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These carbonate rocks are mined throughout the Great Lakes region using large open-pit mines. The largest carbonate mine in the world, Calcite Quarry, appears in this astronaut photograph. The mine has been active for over 85 years. The worked area (grey region in image center) measures approximately 7 kilometers long by 4 kilometers wide, and it is crossed by several access roads (white). The rocks are processed to create crushed aggregate, building stone, soil enhancers, lime, additives to steel, and a host of other products. Calcite Quarry ships between 7 and 10.5 million tons of material each year, thanks to the quarry’s location on the shores of Lake Huron. Nearby Rogers City was once a typical mining company town, but over time it has expanded its economic base as a summer retreat for sailing and tourism.
ISS013-E-62714
Much of Etna’s surface consists of generations of dark, basaltic lava flows that extended outwards from the summit craters. Fertile soils developed on older flows are marked by green vegetation. Although Etna’s current explosive eruptions tend to occur at the summit, lava flows generally erupt through fissures lower down on the flanks of the volcano. Cinder cones, such as Monte Frumento, mark many of the lava flow vents on the volcano’s flanks. There is evidence of larger eruptive events as well. The Valle del Bove to the south-southeast of the summit is a caldera formed by the emptying of a subsurface magma chamber during a large eruptive event. Once the magma chamber emptied, the overlying roof material collapsed downwards.
ISS013-E-66488
This oblique image (looking at an angle) from the International Space Station (ISS) captures an ash cloud first observed on satellite imagery at 11:00 GMT on August 14, 2006. An ISS astronaut took this picture one hour and 45 minutes later. The ash cloud caused the Buenos Aires Volcanic Ash Advisory Center to issue an aviation hazard warning. Minor to moderately explosive eruptions of ash and pumice characterize modern activity at Ubinas. Pumice and ash blanket the volcanic cone and surrounding area, giving this image an overall gray appearance. Shadowing of the western flank of Ubinas throws several lava flows into sharp relief, and highlights the steep slopes at the flow fronts—common characteristics of thick, slow-moving lavas. The most recent major eruption of Ubinas occurred in 1969, although its historical record of activity extends back to the 16th century.
ISS013-E-67242
Snow highlights the peaks of the Banks Peninsula to the southeast of the city. The peninsula has a radically different landscape compared to the adjoining, flat Canterbury Plains, where Christchurch (gray patch to the north) is located. The Banks Peninsula is formed from the overlapping cones of the extinct Lyttelton and Akaroa volcanoes. Subsequent erosion of the cones formed the heavily dissected terrain visible in the image, and sea level rise led to the creation of several harbors around the Peninsula. Erosion continues unabated today, as evidenced by the apron of greenish blue, sediment-laden waters surrounding the Banks Peninsula.
Other interesting features in the image include the braided Waimakariri River to the north-northwest of the city, and the greenish brown waters of Lake Ellesmere at image left. The coloration of the water is due both to its shallow depth (1.4 meters on average) and its high concentrations of nitrogen and phosphorus, which fertilizes the growth of large amounts of green algae.
ISS013-E-65111
Numerous boat wakes of commercial and pleasure craft appear underneath and west of the bridge. The shadow of the bridge’s roadbed appears directly to the west of the bridge itself. Likewise, clouds overhead cast their shadows onto the water’s surface. Regions of greenish-brown water in San Francisco Bay mark water masses with differing amounts of suspended sediment that are streamlined by the strong tidal currents that flow through the strait.
ISS013-E-65526
In this image, the mega-dunes appear as big, rolling lumps that zigzag toward the upper right. The “streets” between these biggest dune chains have been swept clean of sand in places, showing their original surfaces of pale mud and salts. The pale beige-grey of these areas contrasts with the otherwise burnt orange hues. Mesoscale dunes, some of which form octopus-like crests, or star dunes, mark the backs of the mega-dunes. The smallest dunes appear in patches on the eastern sides of the mega-dunes as a tracery of closely spaced crests. Interestingly, the crest orientation of the small dunes differs from the orientation of the mesoscale dunes. This difference is a common effect of local shifts in wind direction, which is influenced by dune height.
The orientation trends in the mega-dunes coincide with two of the four major trends identified in the Great Eastern Sand Sea (or Grand Erg Oriental) immediately to the north. Each orientation shift likely implies a shift in the direction of the dominant wind that formed the dunes, attesting to the climate shifts that have occurred since sand began to accumulate in the central Sahara.
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ISS013-E-81687
The extent of the Day Fire smoke plume can be gauged from the gray urban region of greater Los Angeles (image right, center), which stretches along 80 kilometers (50 miles) of coastline. The plume obscures the northern Channel Islands, but the southern Channel Islands are silhouetted against the ocean, in the foreground. In the days before and after this photo was taken, shifting winds moved the smoke in different directions. On September 17, the plume was caught by westerly winds that steered the smoke back towards California—the leading edge of the gray smoke can be seen heading towards San Clemente Island.
ISS013-E-71468
The comparison image (see also ISS013-E-71473) shows a wide area of the sea around the cay, which encloses a lagoon. Within the lagoon, the water is calmer, and the submerged reef makes a bright blue outline on the downwind side of the islands. Surrounding the lagoon, silvery ocean swells from slightly different directions crisscross the surface. The swells are generally from the east, coming from the direction of the prevailing winds (generally right to left in this image).
This view reveals the small, low islands that fringe the upwind side of the lagoon. These islands seem dwarfed by wave swells, which almost appear to wash over them. Superimposed on the regular swell pattern are thin ribbons and zones of highly reflective surfactants, chemicals such as natural or synthetic oils that change the water’s surface tension. The surfactants trace additional water dynamics around the edges of the reef, following swirling eddies. The dark, rod-shaped object near upper right is likely a ship that navigated into the reef’s shoals. It appears to be trailing an oily substance, which makes an iridescent ribbon along the south side of the lagoon.
The very bright appearance of the Caribbean Sea in these images results from sunglint. Sunglint occurs when the Sun’s light bounces off the ocean’s surface and directly back into a satellite sensor’s field of view or a camera’s lens. While sunglint can create a washed-out appearance to the surface in some situations, it may also reveal details that aren’t visible in other lighting conditions. For example, in many space-based images, the ocean surface appears as a flat, nearly featureless blue expanse.
ISS013-E-71473
This image shows a wide area of the sea around the cay, which encloses a lagoon. Within the lagoon, the water is calmer, and the submerged reef makes a bright blue outline on the downwind side of the islands. Surrounding the lagoon, silvery ocean swells from slightly different directions crisscross the surface. The swells are generally from the east, coming from the direction of the prevailing winds (generally right to left in this image).
The detailed view (see also ISS013-E-71468) reveals the small, low islands that fringe the upwind side of the lagoon. These islands seem dwarfed by wave swells, which almost appear to wash over them. Superimposed on the regular swell pattern are thin ribbons and zones of highly reflective surfactants, chemicals such as natural or synthetic oils that change the water’s surface tension. The surfactants trace additional water dynamics around the edges of the reef, following swirling eddies. The dark, rod-shaped object near upper right is likely a ship that navigated into the reef’s shoals. It appears to be trailing an oily substance, which makes an iridescent ribbon along the south side of the lagoon.
The very bright appearance of the Caribbean Sea in these images results from sunglint. Sunglint occurs when the Sun’s light bounces off the ocean’s surface and directly back into a satellite sensor’s field of view or a camera’s lens. While sunglint can create a washed-out appearance to the surface in some situations, it may also reveal details that aren’t visible in other lighting conditions. For example, in many space-based images, the ocean surface appears as a flat, nearly featureless blue expanse.
