Landforms of British Columbia 1976 - Department of Geography

‘I
,
titularly for those interested in the structure of areas for which geologic maps are
inadequate or lacking.* It is possible to point out the occurrence of numerous
lineaments, but owing to deficiencies in geological information it is not always pos-
sible to interpret their structural significance correctly.
Figure 12. Diagram showing the location of major lineaments.
Figure 12 shows the locations and lengths of the major lineaments whose
descriptions follow.
By far the longest and most prominent lineament in the Province is the Rocky
Mountain Trench ( 1) t (see Plates XXII, XXIVA, and XXXIVB) . It extends along
the western front of the Rocky Mountains in a northwesterly direction for 900 miles,
from the International Boundary almost to the Liard River (see p. 65). The struc-
tures controlling the Trench are complex, variable from section to section, and not
very well known.
“ In certain areas the dominant controlling structure is thrust faulting, whereas
in other areas it is normal faulting, and in still others strike-slip faulting is indicated.
Although the type of faulting varies, there is no area that has been investigated along
the Trench in which faults are not observed or required by the relationships on either
side. If this is true of the unmapped areas as well, then a linear zone of faulting
about 1,000 miles long is indicated. Individual faults within this zone may control
the structural relationships and the position of the Trench locally, but the gross shape
and regional structural relationships are controlled by the zone of faulting as a
whole.“$