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Figure 50. Maps of the Barkerville Terrane divided into arbitrary structural domains marked by
black dashed lines. The equal area nets are plots of A) fold axes of the shear folds for each of
the domains and B) ductile folds for each of the domains. Note the diversification of the fold axes
attitudes to the southwest of the Lightning Creek Anticlinorium.

Lake. Bowman (1889) first described it; and subsequently,
Johnston and Uglow (1926), Holland (1948, 1954),
Sutherland Brown (1957), Campbell et al. (1973) and
Struik (1982a, b). All suggested that the structure was an
anticline.

The antiform folds the regional foliation, is symmet-
ric and changes along trend from a broad arch to an open
fold. It is intersected with a widely spaced axial surface
cleavage where the hinge of the fold is tightest. Folds
flanking the anticlinorium verge toward its axis (Fig. 49).

70

The extent of earlier folds that were folded by the anti-
form are unknown. Earlier I (1982a) speculated that the
antiform may fold recumbent east-verging folds with
limbs on the order of 4 to 8 km long, but such specula-
tions depend on a thorough understanding of the strati-
graphy, something not yet attained. Because the antiform
folds the regional cleavage, it is assumed that it folds the
isoclinal folds associated with that cleavage.

Campbell et al. (1973) and Struik (1981) described the
cleavage of the antiform as arching through its hinge,