Structural Geology for the Dummy Geology Student

Angular unconformities do not cause tilting, Audrey!

We'll be honest: we often rail on the scientific illiteracy of liberal arts graduates, especially when it comes to elementary topics in the sciences. We get it that a J-school graduate doesn't understand string theory or that someone who majored in English literature isn't conversant in organic chemistry. On the other hand, if these people were actually as smart as they think, wouldn't they be able to synthesize information from an authoritative website and regurgitate it back reworded? Not so Audrey Farley, at least based on reading her Sciencing.com article "What Causes Geologic Tilting?"

Our staff geologist (yes, we have one) took a look at what Farley wrote and was, to put it politely, gobsmacked at the utter inanity. He checked her references – three university websites and a conspiracy site called "World Mysteries," full of blather about Edgar Cayce, cryptozoology, and the like. Getting back to Audrey, however... she opened by "telling" her readers that

"Geologic tilting, also known as tectonic tilting, occurs when the earth’s surface layers begin to tilt or slant irregularly. Geologists have studied the tilts of land, lakes and other bodies of water for hundreds of years and developed different theories to account for geologic tilting..."

After reading that crap, coffee came out the noses of everyone at the staff meeting. First, Farley's so-called explanation is circular; second, how can a lake "tilt"? But hey, let's look at some of Audrey's "science" and her list of causes...

1. "VERTICAL FAULTS: ...when mountains or tall elevation in the earth’s surface crack, mountain blocks (the layers of the earth that form the mountain) move relative to the fault and displace the ground surface. The displacement of the surface... typically causes tilting or irregularity in the surrounding land."
2. "HORIZONTAL FAULTS: Horizontal faults... disturb the formation of the earth’s layers and cause irregularities, including tilting. Surface fault ruptures can also cause tectonic subsidence, which is broad tilting of the valley floor. When valley floors tilt, lakes and reservoirs near the valley floor flood and tributary courses are disturbed..."
3. "ANGULAR UNCONFORMITY: Angular unconformity occurs when parallel strata of sedimentary rocks are deposited on layers that are tilted, perhaps as a result of erosion. In short, new layers of sedimentary rocks are compressed on top of layers that are already deformed and tilting, thereby exacerbating tilting and causing further angular discordance."
4. "CHANGES TO MAGNETIC FIELD: Disturbances in the earth’s magnetic field also cause geologic tilting. Diverse phenomena have the potential to disturb the earth’s magnetic field, including passing comets or fluctuations in the sun’s magnetic field. No matter when magnetization is disturbed, the terrestrial axis of the earth is altered. This causes all kinds of geologic and climatological imbalances, including the tilting of lakes and layers of the earth’s surface because of subcrust migration. Essentially, the displacement of magnetic poles causes crustal displacements and other irregularities by dislocating (even over hundreds of years) the underlying strata of the earth."

Wow... We're just plain amazed at Farley's failure to grasp a simple concept. We simply don't have enough  space to attempt to correct all of her misstatements and misconceptions, but we would like to point out that the actual answer to the question comprises A) compression or extension at plate boundaries, B) isostatic adjustment, C) thermal expansion. The rubbish about changes in the magnetic field, which appears to come from the conspiracy site, is especially disturbing. We'll look into it, but in the meantime? Audrey Farley, come on down and get your Dumbass of the Day award!

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