Structural geology: slickenlines record two directions of fault motion
Multiple levels (parallel planes; rock surface curves down to right) of slickensided fault surfaces in an outcrop of Marron Fm. andesitic volcanic rock (in south-central British Columbia), with one of my fingers for scale. Above my finger, the lighter coloured material is a mineral vein (fluid flowed along a fault plane and mineral precipitated from solution) with a patchy distribution now because it is partly eroded away.
The slickenlines present have two different groove lineation directions, diagonal down to the left and down to the right in both the purplish-brown host rock and the light brown vein material. They record two different steep (sub-vertical) directions of fault motion at this site back in the Eocene (ca. 50 million years ago), a time of post-orogenic normal faulting in this part of western Canada.
C. J.R. Devaney
Structural geology: slickenlines record two directions of fault motion
Multiple levels (parallel planes; rock surface curves down to right) of slickensided fault surfaces in an outcrop of Marron Fm. andesitic volcanic rock (in south-central British Columbia), with one of my fingers for scale. Above my finger, the lighter coloured material is a mineral vein (fluid flowed along a fault plane and mineral precipitated from solution) with a patchy distribution now because it is partly eroded away.
The slickenlines present have two different groove lineation directions, diagonal down to the left and down to the right in both the purplish-brown host rock and the light brown vein material. They record two different steep (sub-vertical) directions of fault motion at this site back in the Eocene (ca. 50 million years ago), a time of post-orogenic normal faulting in this part of western Canada.
C. J.R. Devaney