| No matter what your area of expertise, doesn't it just chap your hind end when some birdbrain starts blathering on about something you know, and getting it wrong? Like, say, for instance you're an MD and you overhear some bozo telling everyone that stupid fairy tale about vaccines and autism? Well, a couple of times a year the Antisocial Network's staff geologist crawls out from under the bed and harangues us about people getting geology wrong. Apparently, a lot of folks think this particular corner of science is so simple even they can understand it...
But they're often wrong, such as in the case of a guy name of Tom Wolsey at suite.io (what used to be suite100.com when it was just a content farm). Tom educated his readers bout his unfamiliarity with geomorphology – the study of landforms and their relation to geology – in a post he called "Galisteo--Artists, Landscape, and High Desert."¹
|
We can't really argue much with Tom's description of the town of Galisteo, or of his paean to clay artist Patricia Hoback. We don't know that stuff (though we think someone on the staff may have been to Galisteo once or twice). What we can argue with is his explanation of the feature known as a "hogback":
 |
| Hogback shape |
"Hogbacks are formed when harder sedimentary rock overlays softer sedimentary rock underneath. As the rock weathers, the softer rock erodes leaving the harder rock sitting atop the softer stratum. The resulting ridge is quite pronounced and becomes increasingly steeper as the softer stratum continues to erode."
Well, Wolsey got one thing right: a hogback resembles the ridge of a hog's back. He also got the hard and soft strata relationship right: a hogback forms where resistant strata overlie more easily weathered strata. What he missed – and what is most important to the geology of a hogback – is that the rocks that make up the ridge are tilted. Think about it: if the rocks were flat, the hard layer would break and collapse soon after the soft stuff eroded out from under it: no hogback!
That's not to mention that the steepness of the ridge has nothing to do with how much erosion there's been. That value is controlled by the dip on the rocks, which is a matter of structural geology; not erosion.
Nope, Tom: you didn't think it through before you started babbling - and that's why started handing out the Dumbass of the Day to people like you .
|
¹ This website is now defunct, and archive.org's Wayback machine never made a copy of the post. Oh, well, no loss...
copyright © 2015-2022 scmrak
SI - GEOLOGY
No comments:
Post a Comment