Download Lecture 7. Marine Sediments

GEO/OC 103
Exploring the Deep ….
Today’s Tune
“Pirates of the Caribbean”
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Melinda Jensen
Geosciences Departmental Office
104 Wilkinson Hall
[email protected]
737-1238
“Water World”
At it’s surface the ocean
is in constant motion
with powerful currents
that stretch for
thousands of miles and
towering waves.
Beneath the ocean’s
surface lie hidden
mountain ranges, vast
trenches tens of
thousands of feet deep,
immense hot springs,
and huge volcanoes
spewing molten rock in
massive eruptions.”
“Earth is a unique
planet, possibly one of
the few in the galaxy
that has water.
Nearly 71% of it’s
surface is ocean. From
space, Earth is
brilliantly blue, white in
places with clouds and
ice, sometimes swirling
with storms.
-- T. Garrison
Chapter 1
“Just the Facts…”
 Over 97% of the water on the Earth is in the
ocean.
 The average depth of the ocean is about
4000 meters.
 The Mariana Trench is 11,022 m deep, the
deepest spot on the planet.
 8 tons per sq. in.
 Mt. Everest is “only” ~8667 m above sea level
“Just the Facts…”
 Mauna Kea on the Big Island of Hawaii,
measures ~10,600 m from the ocean
floor, making it the tallest mountain on
the planet (surpassing even Mt. Everest).
 If the Earth’s land surface was leveled
to a smooth ball, the ocean would cover
it to a depth of 2686 m.
“Just the Facts…”
 The ocean contains some 5 trillion tons
of salts
 If dried and spread evenly, that mass would
cover the entire planet to a depth of 45 m.
 On a planetary scale the ocean is
insignificant.
 Its average depth is a tiny fraction of the
Earth’s radius.
Why Study the Ocean?
 Major influence on weather and climate
 Source of food, energy, medical drugs
 Transportation
 Military significance
 Recreational resource
 Major influence on the health of the
planet
 Culture and history
Historical Review
of Oceanography
 Roots traced to ocean exploration.
 Describing the oceans
Historical Review
of Oceanography
 The 18th century was marked by
 Improvements in navigation and
mapping
 Accumulation of data for charts
Temperature, currents
Historical Review
of Oceanography
(Cont.)
 In the United States, Benjamin Franklin
(1769-1770) published the first chart of
the Gulf Stream
Historical Review
of Oceanography
(Cont.)
 In Britain, James Cook (1768-1779)
 Constructed charts of coastlines
especially for the South Pacific
 Secondary discovery the Hawaiian
Islands
Historical Review
of Oceanography
(Cont.)
 In the 19th century curiosity about the
oceans increased and voyages for
scientific purposes were initiated
 Charles Darwin: British naturalist
 Voyage of the Beagle (1831-1836), studied
geology and biology of the South American
coastline
Developed theory of organic evolution
based on natural selection
Published On the Origin of the Species
(1859)
$1200!
The Voyage of the HMS Beagle
Charles Darwin
Route of the HMS Beagle
Historical Review
of Oceanography
(Cont.)
 Edward Forbes: British naturalist (18151854)
 Proposed the hypothesis that no life (azoic)
existed in the oceans below 550 m
Historical Review
of Oceanography
(Cont.)
 Matthew Fontaine Maury: U.S. naval
officer
 Compiled information on winds and
currents
 Published The Physical Geography of the
Sea (1855)
 “Father of physical oceanography”
Historical Review
of Oceanography
(Cont.)
 C. Wyville Thompson: British explorer
 Directed the Challenger Expedition (1872-1876)
 First major scientific expedition
 Globe-encircling voyage
 Chemical, physical, and biological measurements
and collections
 Disproved Edward Forbes “azoic theory” by
collecting sea life from waters as deep as 9000 m
The
Challenger
Expedition
Modern Oceanography
 Major interdisciplinary expeditions e.g., the
Meteor Expedition: German (1925-1927)
–Bottom topography
–Vertical profiles of salinity, temperature,
oxygen
 Subsequent growth, World War II, urgent
need for information on the physical structure
of the oceans
What is Oceanography
Today?
Geological Oceanography
(Marine Geology)
Study of rocks and sediments & processes
responsible for their formation.
Marine Geophysics
Study of rock structure in the ocean
basin, properties of rocks such as
magnetism, occurrence of earthquakes.
Dec 26, 2004
9.0 Eq, Sumatra
275,950 killed
Image courtesy of BBC
March 28, 2005
8.7 Eq, Sumatra
290 killed
Image courtesy of USGS
Physical Oceanography
How and why ocean currents flow, air-sea
interactions such as the generation of
waves by the wind.
Chemical Oceanography
Composition of sea water and the
processes controlling and altering its
composition, including marine pollution.
Biological Oceanography
(Marine Biology)
Organisms that live in the oceans and
their relationships to the environment.
Ocean Engineering
Design and
installation of
oceanographic
instrumentation
and vehicles
Modern Oceanography
(Cont.)
Today ocean research is conducted by
investigators in specialized marine
institutions, as well as universities, and state
and federal agencies
The emphasis is on interdisciplinary,
process-oriented research and international
cooperation
1903
www.sio.ucsd.edu
1930
www.whoi.edu
1949
www.ldeo.columbia.edu
Scripps Institution of Oceanography
UC-San Diego
Woods Hole Oceanographic Institution
Woods Hole, MA
Current and Future
Oceanographic Research
 greater focus on international efforts and
large scale interdisciplinary expeditions
 Many scientists
 Many ships
 “remote sensing”
 “unmanned” platforms
New Technology for Probing the Sea
Seasat-A, the first
oceanographic satellite, was
launched in 1978.
TOPEX/Poseidon satellite launched in 1992.
Summary:
What is Oceanography?
 Broad science focused on the oceans
 Geology/geophysics, chemistry, physics,
biology, engineering
 Highly interdisciplinary
 Also highly collaborative
 We are still exploring (!) but …
 Feeds also into ocean policy,
management, and conservation