UNIT #5 STUDY GUIDE – WEATHERING, EROSION AND DEPOSITION
SURFACE PROCESSES AND LANDSCAPES:
The landscape is a temporary result of processes acting through time due to weathering, erosion and
deposition. The landscape is shaped through the interaction of crustal movement, type of bedrock
(hard or soft), and climate.
Weathering – breaking down of the rock into smaller pieces/sediments by the action of wind, water, or
ice (glacier), which are the major factors of weather conditions.
Erosion – transport of sediments away from their place of origin and deposited elsewhere.
Deposition – sediments deposited into layers in one location.
Water cycle – constant movement of water between the Earth’s surface (groundwater, rivers, oceans)
and the atmosphere (water vapor/clouds).
2 kinds of weathering:
Physical weathering – abrasion (rubbing and grinding together of rocks) [does NOT change the
chemical composition of the rock]
Chemical weathering – rusting or acid reactions [DOES change the chemical composition of the rock]
Weathering occurs when rocks are exposed to the hydrosphere (water), biosphere (humans), and
atmosphere (air).
*THINGS YOU NEED TO REMEMBER:
Weathering is affected by climate: Moist / warm climate favors chemical weathering (faster)
Dry / cold climate favors physical weathering (slower)
Rate of weathering is affected by particle size: smaller surface area weathers faster
More resistant rock (hard minerals) weather slower – soft mineral rock weathers faster
Soil is produced by the weathering (breakdown) of rocks. Layers of soil are called horizons. Crosssectional arrangement of the horizons is call a profile. Leaching is minerals dissolved in soil by water
draining deeper down into soil. Layers of rock is called strata.
Gravity is the primary force that drives all the agents of erosion. The agents of erosion are wind,
water, ice. Running water is the chief agent of erosion on Earth. Greater volume of water and steeper
gradient causes greater velocity (speed) causing greater movement of rock/sediment (erosion).
Streams erode banks on the outside of the curves, and deposit on the inside of the meanders. A
meander is a broad, S-shaped curve stream valley (old stream).
Streams carry sediments through flotation (light, low density materials floating), solution (small
particles dissolved in water), or by suspension (tiny particles that cannot be filtered out), or by
bouncing rolling materials (large materials breaking down). As discharge (volume of water), slope
(gradient), and particle size (rock size) increase, stream velocity (speed) increases.
Stream drainage patterns are determined
by the gradient (slope) of the land. 
Porosity – space between rock particles.
Permeability – ability of water to flow
between rock particles.
Impermeable – rock particles that do not
allow water to flow through.
Infiltration – downward flow of water
into ground. Capillarity – upward flow.
Surface runoff – water flowing over the
ground that can’t infiltrate ground (flood)
Water retention – water that is retained
(stays on the rocks). Greater surface
area (smaller/more particles) has greater
water retention.
In the horizontal sorting of rock material, particles of greater weight (density) settle out first and
the lighter particles go farther out in the water settling out last.
In the vertical sorting of rock material, particles of greater weight (density) settle first (to bottom)
and lighter particles (less dense) settle last (on top).
Climate is based on temperature (hot or cold) and humidity (moisture present)
Types of climate: polar (cold, dry), arid (hot, dry), temperate (hot, dry/cold, wet), tropical (hot, wet)
Dry climate (arid): streams/rivers not always present (flat elevated plateaus)
Wet climate (humid): streams/rivers always present (rounded elevated hills)
“V” shape valley: narrow valley formed from rivers
(rivers and wind—sorted, layered rock)
“U” shape valley: broad valley formed from glaciers (glaciers—unsorted, unlayered rock)
meander: winding “S” shape old river valley formed from erosion by water
Cold climate: glaciers decrease sea level due to increased water held in ice.
Warm climate: global warming increases sea level due to melting glaciers raising sea level.
Ocean waves – sandbar deposition and beaches
Glaciers – striations (scratches) on rocks, unsorted/unlayered rocks, erractics
Wind – pitted and frosted appearance, sand dunes
Landscape development influenced by type of bedrock in region. Rock is resistant (hard minerals) to
forces of weathering and erosion, therefore, little weathering and few surface changes.
ESRT: Landscape Regions of New York State, pg. 2
Bedrock Geology of New York State, pg. 3
Stream Velocity/Particle Size, pg. 6
Minerals, pg. 16