Oceanography Exam 1 (Ch. 1-4)
(Ch.3) fathom
(v.) to understand, get to the bottom of; to determine the depth of; (n.) a measure of depth in water
(Ch.4) Hydrogenous Marine Sediments
*minerals precipitate directly from seawater --manganese nodules --phosphates --carbonates --metal sulfides -evaporites *small proportion of marine sediments *distributed in diverse environments
(Ch.4) calcium carbonate in biogenous sediments
-Coccolithophores (algae) -- photosynthetic, coccoliths (nano-plankton), rock chalk -Foraminifera (protozoans) -- calcareous ooze (along Mid-Ocean Ridges)
(Ch.4) pelagic sediment
-Deeper-water deposits -Finer-grained sediments -Deposited slowly
(Ch.4) Silica in Biogenous Sediments
-Diatoms -- algae: photosynthetic, diatomaceous earth Radiolarians -- protozoans -Siliceous ooze -- if 30% or more of sediment is made up of biogenic material it is called 'ooze'
(Ch.4) Sediments
-Loose materials such as rock fragments, mineral grains, and bits of shell that have been moved by wind, water, ice, or gravity - sediments lithify into sedimentary rock
(Ch.4) Cosmogenous Marine Sediments
-Macroscopic meteor debris -Microscopic iron-nickel and silicate spherules -Tektites -Space dust -Overall, an insignificant proportion of marine sediments
(Ch.4) neritic sediments
-Shallow-water deposits -Close to land -Dominantly lithogenous -Typically deposited quickly
(Ch.4) Biogenous Sediment Composition
-Two most common chemical compounds: Calcium carbonate (CaCO3) and Silica (SiO2) -hard remains of once-living organisms -tiny shells (tests) and biogenic ooze (algae and protozoans
(Ch.3) passive margin
-a continental margin that LACKS a plate boundary -marked by a low degree of tectonic activity -continental crust is always below -shallow gradient w/ deep shelf break
(Ch.4) gas hydrates
-a gas; such as methane, trapped in a lattice-like structure of water molecules -contain twice as much organic carbon as all known fossil fuels
(Ch.3) active margin
-a high degree of tectonic activity (pacific rim) -convergent active margins & transform active margins
why is it necessary to make bathymetry soundings from a ship?
-multi-beam echo sounders provide info in addition to depth, including the composition of the seafloor -the shape of the sea surface as measured by satellites does not exactly mimic the bathymetry of the seafloor -satellites do not actually measure ocean depth -shipboard data is needed to calibrate satellite sea surface height measurements
(Ch.4) lithogenous
-sediment made of rocks eroded from the continents by water wind waves (weathering) - also called terrigenous -reflect the composition of rock from which derived -mainly composed of Quartz
(Ch.3) Bathymetry
-the measurement of ocean depths and the charting of the shape or topography of the ocean floor. -units BELOW sea level.
(Ch.3) suspension settling
-the process by which fine-grained material that is being suspended in the water column slowly accumulates on the seafloor -accumulates over time and covers crust irregularities (crust fracture zones)
(Ch.4) Pelagic lithogenous sediments
-volcanic ash, wind blown dust, fine-grained material transported by deep ocean currents
(Ch.3) HMS Challenger
1872- 1876 First comprehensive survey of the world's oceans (except the Arctic)-> measured depth by sending a weighted rope overboard until it hit the bottom
(Ch.3) Precision Depth Recorder (PDR)
1950s -Focused high-frequency sound beam -First reliable sea floor maps produced -Helped confirm sea floor spreading
(Ch.3) Posidonius
1st attempt to measure ocean depth
(Ch.1) When did our solar systems form?
5 billion years ago
(Ch.1) How long did it take Earth's oceans to form?
500 million years
(Ch.3) submarine fan
A cone-shaped sedimentary deposit that accumulates on the continental slope and rise because of turbidite deposits
(Ch.4) Integrated Ocean Drilling Program (IODP)
A drilling program that replaced the Ocean Drilling Program in 2003 with a new drill ship that has riser technology, enabling cores to be collected from deep within Earth's interior.
(Ch.3) black smokers
A hydrothermal vent on the ocean floor that emits a black cloud of hot, metal-rich water. temps above 350 degrees celsius. Lots of metal sulfide deposits
(Ch. 2) divergent boundary
A plate boundary where two plates move away from each other.
(Ch.1) Uniformitarianism
A principle that geologic processes that occurred in the past can be explained by current geologic processes. "present is key to the past"
(Ch.3) turbidite deposits
A sediment or rock formed from sediment deposited by turbidity currents characterized by both horizontally and vertically graded bedding.
(Ch. 2) convergent plate boundary
A tectonic plate boundary where two plates collide, come together, or crash into each other.
(Ch. 2) mid-ocean ridge
An undersea mountain chain where new ocean floor is produced; a divergent plate boundary.
(Ch.3) mid-ocean ridge
An undersea mountain chain where new ocean floor is produced; a divergent plate boundary.
(Ch.3) Seamounts
An underwater mountain rising from the ocean floor and having a peaked or flat-topped summit below the surface of the sea.
(Ch.3) extremophiles
Archaea that live in extreme environments.
(Ch. 2) transform fault
Area where the earth's lithospheric plates move in opposite but parallel directions along a fracture (fault) in the lithosphere.
(Ch.4) CCD
Calcite Compensation Depth
(Ch.4) abyssal clay
Deep-ocean (oceanic) deposits containing less than 30% biogenous sediment. Often oxidized and red in color, thus commonly termed red clay.
(Ch.3) rift valley
Downdropped area on crest of ridge Marked by fissures and faults Small earthquakes
(Ch.1) Archaen Eon
Earth cools and solidifies, oceans form, high volcanic activity, banded iron formations, seasons, tides and tilt of earth stabilized by moon, life restricted only to oceans (anaerobic microorganisms). Atmosphere: carbon dioxide,methane, ammonia, water vapor
(Ch.1) James Cook
English navigator who claimed the east coast of Australia for Britain and discovered several Pacific islands (1728-1779).
(Ch.1) Bart Dias
Explorer for Portugal Reached the southern tip of Africa
(Ch.3) Seabeam
First multibeam echo sounder that made it possible for a ship to survey strips of the ocean floor up to 60 km wide
(Ch.1) Ferdinand Magellan
First to circumnavigate the globe
(Ch.3) white smokers
Hydrothermal vents between 30°C and 350°C
(Ch.3) warm water vents
Hydrothermal vents that have water temperatures below 30 degrees Celsius and emit water that is clear in color
(Ch.4) Chikyu
It means Earth in Japanese. The world's most advanced scientific drilling vessel. It can drill as deep as 7,000 meters (nearly 23,000 feet). It is part of the Integrated Ocean Drill Program (IODP)
(Ch.1) John Cabot
Italian explorer who led the English expedition in 1497 that discovered the mainland of North America and explored the coast from Nova Scotia to Newfoundland (ca. 1450-1498)
(Ch.1) Stromatolites
Oldest known fossils formed from many layers of bacteria and sediment. *crucial for oxygen production*
(Ch.4) calcareous ooze
Ooze composed of mostly the hard remains of organisms containing calcium carbonate
(Ch.1) Used stick charts to navigate
Pacific Islanders
(Ch.1) Stanley Miller
Scientist. Performed an experiment that produced amino acids under possible primitive earth conditions
(Ch.4) biogenous sediment
Sediment of biological origin. Organisms can deposit calcareous (calcium-containing) or siliceous (silicon-containing) residue.
(Ch.4) cosmogenous sediment
Sediment of extraterrestrial origin.
(Ch.1) Vasco Nunez de Balboa
Spanish explorer who discovered the Pacific Ocean (1475-1519)
(Ch.1) Proterozoic Eon
The eon following the Archean and preceding the Phanerozoic. it extends between 2500 and 542 million years ago. Free oxygen, multi-cellular organisms.
(Ch.3) continental borderland
The ocean floor offshore of southern California characterized by deep basins bounded by steep slopes (escarpments) and faults, islands, and shallow banks.
(Ch.3) Volcanic Arc (Island Arc)
a chain of volcanoes formed above a subducting plate, positioned in an arc shape
(Ch.1) What is the definition of a sea?
a sea is smaller, shallower, composed of salt water, usually enclosed by land, directly connected to ocean
(Ch.3) submarine canyon
a seaward extension of a valley that was cut on the continental shelf during a time when sea level was lower, or a canyon carved into the outer continental shelf, slope, and rise by turbidity currents
How have oceanographers learned most about the geology of the seafloor?
acoustic (seismic) sounding and profiling
(Ch.3) fracture zone
an area of irregular, seismically inactive topography, marking the position of once active transform faults. covered by sediments as you approach the continent
(Ch.1) Crust
basalt, igneous rocks, less homogenous (Light silicate materials)
(Ch.4) Neritic lithogenous sediments
beach deposits, continental shelf deposits, turbidite deposits, glacial deposits
(Ch.4) siliceous ooze
biogenous sediment composed of the silica based shells of single-celled animals and algae
(Ch.4) Wentworth Scale
boulder, cobble, pebble, gravel, sand, silt, clay
(Ch.4) rotary drilling
collects deep ocean sediment cores
(Ch.1) Juan Sebastian del Cano
completed the first circumnavigation around the world
(Ch. 2) oceanic-oceanic convergence
denser plate is subducted, deep trenches generated, volcanic island arcs generated
(Ch 1.) What is outgassing?
density stratification of water vapor, carbon dioxide, hydrogen and other gases
(Ch.4) hyrdogenous sediment
derived from water
(Ch.1) Arabian Explorers
dominant navigators traded extensively in East Africa, India, SE Asia used indian monsoon winds for travel
(Ch.1) Cenozoic Era
era that began about 66 million years ago, known as the "Age of Mammals"
(Ch.1) Vikings
explored North Atlantic settled Iceland & Greenland Erik the Red disc, Greenland Greenland abandoned in 1450 CE due to cooling
(Ch.1) European Explorers
explored mediterranean sea, red sea, and Indian ocean first to circumnavigate Africa Pytheas: greek who sailed using the north star Eratosthenes: correctly determined Earth's circumference
(Ch.4) manganese nodules
hard lumps of manganese and other metals that precipitate around a smaller object
(Ch.4) Cores
hollow steel tube collects sediment columns
(Ch. 2) subduction zone
in tectonic plates, the site at which an oceanic plate is sliding under a continental plate.
(Ch.1) Core
iron & nickel, highest density. outer cire is liquid (metals move by convection)
Why is the East Coast of the US considered a passive margin?
it is far from any plate boundary and experiences no major tectonic activity
(Ch.1) How did our solar systems form?
large cloud of dust and gas began to contract under gravity
(Ch.3) pillow lava
lava that has solidified as rounded masses, characteristic of an eruption underwater. formed when lava quickly cools.
(Ch.1) Mesozoic Era
middle life (245-144 million years ago); rise of mammals and dinosaurs; the rise of birds; extinction of dinosaurs, rise of flowering plants
(Ch. 2) oceanic-continental convergence
more dense oceanic plate dives under continental plate. forms a trench. causes volcanoes, and earthquakes (Andes Mountains)
(Ch. 2) continental-continental convergence
no subduction no volcanoes tall mountains uplifted Himalayas formed from India/Asia collision
(Ch.1) What is radioactive decay?
parent isotopes turn into daughter isotopes
(Ch.4) Distribution of Biogenous Sediments
productivity, destruction, and dilution
Which of the following organisms are responsible for the creation of siliceous ooze?
radiolarians and diatoms
(Ch.1) Mantle
rich in magnesium and iron, part of lithosphere. weaker layer (close to melting point) is asthenosphere. Property: rigid
(Ch.1) What triggers outgassing?
riding of low density gases to the surface
(Ch. 2) lithosperic plates
rigid plates; plates are created & destroyed at plate boundaries; center of plates tend to be stable
(Ch.4) Evaporites
sedimentary rocks formed from minerals left after water evaporates
(Ch.1) Prince Henry the Navigator
sought routes around africa
(Ch.3) hydrothermal vents
spots on the ocean floor where hot gases and minerals escape from earth's interior into the water
(Ch.4) Paleoceanography
study of how the ocean, atmosphere, and land have interacted to produce changes in ocean chemistry, circulation, biology, and climate
(Ch.3) side-scan sonar
technique that directs sound waves at an angle to the seafloor or deep-lake floor, allowing underwater topographic features to be mapped
Oozes are uncommon on continental margins because __________.
the biogenous component tends to be overwhelmed by the amount of lithogenous material derived from the nearby continent
(Ch.3) relief
the difference in elevation between the highest and lowest parts of an area
(Ch.1) Paleozoic Era
the part of geologic time 570-245 million years ago ; invertebrates, fishes, amphibians, reptiles, ferns, and cone-bearing trees were dominant
(Ch.1) Where did the suns energy come from originally?
thermal energy that convected from gravitational energy of original nebula collapse
what is the difference between a fracture zone and a transform fault?
transform faults run between offsets in a mid-ocean ridge while fracture zones extend beyond the offsets
(Ch.1) How did Earth's oceans form?
water vapor expelled into atmosphere by volcanic eruptions, which condensed to from rain that collected on Earth's surface.
