Oceanography Chapters 1-4

BIOGENOUS SEDIMENTS
Derived From Organisms livingin the water sea floor
Calcareous CaCO3
Siliceous SiO2-nH20
Organic Matter (C6H12O6)
If Pelagic sediment are more than 30% biogenic material they are called oozes
Calcareous Oooze (Foram Ooze)
Siliceous Ooze (Diatom Ooze Etc)
CALCAREOUS SEDIMENTS
Foraminifera – Single Cell Animals
Pleropods – Snail like organisms
Coccolithphorids – Single Celled Plants
Coral – multi Celled Colonial Animals
Calcareous Algae – Multicelled plants
Mollusks – Gastropod, Pelecrypods, Cephalapods
DIATOMS
Algae. Snowflake of the sea, Used for filters
Radiolarians
Single Celled Animals
Siliconflagellates
Mixotrophs
Diatoms and Radiolarians Dissolve Rate
Quickly
HYDROGENOUS SEDIMENTS
Form onthe seafloor or within the seidment
Minerals Precipitate directly out of seawater or sediments porewater
Phosphorite
PHOSPHORATES are used as: (Part of Agricultural Revolution)
Fertilizer
Space between sediments is known as ” ” space
Pore Space
Ferromanaganese Modules
Occur on Abyssal Planes with low seidment accumialation and grow slowly over thousands of years
Methane Hydrates
Energy Source
Two Types of Ooze Are
Calcareous and Salicious
Heterotrophs
Have to consume to survive
Sediments Distribution is largely a function of
Water Depth
Surface water productivity
Distance from land
latitue
Global Sea Water Circulation patterns
Continental Shelf Sedimentation
Sea level oscillates by what rate?
120 meteres over 100,000 year intervals
Last Glacial Maximum
Sea level was 400 feet lower 1800 ypd
Sedimentationin the deep sea occurs by:
Bulk emplacement
Bulk Emplacement
The transport of large amoun of sediment as a mass. The transport is induced by gravity
Bulk Emplacement also
Settling of Palagic sediment
Biochemical precipitation
Due to teh Accumulation of a large uildup of river material on teh outer shelf and slope especially during lowered sea level
Bulk emplacement cont.
SLUMPS are:
sediment piles that move as a mass their internal structure (bedding) is retained
Bulk emplacement continued:
MUD FLOWS are:
slumping and transport of mud as a sheet across the shelf
Bulk Emplacement Continued
TURBIDITY CURRENTS
are large slurries in which rapidly move downslope
CALCARIOUS OOZE OCCURS:
In shallow areas and tropical to subtropical environments (warm)
SILICEOUS OOZE OCCURS:
In areas of very high productivity (UPWELLING) and cold waters
RED CLAYS OCCUR
In deepes areas and where oldest deep water occurs
What is the Chemical Forumula for:
CALCITE PRECIPITATION and DISSOLUTION?
CA2+2HCO3 <----> CaCO3+CO2+H20
(Simple Make Shift Biological Formula)
LYUSOCLINE
Zone over which dissolution occurs
CCD
Calcite Compensation depth
The corrosiveness of water to calcite increases downward because:
of higher pressure lower temperature and higher CO2 Concentrations
At CCD CAlcite deposition –
rate of dissolution
CCD Occurs at average depth of
4800 Meters
Abyssal Clays are below CCD?
YES
Five Sediment Sampling Devices
Grab Samplers
Coring Devices
Vibracore
Gravity Core
Piston Cre
Rotary Drills
Significance of Oceanography
(Why is the ocean important?)
Have a major influence on teh weather and climate
Are a source of food energy medical resources bilogical diversity
Are important in transportationa nd trade
Have military significance (Bombing sites/Submarines etc)
Are an important recreational source
Have a major influence on the health of the planet
Career Prospects
USGS NOAA EPA NMFS DOD ONR NRL USACE etc…
Oceonagraphy
Exploration
Earliest Records of exploration date back to
Egyptions 4000BC Navigated the Nile and eastern Mediteranian
Pheonicians 1100 BC -1200 AD navigated the entired mediterranean red sea and indian ocean Africa and British Isles
Greeks 3 and 4th Centuries BC
HERODOTUS
Gree Explorer compiled a map of the world showing the Mediterranean sea as the center surrounded by three land masses North Africa Europe and Asia
PYTHEAS 325 BC GREEK
First to circumnavigate england and sailed north to scotland Norway and Germany
Discovered the tides had to do with phases of the moon
Discovered how to tell your latitude using the N Star
Ptolemy
Produced first world atlas
Overestimated extent of Asia to teh east
Underestimated Circumfrance of the earth
VIKINGS
expored teh far north Atlantic and established colonies in iceland Greenland and Newfoundland during Medival Warm period
Arabs Controlled North Africa and Spain and trade routes eat and became dominant navigators f the time
PORTOLANOS (early charts first appeared)
Compass was Introducted
13th Century
15 and 16th Centuries
Explorations by Europeans increased
The prupose of the European Voyages
find faster safer trade routs to teh orient spurred on by the need for riches and spices
COLUMBUS
Underestimated extent of Atlantic ocean and size of earth due to Ptolemys calculations
MAGELLAN
Underestimated extent of Pacific ocean do to Ptolemy
Circumnavigated teh earth
Established true length of a degree of latitude
Hudnered by Profivision probs mutiny and storms
Killed by natives in Phillippines
Captain James Cook
Used harrison fourth chronometer to produce accurate charts
3 voyages to teh pacific between 1768 and 1779
Charted coasts of teh South Pacific Australia New Zealand and NW North American Haw Isalnds
Made sounding and logged winds currents and water temps
DEFINE NAVIGATION:
In simple terms its necessary to know teh position of the sun or stars related to the time
So accuracte navigation had to wait for accurate clocks that worked on ships
john Harrison successed in making an ACCURATE CHRONOMETETER in 1761
Charles Qyville
Challenger Expedition 1872
LAYERS OF THE EARTH
Lithosphere – Asthenosphere – Mesosphere – Outer Core – Inner Core
Pangaia (Northern Vs Southern parts)
PANGAIA OCEAN
Panthelessa Ocean
PALEOMAGNETISM
Remember the concept of Paleo (Ancient) Magnetism. Can be defined on Polarity Compass needle points toward N and South
Curie Pt/ Temperature
Align themselves along the magnetic field. Crystals of Magnetite get locked into place at that temp. Rock cools.
LINEAR MAGNETIC ANOMALIES
– Age then created GPTS Geomagnetic Polarity Time Scale (6:13) tell the inclination which give you latitude. Can tell where a rock formed basically and based on the paliomagnetism of that rock you can tell that it actually formed wherever said point is.
EAST PACIFIC RISE
Out in the ocean a divergent boundary
The Hawaiin Island chain
gives an idea of where Pacific plate is moving, it tell latitude, very important fundamental data that supports plate tectonics.
Mid Ocean ridges are shallow because
because they are hotter (the rock is hotter which is less dense therefor more buoyant so it rises up) Something more dense is going to sink lower if you take something warmer its going to rise because you have very young or warm rock along the ridges that’s where the sea floor forms that’s where it cools sinks comes out and the abyssal planes are characterized by being flat. For years sediment has been building up except where there are sea mounts.
ABYSSAL PLAINS
Flat for years sediment has been building up
MARIANA TRENTCH IS
Deep Sea Trench
Valcanic Arcs
Subduction Zone
Four Arch Basin
Seizmic From of Subduction
SHALLOW EARTHQUAKES
Associates with Divergent boundaries
Sediments in Mid Ocean Ridge are
Biogeneous Sediments
TURBIDITES
Continental Rise and Slope are buiolt up by these oil is often found
Hydrothermal Deposits
Black Smoke
Coccolithophores
Calcareous Algae (An Autotroph) Made of = CaCO3
So if more than 30 % its Calcareous Ooze but if the dominant is Coccolithophores htan it is Cacareous.
Diatoms
Siliceous (Frustal is the name of skeleton)
Siliceous Chemical Make Up
SiO2+H2O
FORAMINIFERA
Calcareous Single Cell Heterotoph
Radiolarian
Heterotrph Silicious
Radolarians are important bc
Important because things dissolve at different rates. Silic dissolves at a faster rate.
Silicious
(30:04_ Calcite Compensation Data) Below a certain depth calcium carbonate dissolves. At a very deep depth it is pretty much gone. So the amound of Calcium Carbonate going down is equal t otaht going up. “The Snow Line” – Conecepts to be understood
Calcium Carbonate
Water temperature starts dissolving calcium carbonate at a colder temperature. (:41) The temperature is mainly driving down sediments pressure also is also playing effect, which means increased CO2 in water. CO2 – Dissolves Calcium Carbonate. CC=CC Up and Down. RATE OF CC INPUT = RATE OF DISSOLUTIONS.
Bicarbonate
Ca2 + 2HCO3
Ca2 + 2HCO3 <->CaCO3+CO2+H2O
Ca2 + 2HCO3 <->CaCO3+CO2+H2O – Drives Eq to the left therefore calcium carbonate dissolves.
–? surface water ?- underwater