GGR201H5F
Fall 2025
Practical Exercise 3: Sediment Analysis (Part i)
Due: Tuesday 2nd Dec, 9 pm
Outline & rubric
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Practical class
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Assignment component
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Mark
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November 14th
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Part (i) Sediment description, roundness analysis
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November 21st
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Part (ii) Grain size analysis, report briefing
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November 28th
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Q&A
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2nd December
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Online submission by 9 pm
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Total:
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100
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Introduction:
In Practical 3 you will investigate the sedimentary characteristics of seven sediment samples collected from various depositional environments in the Toronto / Oakville / Niagara area; using the results of your analysis (after sessions i-ii) you will attempt to match each sample to one of the seven depositional environments.
Samples / materials:
• Seven sediment samples from various sites in the region (Samples A-G, to be made available in the lab)
• Powers roundness charts (see Practical 3 slides)
• Sediment description flowcharts (see Practical 3 slides)
• Powers roundness recording sheets (attached)
Note – ensure you bring a printed copy of the sediment description and Powers roundness data sheets attached to this document to the practical
Objectives
Each group should commence the following (this exercise will continue next week):
1. Description of each sediment sample; this should include a simple description of the general grain size characteristics (mean grain-size, sorting).
2. Powers roundness analysis on coarse-grained particles. Each group will be assigned a sample for roundness analysis and should classify a minimum of 25 randomly-selected individual clasts using the record sheet attached (note - Sample D only has a few particles of a suitable size for this analysis). Report the results to the class spreadsheet.
Practical 3(i) follow-up:
a) Ensure that your group has completed an individual record sheet that describes all seven
sediment samples in terms of their overall grain-size (note - descriptions can be completed next week if necessary).
b) Aggregated Powers roundness data for each of the samples will be made available on
Quercus; produce a histogram (bar chart) showing Powers roundness classes for each of the sediment samples (note - roundness analysis can be completed next week if necessary).
c) Compare and contrast the roundness characteristics of the samples.
References and other useful literature
• Trenhaile (2016) Chapter 2: Sediments (p.42-46)
• Goudie, A (1990) Geomorphological Techniques (2nd Ed). Routledge. p.127-130. (See Quercus / Files / Resources)
Sediment description
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Sediment
Sample
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Description
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A
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B
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C
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D
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E
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F
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G
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Powers roundness data
Sediment Sample code:
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Roundness class
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No. of clasts (total = 25 minimum):
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Very angular
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Angular
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Sub-angular
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Sub-rounded
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Rounded
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Well rounded
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