Changes

===Structural style===

===Structural style===

Appropriate seismic lines, close to the line of section, define the structural style of the folds and faults, so this style should be incorporated directly into the section.<ref name=Dahlstrom_1970 /> Dip domain construction methods are popular guides to section drawing in both compressional and extensional systems.<ref name=Groshong_1989a />

Appropriate seismic lines, close to the line of section, define the structural style of the folds and faults, so this style should be incorporated directly into the section.<ref name=Dahlstrom_1970 /> Dip domain construction methods are popular guides to section drawing in both compressional and extensional systems.<ref name=Groshong_1989a>Groshong, R. H., 1989a, Half graben structures--balanced models of extensional fault bend folds: Geological Society of America Bulletin, v. 101, p. 96-105.</ref>

[[File:Statistics-overview fig1.png|left|thumbnail|'''Figure 1.''' SCAT plots used to define the complex structure seen in the discovery well of the Rail Road Gap oil field, California. The five plot types are (from left to right) azimuth versus depth (A plot), dip versus depth (D plot), dip versus depth in the direction of greatest curvature (T plot), dip versus depth in the direction of least curvature (L plot), and dip versus azimuth (DVA plot). (From Bengtsen, 1982.)]]

[[File:Statistics-overview fig1.png|left|thumbnail|'''Figure 1.''' SCAT plots used to define the complex structure seen in the discovery well of the Rail Road Gap oil field, California. The five plot types are (from left to right) azimuth versus depth (A plot), dip versus depth (D plot), dip versus depth in the direction of greatest curvature (T plot), dip versus depth in the direction of least curvature (L plot), and dip versus azimuth (DVA plot). (From Bengtsen, 1982.)]]

Modern theories of structural geology generally relate the formation of folds to accommodation on irregular fault surfaces.<ref name=Hamblin_1965>Hamblin, W. K., 1965, Origin of "reverse drag" on the downthrown side of normal faults: Geological Society of America Bulletin, v. 76, p. 1145-1164.</ref> <ref name=Dahlstrom_1970 />) Generally, the folds are more obvious on seismic sections than faults, but fortunately there are geometric rules that allow us to predict one shape from the other<ref name=Suppe_1983>Suppe, J., 1983, Geometry and kinematics of fault-bend folding: American Journal of Science, v. 283, p. 684-721.</ref> <ref name=Verrall_1982>Verrall, P., 1982, Structural interpretation with applications to North Sea problems: Geological Society of London.Course Notes No 3, JAPEC (UK).</ref> <ref name=Gibbs_1983 />; Williams and Vann, 1987<ref name=Williams_etal_1987>Williams, G., and I. Vann, 1987, The geometry of listric normal faults and deformation in their hanging walls: Journal of Structural Geology, v. 9, p. 789-795.</ref> <ref name=Groshong_1989a /> in both extensional and compressional examples. An example of a cross section solution explaining the relationship between extensional rollover and listric faults is shown in [[:Image:Drive-mechanisms-and-recovery_fig1.png|Figure 4]].  

Modern theories of structural geology generally relate the formation of folds to accommodation on irregular fault surfaces.<ref name=Hamblin_1965>Hamblin, W. K., 1965, Origin of "reverse drag" on the downthrown side of normal faults: Geological Society of America Bulletin, v. 76, p. 1145-1164.</ref> <ref name=Dahlstrom_1970 />) Generally, the folds are more obvious on seismic sections than faults, but fortunately there are geometric rules that allow us to predict one shape from the other<ref name=Suppe_1983>Suppe, J., 1983, Geometry and kinematics of fault-bend folding: American Journal of Science, v. 283, p. 684-721.</ref> <ref name=Verrall_1982>Verrall, P., 1982, Structural interpretation with applications to North Sea problems: Geological Society of London.Course Notes No 3, JAPEC (UK).</ref> <ref name=Gibbs_1983 />; Williams and Vann, 1987<ref name=Williams_etal_1987>Williams, G., and I. Vann, 1987, The geometry of listric normal faults and deformation in their hanging walls: Journal of Structural Geology, v. 9, p. 789-795.</ref> <ref name=Groshong_1989a /> in both extensional and compressional examples. An example of a cross section solution explaining the relationship between extensional rollover and listric faults is shown in [[:Image:Drive-mechanisms-and-recovery_fig1.png|Figure 4]].  

[[File:Drive-mechanisms-and-recovery fig1.png|thumbnail|'''Figure 4.''' Modeling extensional fault shapes from the rollover geometry. (a) the Groshong<ref name=Groshong_1989a /> method uses oblique simple shear with a reference grid constructed with a spacing equal to the fault heave. Distance 2 from the rollover up to regional elevation of the same reference bed is transferred to 2&prime;; likewise, 2&prime; + 4 is transferred to 4&prime; and so on to complete the fault trajectory. Interpolation between these points is carried out using a half grid spacing. (b) fault trajectory reconstruction by the Groshong<ref name=Groshong_1989a /> method uses simultaneous modeling of three horizons. Dashed trajectories are individual solutions; solid lines are the preferred solution. (From Hossack, unpubl. Data, 1988.)]]

[[File:Drive-mechanisms-and-recovery fig1.png|thumbnail|'''Figure 4.''' Modeling extensional fault shapes from the rollover geometry. (a) the Groshong<ref name=Groshong_1989b>Groshong, R. H., 1989b, Structural style and balanced cross sections in extensional terranes: Houston Geological Society Short Course Notes, Feb. 24-25, 128 p.</ref> method uses oblique simple shear with a reference grid constructed with a spacing equal to the fault heave. Distance 2 from the rollover up to regional elevation of the same reference bed is transferred to 2&prime;; likewise, 2&prime; + 4 is transferred to 4&prime; and so on to complete the fault trajectory. Interpolation between these points is carried out using a half grid spacing. (b) fault trajectory reconstruction by the Groshong<ref name=Groshong_1989b /> method uses simultaneous modeling of three horizons. Dashed trajectories are individual solutions; solid lines are the preferred solution. (From Hossack, unpubl. Data, 1988.)]]

===Balanced cross sections===

===Balanced cross sections===