Friday Headlines, September 12, 2014
THE LATEST IN THE GEOSCIENCES
Parts of I-15 in Nevada destroyed by flooding!
The oldest mammal?
Exfoliation (in the geologic sense) caught on camera!
I-15 partially open from St. George to Logandale, through to Las Vegas still impassable
One can get through their whole lives thinking that it never really rains in the desert. But then, one wonders, why are there massive deep gorges in arid places? Why are there all those dry drainages? Surely there must be water there sometimes.
The thing about the desert is that when it rains, it RAINS!
Interstate 15 runs through Las Vegas, Nevada northward through the beautiful Virgin River Gorge and on to St. George, Utah. This is a stretch of road I have been on numerous times, all the way back into my childhood. The area is barren. Desolate. Empty. Like a proper desert should be.
Then, it rained. It rained so hard that all the usually dry drainages filled to capacity and overflowed. Waterfalls formed over every steep slope in the Virgin River Gorge. And sheets of water washed away part of Interstate 15 just north of Las Vegas.
Water is a powerful force on the Earth. Even in deserts, its influence is easily seen.
Here are some videos showcasing the power of water in the desert.
Waterfalls in the Virgin River Gorge:
Floodwaters on I-15 sweeping away a van:
Chisel-Toothed Beasts Push Back Origin of Mammals
Geologic time is frequently divided into the “Age of Fishes” (the Paleozoic), the “Age of Dinosaurs” (the Mesozoic), and the “Age of Mammals” (the Cenozoic). This leads to an erroneous image that mammals appeared after dinosaurs went extinct.
Well, ask any paleontologist and they’ll tell you that it’s definitely not true. In fact, dinosaurs and mammals appeared at about the same time, sometime in the late Triassic Period.
This new research shows that a group of fossil animals thought to be closely related to mammals are, in fact, fully mammalian. The oldest member of this group is older (but just barely) than any other fossil mammal previously recognized, meaning that mammals are just a little older than we thought.
This, of course, will be contested and argued and discussed in the scientific community, but it’s interesting, nevertheless.
And mammals are still about the same age as dinosaurs.
A big chunk of the Sierra Nevada caught fracturing on video
Exfoliation is the process by which the outer layers of a rock peel away. When rocks are buried, pressure keeps them together. As they’re exposed, the outer layers essentially pop off due to the lack of pressure.
Exfoliation is something commonly seen. For example:
“GeologicalExfoliationOfGraniteRock” by Wing-Chi Poon – Own work. Licensed under CC BY-SA 2.5 via Wikimedia Commons.
Here’s exfoliation at Half Dome in Yosemite National Park:
“Half dome yosemite nationalpark” by HylgeriaK – Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons.
One might think that the process of exfoliation is slow and invisible. However, it seems that it happens pretty rapidly, as it was caught in this video: