Statistical Analysis of Directional Features - Geomathematics: Theoretical Foundations, Applications and Future Developments - page 290

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Distance (km) South of Periadriatic Lineament near Bruneck

Fig. 8.13 Azimuths ( diamonds ) and dips ( triangles ) of B-axes from six measurement samples
along Gaderbach shown in Fig. 8.12 (Note that along most of this section, the B-axes dip nearly
50 East). Closest to the Periadriatic Lineament, their dip becomes nearly 90 SSW (Also see
Table 7.1 ) (Source: Agterberg 2012 , Fig. 6)

1961 , Appendix III). In Fig. 8.13 , the B-axes measured along the Gaderbach are
projected on a North-South line approximately parallel to the average orientation of
the TRANSALP profile. The method of fitting unit vector fields becomes simplified
when the measurements are along a straight line (North-South directed x -axis in
Fig. 8.13 ). Figure 8.14 shows the corresponding direction cosines together with
cubic polynomial trend lines fitted by the method of least squares. In Fig. 8.15 the
trend lines of Fig. 8.14 are re-plotted as average azimuth and dip curves.
In a general way, the results of the preceding linear unit vector field analysis
confirm the earlier conclusions on North-South regional change in average
B-lineation attitude. Table 8.1 shows results from another test. Original estimates
of mean B-axis orientations for the six measurement samples (Method 1) are
compared with ordinary unit vector means (Method 2), and with values on the
trend lines of Fig. 8.16 at mean distances south of the (Periadriatic) Pusteria
Lineament near Bruneck (Method 3). Differences between the three sets of mean
azimuth and dip values are at most a few degrees indicating that regionally, on the
average, there is a dip rotation from about 45 dip to the east in the south to about
80 dip in the north accompanied by an azimuth rotation of about 120 from
eastward to WNW-ward. It is noted that higher-order polynomials fitted by least
squares rapidly become unreliable near the edges of the study area, where there is
less data control. Thus, the local maximum at the northern edge (in Fig. 8.15 )isnot
clearly established. Widespread occurrence of steeply dipping B-axes near the
Periadriatic Lineament and along the southern border of the Permian (Brixen
granodiorite) intrusion, however,

is confirmed by results derived from other