|
date 05/10/2009 |
|
Yakovlev
Fedor Home-page |
FOLDING formation research Guide: about the study of folded structures of several scale
levels into thin-layered flysch-like sediments in a Hinterland |
|
9. Folded domain morphology and inclined
shearing zones (rank 3) – since 1997. ·Description. Detailed structural sections of NW
Caucasus were used as source of this study. The systematic measurements of
domain geometry properties (Fig. 1) and kind of its statistic study were worked
out. Part of domain has properties (colored sectors at Fig.2) of
“near-thrust” geometry (the angle between axial surface and envelope plain
lead to 180° and the shortening value is increasing at the same time). It is
better seen on diagram (AX-EN/SH, Fig. 3). This phenomenon was used for
comparison the natural objects set with the theoretical models for the
elucidation of mechanisms formation. Simple shearing along inclined zone in
combination with shortening was used in two kinds: initial dip of zone 45°
and 20° (shearing angle of horizontal pressure, Fig.4, and as a shearing
along stratification or basement top, comparatively). For the North-West
Caucasus structures it was shown that such structures has shape of elongated
zones and that these zones have initial inclination of dip near 45° and
combination of iterations as shearing angle 6° and shortening 1%. The
combination of simple shearing along zone (like thrust movement) and
horizontal shortening (flattening) is enough for explanation of main
properties of fold related deformation of these zones. The set of
longitudinal zones exist for East half of NW Caucasus and some diagonal zones
exist for West half of NW Caucasus. ·Publications. First
publication about the phenomena is the preprint (Yakovlev F.L. “The recognition of...”,
1997; PDF-R, N 8 in List-En). The materials about NW Caucasus structures was
published in (Yakovlev F.L. “Mechanisms of linear folding...”, 2003; pictures exist, (PDF-R), N 49 in
Full-List-En), abstract in English (Yakovlev F.
2005. “Inclined zones of ductile...”, 2005; PDF, N 16 â in List-En).
Full paper is not exists, but the material of poster EGU-05 may be download. ·Materials. There are files of domains
geometry measurements, the material of its visualization in peculiar program.
The material of comparison of two models (20 and 45 degrees initial dip)
exists also for different combination of simple shearing and flattening. |
Fig. 1. Main parameters of domain morphology:
shortening value (Sh,
4), dip of axial surface (AX, 3),
dip of envelope plain (EN, 2). Dip
angles are measuring regarding horizontal plain (1). |
||
|
|
|||
|
|
|
|
|
|
Fig. 2. Main
diagnostic diagram, parameters are: AX (vertical axis), EN (horizontal
axis), SH (as colors of points, axis toward obsever) |
Fig. 3. The expression of inclined zone of
plastic shearing in domain morphology. |
Fig. 4. Scheme of inclined zone of plastic simple
shearing (“near thrust” local mechanism ) |
|
|
© 2009, ÈÔÇ ÐÀÍ, ßêîâëåâ |