last update 01/10/2009 

Yakovlev
Fedor Homepage 
FOLDING formation research Guide: about the study of folded structures of several
scale levels into thinlayered flyschlike sediments in a Hinterland 
III.
LOCALE STRUCTURES AND THEIR MECHANISMS ANALYSIS
USING THE STRAIN ELLIPSOID OF DOMAINS
8.
Strain ellipsoid of a fold and of a folded domain (ranks 2, 3) – since
1987. ·Description. There is famous difficulty to generalize the
data of strainanalysis to scale of one fold and larger size objects. The
reason is a heterogeneity of strain. The
solution was found in application of model of multilayer folds formation (point 7) for this problem. The shortening value
of fold is calculated not for horizontal direction but for perpendicular to
axial surface (fig. 1). Thus the ellipsoid of deformation relates to
shortening value of folds and to orientation of axial surface. Maximal length
axis possesses to axial plain and it perpendicular to hinge line, minimal
length axis is perpendicular to hinge line and to axial surface, intermediate
length axis is hinge line. For a folded domain important parameters (fig. 2)
are A) axial plain dip (3), B) folds envelope plane dip (2), fold shortening
value (fold strain ellipse shortening, 4). An orientation of envelope surface
of folds (2, fig. 2) is important as orientation of initial horizontal
position of prefolded layering in isomeric volume.
Such generalization may be used for several aims on next steps of study: mesoscale mechanisms formation elucidation,
retrodeformation of structural sections (balancing of section) and so on. ·Publications. First publication which
used in fact this idea was paper (Yakovlev F.L. “A Study of the Kinematic...”, 1987; (PDF),
N 3 in ListEn). The topic is discussed also in: (Yakovlev F.L. “Investigation
of the processes …”, 2002; PDFR, N 9 in ListEn). The especial description of
topic was short paper (Yakovlev F.L., Voitenko V.N.
“Application of the deformation...”, 2005; PDF,
N 11 in ListEn). 
Fig. 1 The ellipsoid of strain for a fold. 1 – axial surface (ε_{1}),
2 hinge line (ε_{2}),
(ε_{3})– shortening value Sh; 3
– strain ellipse for competent layer; 4 – strain ellipse for incompetent
layer 
Fig.
1 The ellipsoid of strain for folded domain 
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