Page 132 - Fundamentals of Geomorphology

LARGE-SCALE TECTONIC AND STRUCTURAL LANDFORMS 115

On the windward side of the orogen, higher runoff influence upon such continental-scale landforms as
generated by higher precipitation totals leads to higher mountain belts, but there is an important interplay
rates of denudation than on the drier, leeward side. As a between uplift, climate, and denudation.
result, crustal rocks rise more rapidly on the windward
flank than on the leeward flank, so creating a patent ESSAY QUESTIONS
asymmetry in depths of denudation across the orogen
and producing a characteristic pattern of crustal defor- 1 Explain the landforms associated
mation. Such modelling studies indicate that a reversal with active margins.
of prevailing rain-bearing winds will produce a change in
topography, spatial patterns of denudation, and the form 2 Explain the landforms associated
of crustal deformation (Summerfield 2007). In addi- with passive margins.
tion, they show that the topographic and deformational 3 Examine the factors that determine
evolution of orogens results from a complex interplay the major relief features of the Earth’s
between tectonic processes and geomorphic processes surface.
driven by climate.

SUMMARY
FURTHER READING
Geological processes and geological structures stamp Burbank, D. W. and Anderson, R. S. (2001) Tectonic
their marks on, or in many cases under, landforms Geomorphology: A Frontier in Earth Science. Malden,
of all sizes. Plate tectonic processes dictate the gross Mass.: Blackwell Science.
landforms of the Earth – continents, oceans, mountain A detailed and insightful discussion of one of geomor-
ranges, large plateaux, and so on – and many smaller phology’s latest developments, but not easy for trainee
landforms. Diastrophic forces fold, fault, lift up, and geomorphologists.
cast down rocks. Orogeny is a diastrophic process that
builds mountains. Epeirogeny is a diastrophic process Godard, A., Lagasquie, J.-J., and Lageat, Y. (2001) Base-
that upheaves or depresses large areas of continental cores ment Regions. Translated by Yanni Gunnell. Heidelberg:
without causing much folding or faulting. The bound- Springer.
aries of tectonic plates are crucial to understanding many An insight into modern French geomorphology.
large-scale landforms: divergent boundaries, convergent Huggett, R. J. (1997) Environmental Change: The Evolv-
boundaries,andtransformboundariesareassociatedwith ing Ecosphere. London: Routledge.
characteristic topographic features. Incipient divergent You may find some of the material in here of use. I did!
boundaries may produce rift valleys. Mature diver-
gent boundaries on continents are associated with passive Summerfield, M. A. (ed.) (2000) Geomorphology
margins and great escarpments. Convergent boundaries and Global Tectonics, pp. 321–38. Chichester: John
produce volcanic arcs, oceanic trenches, and mountain Wiley & Sons.
belts (orogens). Transform boundaries produce fracture Not easy for the beginner, but a dip into this volume
zones with accompanying strike-slip faults and other will reward the student with an enticing peep at one of
features. Plate tectonic processes exert an important geomorphology’s fast-growing fields.