Exploring Santa Elena Canyon, Part 13: Natigenic Rock Abrasion | Big Bend National Park, Texas, USA
Here we have one of Santa Elena's most profound geologic mysteries—one that cries out for 923-page PhD thesis that will win some aspiring scholar the right to do his or her post-doc at the local Burger King. Don't look at me. I'm too old and having too much fun to waste my time on that.
However, I am willing to share the following field data and hypotheses with any grad student who desperately needs some arcane and meaningless research topic to latch onto.
So here are the facts. Having been detached from one of the canyon walls, this slump block of Cretaceous limestone has come to rest in the bed of the Rio Grande. Seven decades of keen-eyed observational experience tells me that the Earth's gravitational field must have played a key role in this. No thesis material there.
Fortunately, I've also determined that this rock has acquired an strikingly glossy upper surface with a reflectivity quotient close to that of polished marble (see photo above). When I first saw this in person, I experienced a sort of intellectual breakthrough or epiphany. In a flash of unbridled inspiration I correlated this enigmatic feature, so uncharacteristic of the local carbonate rock, with other episodes of my unfunded field work. These were my 1973 and 1976 geophotographic expeditions to study the similarly shiny bedrock surface of the Crest Limestone, also Cretaceous, exposed on the Acropolis of Athens, Greece.
As specialists in the stratigraphy of the Attic-Cycladic Massif have noted, the Crest Limestone on the Acropolis got its shine (not to mention its treacherous slipperiness after a rain) from the wear of untold thousands of feet. Many of these were attached to human visitors who've walked on that natural stone flooring to get a closer look at the Parthenon.
I call this form of erosional activity pedigenic abrasion. Note my fabrication of a new and utterly unnecessary Latin-root term that substitutes for such perfectly good vernacular equivalents as foot polishing and foot wear by footwear. This makes me feel learned, academic, entitled, and priestly.
While there are no masterpieces of ancient Greek architecture in Santa Elena Canyon, nature has produced something else that is just as magnificent, and a lot of turistas come here, too. In fact, I've observed many of then perching on this rock to enjoy the incomparable view.
But the problem is that in this location the human beings do not so much walk on this rock as sit on it. This makes me think we're witnessing a somewhat different process at work: natigenic rather than pedigenic abrasion (natis, Latin = buttocks, English).
The good news is that both of these processes share a common origin, and in fact constitute subcategories of the umbrella concept of touristogenic abrasion.
Well, it's great that we've been able to create some more scientific terminology.
I tell you what: to take a gander at the other photos and descriptions in this series, y'all mosey on down to my my Exploring Santa Elena Canyon album.
And if you'd like to see what the devil I'm talking about with regard to the Acropolis and the Crest Limestone, visit this other Flickr post of mine.
Exploring Santa Elena Canyon, Part 13: Natigenic Rock Abrasion | Big Bend National Park, Texas, USA
Here we have one of Santa Elena's most profound geologic mysteries—one that cries out for 923-page PhD thesis that will win some aspiring scholar the right to do his or her post-doc at the local Burger King. Don't look at me. I'm too old and having too much fun to waste my time on that.
However, I am willing to share the following field data and hypotheses with any grad student who desperately needs some arcane and meaningless research topic to latch onto.
So here are the facts. Having been detached from one of the canyon walls, this slump block of Cretaceous limestone has come to rest in the bed of the Rio Grande. Seven decades of keen-eyed observational experience tells me that the Earth's gravitational field must have played a key role in this. No thesis material there.
Fortunately, I've also determined that this rock has acquired an strikingly glossy upper surface with a reflectivity quotient close to that of polished marble (see photo above). When I first saw this in person, I experienced a sort of intellectual breakthrough or epiphany. In a flash of unbridled inspiration I correlated this enigmatic feature, so uncharacteristic of the local carbonate rock, with other episodes of my unfunded field work. These were my 1973 and 1976 geophotographic expeditions to study the similarly shiny bedrock surface of the Crest Limestone, also Cretaceous, exposed on the Acropolis of Athens, Greece.
As specialists in the stratigraphy of the Attic-Cycladic Massif have noted, the Crest Limestone on the Acropolis got its shine (not to mention its treacherous slipperiness after a rain) from the wear of untold thousands of feet. Many of these were attached to human visitors who've walked on that natural stone flooring to get a closer look at the Parthenon.
I call this form of erosional activity pedigenic abrasion. Note my fabrication of a new and utterly unnecessary Latin-root term that substitutes for such perfectly good vernacular equivalents as foot polishing and foot wear by footwear. This makes me feel learned, academic, entitled, and priestly.
While there are no masterpieces of ancient Greek architecture in Santa Elena Canyon, nature has produced something else that is just as magnificent, and a lot of turistas come here, too. In fact, I've observed many of then perching on this rock to enjoy the incomparable view.
But the problem is that in this location the human beings do not so much walk on this rock as sit on it. This makes me think we're witnessing a somewhat different process at work: natigenic rather than pedigenic abrasion (natis, Latin = buttocks, English).
The good news is that both of these processes share a common origin, and in fact constitute subcategories of the umbrella concept of touristogenic abrasion.
Well, it's great that we've been able to create some more scientific terminology.
I tell you what: to take a gander at the other photos and descriptions in this series, y'all mosey on down to my my Exploring Santa Elena Canyon album.
And if you'd like to see what the devil I'm talking about with regard to the Acropolis and the Crest Limestone, visit this other Flickr post of mine.