CHAPTER 5 ~ OCEAN Sediments
HOMEWORK 1 DUE
(Long Marine lab Field Trip)
Turn in after class
See Syllabus-revised Webpage
• HOMEWORK –problem sets 2
• Late Policy:
Lab assignments are due the week after posting. ~ mondays
• We ask that you complete your work on time, and will deduct 10% of the
credit per day for any late assignments. NO EXCEPTIONS. If you have
questions about or need help on the assignments, we invite you to come
to the TAs' office hours.
• If you can't make office hours, we encourage you to make an
appointment to meet with the TAs.
• TA – Sami
– alesix78@gmail.com
OUTLINE
The Oceans Memory
Foundations of Paleoceanography
Classification of Marine Sediments
Sedimentary Processes
Global Distribution of Sediments
• The Oceans Memory
–Paleoceanography?
Sediments
tell a story
• Study of Oceans sedimentary record
– Analyze Sediment Cores
Challenge Question
What is the
Principle of Superposition?
In a deposit of undisturbed
sedimentary rocks,
oldest rocks at the bottom,
youngest at the top
OUTLINE
The Oceans Memory
Foundations of Paleoceanography
Classification of Marine Sediments
Sedimentary Processes
Global Distribution of Sediments
Foundations of Paleoceanography
• Cesare Emiliani (1922-1995)
– Godfather of Paleoceanography
– Measure ratio oxygen (18O) vs normal oxygen (16O)
• in shells of Fomanifera (plankton)
• Varies w/ temp.
– Good Indicator of seaH2O temp/time
» Cold H2O (high [18O] vs 16O
» Warm H2O (low [18O] vs 16O
» aka - delta O-18
» Look at O-18 in sediment cores
Foundations of Paleoceanography
• Emergence of Kullenberg piston corer
– Cores of 10-20m into ocean basins. . .
• Representing 1-2 million years of sediments
Foundations of Paleoceanography
• DEEP Sea Drilling Projects (Sediment Cores)
• NSF (1971-1982) – Changes in Climate ~ 700,000 years
Climate: Long Range Investigation, Mapping and Prediction
aka (CLIMAP)
– Demonstrated Ice Ages result from Mileneum-Scale deviations
From Earth’s Orbit around Sun
-aka Milankovitch cycle
Milankovitch cycles (1-3)
I
2
Challenge Question?
3
What do the Milankovitch cycles vary the amount of?
Solar radiation that reaches the earth
What can this lead to / result in?
~ 10*C temp changes  Ice Ages
1
From Sediment Cores
2
3
4
Heinrich Events discovered
– What are they?
6
5
Abrupt climate change/ rapid cooling within decades/ centuries
6 in last 75,000 years. . .
Scientists concerned modern lifestyle leading to another. . .
e.g. Global Warming  Mini ice age . . .
http://www.youtube.com/watch?v=Cs56_GqTyIQ&feature=related
• Confirming your Knowledge
– Using plankton (fomanifera) shells what elemental
• ratio is used to gauge cold/warmer sea water temp/time?
– delta O18 vs O16
– What are Heinrich events/ how many occurred in last
75000 years?
• Rapid change in seawater temp/decades, 6
OUTLINE
The Oceans Memory
Foundations of Paleoceanography
Classification of Marine Sediments
Sedimentary Processes
Global Distribution of Sediments
Classification of Marine Sediments
many source types:
-based on grain size
& organism type
Old Ocean Sediments:
Mostly Phytoplankton
Formanifera (carbonate) ooze - 50%
Diatom
(silica) ooze - 15%
Phytoplankton
Ocean Sediment
CORE
OUTLINE
The Oceans Memory
Foundations of Paleoceanography
Classification of Marine Sediments
Sedimentary Processes
Global Distribution of Sediments
Sedimentary Processes
What are they? = production, transport, deposition of sediments
Sedimentary Processes
How and where do sediments move about on the planet?
1. Starts w/ the
Hydrologic Cycle
-Exchange of H2O
b/w various reservoirs
Sedimentary Processes
2. Continental Weathering
– what is it?
Dissolving, fracturing/ chemical alteration of rocks –
-important role in cycling of elements (Iron, Calcium etc. ) and salinity in Sea Water
• Challenge Question
•
What are the 3 types weathering processes?
•
1. Physical – breaking apart of rocks via
– Rock slides, earthquakes, debris flow
•
2. Chemical – dissolving of rocks via
– Natural acidic rain, rivers etc.
•
3. Biological – activities of organisms via
– fracture, dissolve, chemically alter rocks etc.
Sedimentary Processes
• Sediment Sinking
• Grain size effects sinking
– Sediment traps measure carbon flux
• Estimates Global carbon cycle
• Important For study of Climate change
–
plankton
Sedimentary Processes
• Biological sedimentation
– The biological pump – complex
– phytoplankton
Where does CO2 come from?
• aka algae
=
PhytoPlankton ~
=
Trees
Take in CO2 (from Atmosphere)
give off Oxygen
Challenge Q
Which Produces more O2 (Air) for earth
and by how much?
Algae, 70-80%!
Lots of Stored Carbon (CO2) in sediments
Sedimentary Processes
• Calcium-Carbonate (calcite) Compensation Depth (CCD)
– Below certain depth, calcite shells dissolve 
– aka “the lysocline”
– Challenge Q
• What factors influence the solubility (dissolution) of calcite shells?
– Lower temp., Higher pressure
Sedimentary Processes
• Calcium-Carbonate (calcite) Compensation Depth (CCD)
– The CCD - What is it?
• Depth/Region where: solid Calcite shells = dissolving Calcite shells
– No net change (1:1)
• Area of high plankton growth – shallow CCD (Artic, Antartic)
• Area of low plankton growth – deep CCD (Hawaii)
– Based on solubility of Calcite in Water (think of Sugar in Water)
» If have LOTS, area is saturated (need more Liq. space to dissolve it)
ALGAE
HAWAII-clear H2O
ALGAE
Antartic
Green/dark
H2O
Lots of algae
Shells dissolve 
Shells dissolve 
Shells dissolve 
Artic
Green/dark
H2O
Lots of algae
OUTLINE
The Oceans Memory
Foundations of Paleoceanography
Classification of Marine Sediments
Sedimentary Processes
Global Distribution of Sediments
Global Distribution of Sediments
• Calcite (Carbonate) sediments occupy
– ~68% Atlantic
~36% Pacific
• Lower microorganism (algae growth) responsible?
Final Challenge Q
Why does the N. Pacific NOT
have the same Calcite deposition
as the N. Atlantic?
Think Geology
(bathymetry)
No Mid ocean ridge
In N. Pacific for shells
to land on
They dissolve before then
Can settle on something
(calcite)
–Red clay occupies deepest regions
Global Distribution of Sediments
OUTLINE
The Oceans Memory
Foundations of Paleoceanography
Classification of Marine Sediments
Sedimentary Processes
Global Distribution of Sediments
BREAK
Page 73
Fig. 5.9
Fig. 5.18
Fig. 5.2
Fig. 5.5
Fig. 5.7
Fig. 5.8
Fig. 5.8.a
Fig. 5.8.b
Fig. 5.8.c
Fig. 5.12
Page 81
Page 84
TABLES
Tab. 5.1