Lecture 4 Alluvial fans.

Slides:

Advertisements

Similar presentations

Landforms of the Fluvial System

Advertisements

GE Sedimentary processes and products

Landforms Vocabulary Landform Vocabulary

Unit 2: Erosion and Deposition by Water

Four types, braided, meandering, anastamosing and straight

Section 3: Stream Deposition

Objectives Describe how surface water can move weathered materials.

Stream and River Deposits

By the end of the lesson I should know:

Exploring Geology Chapter 16 Rivers and Streams

Water covers 71% of Earth’s surface and is the dominant agent governing environmental processes. The rates of human usage of water outpace the natural.

Due Tuesday, May 31 st at beginning of class Go to and enter 101 in left navbar search field. On G101 web page, download Problem Set.

RIVERS AND ASSOCIATED LANDFORMS

Erosion and Deposition

Lab 8 Stream Processes. Channel Types Braided - steeper, large sediment supply Meandering - less steep, lower sediment supply.

XII. Streams A.The Hydrologic Cycle (components and pathways) B.Stream Velocity (controls and results) C.Drainage Patterns and Landscape Features (results.

Factors affecting erosion and deposition Velocity Gradient – rise over run Channel shape Channel roughness Discharge – amount of water flow per unit.

Channel Networks The drainage basin, or watershed, is the surface around a channel that "sheds water and sediment into that channel" Streams that get their.

Stream Erosion & Deposition

Chapter 16: Running Water. Hydrologic cycle The hydrologic cycle is a summary of the circulation of Earth’s water supply Processes involved in the hydrologic.

Alluvial Fans By Tim Baker & Tom Coburn.

Streams Nancy A. Van Wagoner Acadia University Distribution of Earth's water n What are the percentages? -Oceans - Glaciers - Groundwater - Lakes and.

What makes Earth unique. Where is the water on our planet ?

Streams (Rivers). Runoff: H 2 0 that does not sink into ground Most ends up in streams.

Rivers 11.1 – Zones in rivers From Miller’s Living in the Environment.

Chapter 4: Weathering and Erosion

McKnight's Physical Geography

Rivers: Fluvial Processes

Section 13.1 Streams and Rivers

Stream Erosion and Transport

© 2011 Pearson Education, Inc. Running Water Earth, 10e - Chapter 16.

The hydrologic cycle. Running water Streamflow Two types of flow determined primarily by velocity –Laminar flow –Turbulent flow Factors that determine.

Hydrologic Hazards at the Earth’s Surface

STREAMS & RIVERS Chapter 6.

Alluvial Fan Environments Badwater Fan, Death Valley Mars.

Rivers and Streams. River Systems A river or stream: any body of water flowing downhill in a well defined channel A river or stream: any body of water.

Streams: Transport to the ocean

Section 3: Stream Deposition

River Systems. Objective  Students will describe factors that affect the erosive ability of a river and the evolution of a river system.

Stream/River formation and features

You have learned how to interpret how landforms are the result of a combination of constructive and destructive forces such as deposition of sediment and.

Rivers Almost half of the water that falls to the Earth’s surface eventually ends up in a stream or river (runoff), where it travels overland to the.

STREAMS & RIVERS Chapter 6. REVIEW…. The Water Cycle.

7. Bedforms in coarse-grained channels Step-pool units Cluster bedforms Riffle-pool sequences.

2 pt 3 pt 4 pt 5 pt 1 pt 2 pt 3 pt 4 pt 5 pt 1 pt 2 pt 3 pt 4 pt 5 pt 1 pt 2 pt 3 pt 4 pt 5 pt 1 pt 2 pt 3 pt 4 pt 5 pt 1 pt Mountains, Maps and More Stream.

(,rivers, brooks, creeks, etc.)

AIM: What is a stream/river? Do Now: Answer the following questions in your notebooks. Where does the water come from that fills streams and rivers? Where.

LANDFORMS VOCABULARY Clicker Presentation Created by: Cindy Jarrett Landform Vocabulary Clickers Interactive Presentation Created by: Cindy Jarrett Cindy.

Class 25: Hydrology. Class updates:  Reading: Section Today’s topics:  Water on Earth  Water transport  Water and geology Class 25: Hydrology.

Stream Erosion & Deposition Chapter 6 sections 1 and 2.

 Potholes are formed due to stream or river erosion which initiates by simple plucking out at the riverbed by hydraulic action.  These are variously.

Investigation 3 Go with the Flow. The Grand Canyon is one place where erosion has taken place on a grand scale. Geologists are still trying to figure.

TRANSPORTATION & DEPOSITION in a Stream System.

River Transportation and Deposition

12 River Systems Eric Christiansen Geology 111.

11.2 Stream and River Deposits. Even though flooding along rivers is potentially harmful, many farms are located near rivers. Why do people build along.

River Transportation and Deposition

Chapter 6.2 The Work of Streams

River System Development

Deposition of Eroded Sediments

15-3 Stream Deposition.

Chapter 7- Running Water and Groundwater

Stream Erosion.

Sedimentary Rocks A sedimentary rock is formed by the accumulation and compaction of sediments (rock pieces, minerals, animal parts, or chemical precipitates)

River Systems Chapter 15.

Presentation transcript:

Lecture 4 Alluvial fans

What is an alluvial fan? … a fan-shaped deposit of alluvium found where a stream flows out of a mountain onto flatter terrain.

An alluvial fan in Death Valley Narrow outlet (valley or gorge) Fan apex Radial spreading alluvial fan

An alluvial fan in Death Valley Coarse, channelized debris Sediments become finer-grained

Ok, back to alluvial fans….. The evolutionary stages of alluvial fans

Alluvial fans: Steeper gradient than “normal” river profiles, thus are often dominated by debris flow processes

Kosi megafan, northern India

Migrating fluvial channels

Debris flows Shear stress vs. strain So flow is plug like and ceases as it reaches shallower surface, hence the velocity diminishes Flows also stop as they thin or lose water

Losing water and velocity caused the debris flow to become more viscous and stop, creating a very steep front

Debris flow “channel” on a talus in eastern Sierra Nevada

A closer view Note the existence of the “levees”

The radial deposition of alluvial fan Active depositional lobe

Period of active deposition, massive floods and debris flows

Debris flow fan caused by typhoon, southern Taiwan, 2005

And afterwards…….

So, what will the stratigraphy look like?

Channels near apex of fan

Channel gravels

And suspended load deposits on distal portions of the fan

With bioturbation….

Downslope fining of alluvial fan deposits

Facies relationships, a Devonian fan in Sweden, showing characteristic interfingering of depositional facies

Pleasant Valley, Nevada

Pleasant Valley, Nevada

Three small alluvial fans on Soda Lake Road Is there anything strange of these fans?

Yes! They are offset 6.5 m by the 1857 earthquake