Introduction to Geomorphology Goals of Today s Lecture 1. To introduce you to the course organization. 2. To provide you with an idea of what we will discuss in this class. 3. Review of material you need to know as background to this course Lecture 1 Fall 2016 1
Geomorphologist Department of Geography B.Sc. University of Guelph M.Sc. University of Southern California Ph.D. University of British Columbia Post-Doc University of California, Berkeley I am a geomorphologist interested in landscape dynamics and landscape material transport processes. Most of my current research involves sediment transport processes in rivers including sand dune dynamics, gravel transport, and bedrock erosion. We do field work in big rivers, lakes and shallow marine environments. We also do controlled laboratory experiments to test hypotheses about landscape dynamics the River Dynamics Laboratory. I have a continued interest in scientifically-based stream restoration (naturalization of streams impacted by landuse practices). Current work: Incision of Bedrock Canyons When continents collide Classical view: uplift is controlled by mantle convection cells Two colliding continents will force a thickening of the crust and building of a mountain root Incision of bedrock channels will allow buoyant forces to lift the landscape surface Flow Structure in a Bedrock Canyon Lecture 1 Fall 2016 2
Sand Heads Mission Hope Thompson R. Chilcotin R. Quesnel Introduction to Geomorphology Fraser River, BC Bed Elevation (m) 1400 1200 1000 800 600 400 200 0 McBride Moose L. 0 200 400 600 800 1000 1200 1400 Distance upstream of ocean (Km) Venditti and Church, 2014 5 Venditti et al., Nature, 2014 Flow Structure in a Bedrock Canyon 2009 Observations 50km 1200 khz ADCP GPS GPS 600 khz ADCP Venditti et al., Nature, 2014 6 Flow Structure in a Bedrock Canyon Lecture 1 Fall 2016 3
Depth (m) Height above bed / depth Shear stress (Pa) Introduction to Geomorphology Impacts on shear stress in Iron Canyon 0-10 -20-30 -40 A B C D E F a) Bedrock constrained -200-100 0 100 200 300 400 500 600 700 800 900 1000 1100 Distance from the canyon entrance (m) m/s Flow 1 A:100% b) B:80% C:60% D:40% E:20% F:0% 0.8 1 m s -1 0.6 0.4 0.2 0 log-fit 250 c) D log-fit inv. mom. bal. 200 150 C 100 B A E 50 F 0-100 -50 0 50 100 150 200 Distance from canyon entrance (m) Venditti et al., Nature, 2014 Shear stress will average out through a canyon, incision rate will not! 7 Flow Structure in a Bedrock Canyon 2016 Observations Low flow: Sept High flow: June Lecture 1 Fall 2016 4
2016 Observations Results to come. Lecture 1 Fall 2016 5
http://motherboard.vice.com/ Current work: Taan Fjord Landslide Port Starboard Panorama View Lecture 1 Fall 2016 6
2015 DigitalGlobe, Inc. Taan Landslide Marine Expedition Lecture 1 Fall 2016 7
Results to come. Introduction to Geomorphology (GEOG 213) Instructor: Dr. Jeremy G. Venditti Office: 6236 RCB Email: jeremy_venditti@sfu.ca Office hour: Mon 14:30-15:30 Or by appointment on Mondays Teaching Assistant: Tingan Li TA Office: 6138 RCB Email: Tingan_Li@sfu.ca Office hour: Tues 12:30-13:30 (Or by appointment) Lecture 1 Fall 2016 8
The Course Format Lectures: Mon 12:30-14:20 SECB 1012 Labs: Mon 14:30-16:20 RCB 7110 Tues 10:30-12:20 RCB 7110 There is no lab fee The Readings Required Texts Bierman, P.R. and D.R. Montgomery (2014) Key Concepts in Geomorphology, W.H. Freeman and Company Publishers New York, 494p. Available in Bookstore This is a good introductory textbook. It is the 4 th time I have used it. There are 2 copies on reserve in the library. Note there is a whole series of case studies that accompany the book here: http://serc.carleton.edu/vignettes/index.html Lecture 1 Fall 2016 9
The Readings Required Scholarly Articles (4): Suggested further readings: Important works that expand on topics covered in class The website Readings and lecture materials can be found at my website: http://www.sfu.ca/~jvenditt/ Lecture 1 Fall 2016 10
The Laboratories Labs begin on September 18-19. There are 6 laboratory exercises/assignments. See Tentative Lecture and Laboratory Exercise Schedule for due dates and return dates. Late labs will be penalized 1 grade per day. You may contact myself or the TA regarding lab exercise content, but the TA is better suited to deal with specific questions. The Resource Office The Geography Department has a Resource Office where you can go outside of lab hours to use airphotos and maps. Location: RCB 6209 / 6210 Hours: 8:30 12:00 and 13:00 16:30 The Resource office staff is not there to provide help with the lab exercises. Please see the TA for that kind of guidance. Lecture 1 Fall 2016 11
The Field Trip There will be a mandatory weekend field trip to complement topics covered in lectures and labs. CACHE CREEK FIELD TRIP (Tentative schedule) We leave SFU (from Security) at 8:30 am on Saturday, October 28, 2016 and return to SFU around 17:30 to 18:30 pm on Sunday, October 29, 2016. Students must pay $50 to the Department of Geography to cover the second day of field trip transportation and accommodations. The Grading Laboratory assignments 40% Field trip report 10% Mid-term examination 25% Final examination 25% Important dates 1. MIDTERM: 12:30-14:20, Mon, Oct 30, 2017 2. Field Essay due: 12:30, Mon, Nov 20, 2017 3. FINAL EXAM: 12:00-15:00, Thursday Dec 14, 2017 Lecture 1 Fall 2016 12
The Course Content Geomorphology is the study of Earth s surface and the processes that form it. As such, it is a crucial component of solutions to a wide range of environmental problems and engineering designs. It has even become an important tool for understanding how far-off planets like Mars and Venus have evolved to their current state. This particular course is about Earth s landscape, its present form, and the processes responsible for its large-scale organization. The goal is to provide students with an appreciation of how the landscape around them formed and its continued evolution with particular focus on landscapes of British Columbia, Western North America, and Canada. Our object of interest at the global scale http://www.ngdc.noaa.gov/mgg/image/globalimages.html Lecture 1 Fall 2016 13
Our object of interest at the continental scale In this course we will focus on Western NA, Canada, BC Why does earth s surface look like this? Our object of interest at the local scale Lecture 1 Fall 2016 14
Our object of interest at the local scale Flooding happens at the at local scale Pachena River at base flow April, 2008 The local scale is where the change is most obvious and relevant. Lecture 1 Fall 2016 15
Flooding happens at the at local scale Pachena River April 28, 2008 @ 2pm The local scale is where the change is most obvious and relevant. Flooding happens at the at local scale Pachena River April 28, 2008 @ 4pm The local scale is where the change is most obvious and relevant. Lecture 1 Fall 2016 16
The local scale is where the change is most obvious and relevant. The local scale is where the change is most obvious and relevant. Lecture 1 Fall 2016 17
Our object of interest at the grain-scale This scale controls what happens at the larger scales! Questions we will answer in this course Lecture 1 Fall 2016 18
1. What is the fundamental basis of geomorphology? 2. What controls topographic relief? Bill Dietrich Bill Dietrich Marin County, CA Himalayas Lecture 1 Fall 2016 19
3. Where do landscape materials come from? Weathering, soil production, and bedrock erosion Bill Dietrich David Montgomery 4. How do landscape materials get down from mountain tops to valley floors? D. Montgomery Lecture 1 Fall 2016 20
5. How do landscape materials get from valley floors to their ultimate sink (oceans or lakes) Lena Delta, Siberia David Montgomery 6. How do glaciers modulate landscape development? Barnard Glacier, Alaska Lecture 1 Fall 2016 21
8. Has the emergence of life on this planet affected the large scale topographic organization of the earth? Why Study Geomorphology? 1. Earth s surface is our home! http://visibleearth.nasa.gov/ Lecture 1 Fall 2016 22
Why Study Geomorphology? 1. Earth s surface is our home! 2. All earth s organisms rely on physical characteristics of earth s surface as habitat. 3. Many transport processes (landslides, debris flows, floods, dust stroms) are significant natural hazards Why Study Geomorphology? 1. Earth s surface is our home! 2. All earth s organisms rely (in varying degrees) on physical characteristics of earth s surface as its habitat. 3. Many transport processes (landslides, debris flows, floods, dust storms) are significant natural hazards David Montgomery Lecture 1 Fall 2016 23
Where is this topography? Lecture 1 Fall 2016 24
Distributary Fan: "Smoking Gun" Evidence for Persistent Water Flow and Sediment Deposition on Ancient Mars NASA Press release on 3 November 2003 Lecture 1 Fall 2016 25
The end Review of Geological Concepts or things you should know from GEOG 111 or EASC 101 Reading Assignment: You should review the material on the following slides. If you don t remember some of the material, review you GEOG 111 or EASC 101 textbooks and notes. Lecture 1 Fall 2016 26
Review of Geological Concepts or things you should know from GEOG 111 or EASC 101 Rock Materials: We need to understand the basics of rock materials because they contain information about how they were formed. As such, rock materials allow us to estimate the overall history of a site and the rates of geomorphic processes (weathering rates, transport rates, transport distances). Fortunately, knowledge of a few basic minerals is all that is needed to understand how most landscapes develop. Review of Geological Concepts Rock Types: or things you should know from GEOG 111 or EASC 101 1) Igneous: Form directly from the cooling of magma (e.g. basalt, granite). 2) Sedimentary: layers of this debris get compacted and cemented together (sandstone, mudstone, limestone, Halite). 3) Metamorphic: Rocks whose minerals have become unstable in their environment and are changed into something new (e.g. slate, schist, gneiss, and marble) Lecture 1 Fall 2016 27
http://pubs.usgs.gov/imap/i2781/ From Ritter, 2002 Lecture 1 Fall 2016 28
The portion of the lithosphere that is of greatest interest to us (i.e. the exposed surface) is largely sedimentary rock overlain by loose sediments. From Ritter, 2002 The Rock Cycle Lecture 1 Fall 2016 29
Intrusive Crystallization temperature Introduction to Geomorphology Bowen s Reaction Series First to Crystallize Last to Crystallize The Classification of Igneous Rocks Phaneritic Aphanitic (Coarse Grained) (Fine Grained) Granite Granodiorite Diorite % Silica Rhyolite Dacite Andesite Extrusive Gabbro Basalt Peridotite Lecture 1 Fall 2016 30
Cementation Introduction to Geomorphology Fissility Compaction The Classification of Sedimentary Rocks Clastic (Detrital) Sediments Arkose (Abundant felspar) Graywacke (Abundant rock fragments, felspar & clay) Shale Breccia (Angular pebbles) Quartz Arenite Mudstone (Common name for > 50% silt & clay) Conglomerate Sandstone Siltstone Claystone Gravel Sand Silt Clay 2 mm 0.0625 mm 0.0039 mm Nonclastic (Chemical) Sedimentary Rocks Inorganic Biochemical Limestone (calcite) Dolomite Halite Gypsum Limestone (calcite) Chert Coal Lecture 1 Fall 2016 31
Increasing Metamorphism Introduction to Geomorphology Classification of Metamorphic Rock Foliated Non-Foliated Gneiss (many sed & igneous) Schist (Phyllite) Phyllite (slate) Slate (Shale) Fine Coarse Gneiss Quartzite Quartzite (sandstone) Hornfels (Many sed.) Fine Coarse Particle Size Classification Millimeters (mm) Microns (µm) Boulders 256 Cobbles 64 256 Gravel (Pebble) 2 64 Sand 0.064 2 64-2000 Silt 0.002-0.064 2-64 Clay 0.002 2 Lecture 1 Fall 2016 32
Boulders (>256 mm) Cobbles (64-256 mm) Lecture 1 Fall 2016 33
Gravel (2-64mm) Sand (0.064-2mm) Lecture 1 Fall 2016 34
Silt (64 2 µm) Clay (<2mm) Lecture 1 Fall 2016 35
Grain-size distributions Percent Retained Probability Distribution Function (PDF) 60 50 40 30 20 10 0 0.001 0.01 0.1 1 10 100 Grain-size (mm) Percent Finer Cumulative Distribution Function (CDF) 100 90 80 70 60 50 40 30 20 10 0 0.001 0.01 0.1 1 10 100 Grain-size (mm) Lecture 1 Fall 2016 36
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