Friday, April 1, 2011

slickensides vs slickenlines

In my current job I am learning any number of interesting things as I look things up in the course of editing so as to be certain that terms are being used correctly. Today's noteworthy subject to look up is the difference between the terms "slickensides" and "slickenlines". I only recall the former from my undergraduate structure courses, and neither term has come up in my own research since then. There was a time when looking up such geologic terms meant reaching for a geologic dictionary. These days it can sometimes be more effective to reach for the internet. I just found an interesting article which nicely clarifies the difference between the two words, and why there are two such closely related words in the first place.

Slickensides refers to the planar, polished, surface of a fault plane (the polishing occurring when the rocks rub past one another. Slickenlines, on the other hand, refers to the liner scratches which occur on such a surface, as a projection on one side of the fault scratches a grove onto the other. Most of the slickensides I have seen in the field contained slickenlines. No wonder my teachers and classmates simply used the term "slicks" when discussing them informally in the field.


CJR said...

Interesting. I'm fairly sure that I was taught that slickenlines were slickensides, although it took several rounds of red pen for me to stop calling them slicken*slides*. This terminology makes much more sense.

Edz said...

can a slickenside contain no trace of slickenlines? come to think of it, slickenside is the more "geologic" term to use rather than the latter.

Anonymous said...

As a current student geologist immersed within structural geology this semester, "slickensides" are indeed polished planar features evidencing a fault or rock movement sliding past each other. Slickensides can exist (although quite rare) without slickenlines. It all depends on the grain size from the scratching surface