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Tectonics, Geomorphology andGeologic Materials
(The influence of the physical environment on watershed dynamics.)
A Watershed Dynamics Tutorial
© John F. HermanceFebruary 9, 2003
(Images from Tasa Graphics among others)
Contact information:Jack HermanceEnvironmental Geophysics/HydrologyDepartment of Geological SciencesBrown University, Providence, RI 02912-1846Tel: 401-863-3830e-mail: [email protected]
Regional tectonics can play a controlling role in local watershed dynamics.
(Images from Tasa Graphics cannot be used without permssion of the company.)
Plate tectonics drives current orogenic activity.
Orogenic activity is enhanced at plate boundaries.
How does the “rock cycle” determine local water decisions?
Understanding the evolution of geologic features, generically or on a site specific basis, can give insight into watershed
processes, hence water-related decisions.
Understanding the evolution of geologic features, generically or on a site specific basis, can give insight into watershed
processes, hence water-related decisions.
Igneous rocksIgneous rocks
Understanding the evolution of geologic features, generically or on a site specific basis, can give insight into watershed
processes, hence water-related decisions.
Metamorphic rocksMetamorphic rocks
Understanding the evolution of geologic features, generically or on a site specific basis, can give insight into watershed
processes, hence water-related decisions.
Sedimentary rocksSedimentary rocks
The Northwest US.
The “Rock Cycle” Exposed.The “Rock Cycle” Exposed.
The Northwest US.
Igneous rocksIgneous rocks
Igneous rocksIgneous rocks
BatholithsBatholiths
Intrusive igneous rocks
Intrusive igneous rocks
Extrusive igneous rocks
Extrusive igneous rocks
Metamorphic rocksMetamorphic rocks
Sedimentary rocksSedimentary rocks
The Northwest US.
The Western US.
An Archetype ExampleAn Archetype Example
The Western US.
Physiographic LandformsPhysiographic Landforms
The Western US.
Basin & RangeBasin & Range
The Western US.
Colorado PlateauColorado Plateau
The Western US.
Snake River PlainSnake River Plain
The Western US.
CascadesCascades
The Western US.
Sierra NevadaSierra Nevada
The Western US.
Southern RockiesSouthern Rockies
The Western US.
Northern RockiesNorthern Rockies
The Western US.
Rio Grande RiftRio Grande Rift
The Western US.
California Central ValleyCalifornia Central Valley
The Western US.
Southern Basin & RangeSouthern Basin & Range
The Future(and the past).
The Oldest Bedrock:Shield Areas of the World.
“Basement”; then . . .
“Basement”; now . . .
“Basement”; now . . .Where or what is
“basement”?
Evolution of the crust
Grand Canyon Exposure as a Microcosm of the North American Crust
(From California to Massachusetts.)
Next. we’ll look at the shallow unconsolidated section.
We are interested in glacial features . . .
. . . streambed features . . .
. . . and fluvial deposits.
Sedimentary sorting.
Sedimentary sorting.
Sedimentary sorting.
(Back to metamorphism: Sediments are ephemeral.)
(Metamorphic Grade.)
A digression on glaciers.
The Ice Age
Maximum extent of glaciation.
“Fossil” glacial features.
“Fossil” glacial features.(Moraines.)
Glacial landforms.
Glacial rebound.
Present day mountain glaciers (or not) as “keys to the past”.
Present day mountain glaciers (or not) as “keys to the past”.
Glacier in cross-section.
Glacier in cross-section.
Stresses in a glacier crossing a rock step.
A tour of Canadian glacial forms.
The Athabasca.
A dry valley.
A hanging glacier.
A hanging glacier up-close.
A trip up the Athabasca.(Note principal features.)
The Ice Falls.
The Ice Falls on approach.
The Ice Falls on target.
This is why we came here.
This is why we came here.(Radio waves through ice?)
This is why we came here.(Radio waves through ice?What does this have to do with NASA, and the Lunar Lander (Apollo Program)?)
“Fossil” glacial landforms.
Stream morphology.
Stream morphology.
Stream morphology.
Meanders.
Meanders - Flooded.
Meanders - Flooded -
and buried.
Stages of stream evolution.
Stages of stream evolution.
Stages of stream evolution.
Deltas
Deltas
Drainage patterns driven by bedrock patterns.
Current “geologic” processes can modify “current” hydrology.
Mass movement can modify local hydrology &
vice versa.
Affect of subsurface water on mass movement.
Affect of subsurface water on mass movement.
Affect of subsurface water on mass movement.
Affect of subsurface water on mass movement.
Affect of subsurface water on mass movement.
Evolution of bedrock.
Evolution of bedrock.
Evolution of bedrock.
The paradigm for subsurface hydrology.
Organic layer
Leached layer
Weathered bedrock
Bedrock
Physiography of North America.
Groundwater regions of the US. (Note concordance with geology.)
End of Presentation(Tectonics, Geomorphology and
Geologic Materials)
© John F. Hermance; February 9, 2003
Go to Soil & Water.
