The origins of balanced sections lie in the petroleum industry in the 1950's and 19601s, most obviously in Calgary, Canada. The first published balanced sections are those by Bally, Gordy and Stewart 119661 of the Canadian Rockies. The concepts of thrust-terrain structural styles, upon which they are based, have been developing since Peach and Horne's [I9071 classic work on the Moine thrust zone in Scotland. To begin, how can we define a "balanced" section?

Footwall geometry and the rheoiogy of thrust sheets
Thrust tectonics in the south central Pyrenees
Structural history of high-pressure metamorphic rocks in the southern Vanoise massif, French Alps, and their relation to Alpine tectonic events
Development of conjugate shear bands during bulk simple shearing
Microscopic deformation mechanisms associated with mica film formation in cleaved psammitic rocks
An examination of the cataclastic fabrics and structures of parts of Nisutlin, Anvil and Simpson allochthons, central Yukon: test of the arc-continent collision model
Graphic determination of principal stress directions for slickenside populations: an attempt to modify Arthaud's method

Strain partitioning in the Helvetic thrust belt of eastern Switzerland from the leading edge to the internal zone
Calcite fabrics in a natural shear environment, the Helvetic nappes of western Switzerland
Development of planar and linear fabrics in Dauphinois shales and slates (French Alps) studied by magnetic anisotropy and its mineralogical control
Obduction-related planar and linear fabrics in Oman
Brittle to ductile transition due to large strains along the White Rock thrust, Wind River mountains, Wyoming
Interaction of bed-parallel stylolites and extension veins in boudinage
Foreland deformation in the Appalachian Plateau, central
New York: the role of small-scale detachment structures in regional overthrusting

Genesis of the Batinah m61ange above the Semail ophiolite, Oman
Analysis of faulting in porous sandstones
Displacement features associated with fault zones: a comparison between observed examples and experimental models
Stress and displacement distributions around pyrite grains
Interpretation of fracture and physiographic patterns in Alberta, Canada
Strain and shape-fabric variations associated with ductile shear zones
Dynamic analysis of rough cleavage in the Martinsburg Formation, Maryland
Development of early comp6site cleavage in pelites from West Donegal

The construction of balanced cross-sections

An understanding of the structural elements in the sub-surface is of great importance when establishing new constructions in bedrock, or surveying areas prone to rockslides. In this thesis the focus has been on combining methods within geology, structural geology, geophysics and engineering geology to reach an interdisciplinary understanding and predict sub-surface structures.

R ock masses deform under the action of forces. Rheology (from the Greek 'study of flow') is the branch of physics dealing with the deformation of materials. An understanding of rheology is a prerequisite for the study of deformed domains. Rheological properties of rocks can be described with or without reference to atomic processes (microrheology and macro-rheology).

The previous chapter dealt with planar geological surfaces. A geological surface which is curved is said to be folded. Most folding is the result of crustal deformation whereby rock layering such as bedding has been subjected to a shortening in a direction within the layering. To demonstrate this place both hands on a tablecloth and draw them together; the shortening of the tablecloth results in a number of folds.

Structural geology is obviously one of the more important subjects for geoscientists working in petroleum industry. Folds and faults in deformed rocks make traps for hydrocarbon accumulation. Also, large-scale deformations, the so-called tectonics, control the architecture of petroliferous sedimentary basins. It is the primary job of a structural geologist to interpret geological map and field data, and infer geometry of large scale folds and faults. However, geoscientists with varied specializations and working with different kinds of data may also be called upon to make structural interpretations.

Folds in ductile shear zones are common structures that have a variety of origins. These can be pre-existing folds that become modified or folds developed during the shearing event. Among the syn-shearing folds, a second subdivision is based on the relative age of the folded surface, which can be pre-existing or newly formed during the shearing event. In each of the three categories final fold geometry and orientation show complex relationships with the kinematic frame. The final fold geometry depends on the vorticity within the shear zone, the rheology and the initial orientation of the folded surface relative to the kinematic framework. It follows that folds are complex structures, difficult to use as kinematic indicators. However, in shear zones where undeformed wall rocks with pre-shear structures are accessible and where kinematics can be well established, folds can provide a valuable natural means to understand the initiation and evolution of structures under non-coaxial regimes. We point to the need of discriminating among different plausible categories, based on the nature of the folded surface and on the inherent structural features of each category. <...>