Statistical Analysis of Directional Features - Geomathematics: Theoretical Foundations, Applications and Future Developments - page 294

Fig. 8.17 Azimuth ( lines ) and dip (in symbols) for ( Top ) quadratic and ( Bottom ) cubic unit vector
field fitted to data within rectangle outlined in Fig. 8.16 ; printed symbol for dip 1 (10-20 E),
3 (30-40 E), 5 (50-60 E), A (0-10 W). Strong eastward convergence of azimuth lines suggests
existence of Alpine lineament or zone trough which material was moved upward with considerable
mobility but with preservation of pre-Alpine s -planes and B -lineations (Source: Agterberg 1974 ,
Fig. 115)
realistic provided that the mean azimuth pattern within the relatively low-dip
southwestern part of the area, where there was no data control because of Quater-
nary cover, as well as the low-dip northeastern pattern north of the Periadriatic
Lineament (Western Drauzug), are ignored.
It may be concluded that, in the Pustertal area, the quartzphyllites, which show
subvertical s -plane strike on the average, contain Alpine anticlinal structures
characterized by areas of lower-dipping B-axes that may be accompanied by
eastward convergent mean azimuth lines. The most likely explanation (Agterberg
1961 ) is that these quartzphyllites were squeezed out upwards during the latest
phase of Alpine orogeny between the Austroalpine units north of the Periadriatic
Lineament and the northern edge of the Permotriassic of the Dolomites (Fig. 8.18 ).
This interpretation would be in accordance with a model advocated by Castellarin
et al. ( 2006 , Fig. 9) who assume that the Vibroseis depth-migrated data from the
TRANSALP profile show a steeply north-dipping thrust fault that reaches the
surface at the Periadriatic Lineament (also see next section).