Mary Anning
Courtesy Public domain via WikipediaToday marks the 163rd anniversary of the death of Mary Anning, early British fossilist who discovered the first complete remains of the marine reptiles ichthysaurus and plesiosaurus. Mary sold fossils she collected around Lyme Regis, England, to support her severely impoverished family after her father had died. She had no formal education, other than what her parents had taught her about collecting, but her fossils and knowledge of them were sought out by many of the top geologists of her time. Local folks viewed her activities with suspicion and apprehension since the biblical view of creation was still widely held, and the very idea that the fossils she collected were of creatures that went extinct was disturbing to many. Anning was made an honorary member of the Geological Society of England just prior to her death in 1847. Her portrait and some of the fossils she found are displayed in the British Museum in London.
SOURCES
Mary Anning bio
Wikipedia article
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8.8 magnitude earthquake in Chile
Courtesy Wikimedia CommonsA massive earthquake occurred early this morning (1:34 EST) off the west coast of Chile some 70 miles NNE of the city of Concepcion. The powerful 8.8 magnitude tremor released about 500 times the energy generated by the recent 7.0 earthquake in Haiti. At least 78 people are reported killed, a number which will no doubt rise as information trickles in. Tsunami warnings have been raised across the entire Pacific Basin, including in Hawaii, Australia, and Japan.
Earthquakes are frequent in this area of Chile because it sets on a subduction zone where the Nazca Plate is pushing beneath the South American Plate. The region is also the location of the most powerful earthquake ever recorded on Earth, a 9.5 tremor that struck in 1960.
USGS earthquake center
Richter magnitude scale
More on the May 22, 1960 Earthquake
Plate tectonics
Mount St. Helens
Courtesy jeffwilcoxRescue attempts have been postponed until Tuesday for a hiker who fell into the crater of Mount St. Helens in Washington state. The 50 year-old man was standing near the crater's edge when the cornice he was standing on collapsed, causing him to fall some 500 feet into the crater. Here's the story on CNN.com.
Was a bolide the cause for plate tectonics?
Courtesy Navicore via Wikipedia Creative CommonsRecently, geologist Vicki Hansen, a professor of earth and planetary sciences at the University of Minnesota-Duluth, proposed a hypothesis that plate tectonics were triggered by ancient bolides crashing into Earth.
Plate tectonics arose from Alfred Wegener’s observations that some continents appear to fit together like puzzle pieces and at one time probably made up a single land-mass he named Pangaea that broke up and drifted apart. It was a theory dismissed by most geologists at the time, and Wegener himself was unsure how the process took place (he proposed magnetism or centrifugal force). It wasn’t until the 1960s, more than 30 years after Wegener’s death, that the theory gained wide acceptance. Today, scientists point to convective heat in the Earth’s mantle as the driving force that causes continental drift and sea-floor spreading. As new material is being added along mid-oceanic ridges, older crust is being pushed into other plates in a process called subduction, where one crust sinks beneath another and is remelted back into the mantle. It’s along these boundary zones where the plates collide that most of the world’s earthquakes and volcanoes occur, and where mountain ranges rise up. But what started the process? Why would Pangaea suddenly break up into pieces and begin drifting apart?
Hansen theorized that early in Earth’s history - perhaps as much as 2.5 billion years ago - impacts from large extra-terrestrial objects could have been the catalyst for two prime elements of plate tectonics: the spreading out of new crust, and particularly subduction. Since numerous impact craters can be found on Mars and on the Moon, it’s a good bet that Earth suffered a similar steady barrage of meteor impacts in its formative years. According to Hansen, the Earth’s crust at the time was more uniform in thickness, except in certain zones where mantle heat rising up from below would have caused it to thin.
A meteor or asteroid (one large enough to create a 600 mile-in-diameter crater) slamming into one of those weakened zones could have caused magma to erupt to the surface as flood basalts that would spread out and eventually push against the sides of the crater where they would begin subducting back down into the mantle. Such impacts could have happened several times around the world, enough to put the process of plate tectonics into motion.
Professor Hansen’s theory was first published in Geology magazine, but the study has reached the popular press. I came across it in the most recent issue of Science Illustrated, an interesting and jammed-packed-with-science publication new to me that I found at Barnes & Noble.
Professor Vicki Hansen webpage
UMD Planetary Processes Lab
More about plate tectonics
This nifty video from SEEDMAGAZINE.com shows the scale of significant evolutionary events in Earth's 4.6 billion year history by condensing everything into a single minute.
A strong 7.0 magnitude earthquake hit the island nation of Haiti today at 21:53 UTC. Several buildings have been reported damaged, and a tsunami alert for the Caribbean region has been issued. The initial death toll is reported in the dozens, but that number is expected to rise as rescue workers dig through the rubble. Here's a report from the Associated Press:
Check out this cool hi-def video of the West Mata submarine volcano erupting more than half a mile beneath the Pacific Ocean. The volcano's base is almost 2 miles below the surface and is about 5.5 miles in length and nearly 4 miles wide.
New evidence arises in the flooding of the Mediterranean basin
The Mediterranean Sea at dawn
Courtesy g.naharro via FlickrDuring the late Miocene epoch, waters in the Mediterranean basin evaporated and disappeared several times in what’s termed the Messinian salinity crisis. But at the beginning of the Pliocene epoch, the basin refilled again during an event called the Zanclean Flood. Using drill-hole data and computer modeling, scientists in Europe now have a better understanding of how that event took place, and how it may have only taken a couple of years to refill the entire basin. The research appears in the current issue of the journal Nature.
SOURCE
BBC report
Hard to watch: Will science education take another hit?
Courtesy Annie in BeziersIn an effort to cut costs the powers that be at Michigan State University are considering shutting down the Department of Geological Sciences. The vote to close the department could come as soon as December 1st. This is not good. Read about it here. Dinochick Blogs has posted a reaction to it from paleontologist Chris Noto. Also, you can sign an online petition against it.
Sir Charles Lyell
Courtesy Public domain via Wikipedia CommonsThe foremost geologist of his day, Charles Lyell was born in Scotland on November 14, 1797. He was a proponent of uniformitarianism, and a great influence (and later friend) to Charles Darwin. His most famous book was Principles of Geology, first published in three volumes between 1830-33.
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