Geological Society of America Meets in Denver: Paleocene-Eocene Thermal Warming and Comparisons to Today's Global Warming

      An era of skyrocketing global temperatures started with an impact bang according to research presented September 27, 2016, here in Denver at the Geological Society of America's Annual Meeting.

         Impact debris and evidence of widespread wildfires in eastern North America suggest that a large space rock hit earth around 56 million years ago at the beginning of the Paleocene-Eocene Thermal Maximum, also known as the PETM, a period of rapid warming and huge increases in carbon dioxide.

     The event is one of the closest historic analogs to modern global warming and is used to improve predictions of how earth’s climate and ecosystems will fare in the coming decades.

     Too little is known about the newfound impact to guess its origin, size or effect on the global climate, said Dr. Morgan Schaller of Rensselaer Polytechnic Institute. But it fits in with the long-standing and controversial proposal that a comet impact caused the PETM. “The timing is nothing short of remarkable,” said Schaller at the GSA meeting.

     The impact may have contributed to the rapid rise in CO2 by stirring carbon up into the atmosphere, but it was hardly the sole cause, said Sandra Kirtland Turner, a geochemist at the University of California, Riverside. Her own environmental simulations suggest that the influx of carbon that flooded Earth during the PETM probably took place over at least 2500 years, far too drawn out to be caused by a single event, she said at the same meeting.

     During the PETM, a massive influx of carbon flooded the atmosphere and earth warmed by 5 to 8 degrees Celsius to temperatures much hotter than today. That carbon dump altered the relative abundance of different carbon isotopes in the atmosphere and oceans, leaving a signal in the sedimentary record.

     While searching for that signal in roughly 56-million-year-old sediments from sites up and down the U.S. east coast, Schaller spotted microscopic glassy spheres about the size of a dust mite as seen in SEM:

      These specks resemble those blasted from previously identified large impact events.

     After switching from a black to a white sorting tray to more easily see the black debris, researchers discovered abundant charcoal pieces in the mix, as seen below in a Scanning Electron Microscope (SEM) image. That charcoal likely formed when wildfires sparked by the impact raged across the landscape.

     More evidence of the impact will help researchers to better constrain its location, scope and possible relationship to the start of the PETM, Dr. Schaller said.

Have you ever made a simple change a la "black tray to white tray switch" to discover something new?
Steph

WE ARE CELEBRATING THREE YEARS OF PARTIAL ELLIPSIS OF THE SUN. . .

One-Syllable State of Maine Rocks: Underappreciated Silurian Age Stones

     
      Take a close look at these exquisite Silurian rocks from the state of Maine, USA. (How did I just realize Maine is our only monosyllabic state?) The Silurian, an underappreciated time period, without the cachet of say, the younger Jurassic, is part of the Paleozoic era between the Ordovician and Devonian. Silurian rocks are 443 million years to 416 million years old.

      A significant evolutionary milestone during the Silurian was the diversification of jawed and bony fishes. 

   
       Life also began to appear on land during the Silurian in the form of moss-like, vascular land plants that grew beside bodies of water. Small terrestrial arthropods also began to appear.

       These Maine rocks of the Kittery Formation are old. They show the results of millions of years of deposition, igneous activity, faulting, tectonics, and metamorphism. 

      However, in researching this week's topic, I discovered the "Silurians," a fictional race of reptile-like humanoids in the long-running British science fiction tv series Doctor Who? Those first Silurians are depicted as prehistoric and scientifically advanced sentient humanoids who predate the evolution of man.

      The creatures were called Silurians, after their supposed origins in the Silurian period. However, author John Pertwee claims that "properly speaking", the Silurians should have been called the "Eocenes" (part of the much more recent Cenozoic era.)

     Perhaps Dr. Who needed a geologic consultant to the tv show. E. O. Seen and heard? Background music by Diana Ross and the Eocenes?!

Just call me,
Silurian Steph

Bonus question: without googling or duck duck going, name all current countries of only one syllable.