Geology 106
LECTURE 9 - INTRODUCTION TO SURFICIAL PROCESSES
1- Reminder: Exam review session tonight (5:00-6:00 pm, Room
AB20)
Sample questions and study guide on web home page.
2- Resources: Decker, R.W. and Decker, B.B. (1991) Mountains of Fire;
New York, Cambridge Univ. Press. 198 p.
3- Finish Video on Mt. Pinatubo Eruption (June 1991)
Summary comments on volcanoes and environmental consequences
4- Introduction to Surficial Processes
Surficial Processes = Geologic processes acting on the surface of the
solid earth in contact with the atmosphere and hydrosphere.
Includes: Weathering, erosion, mass wasting, rivers and streams, glaciers,
work of the wind, coastal processes, and groundwater.
Opposing forces that reduce the effects of earthquakes and volcanoes
(tectonism).
Earth has just the right balance of RATES of erosive surficial processes
and constructive internal earth processes to have them nearly in balance.
Geographic features of the earth reflect the relative rates of various
processes acting to either build up or tear down the land. Tectonism dominates
some areas (ex: East face of the Sierra Nevada Mts. and portions of the
San Andreas fault)
Both internal and surficial processes have slow and rapid components.
Short periods of rapid movement followed by long periods of little or no
movement. Long term effect of slow and rapid processes determine long-term
rates.
Rates vary depending on the time period over which the process is averaged.
How do we recognize weathering? What common, every day clues are there
that the processes of weathering are occurring? What are the long-term
consequences of weathering?
Slide overview of various effects of weathering, erosion, and mass wasting.