GE0-3112 Sedimentary processes and products Lecture 4. Sedimentary structures II – sediment massive flows Geoff Corner Department of Geology University.

Slides:

Advertisements

Similar presentations

Flow Regime and Sedimentary Structures

Advertisements

LECTURE OUTLINE: How sediments move – contrast how; 1) air/water moves grains with how; 2) gravity moves grains. 1) Movement through the air; 1) bedload.

GE Sedimentary processes and products Lecture 12. Deep sea Geoff Corner Department of Geology University of Tromsø 2006 Literature: - Leeder 1999.

CLASTIC TRANSPORT AND FLUID FLOW

Landslides, Part 1 La Conchita slide, Jan 2005.

Mass wasting, also known as slope movement or mass movement, is the geomorphic process by which soil, regolith, and rock move downslope under the force.

Chapter Thirteen Mass Movement. Mass Movement Process that transports Earth’s materials downslope by the pull of gravity  Friction, strength, and cohesiveness.

MASS MOVEMENTS. IMPORTANT CONCEPT: ROLE OF GRAVITY Gravity causes the downward and outward movement of landslides and the collapse of subsiding ground.

MASS WASTING AND MASS MOVEMENT

Mass Movements.

For flow of 1 m/s in round-bottom channel of radius 1 m, what is the Reynold’s number? Is the flow laminar or turbulent? Re < 500 laminar Re > 2000 turbulent.

Landforms Vocabulary Landform Vocabulary

Slope Systems – Mass Wasting

Module 1 : The Fluvial Environment Fluvial: Relating to or occurring in a river.

Chapter 6 Landslides & Related Phenomena. Learning Objectives Gain a basic understanding of slope stability and mechanisms of slope failure Understand.

Mass Movements. Mass movement- The down slope movement of earth material under the influence of gravity.

GE Sedimentary processes and products Lecture 2. Fluid flow and sediment grains. Geoff Corner Department of Geology University of Tromsø 2006 Literature:

Sediment Gravity Flow We have discussed two classes of flows that can move particles: Simple dry mass wasting; and conventional fluid flow. A third flow.

Introduction Shear stress movement and/or failure of material Shear strength resistance to movement and/or failure Complications 1. Stress-related Interactions.

Earthquake induced LIQUEFACTION by Jimmy McLauchlan Peat Nicholas Case study: Mexico City, 1985.

Contents Introduction Sedimentology – concepts Fluvial environments

1 Flow, disintegration and lubrication of clay – sandy debris flows: from the laboratory to the field Anders Elverhøi Fabio De Blasio Dieter Issler Johann.

Sediment Gravity Flow Deposits

WHAT CAUSES CLASTIC PARTICLES IN WATER TO MOVE?. START WITH WHAT WE KNOW: Surface waters occur in channels (rivers) or during overland flow. In either.

Soil Types Soil – all unconsolidated material in the earth’s crust Soil includes – Mineral particles – sand and clay Organic Materials – found in topsoil.

Mass Movements at Earth’s Surface

14. Passive Margins and Sediment Transport William Wilcock (w/ some slides from Dan Nowacki) OCEAN/ESS

Lecture 2: Stratigraphic data Boris Natalin. Data from surface outcrops Subsurface data such as well logs, seismic data, and cores Sedimentary rocks:

Erosion GEOLOGY TODAY - Chapter 7 Barbara W. Murck Brian J. Skinner HILLSIDE CREEP N. Lindsley-Griffin, 1999.

Landslides, Part 2 Beverly Hills slide, Feb 2005.

Suspended particle property variations in Gaoping Submarine Canyon Ray T. Hsu and James T. Liu Institute of Marine Geology and Chemistry, National Sun.

Chapter 2: Transportation and Deposition of Siliciclastic Sediment Fluid Flow Particle transportation in a fluid Particle transport by sediment gravity.

Lecture 3 Sediment transport. Processes of transport (And a few examples)

16. Sediment Transport in the Ocean Basins – In Development William Wilcock OCEAN/ESS

16. Sediment Transport across continental shelves William Wilcock OCEAN/ESS 410.

Chapter 12 Mass Wasting.

Mass Movements, Wind and Glaciers

Earth-surface Dynamics Modeling & Model Coupling

Flowing Water: Sediment Transport and Landforms. Medium-term Plan 10/27Lecture 13. The Sediment Factory: Source to Sink 11/01Lecture 14. Flowing Water:

Types of Forces Gravity and Friction. Forces!!!!! PUSH Or A Pull.

Definition LANDSLIDES

Harry Williams, Geomorphology1 Soils on Slopes – Summary: A soil on a slope has strength because of inherent frictional properties, cohesion and normal.

Mass Movement Hazards Mass Wasting:

Chapter 7 Erosion. What is Erosion and Deposition? Erosion – A process that moves the sediments from one location to another, usually by gravity, glaciers,

Faults Earthquakes begin on a fault plane movement will not proceed smoothly away from the fault due to Changes along the length and depth of the fault.

Chapter 6 Prepared by Iggy Isiorho for Dr. Isiorho Sediments and Sedimentary Rocks Index 

Fossil Any remains, imprint, or trace of a living thing from the distant past.

MASS WASTING. SURFICIAL PROCESSES Erosion, Transportation, Deposition on the Earth’s Surface Landscapes created and destroyed Involves atmosphere, water,

Alluvial Fan Environments Badwater Fan, Death Valley Mars.

Submarine Fan Depositional Processes

Waste Treatment, Physical

Aeolian Environments Navajo Sandstone (Jurassic, Utah)Sahara Desert.

4. Properties of Materials Sediment (size) Physical States of Soil Concepts of Stress and Strain Normal and Shear Stress Additional Resistance Components.

Key Concepts Earth surface transport systems Properties of water, air & ice Characterizing fluid flow Grain entrainment Modes of grain movement Sediment-gravity.

1 Natural Disasters Mass Wasting: Landslides

Sedimentology Flow and Sediment Transport (1) Reading Assignment: Boggs, Chapter 2.

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

An introduction to cohesive sediment transport processes

River Transportation and Deposition

Channel Processes and Hjulstrom’s Curve

Mass Wasting Chapter 15. Mass Wasting vs. Landslides ▪ Mass wasting refers to the downslope movement of rock, regolith, and soil under the direct influence.

What are agents of erosion?

Sediment Transport.

Landforms Vocabulary Landform Vocabulary

SACRAMENTO STATE Geology 103 Sedimentology and Stratigraphy Tim Horner Geology Department, CSU Sacramento Lecture #8: Mass movements, sediment gravity.

EROSION the transport of sediment Energy increases

Mass movements Falls, slumps flows Landslide scar/scarp

Lecture 25 Mass wasting and landslide mechanics.

2nd Quarter - Test 2 Review

Presentation transcript:

GE Sedimentary processes and products Lecture 4. Sedimentary structures II – sediment massive flows Geoff Corner Department of Geology University of Tromsø 2006 Literature: - Leeder Ch. 10, 11, 12. Cohesive sediments, sediment gravity flows and deformation structures Cohesive sediments, sediment gravity flows and deformation structures

Contents ► 4.1 Cohesive sediment transport and erosion. ► 4.2 Sediment gravity flows ► 4.3 Soft-sediment deformation

4.1 Cohesive sediments

Clay and cohesion ► Atomic attractions between small clay particles impart cohesive strength. ► Positive-negative electrical charges are ’amplified’ in suspensions in seawater a strong electrolyte) causing particle attraction (flocculation). ► Flocculation is enhanced by organic matter.

Cohesive bed processes

Settling velocity vs. floc size and sediment concentration

Cohesive bed erosion ► Erosion may take the form of:  direct particle-by-particle erosion where floc-floc bonds must be broken.  erosion (re-entrainment) of freshly depsited water-rich suspension from the bed.  mass erosion due to failure above a slide plane.

Erosional bedforms – flute marks

4.2 Sediment gravity flows

Grain-flow avalanches ► Movement by shear between grains and against underlying surface. ► Interstitial fluid plays little part in the motion. ► May involve boulder to sand size; also snow. ► Low friction/high energy

Avalanche deposits

Fluidization and kinetic filtering ► Acoustic fluidization of high energy avalanches? ► Kinetic filtering (sorting) causes inverse grading.

Debris flows ► Extreme form of hyperconcentrated flow. ► Typically silt- to boulder-size particles set in a matrix of clay-grade fines and water. ► Involve transmission of both solid and fluid stresses (excess pore pressure). ► Excess pore pressure gives low shear strength (low friction). ► Density ; velocity >10 m/s not uncommon.

Debris-flow deposits ► Plug flow gives no/little shear fabric or sorting. ► Traces of shear fabric may develop at base and margins. ► Plug flow leaves central channel bordered by high levees.

Debris-flow deposits ► Surging may give weak stratification. ► Waning flow may give normal grading. ► Kinetic filtering may give inverse grading.

Levees and lobes

Turbidity flows ► Cause by movement of density current in water or air downslope. ► Triggered by:  Evolve from slides/slumps.  Hyperpycnal flows from rivers mouths.  Longshore drift to submarine canyons  (Pyroclastic flows; snow avalanches)

Turbidites

\

4.3 Soft-sediment deformation ► Liquefaction: change of state from solid to liquid. ► Pore pressure rather than grain contacts supports the material. ► Caused by:  Shock (earthquake, tides, etc.)  Fluid addition (fluidization).

Deformation structures ► Liquefaction structures:  Sand volcanoes  Convolute lamination  Pillar and dish structures ► Slides and growth faults ► Slumps ► Skrinkage cracks

Sand volcanoes

Convolute lamination

Dish structures

Growth (listric) faults

Slumps

Further reading