~ Mother Earth ~
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Jan Mayen
Jan Mayen Island, a part of the Kingdom of Norway, is a 373 km² arctic volcanic island partly covered by glaciers and divided into two parts by a narrow isthmus. It lies 600 km north of Iceland, 500 km east of Greenland and 1,000 km west of the Norwegian mainland at 71° N 8° W. The island is mountainous, the highest summit being Beerenberg in the north (2,277 m).
Jan Mayen
Economy
Jan Mayen Island has no exploitable natural resources. Economic activity is limited to providing services for employees of Norway's radio and meteorological stations located on the island. It has one unpaved airstrip about 1,585 meters long, and its 124.1 kilometers of coast include no ports or harbors, only offshore anchorages. Commercial whaling took place between 1633 and 1640 by the Dutch but ended when the Dutch team of seven died of scurvy and the Greenland right whale nearly became extinct. A dispute between Norway and Denmark regarding the fishing exclusion zone between Jan Mayen and Greenland was settled in 1988 granting Denmark with the greater area of sovereignty.
Jan Mayen is an integrated geographical body of Norway. Since 1995 it has been administered by the county governor (fylkesmann) of Nordland; however, some authority has been delegated to a station commander of the Norwegian Logistics Organisation-CIS, a branch of the armed forces.
Orthographic projection centred on Jan Mayen Island
History
Henry Hudson discovered the island in 1607 and called it Hudson's Tutches or Touches. Thereafter it was observed several times by navigators who successively claimed its discovery and renamed it. Thus, in 1611 or the following year whalers from Hull named it Trinity Island; in 1612 Jean Vrolicq, a French whaler, called it ÃŽle de Richelieu; and in 1614 English captain John Clarke named it Isabella, but it didn't stick and later in the same year Joris Carolus named one of its promontories Jan Meys Hoel, after the captain of one of his ships. The present name of the island is derived from this, the claim of its 1611 discovery by a Dutch navigator, Jan Mayen, being unsupportable.
The island is inhabited by personnel operating a Long Range Navigation (Loran-C) base with a staff of 14 and a weather services station with a staff of four. The staff members of both stations live in Olonkinbyen (English: Olonkin City), as the living quarters by the Loran-C base are called. The Loran-C system however is being shut down 31st Dec 2005. The island has no indigenous inhabitants, but is assigned the ISO 3166-1 country code SJ, the Internet country code top-level domain (ccTLD) .no (.sj is allocated but not used) and data code JN. Its amateur radio call sign prefix is JX.
Issue #264 -
Grassland
Grassland is one of several types of terrestrial biomes, where grasses form the predominant vegetation, usually mixed with herbs and sometimes with shrubs, but usually without trees. Grasslands dotted with trees are called savanna.
An Inner Mongolian Grassland.
Grasslands usually get 25-75 cm (10-30 inches) of rainfall annually. Fires, natural and human-caused, are important in the maintenance of many grasslands.
Grasslands may occur naturally or as the result of human activity. Grasslands created and maintained by human activity are called anthropogenic grasslands. Hunting peoples around the world often set regular fires to maintain and extend grasslands, and prevent fire-intolerant trees and shrubs from taking hold. The tallgrass prairies in the American Midwest may have been extended eastward into Illinois, Indiana, and Ohio by human agency. Other anthropogenic grasslands include pasture, where forest or shrublands were cleared to create land for intensive grazing.
Tropical and subtropical grasslands are classified with tropical and subtropical savannas and shrublands as the tropical and subtropical grasslands, savannas, and shrublands biome. Notable tropical and subtropical grasslands include the Llanos grasslands of northern South America.
Temperate grasslands are mid-latitude grasslands, including the Prairie of North America, the Pampa of Argentina, calcerous downland, and the steppes of Eurasia. They are classified with temperate savannas and shrublands as the temperate grasslands, savannas, and shrublands biome.
Flooded grasslands are grasslands that are flooded seasonally or year-round, like the Everglades of Florida or the Pantanal of Bolivia and Paraguay. They are classified with flooded savannas as the flooded grasslands and savannas biome, which occurs mostly in the tropics and subtropics.
Montane grasslands are high-altitude grasslands located on high mountain ranges around the world, like the Páramo of the Andes Mountains. They are part of the montane grasslands and shrublands biome.
Xeric grasslands or desert grasslands are sparse grasslands located in deserts and xeric shrublands ecoregions.
Issue #265 -
Grand Prismatic Spring
The Grand Prismatic Spring in Yellowstone National Park is the largest hot spring in the United States, and the third largest in the world, next to those in New Zealand.
Grand Prismatic Spring
History
There is no doubt that many of the Native American people were aware of the Grand Prismatic Spring long before Europeans first saw it but the first records of the Spring are from early explorers and surveyors.
In 1839, a group of fur trappers from the American Fur Company crossed the Middle Geyser Basin and made note of a 300-foot (91 meter) diameter "boiling lake", most likely Grand Prismatic Spring.
In 1870, the Washburn Party, led by General Henry D. Washburn, visited the Spring, noting a 50-foot (15 meter) geyser (later named Excelsior) nearby.
Color
The vivid colors in the spring are the result of pigmented bacteria in the microbial mats that grow around the edges creating the greens, yellows, oranges, and reds and refracted skylight creating the bright blue in the center of the pool. The amount of color in the microbial mats depends upon the ratio of chlorophyll to carotenoids. In the summer, the mats tend to be orange and red whereas in the winter, the mat are usually dark green.
Grand Prismatic Spring from the air showing the coloration that gives the spring its name.
Issue #266 -
Rift
In geology, a rift is a place where the Earth's crust and lithosphere are being pulled apart. Typical features are a central linear downdropped fault segment, called a graben, with parallel normal faulting and rift-flank uplifts on either side. The axis of the rift area commonly contains volcanic rocks and active volcanism is a part of many but not all active rift systems.
Rifts are distinct from Mid-ocean ridges, where new oceanic crust and lithosphere is created by seafloor spreading. In rifts, no crust or lithosphere is produced. If rifting continues, eventually a mid-ocean ridge may form, marking a divergent boundary between two tectonic plates. Failed rifts are ancient to modern features where continental rifting began, but then failed to continue. Typically the transition from rifting to spreading develops as three converging rifts over a hotspot. Two of these evolve to the point of seafloor spreading, while the third ultimately fails, becoming an aulacogen.
Examples of rifts include:
- Great Rift Valley in Africa
- Red Sea
- Lake Baikal, the bottom of the lake is the deepest continental rift on the earth.
- throughout the Basin and Range Province in North America
- the Rio Grande Rift in the southwestern US
- the rift in the middle of the Gulf of Corinth in Greece
- The Reelfoot Rift, an ancient buried failed rift underlying the New Madrid Seismic Zone in the Mississippi embayment
- the Taupo Volcanic Zone in the north east North Island of New Zealand
the Oslo graben in Norway.
Issue #267 -
Java Sea
The Java Sea (Jawa Sea) is a large (310,000 km²), shallow sea in the southern Pacific Ocean. It was formed toward the end of the last ice age when two large river systems were drowned out. It lies in the midst of the Indonesian islands of Borneo to the north, Java to the south; Sumatra to the west, and Sulawesi (Celebes) to the east. To the northwest, the Karimata Strait links it to the South China Sea.
Location of the Java Sea
Fishing is an important economic activity in the Java Sea. There are over 3,000 species of marine life in the area.
The area around the Java Sea is a popular tourist destination. Scuba diving offers a chance to explore and photograph underwater caverns, wrecks, coral, sponges, and other marine life. A number of national parks exist in the area. Near Jakarta, in the Thousand Islands, is Ujung Kulon National Park. Karimun Java is a national park comprising twenty-seven islands. Menjagan Island, near Bali, is in a secluded national park.
The Java Sea was the site of one of the costliest (to the Allies) naval battles of World War II, in February and March of 1942. The naval forces of the Netherlands, Britain, Australia, and the U.S. were nearly completely destroyed trying to defend Java from Japanese attack.
Issue #268 -
Sphalerite
Sphalerite (ZnS) is a mineral that is the chief ore of zinc. It consists largely of zinc sulfide in crystalline form but almost always contains variable iron. When iron content is high it is an opaque black variety, marmatite ((Zn,Fe)S). It is usually found in association with galena, pyrite, and other sulfides along with calcite, dolomite, and fluorite. Miners have also been known to refer to sphalerite as zinc blende, mock lead, false galena and black-jack.
Sphalerite
The mineral crystallizes in the cubic crystal system. In the crystal structure, zinc and sulfur atoms are tetrahedrally coordinated. The structure is closely related to the structure of diamond. The hexagonal analog is known as the wurtzite structure. The lattice constant for zinc sulfide in the zincblende crystal structure is 5.420 angstroms.
Its color is usually yellow, brown, or gray to gray-black, and it may be shiny or dull. Its luster is resinous. It has a yellow or light brown streak, a hardness of 2.5 - 4, and a specific gravity of 3.9-4.1. Some specimens have a red iridescence within the gray-black crystals; these are called "ruby sphalerite." The pale yellow and red varieties have very little iron and are translucent. The darker more opaque varieties contain more iron. Some specimens are also fluorescent in ultraviolet light. The refractive index of sphalerite (as measured via sodium light, 589.3 nm) is 2.37. Sphalerite crystallizes in the isometric crystal system and possesses perfect dodecahedral cleavage. Gemmy, pale specimens from Franklin, New Jersey (see Franklin Furnace) are highly fluorescent orange and/or blue under longwave ultraviolet light and are known as cleiophane, an almost pure ZnS variety.
Crystals of suitable size and transparency have been fashioned into gemstones, usually featuring the brilliant cut to best display sphalerite's high dispersion of 0.156 (B-G interval)—over three times that of diamond. Freshly cut gems are lively with an adamantine luster and could conceivably be mistaken for a fancy-colored diamond in passing, but due to sphalerite's softness and fragility the gems are best left unset as collector's or museum pieces (although some have been set into pendants). Collectors may pay a premium for stones over one carat (200 mg), as clean crystals are usually quite small. Gem-quality material is usually a yellowish to honey brown, red to orange, or green; the two most important sources are the Chivera mine, Cananera, Sonora, Mexico; and the Picos de Europa, Cordillera Cantabrica, near Santander on Spain's northern coast.
Issue #269 -
Libyan Desert
The Libyan Desert is an African desert that is located in the northern and eastern part of the Sahara Desert and occupies southwestern Egypt, eastern Libya and northwestern Sudan. Covering an area of approximately 1,100,000 square kilometers, it is almost the same size of the Indian subcontinent. It is squarish in shape and extends approximately 1,100 km from east to west, and 1,000 km from north to south.
Libyan Desert
Physical Geography
This desert is primarily a sand and boulder plain and is inhabited by the Senussi. The dominant wildlife are sand vipers and scorpions.
Ridges and deep depressions (basins) exist in several parts of the desert, and no rivers or streams drain into or out of the area. The desert's Jilf al Kabir Plateau has an altitude of about 2,000 meters, an exception to the uninterrupted territory of basement rocks covered by layers of horizontally bedded sediments, forming a massive plain or low plateau.
There are 8 important depressions in the Libyan Desert, and all are considered oases except the smallest, Qattara, the water of which is salty. Limited agricultural production, the presence of some natural resources, and permanent settlements are found in the other 7 depressions, all of which have fresh water provided by the Nile or by local groundwater.
The Siwah Oasis, close to the Libyan border and west of Qattara, is isolated from the rest of Egypt but has sustained life since ancient times.
The other major oases include Siwa, Dakhla and Kharga in Egypt, and Jaghbub in Libya and form a topographic chain of basins extending from the Al Fayyum Oasis (sometimes called the Fayyum Depression) which lies sixty kilometers southwest of Cairo, south to the Bahriyah, Farafirah and Dakhilah oases before reaching the country's largest oasis, Kharijah. A brackish lake, Birkat Qarun, at the northern reaches of Al Fayyum Oasis, drained into the Nile in ancient times. For centuries sweetwater artesian wells in the Fayyum Oasis have permitted extensive cultivation in an irrigated area that extends over 2,100 square kilometers.
Key geographic features of the Libyan Desert
The Qattara Depression
The Qattara Depression, which contains the second lowest point in Africa, is approximately 15,000 square km (about the size of Connecticut and Rhode Island), and is largely below sea level (its lowest point is 133 meters below sea level). The sparsely inhabited Qattara Depression is covered by badlands, salt marshes and salt lakes
The Sand Seas
The three sand seas contain dunes up to 110m in height. These cover approx. 25% of the region.
- Egyptian Sand Sea
- Kalansho Sand Sea
- Ribiana Sand Sea
Issue #270 -
Intracoastal Waterway
The Intracoastal Waterway is a 4,800 km (3,000 mile) long recreational and commercial waterway along the Atlantic and Gulf coasts of the United States. Some lengths are natural and others are man made. One of the older portions is the Dismal Swamp Canal in the Great Dismal Swamp in Virginia and North Carolina.
Tug and barge on the Gulf Intracoastal Waterway
The creation of the Intracoastal Waterway was first authorized by the United States Congress in 1919. It is maintained by the United States Army Corps of Engineers. Federal law provides for the toll-free waterway to be maintained at a minimum depth of 12 ft (4 m) for most of its length, but inadequate funding has prevented that from happening. Consequently, shoaling or shallow water are problems along several sections of the waterway; some parts have 7-ft (2.1-m) and 9-ft (2.7-m) minimum depths.
The waterway consists of two non-contiguous segments: the Gulf Intracoastal Waterway, extending from Brownsville, Texas to Carrabelle, Florida, and the Atlantic Intracoastal Waterway, extending from Key West, Florida to Boston, Massachusetts. The two segments were originally intended to be connected via the Cross-Florida Barge Canal across northern Florida, but this was never completed due to environmental concerns.
The Intracoastal Waterway has a good deal of commercial activity; barges haul petroleum, petroleum products, foodstuffs, building materials, and manufactured goods. It is also used extensively by recreational boaters.
Issue #271 -
Mantle
The Earth's mantle is the layer in the structure of the Earth that lies directly under the Earth's crust and above the Earth's outer core. The term is also applied to the structure of other planets. Earth's mantle lies roughly between 30 and 2,900 km below the surface.
Earth cutaway from core to exosphere. Partially to scale.
The boundary between the crust and the mantle is the Mohorovièiæ discontinuity, named for its discoverer, and is usually called the Moho. The Moho is a boundary at which there is a sudden change in the speed of seismic waves. At one time some thought that the Moho was the structure at which the earth's rigid crust moved relative to the mantle. Current research places this zone of movement within the mantle, from 70 km (43 mi) below the ocean crust to 150 km (93 mi) below the continental crust. The mantle just below the crust is composed of cold and therefore rigid mantle fused to the crust but at the same time separated from it by the Moho. This rigid layer of crust and the upper mantle forms the lithosphere.
The mantle differs substantially from the crust in its mechanical characteristics and its chemical composition. It is chiefly the difference of chemistry on which the distinction between crust and mantle is based. Mantle rock consists of olivines, different pyroxenes and other mafic minerals. Typified by peridotite, dunite, and eclogite, mantle rocks also possesses a higher portion of iron and magnesium and a smaller portion of silicon and aluminium than the crust. In the mantle, temperatures range between 100°C at the upper boundary to over 3,500°C at the boundary with the core. Although these temperatures far exceed the melting points of the mantle rocks at the surface, particularly in deeper ranges, they are almost exclusively solid. The enormous lithostatic pressure exerted on the mantle prevents them from melting.
The subregion of the mantle extending about 250 km (155 mi) below the lithosphere is called the asthenosphere. It some regions of the earth, this subregion of the mantle is associated with a region of the mantle that passes seismic waves more slowly. This region is called the low-velocity zone. The cause of this low velocity zone is still debated. Currently theories include the influence of temperature and pressure or the existence of a small amount of partial melt.
Mapping the interior of the Earth with earthquake waves.
Due to the temperature difference between the Earth's crust and outer core there is a convective material circulation in the mantle. Hot material ascends as a plutonic diapir from the border with the outer core, while cooler (and heavier) material sinks downward. This is often in the form of large-scale lithospheric downwellings at plate boundaries called subduction zones. During the ascent the material of the mantle cools down adiabatically. The temperature of the material falls with the pressure relief connected with the ascent, and its heat distributes itself over a larger volume. Near the lithosphere the pressure relief can lead to partial melting of the diapir, leading to volcanism and plutonism.
The convection of the Earth's mantle is a chaotic process (in the sense of fluid dynamics), which is thought to drive the motion of plates. Plate motion should not be confused with the older term continental drift which applies purely to the movement of the crustal components of the continents. The movements of the lithosphere and the underlying mantle are thereby partially decoupled, since due to the rigidity of the lithosphere, a tectonic plate can only move as a whole. Continental drift is therefore only a diffuse image of the movements at the upper limit of the Earth's mantle. The convection of the mantle is not yet clarified in detail. There are different theories, according to which the Earth's mantle is divided into different floors of separate convection.
Although there is a tendency to larger viscosity at greater depth, this relation is far from linear, and shows layers with dramatically decreased viscosity, in particular in the upper mantle and at the boundary with the core.
Due to the low viscosity in the upper mantle one could reason that there should be no earthquakes below approximately 300 km depth. However, in subduction zones, the geothermal gradient can be lowered, increasing the strength of the surrounding mantle, and allowing earthquakes to occur down to a depth of 400 km and 670 km.
The pressure at the bottom of the mantle is ~140 GPa (1.4 Matm). There exists increasing pressure as one travels deeper into the mantle, the entire mantle, however, is still thought to deform like a fluid on long timescales. The viscosity of the upper mantle ranges between 10^21 and 10^24 Pa·s, depending on depth. Thus, the upper mantle can only flow very slowly.
Why is the inner core thought solid, the outer core thought liquid, and the mantle solid/plastic? The melting points of iron rich substances are higher than pure iron. The core is composed almost entirely of pure iron, while iron rich substances are more common outside the core. So, surface iron-substances are solid, upper mantle iron-substances are semi-molten (as it is hot and they are under relatively little pressure), lower mantle iron-substances are solid (as they are under tremendous pressure), outer core pure iron is liquid as it has a very low melting point (despite enormous pressure), and the inner core is solid due to the overwhelming pressure found at the centre of the planet.
Issue #272 -
El Misti
El Misti is a volcano located in southern Peru near the city of Arequipa. This city, the second largest in the country, lies at the foot of El Misti in a fertile valley located 2,400 meters above sea level. El Misti (the gentleman) has become the city's enduring symbol. Most of the city's colonial buildings were constructed from El Misti's white volcanic stone (sillar). The volcano's last eruption was in 1870.
El Misti
Elevation: 19,101 ft (5,822 m)
Coordinates: 16° 17' 40"S, 71° 24' 32"W
Location: Peru
Range: Andes
Type: Stratovolcano
Last eruption: 1784
With its snow-capped, perfect cone, El Misti stands at 5,822 metres and lies between the mountain Chachani (6,057 m) and the volcano Pichu-Pichu (5,669 m). These impressive mountains, located northeast of Arequipa, are visible almost year-round, but especially during winter (May-September).
Issue #273 -
Dardanelles
The Dardanelles (Turkish: Çanakkale Boðazý), formerly known as the Hellespont, is a narrow strait in northwestern Turkey connecting the Aegean Sea with the Sea of Marmara. It is located at approximately 40°13'N 26°26'E. The strait is 61 km (38 miles) long but only 1.2 to 6 km (0.75 to 4 miles) wide, averaging 55 m (180 ft) deep with a maximum depth of 81 m (300 ft). Water flows in both directions along the strait, from the Sea of Marmara to the Aegean via a surface current and in the opposite direction via an undercurrent.
Map of the Dardanelles
Just like the Bosporus strait, it separates Europe (in this case the Gallipoli peninsula) and the mainland of Asia. The major city adjoining the strait is Çanakkale (which takes its name from its famous castles; kale means "castle"). The name Dardanelles derives from Dardanus, an ancient Greek city on the Asian shore of the strait.
The strait has long had a strategic role in history. The ancient city of Troy was located near the western entrance of the strait and the strait's Asiatic shore was the focus of the Trojan War. It was also the scene of the legendary Greek story of Hero and Leander. The Persian army of Xerxes I and later the Macedonian army of Alexander the Great crossed the Dardanelles in opposite directions to invade each other's lands, in 480 BC and 334 BC respectively. The Dardanelles were vital to the defence of Constantinople during the Byzantine period, and since the 14th century they have almost continuously been controlled by the Turks.
Gaining control or special access to the strait became a key foreign policy goal of the Russian Empire during the 19th century. Following the Ottoman Empire's defeat in the Russo-Turkish War of 1828-1829, in 1833 Russia forced the Turks to sign the Treaty of Hunkiar Iskelesi which required the straits to be closed to warships of non-Black Sea powers at Russia's request. This would have effectively given Russia a free hand in the Black Sea.
The treaty alarmed the Western powers, who feared the consequences of potential Russian expansionism in the Mediterranean. At the London Straits Convention in July 1841, Britain, France, Austria and Prussia forced Russia to agree that only Turkish warships could traverse the Dardanelles in peacetime. Britain and France subsequently sent their fleets through the straits to attack the Crimea during the Crimean War in 1853, though this was done as allies of the Ottoman Empire. This convention was formally reaffirmed by the Congress of Paris in 1856, following the Russian defeat in the Crimean War, and it remained theoretically in force into the 20th century.
The Allies made a failed attempt to seize the Dardanelles during World War I, seeking to knock the Ottoman Empire out of the conflict. The Battle of Gallipoli damaged the career of Winston Churchill, the First Lord of the Admiralty who eagerly promoted the use of Royal Navy battleships to force open the straits. The straits were mined to prevent Allied ships from penetrating them, although a British submarine did succeed in evading the minefields and sank a Turkish battleship off the Golden Horn in Istanbul. Sir Ian Hamilton's Mediterranean Expeditionary Force was unsuccessful in its attempt to capture the Gallipoli peninsula, and a withdrawal was ordered in January 1916.
Following the war, the 1920 Treaty of Sèvres demilitarized the strait and made it an international territory under the control of the League of Nations. This was amended under the 1923 Treaty of Lausanne which restored the straits to Turkey but allowed all foreign warships to traverse the straits freely. Turkey rejected the terms of this treaty and subsequently remilitarized the area. The reversion to this old regime was formalised under the Montreux Convention of July 1936. The convention, which is still in force today, treats the straits as an international shipping lane but Turkey retains the right to restrict the naval traffic of non-Black Sea nations. During World War II, when Turkey was neutral for almost the entire length of the conflict, the Dardanelles were closed to the ships of the belligerent nations.
Issue #274 -
Wailua Falls
Wailua Falls is an 80 foot waterfall located in Kauai, Hawaii that feeds into the Wailua River. There is a path to the bottom of the falls, but is is muddy, slippery and quite hazerdous. Some hikers have strung ropes along the path, but officials come by every so often and cut them. This actually makes it less safe while making some politician feel safer.
Wailua Falls
Before Europeans arrived, native Hawaiian men would jump from these falls to prove their manhood. They didn't always survive.
Issue #275 -
Red River Gorge
The Red River Gorge is a canyon system on the Red River in east-central Kentucky. Geologically, it is part of the Pottsville Escarpment.
The Red River Gorge Geological Area
Much of the Gorge has been purchased as part of the Daniel Boone National Forest and has been subsequently reserved as the Red River Gorge Geological Area, an area of around 28,000 acres (over 113 km²). It has been designated a National Natural Landmark. The 13,000-acre Clifty Wilderness Area lies entirely within the gorge.
This intricate canyon system features an abundance of high sandstone cliffs, rock shelters, waterfalls, and natural bridges. There are more than 100 natural sandstone arches in the Red River Gorge Geological Area.
Kentucky's Natural Bridge State Park is immediately adjacent to this area, featuring one of the largest natural bridges.
Because of its unusual and rugged nature, the Red River Gorge features a remarkable variety of ecological zones. It is the farthest southern site where the Canadian yew, Taxus canadensis, is known to grow.
Issue #276 -
Lihou
Lihou is a small tidal island (95 vergees; 7ha) that is part of the Channel Islands. It lies off the west coast of Guernsey and is the most westerly point in the Channel Islands. The island was bought by the States of Guernsey in January 1995. Lihou is connected to Guernsey at low tide by an ancient stone causeway between the island and L'Eree headland. It is part of the Parish of St. Peter's.
This is a map of the Bailiwick of Guernsey. Lihou is on the far left.
On the island are the ruins of the priory of St. Mary which is believed to have been established by Benedictine monks in the 12th century. Until 1415 it was under the control of Mont Saint Michel and thereafter under Eton College until the Reformation when it was closed and fell into disrepair. Local legend accuses the resident monks of being devil-worshippers, although this may be a reaction to the tithes on fishing catches the Prior demanded.
Vraic (seaweed) was harvested and dried on frames set up on the beach. A 1927 factory building produced iodine from seaweed. All traces of the industry disappeared during the German Occupation.
Lihou's bird and marine life makes it an important conservation area.
The house on Lihou was used for target practice by heavy artillery during the German occupation of the Channel Islands during World War II. It has now been rebuilt as accommodation for school groups, and is used as an Educational Resource.
Issue #277 -
Cape Wrath
Cape Wrath (58° 37'36"N, 04° 59'54"W) is a cape in northern Scotland. It is the most northwesterly point of the mainland of Britain. The name Cape Wrath, though perhaps apt when taken in context of its remote and foreboding landscape, is actually derived from the Old Norse for "turning point". Vikings would often turn their crafts for home at Cape Wrath.
Cape Wrath lighthouse
The Cape can be reached only on foot from the south, or by taking a passenger ferry from Keoldale near Durness across the Kyle of Durness, and then walking, cycling or taking a minibus. The journey of around 11 miles to the lighthouse takes the visitor through one of the last remaining wildernesses in Britain. The area is used as a military bombardment range; hence travel to the Cape is restricted at certain times of year. There is a lighthouse at the cape, built in 1828 by Robert Stevenson which was manned until 1998.
Kyle of Durness
Four miles east of the cape, lie the Clò Mór cliffs, the highest sea cliffs of the British mainland.
Trivia
Cape Wrath is one of only two places prefixed with the name "Cape" in the UK, the other being Cape Cornwall in south-western England.
Issue #278 -
Sundial Bridge at Turtle Bay
The Sundial Bridge is a cantilever spar cable-stayed bridge that spans the Sacramento River in Redding, California. It was designed by Santiago Calatrava and completed in 2004 at a cost of US$23,000,000.
Sundial Bridge at Turtle Bay
Official name: Sundial Bridge at Turtle Bay
Carries: Bicycles and pedestrians
Crosses: Sacramento River
Locale: Redding, California
Design: Cantilever spar cable-stayed bridge
Total length: 700 ft
Width: 23 ft
Clearance below: 26 m
Opening date: July 4, 2004
Similar to his earlier (1992) design (the Puente del Alamillo in Seville, Spain), this subtype uniquely does not balance the forces by using a symmetrical arrangement of cable forces on each side of the tower; instead it uses an angled cantilever tower loaded by cable stays on only one side. This requires that the spar resist bending and torsional forces and that its foundation resists overturning. While this leads to a less structurally efficient structure the architectural statement is considered dramatic.
This pedestrian bridge features a single 217 foot (66 metre) mast that serves as a sundial, which can be read in a garden to the north of the bridge. It connects the two sections of Turtle Bay Exploration Park.
The deck is surfaced with transparent structural glass, with a view of the water below as one crosses. The walkway and river are illuminated from beneath the deck at night. It is 700 feet (213 m) in length and crosses the river without once touching the water. The cable stays are not centered on the walkway but instead divide the bridge into a major and minor path.
Issue #279 -
Lake Eyre
Lake Eyre (28°22'S 137°22'E) is, on the rare occasions that it fills, the largest lake in Australia and is the lowest point in Australia (at approximately 15 m (50 ft) below sea level). It is the focal point of the vast Lake Eyre Basin.
Composite Satellite image of Lake Eyre using shortwave infrared, near-infrared, and blue wavelengths.
The lake is located in the deserts of central Australia, in northern South Australia. The Eyre Basin is a large endorheic system surrounding the lakebed, the lowest part of which is filled with the characteristic playa salt pan caused by the seasonal expansion and subsequent evaporation of the trapped waters. Even in the dry season there is usually some water remaining in Lake Eyre, usually collecting in a number of smaller sub-lakes on the playa. During the rainy season the rivers from the northeast (in outback Queensland) flow towards the lake. The amount of water from the monsoon determines whether water will reach the lake and if it does, how deep the lake will get. The lake can also experience minor and moderate floods due to rain falling in the surrounding area. Typically a 1.5 m (5 ft) flood occurs every three years, a 4 m (13 ft) flood every decade and a fill, or near fill four times a century. The water in the lake soon evaporates with a minor and medium flood drying by the end of the following summer.
The Lake Eyre Yacht Club is a dedicated group of eccentrics who sail on the lake's minor floods, including trips in 1997, 2000, 2001 and 2004.
Issue #280 -
Tigris
The Tigris (Old Persian: Tigr, Aramaic Assyrian: Deqlath, Arabic: Dijla, Turkish: Dicle; biblical Hiddekel) is the eastern member of the pair of great rivers that define Mesopotamia, along with the Euphrates, which flows from the mountains of Anatolia through Iraq. (Indeed, the name "Mesopotamia" is a Greek translation from the Old Persian Miyanrudan, which means "the Land between the Rivers". Bethnahrin is the Assyrian word for the area.). The original Sumerian name was idigna, which can be interpreted as "the river that goes", contrasted to its neighbor, the Euphrates, whose leisurely pace caused it to deposit more silt and build up a higher bed than the Tigris. The Greek name tigris comes from the Old Persian word for "tiger" and means "the fast one". It might also be argued to come from Kurdish too. In Kurdish "Tir" means arrow. This means that the river is quick and fast like an arrow.Tîj-Tûj means sharp, pointing and cutting. Since the letter "j" doesn't exist in Greek Tîj-Tûj became Tig later Tigr.In Greek at the end of words -is sonex is used (Tîj-Tijr-Tig-Tigr-Tigris). In Kurdish "Derzi" means needle, meaning that the river is long and straight like a needle (Derzi-Terzi-Tirzi-Tigris). Another name for this watercourse, used from the time of the Persian Empire, is Arvand, which has the same meaning. Today, the name Arvand refers to the lower part of the Tigris (ie, Arvand/Shatt al-Arab) in Persian.
Tigris River in Mosul, Iraq
The Tigris is approximately 1,800 km (1,150 miles) long, rising in the Taurus Mountains of eastern Turkey and flowing in a generally southeasterly direction until it joins the Euphrates near Al Qurna in southern Iraq. The two rivers together form the Shatt al-Arab waterway, which empties into the Persian Gulf. The river is joined by many tributaries, including the Diyala and Zab.
Map of the Tigris-Euphrates watershed
Baghdad, the capital of Iraq, stands on the western bank of the Tigris, while the port city of Basra straddles both the Tigris and the Euphrates. In ancient times, many of the great cities of Mesopotamia stood on or near the river, drawing water from it to irrigate the civilization of the Sumerians. Notable Tigris-side cities included Nineveh, Ctesiphon and Seleucia, while the city of Lagash was irrigated by Tigris water delivered to it via a canal dug around 2400 BC. Saddam Hussein's hometown, Tikrit, is also located on the river and derives its name from it.
The Tigris has long been an important transport route in a largely desert country. It is navigable as far as Baghdad by shallow-draft vessels, but rafts are required for transport upstream to Mosul. River trade declined in importance during the 20th century as the Basra-Baghdad-Mosul railway and roads took over much of the freight traffic.
The Tigris outside Diyarbakýr in Turkey
The river is heavily dammed in both Iraq and Turkey, in order to provide water for irrigating the arid and semi-desert regions bordering the river valley. Damming has also been important for averting floods in Iraq, to which the Tigris has historically been notoriously prone following snowmelt in the Turkish mountains around April. Recent Turkish damming of the river has been the subject of some controversy, both for its environmental effects within Turkey and its potential to reduce the flow of water downstream.
Issue #281 -
Yorke Peninsula
The Yorke Peninsula is a peninsula located north-west and west of Adelaide in South Australia, Australia, between Spencer Gulf on the west and Gulf St. Vincent on the east. It has geographic coordinates of 34°21'S 137°37'E.
Before white settlement in around 1840, Yorke Peninsula was the home to the Narungga people. Today the descendents of these people still live on Yorke Peninsula, supported by the Narungga Aboriginal Progress Association in Maitland, and in the community at Point Pearce near the northern end of Gulf Saint Vincent.
Principal towns include the Copper Triangle towns of Kadina, Moonta and Wallaroo; farming centres of Maitland, Minlaton and Yorketown; and the port of Ardrossan. A number of smaller coastal towns are popular destinations for fishing and relaxing holidays, particular from Adelaide. The south-western tip is occupied by Innes National Park.
Innes National Park at Yorke Peninsula
Yorke Peninsula has never had a railway line along it, only the railway to Kadina and Wallaroo across the top. It is a major producer of grain, particularly barley, so historically this has been sent out by sea. Almost every coastal town has a jetty, which used to be visited by ketches, schooners and later steamships to collect the grain in bags, and deliver fertiliser and other supplies. As the roads have improved, and freight handling techniques have changed from bags to bulk, this became obsolete. A new deep-water port was built near the south eastern tip at Port Giles to export grain in bulk (opened in 1970), and almost all the other ports ceased to be used for freight in the 1950s and 1960s. The only other ports with bulk handling facilities are Wallaroo at the north-western side, and Ardrossan at the top of Gulf Saint Vincent, also used to ship dolomite from a nearby mine for OneSteel. Maitland has a grain receiving depot operated by AWB, serviced only by road.
Issue #282 -
Baja California Desert
The Baja California Desert is a desert ecoregion of Mexico's Baja California Peninsula.
Setting
The ecoregion covers 77,700 square kilometers (30,000 square miles), and includes most of the Peninsula's western slope. It is bounded on the west by the Pacific Ocean and on the east by the Peninsular Ranges. North of 30º north latitude, the Baja California desert transitions to the California chaparral and woodlands. The southern tip of the peninsula lies within the San Lucan xeric scrub ecoregion.
Baja California Desert
The climate is dry and subtropical. Although rainfall is low, the Pacific Ocean provides some humidity and moderates the temperature compared to the Sonoran desert, which lies on the east slope of the Peninsular Ranges.
Flora
The ecoregion is mostly covered by xeric shrubs, which create varying associations based on elevation and soil conditions. The ecoregion has close to 500 species of vascular plants, of which a number are endemic.
Issue #283 -
Bay of Bengal
The Bay of Bengal is a bay that forms the northeastern part of the Indian Ocean. It resembles a triangle in shape, and is bordered on the east by the Malay Peninsula, and on the west by the India. On the northern tip of the "bay" lie the Indian state of West Bengal and the country of Bangladesh, thus the name. The southern extremes reach the island country of Sri Lanka, and the Indian Union Territory Andaman and Nicobar Islands.
Map showing the location of the Bay of Bengal.
Many major rivers of India flow west to east into the Bay of Bengal: in the north, the Ganges River (or Ganga), Meghna and Brahmaputra rivers, and in the south Mahanadi, Godavari, Krishna and Kaveri (sometimes written as Cauvery) rivers. The Sundarbans mangrove forest is formed at the delta of the Ganga, Brahmaputra and Meghna rivers on the Bay of Bengal. The Irrawaddy River of Burma also flows into the bay.
Major Bangladeshi ports on the bay include Chittagong and Mongla. Major Indian ports on the bay include Chennai (formerly Madras), Vishakhapatnam, Kolkata (formerly Calcutta) and Pondicherry.
Cox's Bazar, on the northeastern coast of the bay, is one of the longest unbroken natural beaches of the world.
Issue #284 -
Mer de Glace
The Mer de Glace (Sea of Ice) is a glacier located on the north face of the Mont Blanc, in the Alps. 7 km long and 200m deep, with an area of about 40 sq km. It is the second-longest glacier in the Alps, after the Aletsch Glacier.
Mer de Glace
It originates at an elevation of 3,900 m, and descends down to 1,400 m. It was once easily visible from Chamonix, but has been shrinking and is now barely visible from below.
It is in the Chamonix valley, it was the first place in the valley to have a custom made tourist attraction.
The Mer de Glace, like all glaciers, is constantly renewed under the effect of two phenomena: accumulation, notably due to snowfall and ablation, essentially due to melting. The Mer de Glace flows permanently under the effect of its own weight, crusting crevasses, seracs or pockets of water to form, depending on the type of ground.
The glacier's speed, although not perceptible to the naked eye, is considerable. From more than 120 meters a year in its upper part, the Mer de Glace moves about 90 meters a year in the region of Montenvers, which is about one centimeter per hour.
As soon as the tensions intensify, the glacier is deformed and crevasses appear. These are notably transversal. When there is intense crevasse activity, the breaking up of the glacier by the crevasses forms blocks of seracs.
The crevasses, of variable depth, depending on their positioning, may reach fifty metres. They always form in the same place because of the shape of the glacial valley in which the glacier flows. Disappearing downstream, they are renewed upstream.
Issue #285 -
Welland Canal
The Welland Canal is a ship canal that runs 43.4 km (27.0 mi) from Port Colborne, Ontario on Lake Erie to Port Weller, Ontario on Lake Ontario. As part of the St. Lawrence Seaway, it allows ships to avoid Niagara Falls by traversing the Niagara Escarpment.
Lock 3 of the Welland Canal, with the Garden City Skyway bridge in background.
Approximately 40,000,000 metric tonnes of cargo is carried through the Welland Canal annually by over 3,000 ocean and lake vessels. It was a major factor in the growth of the city of Montreal. The original canal and its successors allowed goods from Detroit, Michigan, Cleveland, Ohio and other heavily industrialized areas of the United States and Ontario to be shipped to the port of Montreal where they were reloaded onto ocean-going vessels for international shipping.
The completion of the Welland Canal made the Trent-Severn Waterway (which links Lake Ontario with Lake Huron) all but obsolete as a commercial traffic route for Great Lakes navagation.
The Port Weller (east, compass north, at Lake Ontario) end of the canal is 99.5 m (326.5 ft) lower than the Port Colborne (west, compass south, on Lake Erie) end. There are eight locks, each 24.4 m (80 ft) by 233.5 m (766 ft). Due to the Garden City Skyway, the maximum ship height allowed is 35.5 m (116.5 ft) (all other crossings are lift bridges or tunnels). Maximum length is 225.5 m (740 ft), and it takes an average of 11 hours to travel between the two ends.
History
Prior to the building of the canal, traffic between Lake Ontario and Lake Erie used a portage road between Queenston and Chippawa, both points on the Niagara River on opposite sides of Niagara Falls.
Aerial photo of Port Dalhousie taken in 1920
The Welland Canal Company was incorporated in 1824 by William Hamilton Merritt, in part to provide a regular flow of water for his mills. Construction began at Allanburg on November 30, at a point now marked as such on the west end of Bridge #11 (former Ontario Highway 20). It opened in 1829, running from Port Dalhousie on Lake Ontario south along Twelve Mile Creek to St. Catharines. From there it took a winding route up the Niagara Escarpment through Merritton to Thorold, where it continued south via Allanburg to Port Robinson on the Welland River. Ships went east on the Welland River to Chippawa, the south end of the portage road.
A southern extension from Port Robinson opened in 1833. This extension followed the Welland River south to Welland, and then split to run south to Port Colborne on Lake Erie. A feeder canal ran southwest from Welland to another point on Lake Erie, just west of Rock Point. With the opening of the extension, the canal stretched 44 km (27 mi) between the two lakes, with 40 wooden locks. The minimum lock size was 33.5 m by 6.7 m (110 ft by 22 ft), with a minimum canal depth of 2.4 m (8 ft).
In 1839 the government of Upper Canada approved a purchase of canal stock due to financial problems. This buyout was completed in 1841, and work began to deepen the canal and reduce the number of locks to 27, each 45.7 m (150 ft) by 8.1 m (26.5 ft). By 1848 a 2.7 m (9 ft) deep path was available not only through the Welland Canal but also the rest of the way to the Atlantic Ocean via the route of the current St. Lawrence Seaway.
Competition came in 1854 with the opening of the Erie and Ontario Railway, running parallel to the original portage road. In 1859 the Welland Railway opened, parallel to the canal and with the same endpoints. Along with this competition, boats were being built bigger than the canal could support. In 1887 a new shorter alignment was completed between St. Catharines and Port Dalhousie. The new route had a depth of 4.3 m (14 ft) and 26 stone locks, each 82.3 m (270 ft) by 13.7 m (45 ft). Even so, the canal was still too small for many boats.
More construction began in 1913 and was not completed until 1932. The route was again changed north of St. Catharines, now running directly north to Port Weller. Only eight locks remained, seven at the Niagara Escarpment and the eighth a control lock at Port Colborne to control the depth of the canal. The depth was now 7.6 m (25 ft), with locks 233.5 m (766 ft) by 24.4 (80 ft).
In the 1950s, with the building of the St. Lawrence Seaway, a depth of 8.2 m (27 ft) was adopted. From 1967 to 1973, the 13.4 km (8.3 mi) Welland By-Pass opened, providing a new shorter alignment between Port Robinson and Port Colborne and bypassing downtown Welland. All three crossings of the new alignment - one an aqueduct for the Welland River - were built as tunnels. Around the same time, the Thorold Tunnel was built at Thorold and several other bridges were removed.
Lock operations
Unlike with previous versions of the canal, ships using the current canal move under their own power during their entire transit of the Welland Canal and its locks. Once a vessel has been securely moored in the lock chamber by a crew of Seaway linehandlers, the huge steel lock gates close behind it and valves are put into operation to fill or empty the lock by gravity flow. About 91 million litres (20 million gallons) of water are required for each lock transit. The time needed to fill a lock is approximately 11 minutes. As the new level is reached, the forward gates are opened and, at a sign from the spotter, a short blast of the ship's whistle signals "cast off" and the vessel proceeds out of the lock.
Issue #286 -
Pacific Ring of Fire
The Pacific Ring of Fire is a zone of frequent earthquakes and volcanic eruptions that encircles the basin of the Pacific Ocean. It is shaped like a horseshoe and it is 40,000km long. It is associated with a nearly continuous series of oceanic trenches, island arcs, and volcanic mountain ranges and / or plate movements. It is sometimes called the circum-Pacific seismic belt.
The Pacific Ring of Fire
About 71% of the world's largest earthquakes occur within the Ring of Fire. The Alpide belt, which extends from Java to Sumatra through the Himalayas, the Mediterranean, and out into the Atlantic, accounts for another 17%, and the Mid-Atlantic Ridge is a third prominent earthquake belt.
The Ring of Fire is a direct consequence of plate tectonics and the movement and collisions of crustal plates. The eastern section of the ring is the result of the Nazca Plate and the Cocos Plate being subducted beneath the westward moving South American Plate. A portion of the Pacific Plate along with the small Juan de Fuca Plate are being subducted beneath the North American Plate. Along the northern portion the northwestward moving Pacific plate is being subducted beneath the Aleutian Islands arc. Further west the Pacific plate is being subducted along the Kamchatka - Kurile Islands arcs on south past Japan. The southern portion is more complex with a number of smaller tectonic plates in collision with the Pacific plate from the Mariana Islands, the Philippines, Bougainville, Tonga, and New Zealand. Indonesia lies between the Ring of Fire along the northeastern islands adjacent to and including New Guinea and the Alpide belt along the south and west from Sumatra, Java, Bali, Flores, and Timor. The December 2004 earthquake just off the coast of Sumatra was actually a part of the Alpide belt. The famous and active San Andreas Fault zone of California is a transform fault which offsets a portion of the East Pacific Rise under southwestern United States and Mexico.
A number of land and sea features are in the Ring of Fire: (here listed clockwise)
* New Zealand
* Kermadec Trench
* Tonga Trench
* Bougainville Trench
* Indonesia
* Philippines
* Philippine Trench
* Yap Trench
* Mariana Trench
* Izu Bonin Trench
* Ryukyu Trench
* Japan
* Japan Trench
* Kurile Trench
* Kamchatka
* Aleutian Islands
* Aleutian Trench
* American cordillera
* Alaska
* Pacific Coast Range
* British Columbia
* Cascade Range
* California
* Mexico
* Middle America Trench
* Guatemala
* Colombia
* Ecuador
* Peru
* Peru-Chile Trench
Issue #287 -
Aneto
Aneto is the highest mountain in the Pyrenees. It lies in the Spanish province of Huesca, in the north of Aragon. It forms the southernmost part of the Maladeta massif. Its French name, Néthou, is falling out of favor as the mountain lies entirely within Spain.
Aneto's summit and glacier seen from the upper Portillon
Elevation: 3,404 metres (11,168 feet)
Location: Huesca, Spain
Range: Pyrenees
Prominence: 2,821m
Coordinates: 42°38'N, 0°40'E
First ascent: July 20, 1842
Easiest route: basic snow/ice climb
Climbing
The mountain's ascent is usually made from the Refuge of the Rencluse (2,140 m). From there, the itinerary traverses the longest part of the glacier that extends to the north of the peak.
The summit is defended by a short rocky passage called the Bridge of Mohammed. It is a narrow ridge of large, stable blocks, with an exposed void on each side. At the summit is an impressive cross and a contrasting view, with the snow-covered Maladeta massif to the north and the somber and dry Alto Aragon to the south.
First Ascent
On July 18, 1842, Platon de Tchihatcheff (Chikhachev), a former Russian officer staying in Luchon, left from Bagnères-de-Luchon accompanied by guides Pierre Sanio de Luz, Luchonnais Bernard Arrazau and Pierre Redonnet. Also in the party were Albert de Franqueville, a Norman botanist, and his guide, Jean Sors. They took the trail from the Hospice de France, crossed the Benasque pass, then spent the night at the shelter of La Renclusa, a simple construction of dry rocks that is now a large mountain refuge.
The next day, they crossed a pass towards Alba pass and lost their way on the south slope around lake Gregueña. Late in the day, at the end of their strength, they took refuge for the night in a cabin near the Vallibierna valley.
As the sun rose the next morning, the group left for the Coroné pass. Despite a fear of crevasses, they decided to approach the summit by the glacier. After climbing a ridge only a few meters wide (baptized the "Bridge of Mohammed" by Albert de Franqueville), they reached the summit on July 20, 1842, where they constructed a cairn and left a bottle containing each climber's name.
First Winter Ascent
The first winter ascent of the mountain was achieved on March 1, 1878 by Roger de Monts, B. Courrèges, and B. and V. Paget.
Issue #288
