Wednesday, December 17, 2014

Transition Weather

This has been a weird weather season.  In November it looked more like January weather.  In December it has looked more like April weather.  Yesterday we had rain overnight and all day, until around 4:30 when the temperatures dropped enough to allow a changeover to snow.  The rain melted enough of the snow that I was able to drive to Sable Lake.  There was a bit of ice on the road, but it was navigable.

It is hard to tell what caused the cracks in the ice, shown in the photo below.  I cannot believe that the ice was thick enough for snowmobiles since it just recently started to freeze over.  Also, the left "path" below heads right over to Sable River, which is the outlet from the lake.  The ice certainly would have been a lot thinner over in that corner of the lake.  Since the beaver damn is located in that corner, I am guessing that the paths may have been formed by beavers.

Over night we received around 3-4 inches of snow.  At least the ground is completely white again.

Monday, December 15, 2014

Agate USB Microscope Camera Photos

I must admit that the sloppy weather has not inspired me to get out and exercise.  I just don't like slushy snow.  So for today's blog posting I am going to share some close up photos taken with my USB microscope camera.

Brazilian agates....

Lake Superior agate...

Sunday, December 14, 2014

New Evidence of a Comet that Hit the Earth 12,800 years ago and Changed History

Scientists and geologists have been studying our planet for hundreds of years.  We may think we understand the significant events that have impacted our world -- especially those that have happened since the last ice age.  But we are still discovering.....

New evidence seems to indicate that a giant comet or asteroid hit North America around 12,800 years ago.  The graphic below shows the debris field left over from the impact.  Geologists are calling this impact leftover path -- the Younger Dryas Boundary Field.  Material scattered by this impact has been found in North America, Central America, parts of South America , Greenland, and most of Europe.  Amazingly, some of these "fragments," are more than a mile in diameter!

Scientists believe that the impact occurred at the end of the last Ice Age.  It appears that the Northern Hemisphere had begun a warming phase, but impact debris blasted into the atmosphere blocking sunlight, which prolonged the deep freeze until approximately 11,500 years ago.  This 1,300 year period of extreme cold is referred to as the Younger Dryas, named after a mountainous tundra wildflower, Dryas octopetala.

So how have scientists determined that there must have been a large impact?   This task was not easy since at the time of the impact much of North America was covered with up to a mile of ice.  Also, so far an impact crater has not been found.  Scientists are not sure if the glacial ice cushioned the impact, or perhaps the space rock disintegrated in the atmosphere before it actually impacted our planet.  But there is evidence.  Not only have the rock fragments been determined to be from the same source, but areas have been found with melted rock, including the Lake Cuitzeo in central Mexico.  

There is also evidence of cataclysmic flooding.   During this period, approximately 35 species went extinct including the mammoth and the saber-toothed tiger.  Also, human tribes disappeared including the Clovis culture in the American Southwest.  

One more clue that this galactic impact occurred is the evidence of high-temperature metamorphosed materials and the creation of nanodiamonds, both of which are created only under extreme and sudden heat and pressure.  These miniature diamonds have been found in the same geologic sediments from six sites across North America—Murray Springs, Arizona; Bull Creek, Oklahoma; Gainey, Michigan; Topper, South Carolina; Lake Hind, Manitoba; and Chobot, Alberta. 

Graphic from above cite originated with:  Kinzie, Firestone, Kennett et al. "Nanodiamond-Rich Layer across Three Continents Consistent with Major Cosmic Impact at 12,800 Cal BP", The Journal of Geology, 2014, volume 122, p. 475–506.
Jörg Hempel,
Julio Marquez,
Yinan Chen,
Heinrich Harder, 

Saturday, December 13, 2014

More NASA photos of Earth

For today's blog posting I checked in with the website

About 4.5 million years ago, the Kashmir Valley was at the bottom of a large lake, encircled by a ring of rugged mountains. Much of the lake’s water has long since drained away through an outlet channel on the valley’s west side. However, evidence of the lake remains in the bowl-like shape and the clay and sand deposits on the valley floor. The mountains surrounding Kashmir Valley now trap air a bit like they once trapped water. The high ridges can set up airflow patterns that concentrate smoke and other airborne pollutants near the valley floor, causing outbreaks of haze.

The ongoing eruption at Zhupanovsky volcano has left its mark on the mountain’s slopes. Ash—in the air and on the snow—is visible in these images.  Zhupanovksy, located on Russia’s Kamchatka Peninsula, began erupting on June 6, 2014. November 2014 began with a strong explosive event at the volcano, which tapered into a series of moderate explosive events toward the end of the month. According to the Global Volcanism Program, the explosions at Zhupanovksy are phreatic, caused by the nearly instantaneous vaporization of water by hot material below the surface.

Volcanic activity along the western edge of the Pacific “Ring of Fire” gave rise to a tiny island in late November 2013. Since then, the new island has fused with nearby Nishinoshima and continued to grow. When it was last measured by the Japanese coast guard, the island covered 1.89 square kilometers (0.73 square miles). Its highest point was 100 meters (328 feet) above sea level.
Volcanologists find no signs that the eruption is abating and expect the island to grow two or three times its current size, according to news reports.

On November 5, 2014, spiral-shaped Super Typhoon Nuri lost its eye and began to morph into a comma-shaped extratropical cyclone as it approached the cool waters of the Bering Sea. After undergoing a rapid strengthening process meteorologists call “bombogenesis,” what emerged was one of the most intense extratropical cyclones ever recorded in the North Pacific, a storm with a minimum central pressure that plunged to 924 millibars. (For comparison, the all-time record low for an extratropical cyclone is 913 millibars.)

Two weeks later, the downstream effects of the Bering Sea Superstorm lingered on—in the form of a massive lake effect snowstorm that dropped several feet of snow in communities just east of Lake Erie. While the Bering Sea Superstorm did not directly cause the snow event in New York, it did set the stage for it by nudging the jet stream into an unusual shape that sent a pulse of cool Arctic air south over the central United States.

As that dry, cool air rushed over the Great Lakes, it picked up moisture from the comparatively warm waters of the lakes, creating long cloud lines known as cloud streets. NASA satellites captured this view of clouds streets moving southeast across Lake Superior and east across the other lakes on November 18, 2014.

When clouds reached the edges of the lakes and crossed back over land, they cooled down even more. (Air is generally cooler over land than water, and also the clouds get pushed upward by the land surface.) Lower temperatures and increased altitude make it harder for clouds to retain moisture, so instead they drop it as snow. In this case, the west-southwesterly winds lined up perfectly with the long axis of Lake Erie, so the air was able to pick up an extraordinary amount of moisture. According to the National Weather Service, more than 60 inches (152 centimeters) of snow had fallen by November 18 and more was forecasted to fall.

Captured at the same moment as the natural-color image (top), the false-color image (bottom) was made by assigning blue light to show up as red, and two shortwave infrared bands to show up as green and blue. This band combination is useful for distinguishing between snow on the ground (dark pink), ice clouds (light pink), and water clouds (white). Bare ground is green.

NASA image by Jeff Schmaltz, LANCE/EOSDIS Rapid Response. Caption by Adam Voiland, with information from Hiren Jethva and Ritesh Gautam. 
NASA Earth Observatory image by Jesse Allen, using Landsat data from the U.S. Geological Survey. Caption by Kathryn Hansen.
NASA Earth Observatory image by Jesse Allen, using Landsat data from the U.S. Geological Survey. Caption by Adam Voiland.
NASA Earth Observatory image by Jesse Allen and Adam Voiland, using VIIRS data from the Suomi National Polar-orbiting Partnership. Suomi NPP is the result of a partnership between NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. Caption by Adam Voiland.

Thursday, December 11, 2014

Sunny Winter Dunes Snowshoe

Yesterday the beautiful sunshine convinced my exercise partner, Lois Fite, and I to snowshoe up in the Grand Sable Dunes in the Pictured Rocks National Lakeshore.  The temperature was in the 20s, but there was no wind.   The pictures do not give the beauty of the winter dunes any justice.

Sable Lake is nearly frozen.  There are just a few open water spots showing....

I just love the contrast in color between the dune grass and the white snow.

There are only a few places in the dunes where the sand is showing through.

Looking north toward Lake Superior....

Wednesday, December 10, 2014

Incredible Icicles on Lake Superior Shoreline

After finishing up my last show of the year in Marquette last weekend, I stayed over Sunday night so that my friend, Helen, and I could go on an adventure on Monday.  We headed north of town toward Big Bay and snowshoed the Little Presque Isle Trail.

The icicles on the shoreline were fantastic.

The photo below shows Sugarloaf Mountain.

Here are a few photos that I took at the TV6 art show in the Superior Dome.