GEOG 309 - Physical Geography Field Course Reading Package - Traverse Church M. and J.M. Ryder. 2007. Chapter 2 – Physiography of British Columbia [Draft]. In Compendium of Forest Hydrology and Geomorphology in British Columbia [In Prep.] R.G. Pike et al. (editors). B.C. Ministry of Forests and Range Research Branch, Victoria, B.C. and FORREX Forest Research Extension Partnership, Kamloops, B.C. Land Management Handbook (TBD). URL: http://www.forrex.org/ program/water/compendium.asp R.D. Moore, D.L. Spittlehouse, P.H. Whitfield, K. Stahl. Chapter 3 – Weather and Climate [Discussion Draft]. In Compendium of Forest Hydrology and Geomorphology in British Columbia [In Prep.] R.G. Pike et al. (editors). B.C. Ministry of Forests and Range Research Branch, Victoria, B.C. and FORREX Forest Research Extension Partnership, Kamloops, B.C. Land Management Handbook (TBD). URL: http://www.forrex.org/program/water/compendium.asp Eaton B., and R.D. Moore. 2007. Chapter 4 – Regional Hydrology [Draft]. In Compendium of Forest Hydrology and Geomorphology in British Columbia [In Prep.] R.G. Pike et al. (editors). B.C. Ministry of Forests and Range Research Branch, Victoria, B.C. and FORREX Forest Research Extension Partnership, Kamloops, B.C. Land Management Handbook (TBD). URL: http://www.forrex.org/program/water/ compendium.asp John J. Clague (2000): ‘Recognizing order in chaotic sequences of Quaternary sediments in the Canadian Cordillera’ Quaternary International 68-71, 29-38 These readings are a required part of the GEOG 309 course. Compendium of Forest Hydrology and Geomorphology in British Columbia Chapter 2 — Physiography of British Columbia M. CHURCH AND J.M. RYDER Discussion Draft This chapter has been made available for discussion purposes in advance of the final Compendium publication. While the material has been peer-reviewed, we encourage your comments on this draft. Feedback may be forwarded to [email protected] until March 31, 2008. This publication has been funded in part by the British Columbia Ministry of Forests and Range through the Forest Investment Account – Forest Science Program. © 2007 FORREX Forest Research Extension Society and B.C. Ministry of Forests and Range Church M. and J.M. Ryder. 2007. Chapter 2 – Physiography of British Columbia [Draft]. In Compendium of Forest Hydrology and Geomorphology in British Columbia [In Prep.] R.G. Pike et al. (editors). B.C. Ministry of Forests and Range Research Branch, Victoria, B.C. and FORREX Forest Research Extension Partnership, Kamloops, B.C. Land Management Handbook (TBD). URL: http://www.forrex.org/program/water/compendium.asp 1 Chapter 2 – Physiography of British Columbia [Draft August 2007] Introduction.................................................................................................................................... 3 Tectonic Setting and Geology...................................................................................................... 5 Tectonic History........................................................................................................................... 5 Geology ....................................................................................................................................... 9 Igneous rocks........................................................................................................................ 11 Sedimentary rocks ................................................................................................................ 13 Metamorphic rocks................................................................................................................ 16 Glaciation ..................................................................................................................................... 16 Glacial History ........................................................................................................................... 16 Glacial Deposits ........................................................................................................................ 23 Holocene Epoch........................................................................................................................... 30 Holocene History....................................................................................................................... 30 The Contemporary Landscape.................................................................................................. 33 Soil Development ...................................................................................................................... 37 Human Influence in the Contemporary Landscape ................................................................. 41 Conclusion ................................................................................................................................... 43 References ................................................................................................................................... 44 © 2007 FORREX Forest Research Extension Society and B.C. Ministry of Forests and Range Church M. and J.M. Ryder. 2007. Chapter 2 – Physiography of British Columbia [Draft]. In Compendium of Forest Hydrology and Geomorphology in British Columbia [In Prep.] R.G. Pike et al. (editors). B.C. Ministry of Forests and Range Research Branch, Victoria, B.C. and FORREX Forest Research Extension Partnership, Kamloops, B.C. Land Management Handbook (TBD). URL: http://www.forrex.org/program/water/compendium.asp 2 Chapter 2 – Physiography of British Columbia [Draft August 2007] Chapter 2 – Physiography of British Columbia M. CHURCH AND J.M. RYDER Introduction British Columbia lies astride the Western Cordillera of North America, a broad and complex system of mountains and plateaus that has developed over nearly a billion years on the leading edge of the North American continental plate. In the northeast, the province extends beyond the mountains into the Alberta Plateau. Consequently, the contemporary landscape exhibits a wide variety of landforms and materials, ranging from high mountain peaks, through broad, rolling plateaus, to alluvial valleys. This chapter presents an overview of the contemporary landscape of British Columbia, highlighting rock and soil materials and their properties, and explains how the landscape has developed. Figure 1 shows the major physiographic divisions of the province, reflecting the present topography. The divisions are based on topographic boundaries. In this chapter, rather than elaborately describe the physiography, we will consider the major elements that have created the topography and the principal attributes of the physical landscape— landforms, surface materials, and soils. The present topography is the consequence of the interaction of three principal factors: tectonic history, rock types, and climate. Tectonic history is the sequence of earth movements—mobilized by forces within the earth—that has produced the large-scale arrangement and elevation of major topographic features. Hence, the major physiographic units of the landscape (Figure 1) are largely tectonically determined. Tectonics also accounts for the distribution of the rock types exposed at the surface today, which have influenced the character of the soil materials that mantle the surface (surficial materials). These, in turn, have a major influence on the terrestrial components of the hydrologic cycle. © 2007 FORREX Forest Research Extension Society and B.C. Ministry of Forests and Range Church M. and J.M. Ryder. 2007. Chapter 2 – Physiography of British Columbia [Draft]. In Compendium of Forest Hydrology and Geomorphology in British Columbia [In Prep.] R.G. Pike et al. (editors). B.C. Ministry of Forests and Range Research Branch, Victoria, B.C. and FORREX Forest Research Extension Partnership, Kamloops, B.C. Land Management Handbook (TBD). URL: http://www.forrex.org/program/water/compendium.asp 3 Chapter 2 – Physiography of British Columbia [Draft August 2007] Figure 1 Physiographic regions of British Columbia. (Simplified after Mathews [1986]: Mathews’ lowest order units have been omitted). Relief data from digital files of the United States Geologic Survey. The physiographic divisions are also superimposed on maps of geology (Figure 3), glacial features (Figure 4), glacial deposits (Figure 6), and soils (Figure 9) so that the reader can determine the principal attributes of the physical landscape in each topographic division. Reproduced with the permission of the Minister of Public Works and Government Services Canada, 2007 and Courtesy of Natural Resources Canada, Geological Survey of Canada. © 2007 FORREX Forest Research Extension Society and B.C. Ministry of Forests and Range Church M. and J.M. Ryder. 2007. Chapter 2 – Physiography of British Columbia [Draft]. In Compendium of Forest Hydrology and Geomorphology in British Columbia [In Prep.] R.G. Pike et al. (editors). B.C. Ministry of Forests and Range Research Branch, Victoria, B.C. and FORREX Forest Research Extension Partnership, Kamloops, B.C. Land Management Handbook (TBD). URL: http://www.forrex.org/program/water/compendium.asp 4 Chapter 2 – Physiography of British Columbia [Draft August 2007] Climate controls the hydrologic cycle and determines the processes of rock weathering, erosion, and sediment transfer at the surface of the earth. These geomorphological processes create the landforms and soils within the landscape. The temporal scale for tectonic processes is in the order of 1 million years and the spatial