But for this blog posting, I decided to check on new photos from NASA's earth observatory webpage at http://earthobservatory.nasa.gov/.
The above photograph from an astronaut on the International Space Station features the former U.S. Borax mine, located to the northwest of Boron, California. Now owned by the Rio Tinto Group, it is the largest open-pit mine in California and is among the largest borate mines in the world.
Borates are chemical compounds that include the element boron (B) and are important as providers of an essential plant micronutrient, for metallurgical applications, and as components of specialized types of glass, anticorrosive coatings, fire retardants, and detergents.
The geologic setting is a structural, nonmarine basin—a permanent shallow lake—fed by thermal springs rich in sodium and boron that existed approximately 16 million years ago. The first mining claim in the area was filed in 1913 following the discovery of boron-bearing nodules during well drilling. Much of the mine workings were underground until 1957, when U.S. Borax changed to open-pit mining.
The open pit spreads across approximately 54 square kilometers (21 square miles). Concentric benches along the pit wall are accentuated by shadows and mark successive levels of material extraction. Mine tailings are visible as stacked terraces along the northern boundary of the mine. Ore processing facilities occupy a relatively small percentage of the area, and are located directly to the west of the open pit.
The Rio Tinto mine is one of Earth’s richest borate deposits. Together with mines in Argentina, they produce almost 40 percent of the world’s supply of industrial borate minerals. Astronaut photograph ISS037-E-22990 was acquired on October 30, 2013 by the Expedition 37 crew.
THe above photo shows one of the most powerful typhoons on record slammed into the Philippines on November 7–8, 2013. Wind and flood damage to the region was expected to be extensive, but impassable roads and hampered communications systems made it difficult to assess the full impact to life and property.
Super Typhoon Haiyan (locally named Yolanda) made its first landfall at 4:40 a.m. local time on November 7th. Preliminary reports suggested the storm roared ashore near Guinan (Samar Province), where ground stations recorded sustained winds of 235 kilometers (145 miles) per hour and gusts to 275 kilometers (170 miles) per hour. According to remote sensing data from the Joint Typhoon Warning Center, sustained winds approached 315 kph (195 mph) just three hours before landfall, with gusts to 380 kph (235 mph).
The two images were taken just four days apart displaying the difference in fall colors. Within just a few days the trees surrounding Lake Superior and Lake Michigan have gone from a deep green to a vibrant orange as autumn steals across the region.
The two photos above show islands in northern Lake Michigan. Over thousands of years, retreating glaciers scoured and carved out much of the basin that now holds Lake Michigan. But in some parts of the lake, patches of erosion-resistant rock still protrude above the water. A cluster of small islands in the far northern reaches of the lake—the Beaver Island archipelago—are composed of limestone bedrock covered with a layer of sand and gravel (glacial “till”).
Except for Beaver Island, the largest of the group, the islands are unpopulated. About 700 people live on Beaver Island, mainly in a small town on the northern part of the island. A Native American community survived on Garden Island until as recently as the 1900s, but the size of the community dwindled until the last remaining resident died in the 1940s.
The bottom image of Garden and Hog islands was captured on May 24, 2013. The upper image, a broader view, shows Beaver Island and the other islands in the context of the great lake. Dense forests, swamps, and sandy beaches dominate the landscape. Offshore, deeper waters appear dark blue, while shallow areas are turquoise.
The shallows around Garden and Hog islands contain numerous parallel rock ridges interspersed by deeper channels. These reef areas offer ideal spawning ground for various species of fish, notably lake trout and perch. Federal and state resource managers have attempted to replenish depleted lake trout populations by stocking northern Lake Michigan waters.
The Mackinac Bridge spans a stretch of water five miles wide between Michigan’s lower and upper peninsulas. The strait connects Lakes Michigan (left) and Huron (right). The bridge is a combination of pier-supported spans with a high, central suspension sector that allows passage of lake steamers. The suspension sector is the longest in the Americas (8, 614 feet or 1.6 miles). Prior to construction of the bridge, the only passage across the straits was by ferryboat.
This pair of images shows the Mackinac Straits while they were still frozen (top) and as they began to thaw (below). The March 22 view shows shipping lanes opened by ice breakers. A narrow passage connects the cleared shipping channel to the small town of St. Ignace at the north end of the bridge (Mackinaw City appears at the south end). The April view shows the ice broken into a series of irregular rafts that appear gray against bright water. The whitish appearance of the water is not snow or ice, but instead is sunlight glinting off the water back to camera. The shipping channel is maintained even through remnants of the ice mass, but the ice ridges can be hazardous to shipping until the last of the ice breaks up.