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Beautiful graphics from NPS depicting landforms created by flowing water of rivers.

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Illustration of channel features from Chaco Culture National Historical Park geologic report.
Source: Trista L. Thornberry-Ehrlich, Colorado State University.

A floodplain is the relatively flat surface adjacent to the river or stream. During floods, when the stream overflows its banks, water flows over the floodplain and deposits sediment. Through fluvial processes, streams construct floodplains that accommodate their maximum flood capacity. Geomorphic features of the floodplain include:

Natural Levees-River may be immediately flanked by a buildup of sediment that forms natural levees. These provide some defense against flooding, but are occaisionally breached in areas producing flood-plain splays-coarse fan-shaped deposit of sediment created during high flow events.

Oxbows and oxbow lakes-See below, features of a Meandering Stream Channel.

Point Bars-See below, features of a Meandering Stream Channel.

Terraces

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River Systems and Fluvial Landforms - Geology (U.S. National Park Service)

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A floodplain is the relatively flat surface adjacent to the river or stream. During floods, when the stream overflows its banks, water flows over the floodplain and deposits sediment. Through fluvial processes, streams construct floodplains that accommodate their maximum flood capacity.

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Lesson demonstrating the geologic process of sediment sorting.

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Grade Level:

Upper Elementary: Third Grade through Fifth Grade

Subject:

Science

Lesson Duration:

60 Minutes

State Standards:

Thinking Skills:

Analyzing: Break down a concept or idea into parts and show the relationships among the parts. Evaluating: Make informed judgements about the value of ideas or materials. Use standards and criteria to support opinions and views.

Essential Question

How does sediment size and layering in sedimentary rock describe how a material was deposited?

Objective

Students will demonstrate the geologic process of sediment sorting. Sorting describes how fine to coarse grain sediments are distributed (settle), and how they will eventually lithify into sedimentary rock. Students will mimic sois deposition in a lake setting so as to better visualize the layering of the shale deposits in the Florissant Formation.

Background

Sorting describes how sediments are distributed based on their size.

Terms describing sorting in sediments

Very well sorted - sediment sizes are very similar in size within a strata.

Well sorted

Moderately sorted

Poorly sorted

Very poorly sorted - sediment sizes vary largely and are mixed in sizes (small to large) within a stata (layer).

Degree of sorting indicates the energy, rate, and duration of deposition and how the sediments were transported (i.e., volcanic debris flow, streams, wind, glaciers, still water etc).

Sediments can also get reworked after being deposited through a process called winnowing which is the removal of finer material from coarser material.

Sediment sorting is useful in geology to help determine the timespan of a depositional event and, also, a possible source of the event. If the strata contain fossils, knowledge of sediment sorting helps paleontologists get a more complete picture of how and when a fossilization event occurred.
Preparation

Materials needed:

Plastic lidded jar

Water

Arrow shaped post-its

Small containers with lids

"Sedimentator" sorting tube

Rock sample boxes

Sorting & grain size chart

Assessment materials enough for each group

Material in General Supply kit
Preparation

check activity and general supply kit bins for sufficient reusable supplies: soils, post-its, pitchers, beakers, etc

make copies of assessment materials and sorting images, if necessary

arrive to location early enough to prepare experiment tables for each group: small cups of soil samples, beakers, etc.

Materials
Download Sorting and Grain Size Chart
Lesson Hook/Preview

Lakes are home to an abundance of plant and animal life but can be "home" to an abundance of geologic stories also! Particles of soils, minerals, and rocks can be described by their size and shape as well as by how the materials form sedimentary layers. The layers, or strata, are deposited in lakebeds in known patterns called sorting. Students will mimic the action of sediment sorting as it occurred in Ancient Lake Florissant using differing sizes of sediment materials mixed inside lidded jars.

Procedure

Procedure

1. Have students separate into small groups of 4 or 5.

2. Give a brief lesson on sediment sorting and the purpose of this experiment-use Sedimentator Sediment Tube to show process. Students may enjoy a demonstration by you of the experiment, with explanations of each step, before they begin their own experiment. (page 2 "Lesson Hook and Background")

3. Work with the class to answer assessment question #1.

4. Give each group a lidded jar, a stopwatch, sharpie, pack of sticker arrows, and small sample cup of each type of rock and plant material.

5. Have students take turns pouring all the sediments together inside of the plastic jar. The jar should be about ½ full but no more than 2/3 full.

6. Give students a beaker of water. They will add enough water to the soils for the jar to be approximately ¾ full, but no more. Jars will need a bubble of air to facilitate mixing. Have students screw the lid tightly back onto the jar. Double check lid tightness of each jar for the students!!

7. Have students take turns shaking their group's jar. They can use the stopwatch to ensure the jars stay in motion for a minimum of 2 minutes.

8. As soon as students are done shaking the jar, have them place it onto a flat surface then start the stopwatch.

9. In the space for question #2, Record the time in which the first sediments begin sinking to the bottom of the jar, Record times for each additional layers as they begin to form.

10. After seeing distinct layers in the jar, students will place an arrow sticker at the point of each visible layer.

11. Write observations in question #3 for the first layer, describing the size of the sediments.

12. Work with the class to make observations about each layer. Make notes in question #4.

13. Discuss observations with students and work as a group to answer question #5.

**Keep all containers! Wash, dry and return to bins.**
Vocabulary

Assessment Materials

Sediment Sorting Assessment

1. Describe a natural action that can lead to sediment sorting. Would you expect your example be very poorly sorted or very well sorted or somewhere in between? Why?

2. Time sediments began sinking:

Time for layer 2 to form:Time for layer 3 to form:Time for layer 4 to form:Time for layer 5 to form:

1. Describe which sediments formed the first layer. What was the size, shape, or name of the material?

2. How many layers in total formed inside the jar? How would your rate the quality of sorting that happened in this experiment?

3. Based on the layering of the sediments in the experiment jar, can we determine what type of environment the jar is intended to represent?

Rubric/Answer Key

1. Examples can include flowing rivers, wind, volcanic debris flows, etc. Students can have many answers that should include the idea that increased energy into the deposit means less sorting will occur.

2. Times will vary. Students may struggle with when to record a time as they may not expect the sinking to be quick or may expect very distinct layers. Take an average time for the class for each layer and discuss how or why some sediments settled quickly while others remain in suspension.

3. Gravel, sand, clay, silt, with plant materials scattered throughout the layers. Students will notice that layers are not distinct stripes. Clay and silt may be difficult to see or tell apart, but the silt will remain in suspension. Students should describe each type of material as best as they can using words that involve comparative size and weight.

4. The number of layers formed should be the same number as the different layers of sediment added: 5. The layers separate based on the size of the sediments making up each layer, with the bottom layer being the heaviest and larges. Not all layers will be perfectly formed and some materials, like the plant debris, will be mixed throughout. This could be described as moderate to well sorted.

5. We know the layers were formed in a low energy environment because the jar is an closed space where the only energy available is what we put into it. The rock layers form as the sediments settle to the bottom, which occurs as soon as we stop putting energy into the enclosed environment. This describes any naturally occurring environment where intense energy my cause the sediments (such as a volcanic eruption) but the intense energy is brief and allows settling of materials into a mostly sorted pattern. This is consistent with a low energy environment like a still and/or deep body of water.

Contact Information
Email us about this lesson plan

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Sediment Sorting - Teachers (U.S. National Park Service)

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Grade Level: Upper Elementary: Third Grade through Fifth Grade Subject: Science Lesson Duration: 60 Minutes State Standards: Thinking Skills: Analyzing: Break down a concept or idea into parts and show the relationships among the parts. Evaluating: Make informed judgements about the value of ideas or materials.

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Mystery Science Lesson: Why is there sand at the beach?

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Mystery Science Lesson: Why is there sand at the beach?

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Students investigate the effects of rocks tumbling in a river. Based on their observations, they construct an explanation for why there is sand at a beach. In the activity, Rocking the River, students pretend to be a river and tear up pieces of construction paper to model what happens to rocks as they travel along the river.

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In this lesson, students investigate the effects of rocks tumbling in a river. Based on their observations, they construct an explanation for why there is sand at a beach.

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Nat Geo article on different basins and how they form.

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A basin is a depression, or dip, in the Earth's surface. Basins are shaped like bowls, with sides higher than the bottom. They can be oval or circular in shape, similar to a sink or tub you might have in your own bathroom. Some are filled with water. Others are empty.

Basins are formed by forces above the ground (like erosion) or below the ground (like earthquakes). They can be created over thousands of years or almost overnight.

The major types of basins are river drainage basins, structural basins, and ocean basins.

River Drainage Basins

A river drainage basin is an area drained by a river and all of its tributaries. A river basin is made up of many different watersheds.

A watershed is a small version of a river basin. Every stream and tributary has its own watershed, which drains to a larger stream or wetland. These streams, ponds, wetlands, and lakes are part of a river basin. The Mississippi River basin in the U.S., for instance, is made up of six major watersheds: the Missouri, Upper Mississippi, Ohio, Tennessee, Lower Mississippi, and Arkansas-Red-White Rivers.

Every river is part of a network of watersheds that make up a river system's entire drainage basin. All the water in the drainage basin flows downhill toward bigger rivers. The Pease River, in northern Texas, is part of the Arkansas-Red-White watershed. It is a tributary of the Red River. The Red River is a major tributary of the Mississippi River, which flows into the Gulf of Mexico.

The Amazon Basin, in northern South America, is the largest in the world. The Amazon River and all of its tributaries drain an area more than 7 million square kilometers (about 3 million square miles).

Structural Basins

Structural basins are formed by tectonic activity. Tectonic activity is the movement of large pieces of the Earth's crust, called tectonic plates. Tectonic activity is responsible for such phenomena as earthquakes and volcanoes. The natural processes of weathering and erosion also contribute to forming structural basins.

Structural basins form as tectonic plates shift. Rocks and other material on the floor of the basin are forced downward, while material on the sides of the basin are pushed up. This process happens over thousands of years. If a basin is shaped like a bowl, a structural basin is shaped like a series of smaller bowls, stacked inside each other. Structural basins are usually found in dry regions.

Some structural basins are known as endorheic basins. Endorheic basins have internal drainage systems. This means they don't have enough water to drain to a stream, lake, or ocean. The water that trickles into these types of basins evaporates or seeps into the ground.

When enough water collects in an endorheic basin, it can form a very salty lake, such as the Dead Sea, between Israel and Jordan. While water evaporates into the atmosphere, minerals remain. The remaining water becomes even saltier. The Dead Sea is one of the saltiest natural body of water on Earth. Its shore, about 400 meters (1,300 feet) below sea level, is Earth's lowest dry point.

Death Valley, in the U.S. state of California, is another endorheic basin. At about 86 meters (282 feet) below sea level, it is the lowest place in North America. The water draining into Death Valley from its few streams does not exit the basin to a river or estuary. It evaporates or seeps into the ground.

A lake basin is another type of structural basin. Lake basins often form in valleys blocked by rocks or other debris left by a landslide, lava flow, or glacier. The debris acts as a dam, trapping water and forming a lake. Hunza Lake in Pakistan was formed when an earthquake triggered a massive landslide in 2010. The debris dammed the Hunza River, in addition to killing 20 people and destroying the village of Attabad. The Hunza River continues to flow into the lake basin, and many geologists and villagers worry the basin won't be strong enough to hold the water.

Lake basins may also be carved out by glaciers-huge masses of ice-as they move down valleys or across the land. When the glaciers move, the basins they create remain. During the last ice age, glaciers carved the basins of the Finger Lakes, in the U.S. state of New York.

Sedimentary basins are a type of structural basin that aren't shaped like typical basins, sometimes forming long troughs. Sedimentary basins have been filled with layers of rock and organic material over millions of years. Material that fills up the basin is called sediment fill.

Sedimentary basins are key sources of petroleum and other fossil fuels. Millions of years ago, tiny sea creatures called diatoms lived and died in ocean basins. Eventually, these ancient oceans dried up, leaving dry basins. The remains of the diatoms were at the bottom of these basins. The remains were crushed under billions of tons of sediment fill, over millions of years. In the right conditions, the pressure of the sediment fill turns the diatom remains into petroleum.

The Niger Delta sedimentary basin, in the countries of Nigeria, Cameroon, and Equatorial Guinea, is one of the most productive petroleum fields in Africa. In North America, the Western Canadian Sedimentary Basin is one of the continent's largest suppliers of gas and coal.

Ocean Basins

Ocean basins are the largest depressions on Earth. Edges of the continents, called continental shelves, form the sides of ocean basins.

There are five major ocean basins, coordinating with the major oceans of the world: the Pacific basin, the Atlantic basin, the Indian basin, the Arctic basin, and the Southern basin. Many smaller basins are often considered oceanic basins, such as the North Aleutian Basin, between the Pacific and Arctic Oceans.

Tectonic activity constantly changes ocean basins. Seafloor spreading and subduction are the most important types of tectonic activity that shape ocean basins.

Seafloor spreading happens along the boundaries of tectonic plates that are moving apart from each other. These areas are called mid-ocean ridges. New seafloor is created at the bottom, or rift, of a mid-ocean ridge. Ocean basins that have mid-ocean ridges are expanding. The Atlantic basin, for instance, is expanding because of seafloor spreading.

Subduction happens along the boundaries of tectonic plates that are crashing into each other. In these subduction zones, the heavier plate moves underneath, or subducts, the lighter one. Ocean basins that experience subduction, such as the Pacific basin, are shrinking.

Even though ocean basins make up more than 70 percent of the total land on Earth, scientists know relatively little about them. Some oceanographers (and some astronomers!) say that we know more about the surface of the moon than we do about the surface of the ocean floor.

It is very difficult to get information about landforms of the ocean basin, such as trenches and mid-ocean ridges. These landforms are thousands of feet below the surface of the water. Few instruments can endure the intense pressure, cold, and dark at the bottom of ocean basins. Occasionally, researchers themselves explore ocean basins in special submarines called submersibles.

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A basin is a depression, or dip, in the Earth's surface. Basins are shaped like bowls, with sides higher than the bottom. They can be oval or circular in shape, similar to a sink or tub you might have in your own bathroom. Some are filled with water. Others are empty.

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Students build puzzle using fossils as evidence for continental drift, step in the development in plate tectonics theory.

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Wegener's Puzzling Continental Drift* Evidence

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This lesson explores the evidence of continental drift* presented by Alfred Wegener and provides students the opportunity to complete a continental drift* puzzle exercise. *Continental drift is the term that Wegener used in 1912; today we use the term plate tectonics.

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3D models of fossils, rocks, animals and more.

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3D models by RISD Nature Lab (@RISDNaturelab)

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View 3D models by RISD Nature Lab (@RISDNaturelab)

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NPS: Convergent Boundaries Subduction Zones

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NPS: Convergent Boundaries Subduction Zones

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An in depth (advanced) look at convergent plate boundaries along western North America.

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Aniakchak National Monument and Preserve is on the Alaska Peninsula. The eruption of Aniakchak Volcano about 3,500 years ago rivals the eruption and collapse of Mt. Mazama that formed Crater Lake. The original composite volcano was about 7,000 feet (2,000 meters) high, but lost about 2,500 feet (750 meters) of its height. The 6-mile (10-kilometer) wide caldera is about 2,000 feet (600 meters) deep. Like Mt. Mazama, Aniakchak spewed lava across its caldera floor for centuries after its collapse. The volcano is still active, having erupted in 1931. But unlike Mt. Mazama, Aniakchak no longer holds a large lake because the caldera wall is breached.

Katmai National Park and Preserve lies where the world's largest volcanic event of the 20th Century occurred. In 1912 the Katmai region erupted an estimated 7 cubic miles (30 cubic kilometers) of ash and pyroclastic material, roughly 50 times the amount that came out of Washington's Mt. St. Helens in 1980. The collapse caldera from the Katmai eruption is about 3 miles (5 kilometers) across and 2,000 feet (600 meters) deep. The caldera has partially filled with water - an approximately half-scale version of the better-known Crater Lake in Oregon. Katmai volcano did collapse, but unlike Mt. Mazama 7,700 years before, the material expelled from its magma chamber did not spew forth out of the top of the volcano. Rather, it flowed underground to a vent 6 miles (10 kilometers) away! The vent was the source for most of the ash and pyroclastic flows expelled during the 1912 eruptions, and has since filled with a lava dome known as Novarupta.

At 20,625 square miles (53,396 square kilometers), Wrangell - St. Elias National Park and Preserve is the largest U. S. national park - six times the size of Yellowstone. The park is a complex amalgamation of blocks of continental and oceanic crust that have slammed into North America. Poking through the mass of some of the highest mountains in North America are very young volcanoes formed by the ongoing Pacific Plate subduction. Among them are Mt. Wrangell, a 14,163 foot (4,317 meter) volcano that last erupted during the early part of the 20th Century.

Lake Clark National Park and Preserve contains an active composite volcano with a profile and recent history reminiscent of Mt. St. Helens. In 1989 and 1990, Mt. Redoubt, on the eastern side of the park, had four explosive eruptions that resulted in large volumes of ash and mudflows. And, as at Mt. St. Helens, a lava dome later grew within the breached crater near the mountain's summit.

Volcano Monitoring in National Parks

The eruption of Mt. Redoubt, an active volcano in Lake Clark National Park, illustrates how a volcano can pose an unexpected hazard in our modern age - and why monitoring volcanic activity is so important (see photo below). On Dec. 15, 1989 a jet with 244 passengers and crew was en route from Amsterdam to Anchorage. Without warning the plane flew right through the eruption cloud at 25,000 feet (7,500 meters) altitude. Silica-rich ash melted and coated the hot engine turbines with glass, causing all four of them to shut down. After a terrifying free-fall that lasted 8 minutes, the pilots finally managed to restart the engines at only 6,000 feet (2,000 meters). Fortunately, no one was injured. But the incident highlighted the importance of monitoring volcanic activity and making the information immediately available to the airline industry and other segments of the public.

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Convergent Plate Boundaries-Subduction Zones - Geology (U.S. National Park Service)

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Aniakchak National Monument and Preserve is on the Alaska Peninsula. The eruption of Aniakchak Volcano about 3,500 years ago rivals the eruption and collapse of Mt. Mazama that formed Crater Lake. The original composite volcano was about 7,000 feet (2,000 meters) high, but lost about 2,500 feet (750 meters) of its height.

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In honor of Earth Day 2018, Amplifier released a series of artworks designed through collaborations between comic artists and environmental leaders.

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Weather/Climate: El Nino and La Nina Explained

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Weather/Climate: El Nino and La Nina Explained

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US Department of Commerce, National Oceanic and Atmospheric Administration

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El El Nino and La Nina are complex weather patterns resulting from variations in ocean temperatures in the Equatorial Pacific.

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Season 45 Episode 7 | 1h 53m 21s |

Disastrous hurricanes. Widespread droughts and wildfires. Withering heat. Extreme rainfall. It is hard not to conclude that something's up with the weather, and many scientists agree. It's the result of the weather machine itself-our climate-changing, becoming hotter and more erratic. In this 2-hour documentary, NOVA will cut through the confusion around climate change.

Aired: 03/09/18

Expires: 04/17/21

Rating: TV-PG

Problems Playing Video? Report a Problem |

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NOVA | Decoding the Weather Machine | Season 45 | Episode 7

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Season 45 Episode 7 | 1h 53m 21s | Disastrous hurricanes. Widespread droughts and wildfires. Withering heat. Extreme rainfall. It is hard not to conclude that something's up with the weather, and many scientists agree. It's the result of the weather machine itself-our climate-changing, becoming hotter and more erratic.