GEOLOGY STUDY GUIDE Module exam GL4 June 2004

SEDIMENTARY ROCKS
Geology Department, GreenheadCollege, Huddersfield.

Jurassic Rocks, Stair Hole, Dorset

Your name .....……………………...... Date ...... ……………......
LEARNING TARGETS
margin notes
When you have completed this study guide, you will:
  • Have revised weathering processes and carried out a coursework on this topic
  • Know about erosion and transport in river, ice and wind currents
  • Use Hjulstrom’s graph to show particle transport in river currents
  • Use specimens and microscope slides to revise sedimentary textures
  • Use fabric analysis to draw conclusions about sedimentary environments
  • Understand sediment maturity
  • Learn more about biogenic rocks

Resources
Here is a choice of resources to use. You do not need to look at them all but clearly the more you read the better your knowledge of case studies will be. Tick the box once you have used the resource.
If you read a photocopied extract then highlight it to help you reread it for revision. If you make notes from a video tape make sure that the notes are headed with the name of the tape so that you know the source of your information. Case studies are very useful for essay questions so you should keep a separate list of the examples that you have researched.

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 / SR1
SR2
SR3
SR4
SR5
SR6
SR7
SR8
SR9
SR10
SR11
SR12
SR13
SR14
SR15
SR16
SR17
SR18
SR19
SR20
SR21 / Understanding Geology David Webster p 42 -78
Geoscience Edwards and King p 79 -98
Geological Science by Andrew McLeish p 67 –114
Exercise on breakdown of rocks and minerals
Investigating Urban Weathering Geography Review March 1992
Hjustrom’s Graph and questions
Powerpoint of transport and erosion environments
Where has all the granite gone? Tape 17 and 24 22mins
From Snowdon to the SeaTapes 10and 22 22mins
Powerpoint of thin sections of sedimentary rocks
Fabric Analysis exercise

Processes and Analysis Sedimentary Book 1 Chris King

Conglomerates. Geol. Today. July/August 1990

Interpreting sediments. Tapes 4 and 15, 22mins
Strahler, A. and Strahler, A. Introducing Physical Geography Chap 13
Skinner, B.J. and Porter, S.C., The Dynamic Earth Chap 7
Library Greensmith, J.T. Petrology of the Sedimentary Rocks
Library OU Surface Processes
Library Tucker, M. The Field Description of Sedimentary Rocks
Library Tucker, M. Sedimentary Petrology
Video Sedimentary rocks: The Key to Past environments Tape 46 30mins
Websites




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There are many other websites you could search.
margin notes / ACTIVITY 1 : WEATHERING
TASK 1 CHECK YOUR KNOWLEDGE
Read through your AS notes on sedimentary rocks.
You will be tested on this part of the specification so it is essential to understand it before you continue to the A2 course.
TASK 2 WEATHERING
Define weathering using SR1 p 42, SR2 p 79 and SR3 P67. You may find that definitions vary, so write your own version.
Most people confuse weathering with erosion. Discuss the essential difference between the two and write a note to yourself so that you don’t forget.

TASK 3 KINDS OF WEATHERING

Carbonation, bacteria and organic activity, oxidation, hydrolysis, freeze-thaw (frost shattering), expansion-contraction (insolation) (exfoliation), crystal growth (gypsum and salt), solution, root growth, hydration.
These are all types of weathering. Draw a table as shown below to classify them into physical, chemical and biological weathering. The table may take up more than one side of paper. The textbooks use a variety of terms for the same process so when you draw up a definition keep it simple.
PROCESSPHYSICALCHEMICALBIOLOGICAL DEFINITION
TASK 4 BREAKDOWN PRODUCTS OF WEATHERING
Complete SR4 so that you are aware of the materials which are produced by weathering of rocks and minerals.
TASK 5 WEATHERING COURSEWORK
Think about how you can identify and assess the processes of weathering that have taken place in your district. How easy is it to tell which type of weathering is having an effect on local rocks? Go through the list of processes in Task 3 and suggest which you might expect to find in West Yorkshire and how you could assess them. Read SR5. Your coursework sheet will give you more guidance on how to start this piece of research.
ACTIVITY 2 : CLASTIC ROCKS
TASK 6 EROSION
Define erosion using SR1, SR2 and SR3. Make notes on the processes of abrasion and attrition, which are the two main types of erosion occurring in environments such as sea shores, rivers and mountains.
Use this box for notes
margin notes / TASK 7 TRANSPORT
Transport of material takes place in currents, such as rivers, winds, offshore currents and glaciers. Revise the words saltation, bed load traction, suspension and solution using SR1, SR2 and SR3.
TASK 8 HJULSTROM’S GRAPH
Hjulstrom’s graph (SR 6) is useful as a method of analysing the work done by currents to transport and deposit sediments. It relates the velocity of a current to the size of the particle or clast the current is able to carry.
Carry out the exercises on Hjustrom’s curve once you have talked it through in lessons.
Then write down an explanation of these statements:
  1. It is harder for currents to pick up particles than it is to carry them.
  2. Clay particles are harder to pick up than sand grains.
  3. The higher the velocity of the current the larger the particles that can be carried.
  4. Clay and silt particles can only settle out (be deposited) in still water.
  5. Using a log-log graph to show the velocity - particle size relationship is helpful.

TASK 9 ENVIRONMENTS OF TRANSPORT, EROSION AND DEPOSITION
Read SR2 p 90-95 on sedimentary environments, taking note of the block diagrams which show graphic logs of the sediments found in each environment. These are listed below:
Screes and alluvial fans
Rivers and streams (braided and meandering)
Flood plains
Glacial environments
Desert sand dunes and sabkhas
Deltas
Use the table on the back of SR6 of these environments, giving information on grain size of sediments, likely sedimentary structures and thickness of sedimentary layers.
TASK 10 ENVIRONMENTS OF TRANSPORT, EROSION AND DEPOSITION

Watch the powerpoint (SR7) of different environments and make comments on the processes taking place and the sediments that result.

TASK 11 VIDEOS
Watch From Snowdon to the Sea (SR8) or Where has all the granite gone? (SR9) These programmes will help you visualise the sedimentary environments we have talked through in lessons.
Use this box for notes
margin notes / TASK 12 MARINE DEPOSITION
Read SR2 p 96-98. Once a river reaches the sea, processes of deposition become more important. Revise the process of flocculation.
Draw a diagram/table to revise the spatial distribution of onshore and offshore sands, silts and muds on beaches, continental shelf, continental slope and abyssal plain. For each environment mention grain size of sediments, likely sedimentary structures, thickness of sedimentary layers and associated fossils that could be found in the Rock Record.
TASK 13 MATURITY OF SEDIMENTS
Write down an explanation of sediment maturity after reading SR2 p 85. Can you explain the difference between mineralogical maturity and textural maturity? Give examples of each, using arkose, orthoquartzite and greywacke.
TASK 14 TEXTURE SLIDES
Draw labelled diagrams to illustrate the texture of selected thin sections of sedimentary rocks magnified x 10 through a microscope (SR10).
TASK 15 FABRIC ANALYSIS – PARTICLE SIZE AND MATURITY
Fabric analysis is the term used for the analysis of texture and composition of sediments. Complete SR11. This is an exercise to help you relate particle size, maturity and environment of deposition together for 5 different sediments A to E.
TASK 16 FABRIC ANALYSIS – PRACTICAL
Now you should be able to link particle size, shape, composition and maturity to environments of deposition.
There are a number of sediments in the classroom which have been collected from specific localities for you to analyse. Read SR12 p 45-48.
●Using SR12 p 45 write out the Wentworth scale for clastic sediments.
●Choose 3 sediments and analyse them for grain size, grain shape and sorting. You can find out about grain size by sieving. You will be given instructions for using a set of sieves and scales in class. You will need to share sieves and brushes on your table. Take great care with the sets of sieves. Do not waste sediment and clear up after yourselves.
●Take a few grains of each sediment, put it on a piece of dark sugar paper and cover with sticky-backed plastic so that you can look carefully at the shape and composition of the particles. You may need to use a lens.
●Draw a bar graph to show mean grain size and sorting for each sediment. and write a brief conclusion on the graph about the maturity of the sediment.
●Draw frequency curves for each sediment so that you can compare their textural maturity. For each sediment write a brief conclusion about its textural and compositional maturity and link it to its environment of deposition.
Use this box for notes
margin notes / TASK 17 DIAGENESIS
Read SR12 p.74-78, SR 3 p103-104 and SR2 p85-86. Make notes on
●compaction
●cementation
●pressure solution
●solution
●recrystallisation
●replacement by calcite, dolomite and silica
●authigenic clay minerals formation.
TASK 18 PRACTICAL
Complete a practical on clastic rocks, looking at a variety of sandstones (greywacke, orthoquartize, arkose), conglomerates, breccias, shales, mudstones and siltstones.
TASK 19 CONGLOMERATES AND BRECCIAS
Read SR13 on conglomerates for a detailed understanding of these rocks, which occur in a number of environments. Make a note of the meaning of these phrases: oligomict, polymict, clast-supported and matrix-supported.
Complete to questions on the back or the articles.
Deadline …………………………………………….
ACTIVITY 3 : BIOGENIC ROCKS
TASK 20 LIMESTONES
You already know from GL 1 how limestones are precipitated. Read SR1 p 70, SR2 p96-97 and SR3 p101 on limestones and make a note of any information you have forgotten.
TASK 21 PEAT AND COAL
Coal was formed from the remains of trees and plants. Read SR1 p71-72 to revise your GL1 information and then make notes on SR2 p156-157 to increase your detailed knowledge. Draw the diagram of the coal measure cyclothem Fig 9.4 p157 and remind yourself of the cyclothems you studied on the shore at Corrie, Arran, by looking back at your field report.
TASK 22 BGS MAPS
Watch slides and use selected BGS maps to see how sedimentary rocks are shown.
TASK 23 RESOURCES
Other videos and library books are listed in the resource list. Take some books out of the library over the holidays and browse through them.
TASK 24 EXAM QUESTION PACK

Complete the GL4 Sedimentary Rocks EQP

Deadline……………………………………

Use this box for notes

ESTA GEOTREX The Geology Teachers Resource Exchange

Contributor: Alison Quarterman Establishment: GreenheadCollege Date:May 05

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