lecture 1 cards Flashcards
Captain James Cook
HMS Endeavor 1748-1779 Pacific Ocean. Inaugurated great collecting phase of 18th century sciences
Alexander von Humboldt
1779-1804 Central and south america
Edward Forbes
Shetland Sea, Benthos, 1830s-40s. Showed depth related zonation
Charles Darwin
HMS Beagle, 1831-1836, south america and pacific
HMS Beagle
sailed by Charles Darwin to south america and pacific
Charles Wyville Thompson
HMS Lightning 1868 and HMS Porcupine, first oceanocraphy book, the depths of the sea. Persuaded british admiralty to outfit a ship and sponsor expedition to study ocean floor
Challenger Expedition
Thompson and Murray were leaders aboard this–worldwide exploration of the sea. 3.5 years 1872-1875. deepwater soundings and dredgings. Acquired contours of ocean floor, collections of biota, plots of ocean currents and temperature.
HMS Challenger
worldwide expedition to explore the depths of the sea
Victor Hensen
Father of german oceanography, called plankton the blood of the sea, wanted to improve german fisheries in the baltic and north sea.
Plymouth Laboratory
In the British School, 1930s and 40s, studied plankton biology in the english channel.
Louis and Alexander Agassiz
promoted marine science in 19th and early 20th centuries, founded museum of comp. zoology at harvard
1870s shore based laboratories
Marine Biological Laboratory in MA, Friday Harbor Laboratory in WA, Scripps Institute of Oceanography in CA, Woods Hole Oceanographic Institution in MA
Gordon A. Riley
impacted modern plankton studies, application of math on plankton population size
Bruce Heezen
seafloor mapping, created more support for idea of continental drift
Subdivisions in the world ocean
5
Subdivisions of oceans
20
Gradient from land to ocean
continental shelf, shelf break, continental slope, continental rise, abyssal plain
Continental shelf
big changes in sea level, goes out 100-200 m in depth
Continental slope
about 4 degree angle, submarine canyons, turbidity currents
Abyssal plain
sea floor, about 5,000m in depth
Three types of sediment in ocean
lithogenous, biogenous, aeolian
Lithogenous soil
sediments from land
Biogenous soil
sediments of biological origin, CaCO3 and SiO2 oozes
Aeolian
Red clay, wind blown sediments
Hydrogenous soil
manganese nodules
Continental crust
Land. Made up of igneous granite. Thickness of 35km.
Granite
Igneous rock, intrusive
Oceanic crust
Made of igneous basalt, about 7km thick.
Basalt
Igneous, extrusive.
Mantle
Molten layer, asthenosphere. Density of about 3.3 g per cubic cm
Isostasy
When state of ice masses changes the level of the continents. When ice melts, continents rise because of reduction in pressure.
Maximum ages of rocks in the oceans
160-180 million years
Subduction
When the oceanic crust goes beneath continental crust at edges of continents because oceanic crust is more dense, goes into the mantle
Plate tectonics
The idea of the crust being subdivided and being able to shift. Location and frequency of earthquakes concentrated along mid-oceanic ridges and margins of continents. Major plates bounded by areas of high seismic activity.
Alfred Wegener
proposed theory of continental drift in 1912
Theory of continental drift
supercontinent Pangea that broke apart and drifted to the locations we observe today, based on fit of coastlines in atlantic ocean and otherwise, variety of plant and animal fossils in common
Rock magnetism
Earth acts as a bar magnet and when new basalt is formed the magnetite orients to the poles, which wander and change in intensity and switch polarity
Sea floor spreading
When new basalt is created it spreads across seafloor and subducts under continental crust.
Evidence for sea floor spreading
rock dredgings show that basalt is youngest at ridges and older at flanks, sediments got thicker with distance from ridges, trenches found around continental margins due to subduction
Ocean ridge system
Upwelling of magma in oceanic ridges, spreading and subduction, when magma descended it produced pressures that created volcanoes
Where do earthquakes occur
where there is subduction, rifting, transform faults
Subduction
Plates collide
Rifting
Plates pull apart
Transform faults
Plates slide past each other