenous Sediment

Derived from extraterrestrial sources.

Paleoceanography

Study of interations of the ocean, atmosphere, and land in producing changes in ocean chemistry, circulation, biology, and climate.

Gravity Corer

Hollow steel tube with a heavy weight on top that was thrust into the sea floor to collect the first cores (cylinders of sediment and rock).

Eroded Material

Rocks on continents or islands, overtime weathering agents (water etc.) break rocks into smaller pieces.

Neritic

Deposits found on continental shelves and in shallow water near islands; these deposits are generally coarse grained.

Sorting

Measure of the uniformity of grain sizes and indicates the selectivity of the transportation process.

Pelagic

Deposits found in the deep-ocean basins and are typically fine grained.

Glacial Deposit

Poorly sorted deposits containing particles ranging from boulders to clays may be found in the high-latitude portions of the continental shelf.

Ice Rafting

Process in which rock particles trapped in glacial ice are carried out to sea by icebergs that break away from coastal glaciers.

Abyssal Clay

Composed of at least 70% (by weight) fine, clay-sized particles from the continents.

Biogenous Sediment

The hard parts (shells, bones, and teeth) of living organisms ranging from minute algae and protozoans to fish and whales.

Tests

Tiny shells that begin to sink after the organisms die and continually rain down in great numbers onto the ocean floor.

Ooze

Resembles very fine-grained, mushy material that contains at least 30% biogenous test material by weight.

Algae

Microscopic algae that are primarily aquatic, eukaryotic, photosynthetic organisms, ranging in size from microscopic single cells to large organisms like giant kelp.

Protozoans

Any of a large group of single-celled, eukaryotic, usually microscopic organisms that are generally not photosynthetic.

Biogenous

Algae and protozoans are significant because they contribute to what kind of sediments?

Diatomaceous Earth

When ooze lithifies, it becomes __ , a lightweight white rock composed of diatom tests and clay.

Radiolarians

Microscopic single-celled protozoans, most of which are also planktonic that usually display well-developed symmetry.

Coccolithophores

Significant sources of calcium carbonate biogenous ooze, microscopic algae that are known as nannoplankton.

Calcareous Ooze

Deposits comprised primarily of tests of foraminifers, coccoliths, and other calcareous-secreting organisms.

Globigerina Ooze

One of the most common types of foraminifer ooze named for a foraminifer that is especially widespread in the Atlantic and South Pacific oceans.

Productivity

Number of organisms present in the surface water above the ocean floor.

Destruction

Occurs when skeletal remains (tests) dissolve in seawater at depth.

Dilution

Occurs when the deposition of other sediments decreases the percentage of the biogenous sediment found in marine deposits.

Limestone

Warm, shallow-water shelves and around tropical islands are carbonate deposits.

Stromatolites

Lobate structures consisting of fine layers of carbonate that form in specific warm, shallow-water environments.

Diatomaceous

When the siliceous ooze consists mostly of diatoms, it is called ___ ooze.

Radiolarian

When the siliceous ooze consists mostly of radiolarians, it is called ooze.

Carbon Dioxide

If ocean depth contains more ,calcareous ooze dissolves.

Silica

The ocean is undersaturated with _ at all depths.

Lysocline

The depth in the ocean at which the pressure is high enough and the amount of carbon dioxide in deep-ocean waters is great enough to begin dissolving calcium carbonate.

Calcite Compensation Depth (CCD)

Depth at which the pressure is high enough and the amount of carbon dioxide in deepwater is great enough to begin dissolving calcium cabonate, all sediment does not contain much calcite because it dissolves readily.

Precipitate

Chemical reactions within seawater that causes certain minerals to come out of solution.

Manganese Nodules

Rounded, hard lumps of manganese, iron, and other metals.

Phosphates

Phosphorus-bearing compounds that occurs abundantly as coatings on rocks as nodules on the continental shelf and on banks at depths shallower than 1000 meters.

Aragonite & Calcite

These are 2 of the most important mineral in marine sediment minerals contains that are composed of calcium carbonates.

Salt Deposits

Evaporites can form these kinds of deposits.

Cosmogenous Sediment

Are unusually tall features that reaches from the sea floor all the way above sea level (2 types micrometeoroties and microtektites).

Tektites

Small globular masses that composed of silicate rock material and show evidence of being formed by extraterrestrial impact events on Earth or other planets that eject small molten pieces of crust into space.

Spherules

Composed mostly of iron and nickel formed asteroid belt between the orbits of Mars and Jupiter and are produced when asteroids collide.

Core

This term is used to describe long cylinders of sediment being cut in half.

Hypos

The height or elevation for graphic purpose.

Weathering

Process of breaking down rock is known as:

River System

Type of transportation that utilizes moving water to carry materials:

Settling

Process when material is deposited:

Organic/Fecal Matters

What part of marine sediment that we derive petroleum from?