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earthstory reblogged
Last summer in Etretat. The weather was like I always imagined it in the Normandie to be. windy and dusty.
Timing a sunset
This post may entirely be an excuse to post a Monet painting on this page. This is a photo of the painting “Étretat: Sunset” produced by Claude Monet during a 3 week visit to Normandy in 1883.
Texas State University astrophysicist Donald Olson and his research team visited this location on the coast of France and took a series of measurements of the path of the sun relative to other observable points. By projecting the sun’s path back in time, they estimated that Monet painted this work between Feb. 3 and Feb. 7, 1883. Then, by adding tidal chart data, they estimated that the time reflected in this painting is Feb. 5, 1883 at 4:53 p.m. local time, to within one minute.
Of course, that estimate assumes that a human painter is perfectly accurate in where he placed the sun and the tides to within a high precision. Whether or not that is the case, I personally find a story like this extracted from a work of art to be quite masterful as well.
-JBB
Image credit: wikipaintings (public domain) http://www.wikipaintings.org/en/claude-monet/the-manneport-cliff-at-etretat-sunset#close
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Drone views along the sea cliffs and arches, Étretat, Normandy, France. The rocks are bedded cherts and limestones.
The cliffs of Étretat
The white cliffs of Dover are mirrored by these similar looking cliffs in upper Normandy, France. Along this 130 kilometer stretch of the so called Alabaster coast lies the small town of Étretat. Claude Monet and other Impressionists of the nineteenth century were attracted by the picturesque setting of the small village and famously painted the spectacular coastline.
Étretat is known for its three natural arches and white cliffs that tower high over the Atlantic Ocean. The Alabaster coast is actually made out of chalk and flint and not alabaster. It received its deceiving name due to the beautiful white color of the cliffs.
The Alabaster coast and the Cliffs of Dover have a similar geological history. The sedimentary remains of various marine microorganisms became accumulated over time and created these spectacular coastlines. In between the chalk are bands of flint which were derived from siliceous organisms.
The soft chalk is highly sensitive to erosion and under the effect of swell, frost, water seepage, wind and waves the cliffs are eroded about twenty centimeters a year. The chalk is rapidly dissolved in the sea whereas the flint forms the pebbles along the shore. The pebbles act as a natural barrier protecting the bottom of the cliffs against the waves. Furthermore, they are a valuable industrial resource which can be used in many ways.
Xandi
Image Credits: http://bit.ly/1MGSllu http://bit.ly/236hwCc Sources: http://bit.ly/1X2SccB http://bit.ly/1RC3eSL http://www.estrancitedelamer.fr/anglais/AFALAISE.htm
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Of millstones and fossils Geology is often of great service to archaeology. The most obvious one is reconstructing the palaeo-environment of a dig site, which takes a large team of specialists in such matters as pollen, ecology or soils. Geophysics also comes to the rescue, used to map old roads and house foundations or discover ancient buried Saharan rivers using radar. Geochemistry helps reconstruct trade routes and exchange networks using gemstones, precious metals or obsidian. Advanced analysis of teeth allows us to find out where people grew up and trace their migrations. Now fossils have come to the rescue, helping to prove that 19th century millstones used in Ohio grain mills actually came from France, as their name (French millstones) suggested. They proved the origin of the chert (known as buhr) in the Tertiary formations of the Paris Basin, those layers that rest over the famous Cretaceous chalk that forms the white cliffs of Normandy (and Dover). These rocks were instrumental in reconstructing the evolutionary developments between the fossils in the secondary rocks (up to the end Cretaceous meteorite impact and mass extinction) below and the life forms currently existing. They also proved that the sea had transgressed repeatedly onto the land, by their alternations of marine and freshwater fish, and event thought impossible at the time. Similar rocks exist in Ohio, and it was uncertain whether the name was just a moniker or reflected their actual origin. Both algae and snails proved the French origin, and the Ohio cherts turned out to be much older, dating from the late Paleozoic of 300 million years ago (compared to the less than 65 million years for the French chert). The Ohio rocks are also of marine origin, while the French ones are freshwater sediments. These stones were widely exported as ballast in ships, and manufactured in cities such as Cleveland and Cincinnati. They were preferred over the local chert because they produced fine white flour more easily. To confuse matters further, some of the millstones were made of local stone, and resemble the French product at a macro level. Past posts on geology and our human past: The king of Stonehenge's teeth:http://tinyurl.com/pnsv2en Tracing ancient gold: http://tinyurl.com/c9nba7f Geochemistry and obsidian trade routes:http://tinyurl.com/kbda4wo Did Neanderthal paint in Spanish caves:http://tinyurl.com/lycavqd Loz Image credit: SEPM http://phys.org/news/2014-06-scientist-fossils-historic-ohio-millstones.html