Oceanography exam 1

Former from cooled magma/Lava

Igneous Rock

Formed from the cementation and compaction of sediment

Sedimentary rock

Formed from intense heat and pressure

Metamorphic Rock

The process of converting loose sediments into sedimentary rock through compaction and cementation

Lithification

Formed outside of the mantle. Fast cooled. Small crystals (rock type).

Extrusive Rock

Formed inside the mantle, cooled slowly, large crystals, (rock type)

Intrusive rock

Thick, less dense, buoyant, granite based crust type

Continental crust

Thin, dense, basalt based crust type

Oceanic crust

Earth's rigid, rocky outermost layer of the mantle comprising the crust

Lithosphere

a plastic layer of the upper mantle located directly below the lithosphere that allows tectonic plates to move

Asthenosphere

the geologic process where tectonic plates diverge at mid-ocean ridges

Sea floor spreading

the geological theory that Earth's continents move slowly across the planet's surface over geological time

Continental drift

a convergent plate boundary where two tectonic plates collide and the denser plate (usually oceanic) is forced beneath the lighter, overriding plate into the Earth's mantle

Subduction zone

a tectonic boundary where two plates move apart from each other, allowing magma to rise from the mantle, create new crust, and form rift valleys or mid-ocean ridges

Divergent boundary

location where two or more lithospheric plates move toward each other and collide

Convergent boundary

a tectonic plate margin where two plates slide horizontally past one another, neither creating nor destroying lithosphere

Transform boundary

a curved, chain-like chain of volcanic islands or mountains formed at convergent plate boundaries, where an oceanic plate subducts beneath another oceanic or continental plate

Island/volcanic arc

a massive underwater volcanic range formed at divergent tectonic plate boundaries where new oceanic crust is created as plates pull apar

Mid ocean ridge

the submerged, shallow-water zone of transition between the continental crust of the dry land and the deep oceanic crust

Continental margin

thick, accumulated sediments, wide continental shelves, and a lack of significant earthquake or volcanic activity not on an active plate boundary

Passive margin

a tectonic plate boundary, characterized by high geological activity, featuring narrow continental shelves, steep slopes, and deep ocean trenches

Active margin

a volcanic region fed by a deep, stationary plume of abnormally hot mantle material rising from within the Earth, creating volcanoes on the surface

Hotspot

the geological process of ocean basins opening and closing due to plate tectonics (continental rifting, seafloor spreading, subduction, and continent-continent collision)

The Wilson cycle

the measurement of depth of water in oceans, seas, or lakes.

Bathymetry

the submerged, gently sloping extension of a continent’s landmass

Continental shelf

the submerged,, distinct boundary where the shallow, gently sloping continental shelf, marking the edge of the continent's geological footprint

Continental break

the steep, submerged incline extending from the outer edge of the continental shelf down to the deep ocean floor ending in oceanic trench

Continental slope

gently sloping accumulation of sediment at the base of the continental slope, transitioning smoothly to the flat abyssal plain

Continental rise

fast, downhill flow of dense, sediment-laden water, triggered by events like earthquakes, landslides, or floods, acting like an underwater avalanche that deposits sediment in layers called turbidites

Turbidity currents

Steep-sided, V-shaped valleys incised into the seabed of the continental slope and shelf, acting as major conduits for transporting sediment and nutrients to the deep sea

Submarine canyons

a massive, underwater geological structure resembling a river delta, formed by turbidity currents settling on the deep seafloor

Deep sea fan

an underwater plain on the deep ocean floor, formed by the accumulation of fine-grained sediments, such as clay and silt, which blanket the rugged oceanic crust over millions of years.

Abyssal plain

An underwater mountain, formed primarily by volcanic activity, they are typically cone-shaped, isolated, and act as critical, biodiversity-rich hotspots for deep-sea ecosystem

Seamount

a long, narrow, V-shaped depression in the ocean floor, formed by subduction at convergent plate boundaries

Ocean trench

shallow-water marine sediments accumulated on the continental shelf

Neritic deposits

fine-grained, deep-sea sediments that accumulate slowly (centimeters per millennium) on the open ocean floor, far from continental margins

Pelagic deposits

inorganic, land-derived material derived from the physical and chemical weathering of pre-existing rocks on continents and islands. These sediments are transported to the ocean via rivers, wind, ice, and gravity, settling primarily on continental shelves and slopes as sand, mud, and clay.

Lithogenous sediment

Sediment made up of the remains or waste products of living organisms, such as shells, bones, teeth, and skeletons, primarily from microscopic plankton or larger animals like corals

Biogenous sediment

Biogenous sediment made of greater than 30% organic remains

Ooze

the ocean floor level where the rate of calcium carbonate (calcite) supply from the surface equals the rate of its dissolution, meaning below this depth, calcite shells don't accumulate in sediments

Calcite compensation depth (CCD)

marine deposits formed from minerals that precipitate directly out of seawater through chemical reactions, often under specific conditions like evaporation or near hydrothermal vents

Hydrogenous sediment

the rarest type of marine sediment, consisting of material derived from outer space that settles on the ocean floor

Cosmogenous sediment

Where does calcareous ooze accumulate/deposit?

Warm shallow water in mid latitudes

where does siliceous ooze accumulate/deposite

on the deep-ocean floor in areas of high surface productivity, specifically beneath polar regions

What is the cascadia subduction zone

A convergent plate boundary where the Juan de Fuca oceanic plate slides beneath the North American continental plate