Friday Headlines, January 31, 2014
THE LATEST IN THE GEOSCIENCES
Hey! One-twelfth of 2014 is over. Already. Wow.
Plate tectonics is billions and billions and billions of years old
Faults in the midwestern United States are still active.
One fundamental question in geology is when did plate tectonics start on Earth. That is, when did the creation and recirculation of crust begin?
How do you even answer such a question?
Subduction is the process of drawing of the Earth’s crust back down into its interior, while new crust is being formed elsewhere. This recycling of crust is typically associated with volcanoes – and not just any old volcanoes, but special ones, recognized by the type and chemical composition of the lava that comes out. The authors of this new paper show that time at which a subduction zone formed can be identified by the chemical signature of the lava rock left behind.
Armed with this new information, the authors were able to show that subduction was occurring in what is now the province of Quebec, Canada either 4.4 and 3.8 billion years ago, depending upon the age of the rock (which is another topic altogether).
That was a long time ago.
What’s more, the deep sea environments that held the volcanoes found in subduction zones were also good environments for early life on Earth to proliferate. Thus, it’s possible that a subduction zone in what is now North America may have been and important place in the early evolution of life on this planet.
Earthquakes in the Midwestern United States are difficult to explain. There’s no tectonic plate boundaries nearby to provide an easy explanation. No volcanoes. No big mountains, even.
Yet, some of the biggest earthquakes in recorded history that have occurred in North America occurred in the Midwest. Most notably, there was the New Madrid quake (more properly, quakes) that happened in 1811 through 1812.
Small earthquakes continue in this part of the continent. Some claim these are continuing aftershocks from the New Madrid earthquakes 200 years ago. Some claim that many of the quakes are man-made.
This new report suggests that the continued seismicity in the center of the continent is due to continued activity along faults in the mid-continent. Thus the seismic risk remains high.
In the category of ‘Evolution is cool,’ I give you the “Devil Frog” Beelzebufo ampinga.
Yes, Beelzebufo is it’s scientific name, and, yes, it basically means ‘devil frog.’ Don’t ever think that scientists don’t have a sense of humor.
But it gets better. Beelzebufo lived during the Cretaceous Period, at the same time as some of the best-know dinosaurs like Tyrannosaurus rex. It lived in what is now Africa. T. rex was in North America, so it wasn’t concerned about Beelzebufo. Actually, I don’t know if they were alive at the exact same time, but nevertheless, it was a long, long time ago.
Beelzebufo was a carnivore with lots of sharp teeth that likely hunted like the modern bullfrog does – hiding then ambushing its prey.
What’s particularly cool about Beelzebufo is its armor. That’s right. Armor. It had large flanges on its skull and thickened bony plates in its skin, presumably to serve as protection. What is unclear is what it was protecting itself from.
This research was published in the open access journal PLOSone. You can read the technical paper here.