OCEANS ON PLANETS


Geo 196: OCEANS ON PLANETS

CLASS SCHEDULE Semester II - 1999/2000
(N Hour 3:00 PM-5:20 PM, WEDNESDAYS)
LINCOLN FIELD 105

Week 1 - 5:00 PM January 26th (Wednesday) LF 105: Introduction to Oceans on Planets:
Thursday, January 26th: 4 PM, MH 115: Gerald Schubert, "Interiors and Magnetic Fields of the Galilean Satellites".

Earth Themes:
-The Earth's hydrosphere: The hydrologic cycle:
-Where is the water and how does it move? -What are the reservoirs and systems and what is their stability?
-Systems and processes: Oceans, the cryosphere, groundwater.
-Processes, morphology, and recognition.
-Origins of water on Earth.
-Evolution of water on Earth: Waterworld to Snowball Earth. -Catastrophic Redistribution:
-Flooding: Channeled scablands.
-Filling: The Mediterranean and the Black Sea.
-Dessication: The Aral Sea and evaporite basins. -Relation of the hydrosphere to the biosphere. -What are the major questions and unknowns for Earth?


Week 2 - February 2nd (Wednesday) LF 105: Earth 1: Earth Themes:
-The Earth's hydrosphere: The hydrologic cycle:
-Where is the water and how does it move? -What are the reservoirs and systems and what is their stability?
-Systems and processes: Oceans, the cryosphere, groundwater.
-Processes, morphology, and recognition.

This week we will discuss the hydrologic cycle and how it works on Earth, also emphasizing the nature of features and structures that permit recognition of the different reservoirs. We will start with a lecture and then go to discussion of these points.

Readings: Readings are on the table in Lincoln Field 105.

Earth, An Introduction to Physical Goloogy, E. J. Tarbuck and F. K. Lutgens.

Chapter 10: Running Water, p. 231-266.
Chapter 11: Groundwater, p. 267-292.
Chapter 12: Glaciers and glaciation, p. 293-326. page 228: The sensitive permafrost landscape.


Week 3 - February 9th (Wednesday) LF 105: Earth 2:
-Origins of water on Earth.
-Evolution of water on Earth:
-Waterworld to Snowball Earth.

This week we will follow up on our discussion of the hydrologic cycle and address the questions of where water comes from originally and how much the budget of water might change with time. Specifically, we will ask the questions:

-What are the sources and sinks of water during the formation and evolution of the Earth and planets?

-How might these sources and sinks have changed with time?

-What are the implications for the hydrologic cycle with time?

Brad Thomson and Patrick Russell will present a summary of these issues based on key elements of the following readings. Please read the general, and as much of the specific readings as possible.

General:
Kasting, James, F., The origins of water on Earth, The Oceans, 9, 16-22, 1998.

Chyba, C. F., Impact delivery and erosion of planetary oceans in the early inner solar system, Nature, 343, 129-133, 1990.

Kasting, James, F., Toon, Owen B., and Pollack, James, How climate evolved on the terrestrial planets, Scientific American, 258, 90-97, 1988.

Holland, Heinrich D., The evolution of seawater, 559-567.

Harrison, C. G. A., Constraints on ocean volume change since the Archean, Geophys. Res. Letts., 26, 1913-1916, 1999.

Detailed:
Pollack, J. B. and Yung, Yuk L., Origin and evolution of planetary atmospheres, Ann. Rev. Earth Planet. Sci., 8, 425-487, 1980. See particularly, Sources of atmospheric gases, p. 428-438, and sinks p. 438-448, Earth, p. 453-461, and Conclusions p. 481-484.

Fanale, Fraser P., Planetary volatile history: Principles and practice, 135-175. See particularly, p. 137-143, p. 161-167.


Week 4 - February 16th (Wednesday) LF 105: Earth 3: -Evolution of Water on Earth:
Snowball Earth and Catastrophic Redistribution:
-Snowball Earth.
-Filling: The Mediterranean and the Black Sea.
-Dessication: The Aral Sea and evaporite basins.

This week we will start with consideration of what happens in the snowball Earth scenario in preparation for the talk by Dan Schrag on Thursday, February 17th at 4 PM in MH 115. We will then discuss examples of large-scale migration of oceanic and sea water. Finally we will consider the situation of the Aral Sea as an example of a sea that is drying up rapidly and its similarities to evaporite basins. Specifically, we will ask the questions:

-What happens to the hydrologic cycle in a snowball Earth?

-What are the typical features associated with catastrophic flooding and how might they be recognized on other planets?

-What is the range of conditions in which rapid dessication can occur?

-How does catastrophic flooding and rapid dessication alter the hydrologic cycle?

Please read as much of the general reading as possible.

General:
Snowball Earth, Scientific American

K. J. Hsu, Origin of saline giants: A critical review after the discovery of the Mediterranean evaporite, Earth-Science Reviews, 8, 371-396, 1972.

Judith McKenzie, From desert to deluge in the Mediterranean, Nature, 400, 613-614, 1999.

W. Krijgsman, et al., Chronology, causes and progression of the Messinian salinity crisis, Nature, 400, 1999.652-655, 1999.

Aral Sea


Week 5 - February 23rd (Wednesday) LF 105: Earth 4: -The Hydrologic Cycle: Synthesis:
-The groundwater system as a geologic agent. -The hydrological cycle and its influence on climate. -What are the major questions and unknowns for Earth?

This week we will start with an assessment of how groundwater systems operate and how signifcant they are as a geologic agent. We will then consider the relationship between the hydrologic cycle and climate. Finally we will synthesize some of the knowns and unknowns about the Earth. Specifically, we will ask the questions:

-What role does groundwater play and how might it differ on other planets?

-What are some of the major unknowns in how the hydrologic cycle influences climate and how might we determine these unknowns?

-What remaining questions need to be addressed for the Earth's hydrologic cycle and how might other planets provide new insight?

Please read the following papers

General:

Jozsef Toth, Groundwater as a geologic agent: An overview of the causes, processes, and manifestations, Hydrogeology Journal, 7, 1-14, 1999.

Moustafa T. Chahine, The hydrological cycle and its influence on climate, Nature, 359, 373-380, 1992.


Week 6 - March 1st (Wednesday) LF 105: Mars 1:

Week 7 - March 8th (Wednesday) LF 105: Mars 2: (Jordan and Carolyn)

-Past Water History and Reservoirs:
-Fluvial erosion: Valley networks and outflow channels.
-Ancient oceans: Formation, evolution, and loss.
-Ancient polar deposits: Evidence and implications.

This week we will continue with an assessment of the geological evidence for the past history of water on Mars. Where did it reside, how much was there, how and where did it migrate? What evidence do we have for groundwater systems, how might they operate and how signifcant were they as a geologic agent?

-Did water ever precipitate out of the atmosphere and run across the surface of Mars?

-Was the precipitation in the form of rain or snow? How would we tell?

-Were there ever large-scale standing bodies of water on Mars and if so, where did they go.

-Is there evidence for significant groundwater in the history of Mars and if so, is it still there at present?

-Is there any evidence for significant ancient polar deposits and how do they fit into the record of the rest of the water reservoirs?

Please read the following papers and chapters:

M. Carr, Water on Mars, Chapter 4: Valley Networks.

M. Carr, Water on Mars, Chapter 3. Outflow Channels.

J. W. Head, H. Hiesinger, M. Ivanov, M. Kreslavsky, S. Pratt, B. Thomson, Possible ancient oceans on Mars: Evidence from Mars Orbiter Laser Altimeter data, Science, 286, 2134-2137, 1999.

Several LPSC 31 Abstracts on ancient polar deposits (#1119, 1117, 1118, 1116, 1121, 1206; these are in the abstract book on the box)


March 15th: LPSC, no class:

Week 8 - March 22 (Wednesday) LF 105: Mars 3: Thursday, March 23rd, 4 PM, MH 115: Steve Clifford, "The history of Water on Mars".

March 29th: Spring Recess, no class:

Week 9 - April 5th (Wednesday) LF 105: Mars 4:

Outer Planet Satellite Themes:
-Europa's hydrosphere: The hydrologic cycle:
-Formation and evolution of the hydrosphere on Europa -The hydrologic cycle: Lithosphere, hydrosphere, and cryosphere relations.
-Europa: Physical and chemical oceanography. -Geological evidence for the present state of the global ocean. -What are the major questions and unknowns for Europa?
-Oceans on Ganymede and Callisto: Crypto-oceans and their evolution. -Oceans on Titan: Evidence, nature and implications.

Week 10 - April 12th (Wednesday) LF 105: Europa 1.

Week 11 - April 19th (Wednesday) LF 105: Europa 2; Ganymede and Callisto.

Week 12 - April 26th (Wednesday) LF 105: Titan.

Week 13 - May 3 (Wednesday) LF 105: Reports on research papers: Comparison and synthesis: Oceans and the hydrologic cycle