Oceans Exam 1
Archeological evidence suggests that boat technology was developed about ________ years ago.
40,000
Average continental elevation
840 meters
Which of the following is an example of a continental transform plate boundary?
San Andreas Fault
Prior to 1768, which of the following claimed the most human lives at sea?
Scurvy
The tectonic forces called slab pull and slab suction may act in unison at which type of plate boundary?
convergent
Using the profile view of the Mid-Atlantic Ridge in Figure 2.19a, calculate its total spreading rate over the past 50 million years (divide total distance by time). Then do a similar calculation for the East Pacific Rise (Figure 2.19b) and compare the two.
Mid-Atlantic Ridge: 280 miles/50 million years = 0.0000056 miles/year0.0000056 miles × 5280 ft/mile × 12 in/1 ft = 0.35 inches/yearEast Pacific Rise: 230 miles/15 million years = 0.000015 miles/year = 0.97 inches/year
continental transform fault
cuts across continent (san andreas fault)
All continents fit together with the least number of overlaps and gaps when the continents are matched along ________.
edges at around 2,000 meters depth
Which of the following is the standard unit of ocean depth?
fathom
The study of the structure of the sea floor and how the sea floor has changed through time is an example of ________ oceanography.
geological
Contanental crust is predominantly composed of the igneous rock called ________.
granite
The mechanism by which populations evolve and new species develop is called ________.
natural selection
Chains of extinct volcanoes that are progressively older as one travels away from a hotspot are called ________.
nemataths
Most large earthquakes occur along which of the following?
ocean trenches
Volcanoes on the seafloor that are flat-topped because of wave erosion are called ________.
tablemounts
Underwater avalanches of muddy water mixed with rocks and debris are ________.
turbidity currents
Worldwide, scientist estimate that there are about 125,000 known seamounts, many of which originated at _____ centers
volcanic
The most likely place for the basic building blocks for the development of life to interact and produce life is in Earth's ________.
ocean
oceanic transform fault
ocean floor only
Claudius Ptolemy
produced fairly accurate world map around 150 A.D. -erroneously updated Eratosthenes original circumference estimation, later causing Christopher Columbus to believe he had reach Asia.
Our world ocean can be divided into four principal oceans plus an additional ocean, based on the ________ of the ocean basins and the ________ of the continents.
shape; position
Hydrogenous Marine Sediments
*minerals precipitate directly from seawater --manganese nodules --phosphates --carbonates --metal sulfides *small proportion of marine sediments *distributed in diverse environments
Paleoceanography
- study of how ocean, atmosphere, and land interactions have produced changes in ocean chemistry, circulation, biology, and climate
•Precision Depth Recorder (PDR)
-1950s -Focused high-frequency sound beam -First reliable sea floor maps produced Helped confirm sea floor spreading
Deep Sea Drilling Project (DSDP)
-1966 -Glomar Challenger drilling ship -Core collection in deep water -Confirmed existence of sea floor spreading •Ocean floor age •Sediment thickness Magnetic polarity
Two Chemical Compounds in Biogenous Sediment
-Calcium carbonate (CaCO3) -Silica(SiO2or SiO2·nH2O)
Metal Sulfieds
-Contain: •Iron •Nickel •Copper •Zinc •Silver •Other metals -Associated with hydrothermal vents
•Autotrophs
-Evolved later -Manufacture own food supply
Sediment Distribution (Pelagic)
-Finer-grained sediments -Deposited slowly -Deeper-water deposits -Examples: particles from volcanic eruptions, windblown dust and abyssal clay
Evaporites
-Minerals that form when seawater evaporates -Restricted open ocean circulation -High evaporation rates Halite (common table salt) and gypsum
Processes for Distribution of Biogenous Sediments
-Productivity •Number of organisms in surface water above ocean floor -Destruction •Skeletal remains (tests) dissolve in seawater at depth -Dilution •Deposition of other sediments decreases percentage of biogenous sediments
What is the difference between a hypothesis and a theory?
A hypothesis is a tentative, testable statement, or an initial idea about a concept. A theory is a well-substantiated explanation of some aspect of the natural world that can incorporate facts, laws, logical inferences, and tested hypotheses. A hypothesis has not been extensively tested or observed, whereas a theory has.
Which of the following is an example of an oceanic-oceanic convergent plate boundary?
Aleutian Islands
The first person to advance the idea of mobile continents or continental drift was ________.
Alfred Wegener
Which of the following is an example of an oceanic-continental convergent plate boundary?
Andes Mountains
Which of the following is characteristic of oceanic-continental convergent plate boundaries?
Andesitic volcanoes
Which of the following rocks is the most reliable one used to collect information about Earth's magnetic field where and when the rock originated?
Basalt
Active continental margins are characterized by which of the following?
Deep-sea trenches
Eratosthenes
Determined that the Earth is round and calculated its circumference
Which of the following is an example of the embryonic stage of the Wilson Cycle?
East Africa
Which of the following is an example of an oceanic-oceanic divergent plate boundary?
East Pacific Rise
Sediments
Eroded particles -Fragments of dust, dirt, other debris
Which of the following is an example of a continental-continental convergent plate boundary?
Himalayan Mountains
The Big Island of Hawaii is an example of a volcanic island associated with volcanic activity at a ____.
Hotspot
Which ocean is mostly, but not entirely, in the southern hemisphere?
Indian Ocean
Bathymetry
Measures the vertical distance from the ocean surface to mountains, valleys, plains, and other sea floor features
Which of the following is an example of an oceanic transform plate boundary?
Mendocino Fault
Which of the following fossils was used as data to help reconstruct Pangaea because it was a reptile found in South America and Africa?
Mesosauras
Is a linear sea floor feature that has the following properties a transform fault, a fracture zone, or neither? It is seismically active, it occurs between offset mid-ocean ridge segments, and the relative movement between two points on either side of the feature is in the same direction
Neither transform or fracture zone
3 types of convergent boundaries
Oceanic-Continental -Where denser oceanic crust subjects and a continental arc is created
The first humans from Western Hemisphere known to have developed the art of navigation were the ________.
Phoenicians
Which of the following is an example of a continental-continental divergent plate boundary?
Red Sea
The first recorded attempt to measure the ocean's depth was conducted using which of the following techniques?
Sounding
Volcanic peaks that are below sea level but rise more than 1 km above the deep-ocean floor and have a flattened top are called ____.
Tablemounts
What are some differences between the lithosphere and the asthenosphere?
The lithosphere is a thin, relatively cool, rigid layer that includes all of the crust and the topmost portion of the mantle that acts as a single unit floating on the asthenosphere. It is about 100 kilometers, or about 62 miles, thick. In contrast, the asthenosphere is a relatively thick, hot, highly viscous, plastic region of Earth. The asthenosphere corresponds to the upper mantle, and it is about 700 kilometers, or about 430 miles, thick. When force is applied to the lithosphere, it will fracture. When a gradual force is applied to the asthenosphere, it will deform without fracturing.
Which of the following statements is TRUE of the lithosphere?
The lithosphere is composed of the crust and the uppermost portion of the mantle.
Harry Hess suggested which of the following?
The volcanic mid-ocean ridges were formed due to sea floor spreading
How does the presence of oxygen in our atmosphere help reduce the amount of ultravioletradiation that reaches Earth's surface?
Ultraviolet radiation is absorbed by oxygen in the form of ozone (O3) molecules in the upper atmosphere.
Most of the explorations by northern and western Europeans during the Middle (Dark) Ages were undertaken by ________.
Vikings of Scandanavia
What is a linear sea floor feature that is seismically active, occurs between offset mid-ocean ridge segments, and the relative movement between two points on either side of the feature is in the opposite direction?
Transform Fault
Warm-water (From 30°C to 350°C) hydrothermal vents form ________.
White smokers
The Alpine Fault of New Zealand is an example of ________ plate boundary.
a continental transform
The Alps are an example of ________ plate boundary.
a continental-continental convergent
The East Africa Rift Valleys are an example of ________ plate boundary.
a continental-continental divergent
The Gulf of California is an example of ________ plate boundary.
a continental-continental divergent
Volcanic features on the ocean floor that are less than 1,000 meters tall are called
abyssal hills
Radioactive materials can sometimes be used to determine the ________.
age of rocks
The Mendocino Fault is an example of ________ plate boundary.
an oceanic transform
The Peru Chile Trench is an example of ________ plate boundary.
an oceanic-continental convergent
The Mid-Atlantic Ridge is an example of ________ plate boundary.
an oceanic-oceanic divergent
One of the reasons that free oxygen in our atmosphere is important to the development and maintenance of life on Earth is because oxygen ________.
can form ozone and block some UV radiation
Satellites use microwave beams to measure sea level to an accuracy of four ____.
centimeters
Directly seaward of the continental shelf is a more steeply sloping region called the ________.
continental slope
Older lithosphere is destroyed in association with ____.
deep-sea trenches
Earth is a layered sphere with the ________-density material found near the center of Earth and the ________- density material located near the surface.
highest; lowest
The direction of motion along a seafloor transform fault is ____.
in the same direction as the plates are spreading
Based on the Theory of Plate Tectonics, you would expect to find ________ heat flow at the mid-ocean ridge and ________ heat flow at subduction zones when compared to other parts of the crust.
increased; decreased
The island of Java is an example of a volcanic island associated with volcanic activity at a ____.
island arc
Terrigenous sediment is another name for which of the following?
lithogenous sediment
Tectonic plates are pieces of the ________ that float on the more fluid ________ below.
lithosphere; asthenosphere
Magnetic dip
magnetite particles in sedimentary rocks or igneous rocks such as basaltalign with Earth's magnetic field
The seafloor magnetic pattern is best described as ________.
parallel to and symmetric about mid-ocean ridges
with respect to mid-ocean ridges, transform faults are
perpendicular to the ridge axis
The oldest fossilized remains of organisms are primitive ________ bacteria recovered from rocks formed on the sea floor about 3.5 billion years ago.photosynthetic
photosynthetic
The dissolution of the thick tests of foraminifers below the CCD is an example of the _______ of biogenous sediment
productivity
The very earliest forms of life probably ________.
required an external food supply
Greek Pytheas
sailed northward using a simple method to determine latitude in 325 BC. Navigated using North Star.
Thor Heyerdahl
sailed on a balsa raft (KON TIKI) to demonstrate migration of South Americans to Pacific Ocean islands
Volcanic peaks that are below sea level but rise more than 1 km above the deep-ocean floor and have a pointy top like an upside-down ice cream cone are called ____.
seamounts
Suspension settling
sediments settle out of water and accumulate on ocean floor.
Oceanographers who want to know about ocean structure beneath the sea floor use which of the following techniques?
seismic refection
The correct order of seafloor features from the coast to the mid-ocean ridge is ________.
shelf, slope, rise, abyssal plain
carbon dioxide, water vapor, sulfur dioxide, and methane
simple organic compounds
Frederick Vine and Drummond Matthews determined that new ocean floor was being produced at ocean ridges by examining ________.
the magnetic pattern of rocks on the seafloor
Which of the following is the most convincing piece of evidence set forth to support the concept of sea floor spreading?
the oceanic pattern of alternating reversals of Earth's magnetic field
To find the largest area of the ocean with the oldest ocean crust, you should go to the ________.
western Pacific
Sediment origins
worn rocks, living organisms, minerals dissolved in water, outer space
Tectonic plates move about as fast as ________.
your fingernails grow
Calcium Carbonate in Biogenic Sediments
•Coccolithophores -Also called nannoplankton -Photosynthetic algae -Coccoliths- individual plates from dead organism •Rock chalk -Lithifiedcoccolith-rich ooze White Cliffs of southern England (Dover) •Foraminifera -Protozoans -Use external food Calcareous ooze
three major ocean provinces
•Continental margins -Shallow-water areas close to shore •Deep-ocean basins -Deep-water areas farther from land •Mid-ocean ridge -Submarine mountain range
Continental Margin Features
•Continental shelf -Generally flat zone extending from shore beneath ocean surface to shelf break •Shelf break -Point at which a marked increase in slope angle occurs •Continental slope -The slope between the outer edge of the continental shelf and the deep ocean floor •Continental rise -Underwater hill composed of tons of accumulated sediment.
Silica in Biogenous Sediments
•Diatoms -Photosynthetic algae -Diatomaceous earth •Radiolarians -Protozoans -Use external food •Tests- shells of microscopic organisms •Tests from diatoms and radiolarians generate siliceous ooze.
Marine Sediment Collection
•Early exploration used dredges. •Modern exploration -Cores- hollow steel tube collects sediment columns -Rotary drilling - collects deep ocean sediment cores
Lithogenous sediments are
•Eroded rock fragments from land •Also called terrigenous •Reflect composition of rock from which derived •Produced by weathering -Breaking of rocks into smaller pieces
manganese nodules
•Fist-sized lumps of manganese, iron, and other metals •Very slow accumulation rates •Many commercial uses •Unsure why they are not buried by seafloor sediments •Considered "the most interesting unresolved problem in marine chemistry."
energy resources
•Gas Hydrates -Also called clathrates -High pressures squeeze chilled water and gas into ice-like solid -Methane hydrate: smost common
Biogenous Sediments
•Hard remains of once-living organisms •Two major classifications: -Macroscopic •Visible to naked eye •Shells, bones, teeth -Microscopic •Tiny shells or tests •Biogenic ooze •Mainly algae and protozoans
Marine Sediment Classification
•Lithogenous- derived from land •Biogenous- derived from organisms •Hydrogenousor Authigenic- derived from water •Cosmogenous- derived from outer space
Modern Bathymetry Measuring
•Multibeam Echo Sounders -Multiple simultaneous sound frequencies. •Sonar -Sound navigation and ranging (acronym) •Seabeam -Firstmultibeamecho sounder -Map sea floor strips up to 60 km (37 mi) wide
Sediment Distribution (Neritic)
•Neritic -Dominantly lithogenous -Typically deposited quickly -Close to land -Shallow-water deposits -Examples: beach, continental shelf, turbidite, glacial deposits
grain size
•One of the most important sediment properties •Proportional to energy of transportation and deposition Classified byWentworth scale of grain size
Cosmogenous Marine Sediments
•Overall, insignificant proportion of marine sediments •Macroscopic meteor debris •Microscopic iron-nickel and silicate spherules (small globular masses) -Tektites -Space dust
Continental Margins
•Passive -Not close to any plate boundary -No major tectonic activity -East coast of United States •Active -Associated with convergent or transform plate boundaries -Much tectonic activity -West coast of United States
Energy Resources (The problem)
•Release of sea floor methane may alter global climate. •Warmer waters may release more methane. •Methane release may cause underwater slope failure. -Tsunami hazard
other resources
•Sand and gravel -Aggregate in concrete -Some is mineral-rich •Evaporative salts -Form salt deposits -Gypsum - used in drywall -Halite - common table salt •Phosphorite- phosphate minerals Fertilizer for plants •Manganese nodules and crusts -Lumps of metal -Contain manganese, iron, copper, nickel, cobalt Economically useful
Measuring Bathymetry
•Soundings -Posidoniusmade first sounding in 85 B.C. -Line with heavy weight -Sounding lines used for 2000 years •Fathom -Unit of measure -1.8 meters (6 feet)
Texture and Enivornment
•Texture indicates environmental energy -High energy (strong wave action) - larger particles -Low energy - smaller particles Larger particles closer to shore
turbidity current
•Underwater avalanches mixed with rocks and other debris •Sediment from continental shelf •Moves under influence of gravity Sediments deposited at slope base
National Science Foundation (NSF)
•formed Joint Oceanographic Institutions for Deep Earth Sampling (JOIDES) in 1963 -Scripps Institution of Oceanography -RosenstielSchool of Atmospheric and Oceanic Studies -Lamont-Doherty Earth Observatory of Columbia University -Woods Hole Oceanographic Institution
Magnetometer
•instrument towed behind ocean vessel -Measures Earth's magnetic field and how it was affected by sea floor rocks
Magnetic anomalies
•regular pattern of north-south magnetism "stripes" •Stripes were symmetrical about long underwater mountain range
Texture
•size and shape of particles •Mineral composition
Arctic Ocean
- Seven percent the size of the Pacific Ocean - Shallowest world ocean - Permanent layer of sea ice a few meters thick
Early exploration of the oceans
-Archeological evidence of boat technology 40,000 years ago -Early explorers used boats to seek new fishing grounds for food -Boats used to move heavy and or large objects -The ocean facilitated trade and interactions between cultures
Southern Ocean or Arctic Ocean
-Circumnavigates Antartica -Is really the parts of the Pacific, Atlantic, and Indian Oceans that lie south of 50 degree south Latitude
Atlantic Ocean
-Half the size of the Pacific Ocean -Shallower than the Pacific Ocean -Separates the old world from the new world
Pacific peoples
-No written records exist of Pacific human history before the 16th centure -Archeological evidence suggest island occupation by people from New Guinea as early as 4000-5000 b.c
Before the 15th center, Europeans considered the seven seas to be the following
-Red sea -Mediterranean Sea -Persian Gulf -Black Sea -Adriatic Sea -Caspian Sea -Indian Ocean
Indian Ocean
-Smaller than the Atlantic Ocean -Similar depth as the Atlantic Ocean -Primarily in the Southern Hemisphere
•Heterotrophs
-Very earliest life -Require external food supply
Pacific Ocean
-Worlds Largest Ocean (Accounts for more than half of Earths Ocean Space - Worlds deepest ocean -Earths largest geographic feature -Named in 1520 by Ferdinand Megellan
Average Ocean Depth
3682 meters
Cite the lines of evidence Alfred Wegener used to support his idea of continental drift. Why did scientists of the time doubt that continents had drifted?
Alfred Wegener used the following evidence to support continental drift: ✓ The fit of the continental margins across ocean basins ✓ Matching rock sequences and mountain ranges on different continents ✓ Climate evidence such as glacial deposits in areas that are now close to the Equator ✓ The distribution of organisms across continents that are separated by oceans that these organisms could not have crossed Although the evidence in support of continental drift seems compelling, scientists in Wegener'stime rejected the idea of continental drift because the mechanisms Wegener proposed as driving continental movement seemed too far-fetched to be plausible. Some scientists felt that Wegener'sproposal ran contrary to the understanding of the laws of physics in the early 20th century. Whensea floor spreading data became available in the 1950s and 1960s, Wegener's ideas aboutcontinental movement were combined with these data to provide a more current model that explained crustal movement.
The great oxidation event resulted in the massive die-off of which of the following?
Anaerobic bacteria
Middle Ages
Arabs dominant navigators in the Mediterranean Sea -Traded extensively with East Africa, India, and Southeast Asia -Learned to use Indian Ocean monsoon winds for travel
Isostatic adjustments are the result of the buoyancy of Earth's lithosphere as it floats on the ________ below which is denser and plastic like.
Asthenosphere
The four principal ocean basins (plus an additional ocean) on Earth are the ________.
Atlantic, Pacific, Indian, Southern, and Arctic Oceans
The European "Age of Discovery" began with ________.
Christopher Columbus' discovery of the "New World"
Regarding glacial ages, why is it unlikely that the entire world was covered by ice 300 million years ago?
Coal deposits that are 300 million years old originated in large semitropical swamps.
Which of the following statements regarding continental and oceanic crust is TRUE?
Continental crust is thicker and less dense than oceanic crust.
3 types of convergent boundaries
Continental-Continental -Where continental crust is too low to densify to subduct, instead a tall uplifted mountain range is created.
What is density stratification, and how did it change Proto-Earth?
Density stratification is a result of gravitational forces and results in the layering of materials as a function of density. The denser (heavier) material is found beneath the lower density (lighter) material. This caused Proto-Earth (and other protoplanets) to undergo internal rearrangement as the heavier materials migrated to the center to form a heavy core. The result is a layered Earth with the lowest-density material on the surface and the greatest-density material in the core.
List some of the major achievements of Captain James Cook.
During his three ocean voyages, Captain James Cook (1728-1779): ● Explored the southern oceans and charted the coasts of New Zealand and Australia. ● Was the first person to cross the Antarctic Circle in his search for a southern continent, Terra Australis. ● Discovered the Sandwich Islands and South George Island after failing to find the southern continent. ● Found a means of preventing scurvy, a disease resulting from vitamin C deficiency. ● Proved the value of John Harrison's chronometer to determine longitude. ● Determined the outline of the Pacific Ocean. ● Led the way in sampling subsurface water temperatures, measuring winds and ocean currents, sounding to estimate depth, and data collection on coral reefs. ● Discovered the Hawaiian Islands and looked for the Northwest Passage around North America.
Describe the important events in oceanography that occurred during the Age of Discovery in Europe.
During the 30-year period from 1492 to 1522 (the Age of Discovery), the Western world came torealize the vastness of Earth's oceans. Europeans explored the continents of North and SouthAmerica. The circumnavigation of Earth was completed for the first time. Europeans discovered populations of indigenous peoples on other continents and islands. Bartholomeu Diaz, Vasco daGama, Christopher Columbus, Vasco Nứñez de Balboa, and Ferdinand Magellan madeimportant contributions to ocean exploration during the Age of Discovery.
What is the age of Earth? Describe the major events that demark the boundaries between these time periods: (a) Precambrian/Proterozoic, (b) Paleozoic/Mesozoic, and (c) Mesozoic/Cenozoic.
Earth is 4.6 billion years old. (a) The boundary between the Precambrian and Proterozoic is marked by an explosion of life and the appearance of shelled organisms, particularly trilobites. (b) The Paleozoic/Mesozoic boundary saw one of the largest mass extinctions in Earth's history,with 90% of marine species going extinct. (c) The Mesozoic/Cenozoic boundary is marked by the extinction of the dinosaurs and the subsequent rise of mammals.
Describe the origin of Earth's atmosphere. How is its origin related to the origin of Earth'soceans?
Earth's initial atmosphere was also outgassed from the interior along with the oceans, but its composition has changed through time.
Earth has had three atmospheres (initial, early, and present). Describe the composition and origin of each one.
Earth's initial atmosphere was composed of hydrogen and a small amount of helium. The atmosphere was outgassed from Earth's interior, and it was replaced by the release of gases from the mantle by outgassing through volcanic activity to form an early atmosphere. These gases included water vapor, carbon dioxide, and smaller concentrations of other gases. The present atmosphere is composed mostly of nitrogen and oxygen gas. Atmospheric oxygen was produced by photosynthetic activity (or possibly outgassing from the mantle about 2.5 billion years ago).Oxygen began to be a significant constituent of Earth's atmosphere about two billion years ago.
Describe what Earth's magnetic field looks like and how it has changed through time.
Earth's magnetic field resembles the magnetic field produced by a large bar magnet. Barmagnets have ends that are oppositely charged. The magnet ends are usually designated by "+" and "-" or "N" (for north) and "S" (for south). This opposite polarity causes magnetic objectsto align parallel to the magnetic field produced by the bar magnet. Although Earth does not actually have a bar magnet inside, it behaves as if it did. Invisible lines of magnetic forceoriginating from within Earth travel through the planet and out into space, Nature of Earth'sMagnetic Field). The strength of Earth's magnetic field has changed through time (on the geologic time scale). Additionally, Earth has experienced many dozens of magnetic field polarity reversals during the last 100 million years.
The first person we are aware of who determined the circumference of the Earth using trigonometry and the angle of sunlight at Alexandria, Egypt, was ________.
Eratosthenes
Describe the origin of Earth's oceans.
Evidence suggests that the oceans came from inside Earth by the process of outgassing. About four billion years ago, the surface of Earth cooled sufficiently to allow the water vapor beingpumped into the atmosphere by volcanoes to condense and settle on Earth's surface.
Have the oceans always been salty? Why or why not?
Evidence suggests that the oceans have always been salty because many of the compounds erodedfrom surface rocks (where the ocean's salinity originated) contain elements that comprise salt:chlorine, sodium, magnesium, and potassium.
Phonecians
First from Western Hemisphere to develop Navigation arts -Navigated circa 2000 BC -Explored Mediterranean Sea, Red Sea, and Indian Ocean -First circumnavigation of Africa 590 BC -Reached the British Isles
What was the impetus for studying ocean processes that led to the great expansion of the science of oceanography?
Humans have always used the oceans for a variety of purposes. However, as scientists began to study how ocean geology, chemistry, and physics work with biology to create good fishing grounds, we have come to realize how much of an impact humans have on the ocean. The result is an expansion of the science of oceanography.
A tentative, testable statement about the general nature of a phenomenon is called a/an ________.
Hypothesis
Can a theory ever be so well established that it becomes a fact? Explain.
If an observation is repeatedly confirmed—that is, made so many times that it is assumed to be completely valid—then it can be called a scientific fact. As observations are made, humans attempt to sort out the observations to reveal underlying patterns. From these attempts to sort, humans develop hypotheses that predict certain occurrences that then lead to refinements of the hypotheses. If a hypothesis has been strengthened by additional observations and if it is successful in predicting additional phenomena, then it can be advanced to a theory.
What happened to the nebular gas that remained from the formation of the planets and their satellites?
It was blown away by the solar wind.
Briefly comment on the phrase "scientific certainty." Is it an oxymoron (a combination ofcontradictory words), or are scientific theories considered to be the absolute truth?
Knowledge about the natural world is constantly changing because we are always adding new observations and data to our knowledge base. As new data become available (frequently due to new technologies giving more detailed and accurate data), hypotheses, theories, and scientific facts are reexamined for consistency with the new information. As long as new data is being added, the nature of scientific truth will be subject to change. Thus, the phrase "scientific truth"is an oxymoron. Over time, scientific statements generally form a sequence of increasingly accurate statements, eventually coming to a point where they are no longer questioned. It is accurate to say that science arrives at that which is probably certain, based on available data.
What was Stanley Miller's experiment, and what did it help demonstrate?
Laboratory experiments by Stanley Miller in 1952 showed that exposing a mixture of compounds that were thought to exist in the early atmosphere (hydrogen, carbon dioxide, methane, ammonia, and water) to ultraviolet light plus an electrical spark (simulating the effect of lightning) will produce a large assortment of organic molecules that are the basis for life.
Deepest ocean trench
Mariana Trench at 11,022 meters
Highest continental mountain
Mount Everest at 8850 meters
3 types of convergent boundaries
Oceanic-Oceanic -Where the older denser sea floor subjects and an oceanic island are created
What does it mean when oceanography is called an interdisciplinary science?
Oceanography often examines in detail all the different disciplines of oceanography. It covers all disciplines of science as they pertain to the oceans.
When did the supercontinent of Pangaea exist? What was the ocean that surrounded the supercontinent called?
Pangaea existed about 200 million years ago. The single largest ocean surrounding Pangaea was Panthalassa.
Why does a map of worldwide earthquakes closely match the locations of worldwide plate boundaries?
Plate boundaries are locations where plates interact. Earthquakes frequently occur in areas where convergent or transform plate movements occur. There is a high correlation between worldwide earthquake location and plate boundaries.
Most lithospheric plates contain both oceanic- and continental-type crust. Use plate boundaries to explain why this is true.
Plate boundaries rarely follow continental margins, so most large plates contain a continent (continental crust) as well as a large area of ocean floor (oceanic crust).
Pacific Navigators
Populated by voyagers -Polynesia -Melanesia -Micronesia
How was proto-Earth different from Earth today?
Proto-Earth was a large mass with perhaps a 1000 times greater diameter than the present Earth, and Proto-Earth was 500 times more massive than Earth today. Proto-Earth was devoid of life or oceans. It is believed that Proto-Earth was a homogenous planet with uniform composition throughout the planet. Proto-Earth had an atmosphere that was largely hydrogen and helium.
Describe how the half-life of radioactive materials can be used to determine the age of a rock through radiometric age dating.
Radioactive materials have a characteristic half-life, which is the time required for one-half of the atoms in a sample to decay to other atoms. The older the rock is, the more radioactive material will have been converted to decay product. Analytical instruments can accurately measure the amount of radioactive material and the amount of resulting decay product in rocks. By comparing these two quantities, the age of the rock can thus be determined.
Describe the differences between oceanic ridges and oceanic rises. Include in your answer why these differences exist.
Spreading rates (the total widening rate of an ocean basin resulting from the motion of both plates away from the spreading center) vary along the mid-ocean ridge and profoundly affect the slope of the mountain range. The faster the spreading rate, the broader the mountain range associated with the spreading center. The rapidly spreading and gently sloping portions of the mid-ocean ridge are called oceanic rises. The slower and steeper-sloped areas of the mid-ocean ridge are called oceanic ridges. Oceanic ridges and oceanic rises are both part of the global mid- ocean ridge system.
Describe the steps involved in the process of science, starting with an observation about the natural world.
Step 1: Observation: Ask Questions and Establish Scientific Facts Step 2: Hypothesis: Make Generalization Step 3: Test: Perform Experiment Step 4: Theory: Draw Conclusion
How did the Moon form?
The Moon formed due to the impact of a Mars-sized body with the Earth.
While the Arabs dominated the Mediterranean region during the Middle Ages, what were the most significant ocean-related events taking place in northern Europe?
The Vikings roamed the North Atlantic from the 8th to the 13th centuries. Erik the Red sailed to establish colonies in Baffin Island in 891, and his son, Leif Eriksson, visited Vineland (now Newfoundland, Canada) in 995.
Describe sea floor spreading and why it was an important piece of evidence in support of plate tectonics.
The age relationships and pattern of symmetric stripes on the sea floor with respect to the axis of the mid-ocean ridge indicate that sea floor spreading occurs along the mid-ocean ridge. With sea floor spreading as a mechanism, many of the arguments against continental drift could no longer be supported, so it helped to advance the development of continental drift and the formation of plate tectonic theory.
Discuss the origin of the solar system using the nebular hypothesis.
The nebular hypothesis suggests that bodies of the solar system formed from an enormous nebular cloud composed predominantly of hydrogen and helium with a small fraction of heavier elements. As the large dust cloud revolved around its rotational center, the Sun began to form due to the concentration of particles under gravitational forces. In the earliest stages, the volume of the Sun may have been equal to the diameter of our solar system today. As the nebular matter that formed the Sun contracted, a small percentage of it was left behind in small eddies (similar to whirlpools in a stream). This material flattened itself into an increasingly compact disc. The disc became so compact that it became gravitationally unstable and broke apart into separate smaller clouds. These smaller clouds were the protoplanets and their orbiting satellites. These bodies became the modern-day planets and their moons.
divergent plate boundary
Where plates are moving apart, -such as the mid-ocean ridge -EX. Red Sea, gulf of California, mid-atlantic ridge, east pacific rise, east Africa rift valleys
convergent plate boundary
Where plates are moving together -Such as at deep ocean trenches EX. Peru-chile, Andes Mountains, Mariana Trench, Aleutian Islands, Humalays Mountains, Alps
transform plate boundary
Where plates slide past each other -such as at a transform fault -EX Mendocino Fault, Eltanin Fault, San Andreas Fault, Alpine Fault
Oceanic crust is primarily ________.
basalt
According to the fossil record on Earth, the earliest-known life-forms lived in sea floor rocks about 3.5 ________ years ago.
billion
Earth's atmosphere became oxygen rich about 2.45 ________ years ago.
billion
Earth's primordial atmosphere most likely included ________.
carbon dioxide, water vapor, sulfur dioxide, and methane
Although Earth's oceans have existed since early in the formation of the planet, its ________ must have changed.
chemical composition
The separation of the Earth into layers while it was molten was the result of the ________.
differing densities of the elements that make up the Earth
Plate tectonics and evolution, which are held with a high degree of confidence because of rigorous testing and verification, are examples of ________.
theories
Current scientific knowledge indicates that the most likely origin of most of Earth's oceans was due to ________.
water vapor released from volcanic outgassing
Layers by chemical composition
•Crust -Low-density, mainly silicate minerals •Mantle -Mainly iron (Fe) and magnesium (Mg) silicate minerals •Core -High-density, mainly iron (Fe) and nickel (Ni)
Layers by Physical Properties
•Lithosphere •Asthenosphere •Mesosphere •Outer core •Inner core
Sea Floor Spreading
•Mid-ocean ridge - spreading center •Subductionzones - oceanic trench site of crust destruction •Subductioncan generate deep ocean trenches.
Earthquakes as Evidence
•Most large earthquakes occur at subductionzones. •Earthquake activity mirrors tectonic plate boundaries.
Paleomagnetism
•study of Earth's ancient magnetic field -Interprets where rocks first formed
What are the four main disciplines or subfields of study in oceanography?
●Geological oceanography—studies sea floor structure, features, and change over time ● Chemical oceanography—studies chemical composition and properties of seawater; pollutants ● Physical oceanography—studies waves, tides, currents, ocean-atmosphere relationship, and transmission of light and sound in the oceans ● Biological oceanography—studies ocean life-forms