weathering, erosion, deposition

Abrasion

When rock particles hit and rub against each other. This is a form of physical weathering. This causes the rock particles to become rounder in shape.

Agent of Erosion

What is responsible for actually CARRYING the weathered pieces of sediment. The four agents of erosion are Wind, water, glaciers (ice) & gravity. The way the sediments LOOK after they are deposited tell you which agent was responsible for eroding them: Regardless of the agent, GRAVITY is the force that causes the agent to move.

Alpine Glacier

A glacier that forms in the mountains and gravity makes it scrape down the valleys.

Arete

When an alpine glacier ‘ scoops’ out two sides of a mountain. (2 cirques) as it scrapes downhill, leaving a sharp ridge.

Barrier Island

A protective, skinny island on an ocean coastline. Fire Island, Myrtle & South Miami Beach are. examples of this.

Carrying Power

The ability of a river/stream to carry sediment. Related to the slope, volume & width of the river.

Chemical Weathering

When a rock breaks down due to a chemical reaction. This will increase in a moist, warm climate. Normally the substances are oxygen, water and carbon dioxide.

Cirque

When an alpine glacier erodes ONE side of a mountain, Kind of like stealing a scoop of ice cream with a spoon.

Colloid

Smaller than a piece of clay but NOT dissolved. Takes a LONG time to settle to the bottom. In other words it stays in SUSPENSION for a long time.

Continental Glacier

A huge glacier (also called an ice skeet) that covers relatively flat land. Forms from the accumulation of snow that simply does hot melt. During the last ICE AGE, a continental glacier scraped and yanked all sorts of rock material to this final latitude, forming Long Island.

Delta

When a river dumps into a large body of water, its speed suddenly slows down so sediment is dumped (deposited). This formation is called a DELTA.

Deposition

First comes weathering, then erosion, THEN deposition. Big round, dense particles will land at the bottom of a non-moving body of water. (quiet medium) first.

Discharge

The amount of water flowing past a point of the river in a given amount of time.

Drumlins

Weird! Formed from glaciers

Dynamic Equilibrium

The amount of Sediment picked-up

Erosion

When sediment is being picked up by one of the four AGENTS OF EROSION to be carried to a new location.

Erosional-Depositional System-A region in which erosion is happening (dominant) in some locations and depositions is dominant in others.

Erratic

One of those huge boulders that we see lying around that was carried by a glacier, plucked off of bedrock from SOMEWHERE

Flood Plains

The flat land on both sides of a river: This is the result of the seasonal flooding of the river from spring rains

Frost Action (Ice Wedging)

The most frequent and common form of physical Weathering, Rocks will break down into smaller pieces because water in hairline cracks will expand when it freezes. This causes the crack to become wider. Eventually the crack will become so big that it falls off.

Glacier

When there is a lot of snow that doesn't melt, it packs and crystallizes, becoming ice. Just like a really hard core snowball. That's why glaciers are that beautiful light blue color. However, glaciers can also be VERY' dirty, because they erode a great deal of sediment as they bulldoze and ice wedge tremendous amounts of sediments as they slowly move.

Graded Bedding

Just like you get grades, A,B, C, etc. Sediments get deposited in some sort (no joke intended) of order from bottom to top, perhaps over and over and over again in a seasonal pattern. The pattern can be the result of size, shape or density.

Gravity

The FORCE responsible for all agents of erosion.

Groin

Medium sized, narrow, pile of rocks or other material built perpendicular to the shore line to keep the sand on the beach.

Horizontal Sorting

When sediments are sorted by size; shape or density from one place to another (NOT top to bottom!).

Horn

When three CIRQUES meet to take a mountain peak. The Alps are all like this. A wonderful example is the famous Matterhorn which is a well known place for mountain climbers.

Humus

The rotting, organic, decomposing, poopy, plant & animal portion of soil.

Jetty

Robust, man-made perpendicular structure that is longer than a groin and protects the shoreline from erosion.

Kettle Lakes

A result from the passage of a continental glacier. When a HUGE chunk of ice breaks off and gets buried, it makes a big hole in the ground which reaches below the water table. This results in the formation of a lake. Lake Ronkonkoma is an example of this. There are many other smaller ones on LI. Kettle Lake Park used to be across Nicoll's Rd. before a development was built.

Load

The sediment that is being carried by a river/stream/creek.

Longshore Drift

This "rip current'' that we feel is the result of waves that are being bounced off of barrier islands. This is why we always have to walk BACK to our beach blankets!!

Meander

The curves in an older river. Erosion happens on the outside of the bend, deposition happens on the inside or the curve.

Moraine

The bulldozed pile of sediment that is left behind by a glacier. Can be left in the front or on the sides.

Mouth

Where river water dumps into the ocean or lake.

Outwash Plain

Where the melting water from a glacier rushes out from underneath a glacier, depositing all its smaller sediments. The south shore of Long Island received all of this sediment; that's why it has all those beautiful sandy beaches that we love!!

Oxbow Lake

In really old rivers that have really twisty, turning meanders, the river cuts through forming curved lakes called OXBOW LAKES.

Parent Material

The bedrock from which a soil is made. If the soil is found on top of its parent material it is called RESIDUAL SOIL; if not it is considered a TRANSPORTED SOIL.

Physical Weathering

When a rock is broken down into smaller pieces as a result of a FORCE. Examples of physical weathering include frost action, abrasion; root action, exfoliation, pressure release.

Residual Soil

A soil that is found directly above its parent material.

Resistant

When a rock is difficult to weather or break down into smaller pieces.

Sand Dune

A pile of sand sized sediment that is the result of erosion due to wind.

Sediment

Pieces of rock that have been weathered.. The size categories include: boulders, cobbles, pebbles, sand, silt, clay, colloids and dissolved minerals..

Soil

A combination of weathered bedrock and humus.

Soil Profile

A side view of the layers of a fully developed mature soil. These layers include the topsoil (A HORIZON) which is rich in humus: the subsoil (B horizon) which contains clays, sand and rock particles, partially weathered bedrock (C Horizon), and the bedrock

Solution

When the minerals in sediment dissolve in water. In this case, the rock material is traveling as fast as the water.

Source

Where the river begins its trip.

Stream/Channel

The walls and bottom of a river/stream/creek. An older, mature river is wider and has meanders and oxbow lakes. River valleys/channels are V-shaped.

Striations

The scratch marks on bedrock that are made by a glacier as they scrape their way over bedrock.

Suspension

Very small colloidal silt and clay sized sediment will travel in water in this fashion. This will make the water look “muddy” so that the water takes on the color of the sediment. When the water stops moving, the sediment will slowly settle. That's why lakes have mushy-gushy bottoms.

Talus

Piles of unsorted angular sediments deposited at the bottom of a cliff (Gravity)

Till

The mixture of sediment that is deposited in the moraines of a glacier.

Topsoil

The humus-rich, dark colored, soils of the A horizon.

Transported Soil

A soil that has been eroded. The soils of LI have all been transported from the North of us.

Unsorted/Sorted Deposits

Unsorted deposits have been left by the agents of erosion that start with the letter “G” (gravity, groundwater and glaciers). Sorted deposits have been deposited by agents of erosion that start with the letter “W” (wind, water, waves)

U-Shaped Valley

When a valley has a rounded bottom if it has been carved out by a glacier.

Velocity

Speed. The faster water is moving, the more CARRYING POWER it has.

Vertical Sorting

When the sediments have been arranged according to size, shape, or density from top to bottom.

V-Shaped Valley

When a valley has a V-shaped bottom, it has been carved out by rivers, streams, creeks.

Wave

Disturbance in the surface of a body of water caused by wind.

Weathering

The breakdown of rocks into smaller pieces called SEDIMENTS.

Weathering Rate

How quickly a particular rock will break down into sediment sized pieces. This is the result of climate, particle size, mineral composition and shape.