Surface Morphology of Basalt Columns at Svartifoss, VatnajökulsÞjóðgarður, Southern Iceland
Figure 4
Aspects of hackled surfaces within the horizontal striations. (a) Crescent-shaped hackling is a common surface feature on the horizontal striations. Arrows indicate base of striation (lens cap diameter is 72 mm). (b) The relief of the hackles is more pronounced near the lower margin of the striation in which they occur (arrows). (c) The orientation of the curvature of the hackles commonly reverses between adjacent striations (arrows indicate direction in which the curvature opens). (d) In rare instances, the orientation of the hackle curvature reverses within a striation. Vertical arrow indicates the point of reversal; horizontal arrows indicate orientation of curvature.
