A crater was a large earthenware vessel used for mixing wines in Greece and Rome. The term also describes the outlet of a volcano or the hole made in the earth by an explosion. Research Crater
Mountains are often classified according to their mode of formation: Fold
mountains; Block mountains; Residual mountains; Volcanic mountains.
High mountain chains such as the Himalayas, Andes, Alps, and Rockies are known as new fold mountain systems. The term 'fold' is a reference to the way in which such mountains have been formed. Throughout millions of years slow movements of the earth's crust have caused these
mountains to be raised. The movements which have resulted in mountain buildings were not, however, vertical uplifts. They were primarily horizontal movements, the effect of which was to cause the crust of the earth to 'wrinkle', in a similar way to which a tablecloth wrinkles if it is pushed along the table. The arched or upraised parts of the folds are known as anticlines and the troughs as synclines. These folds can vary greatly in size. Mountain building is undoubtedly due to some deep-seated cause. For a long period the most simple explanation was that folding was entirely due to the cooling and contraction of the earth, so that the crust, already cold and shrunken, had to wrinkle to fit itself to the still cooling and contracting 'core'. One of the objections advanced against this theory is that the amount of shrinking necessary to account for the Himalayas, Alps, etc., seems to be greater than the mere contraction of the earth would allow. While the theory of contraction cannot be completely rejected, serious consideration must be given to the more recent explanations of mountain building. For instance, Wegener suggests that mountain building may be due to the 'wrinkles' produced by the drifting of a continental mass, e.g. that the Alps were formed by the northward drift of the African continent towards the more stable blocks of Central Europe. As the African mass drifted slowly northward the zone between it and the European mass became narrower, and the land was raised into high ridges or folds. The raising of the Alps was accompanied by the formation of the deep trough which contains the Mediterranean Sea. The same hypothesis would account for the building of the Himalayas and the depression of the Indo-Gangetic trough by the northward drift of the Deccan mass.
During the physical history of the earth, mountain building appears to have proceeded more actively at some periods than others. Fold mountains are, therefore, not all of the same age. The newest group of fold mountains include the Himalayas, Alps, Rockies, and Andes. During an earlier period of folding (the Carboniferous) the Pennines, Appalachians, the Cape Ranges of South Africa, and the Dividing Range of Australia were uplifted. A still earlier period of folding accounted for the original mountains of Scotland and Norway, of which the present mountains are merely the worn down stumps. The older fold mountains, which have been subjected to the forces of denudation (such as the weather, rivers, glaciers, etc.) for long geological periods, are much lower and less rugged than the newer fold mountains. The term 'new fold' is applied to the mountain ranges which have been folded most recently, but they seem very old when their age in actual years is considered because they were uplifted many millions of years before historic time. Mountain building is a very long and slow process; and in the case of certain mountain chains, such as the Andes and the mountains of Japan, is probably still proceeding.
The new fold mountain systems of the world, except in such instances as the simple low folds of the Weald (South-east England), usually consist of high parallel ranges, the average height being well over 3000 metres. In the Himalayas' the highest peak rises to 8840 metres; in the Andes 7000 metres; in the Rockies 6000 metres; in the Alps to 4600 metres. Vast though these heights appear, the wrinkles of the earth's crust are only slight. The highest mountain in the world (MountEverest) is about five miles high, so that on a globe of 40 cm, diameter it would protrude only 2.5 mm. Most of the active volcanoes are found in the neighbourhood of fold mountains, where the crust of the earth has been fractured during the process of folding. All around the PacificOcean there are many active and extinct volcanoes, as in New Zealand, the East Indies, Japan, and North, Central, and South America. Another belt of active volcanoes is associated with the fold mountains of the West Indies. The mountains of this type are characterised by ruggedness of relief in contrast to the smooth and rounded contours of mountain areas which have been subjected to weathering agents for long periods of time. This is obvious if pictures of the Alps and the Scottish Highlands are compared.
Mountains are effective climatic barriers, and the climates of regions on either side of a high mountain range are very different. For example, the coast lands of British Columbia have an equable climate and a heavy rainfall, while the lands to the east of the Rockies have an extreme climate and light rainfall. Again, the climate of the mountainous areas differs from that of the adjacent lowlands. The great mountain systems of the world are mainly important for their minerals, and, in the temperate zone, for their lumber. In the plateau regions of some mountain systems agriculture has been made possible by irrigation, and above the forests in temperate areas there are valuable alpine pastures. The swift streams of mountains are frequently sources of hydro-electric power, especially in countries which have no coal, such as Switzerland and Norway. In North America, the Western Cordillera provides gold, copper, lead, and silver, especially in the states of Nevada and Montana. The Andes provide tin and copper (Bolivia), gold and platinum
(Colombia), and silver (Peru). The Highlands of East Australia are important for copper and gold. The lumbering industry is specially important in British Columbia, Washington, and Oregon (soft woods), the Central American mountainous lands (hard woods), the Himalayan slopes (teak and sal), and the Scandinavian mountains (soft woods).
To provide food for the mining communities in inaccessible mountain areas, agriculture has been developed. There are numerous irrigation schemes in operation in most of the mountain states of the USA, e.g. at SaltLake City in Utah. Similarly, the Andean states, e.g. Bolivia, grow small quantities of cereals in the plateau areas. Mountain pastures have been utilised most extensively for cattle rearing in Switzerland and Scandinavia. The vast central plateau of Asia is, owing to difficulty of access and climatic extremes, so isolated from other regions that very little development of any kind, on modern lines, has taken place. High mountain ranges are also barriers to communication, and so tend to separate peoples. Traffic across mountains is limited to the passes, which are often so high as to be snowbound in winter. Such ranges as the Alps, Andes, etc. can only be crossed with great difficulty or by expensive tunnelling.
It sometimes happens that movement of the earth's crust occurs along cracks or faults. Where such movement leaves a block of higher land standing between two areas of lower land, the highland is known as a 'Block Mountain' or horst. The Vosges and Black Forest Mountains are examples of such formations These mountains are usually very steep-sided, and often the summit levels are roughly the same.
When an area of highland remains standing above the general level after rivers and other natural agents have lowered the surface of the surrounding area, the name residual mountain is used. Sometimes such highlands are called 'mountains of denudation'. This term can usually be applied to the mountain ridges associated with 'dissected plateaux'. Included in this class are the mountain ridges of the Highlands of Scotland, the Sierras of Central Spain, and the Mesas and Buttes of the western plateaulands of the United States.
Mountains may be formed by volcanic material piled up around a crater, such mountains are popularly known as volcanoes. Research Mountains
Tethys is a satellite of Saturn. It was discovered by Giovanni Domenico Cassini in 1684. It has a nearly circular equatorialorbit at 294,660 km from the planet's centre. Its diameter is 1,060 km and its density is 1,200 kg/m3, indicating a predominantly icy composition. All parts of its surface are heavily cratered. Two outstanding topographic features are the giantOdysseuscrater, 400 km in diameter, and a trench or large valley, Ithaca Chasma, about 100 km in width and several kilometres deep. Research Tethys
A volcano is a vent in the earth's crust from which molten rock, ashes and steam are ejected. The lava tends in time to heap up a conical eminence round the vent, thus forming the crater or cup, or even a volcanic mountain. Research Volcano
Empedocles was a Greek philosopher. He was born in 495 BC at Sicily and died in 435 BC. HE is said to have introduced the democratic form of government in his native city, and the Agrigentines regarded him with the highest veneration as public benefactor, poet, orator, physician, prophet, and magician. Aristotle states that he died in obscurity, at the age of sixty years, in the Peloponnesus; but he is also said to have thrown himself into the crater of MountEtna, in order to make it be believed, by his sudden disappearance, that he was of divine origin. According to Lucian, however, his sandals were thrown out from the volcano, and the manner of his death revealed. Empedocles holds earth, water, fire, air, as the four fundamental and indestructible elements from whose union and separation everything that exists is formed. To these material elements are added the two moving or operative principles of love and hatred, or attraction and repulsion. Research Empedocles
Spartacus was a Thracian soldier who commanded the insurgents in the third Servile War of Rome. Originally a shepherd, he was taken prisoner by the Romans and trained in the gladiators' school at Capua, from whence in 73 BC he escaped with seventy others to the crater of Vesuvius. Having scattered a blockading force, he gathered an army of runaway gladiators and slaves, estimated at around 100,000 men, and devastated Italy from one end to the other until in 71 BC he was defeated and killed by Marcus Crassus. Research Spartacus
In Greek mythology, Atlantis was an island continent, said to have been claimed by the sea following an earthquake. The Greek philosopher Plato created what was once thought to be an imaginary early history for it and described it as a utopia. Research during the early and mid-20th centuries suggested very strongly that the Empire of Atlantis refers to the Minoan empire based on the island of Crete, an empire which was destroyed - as Plato described it 1000 years later - by an enormous volcanic eruption on a nearby island which left a crater over 80 km square, and caused massive tidal waves which washed the people of the surrounding islands to their deaths. Excavated buildings reveal frescoes on their walls with scenes which match the descriptions of a tranquil life based around commerce and the sea described by Plato. However, the Minoan civilisation did not die out with the destruction of the empire. Writings found in Crete which predate the ancient Greek civilization refer to many of the gods associated with later Greek mythology, suggesting that the Greeks adopted at
least some Minoan culture. Research Atlantis
A peptic ulcer is a chronic sore or crater extending through the protective mucousmembrane lining and penetrating the underlying muscular tissue of the gastrointestinal tract. The areas most commonly affected are the upper part of the duodenum, the stomach. The cause of peptic ulcers is largely unknown, but stress is known to be a contributor in some cases. Research Peptic Ulcer
The Matra Durandal is a French air-launched runway cratering bomb produced since 1977. The Durandal is fitted with a 100 kg warhead which is exploded by a timer delay after the bomb has penetrated the surface of the target runway, creating a crater some five metres wide and two metres deep. Research Matra Durandal
About the towns of Petersburg and Richmond, Virginia from June, 1864, to April, 1865, there was the most celebrated campaign of the American Civil War. Gradually Ulysses Simpson Grant had forced Robert E Lee's Army of Northern Virginia southward until the Confederates lay posted about Petersburg and Richmond. Ulysses Simpson Grant's army, including drivers, camp followers, etc., numbered nearly 120,000 men, while Robert E Lee was at the head of about 70,000. By June the 10th, 1864, the Confederates were strongly posted, Robert E Lee, with the main command, at Petersburg, and Longstreet on the left at Chapin's Bluff, the line extending along the Boydton Road and Hatcher's Run eastward.
The campaign was opened by Butler, then commanding the Army of the James at Bermuda Hundred. On June the 10th, a Federal force was sent by him under Gillmore and Kautz to destroy the Appomattox bridges and attempt the capture of Petersburg. This expedition failed signally. On June the 14th, Ulysses Simpson Grant sent Smith with a large force upon a similar expedition. Smith delayed, thus giving the Confederates time to assault and defeat him. Ulysses Simpson Grant lost 9000 men in these two expeditions.
The siege of Petersburg practically commenced on June the 18th. Butler had affected a valuable lodgment at Deep Bottom, and, on the twenty-first, forces under Hancock and Wright endeavored to destroy the Weldon Road, but this was frustrated by Hill, who attacked and defeated the Federals disastrously. Then followed Sheridan's victory at Yellow Tavern and Wilson's and Kautz's raid.
On June the 25th, Burnside proposed and began the construction of a mine to blow up the Confederate lines about Petersburg. This mine was in the process of construction until July the 23rd, and was sprung on July the 30th. It consisted of a shaft 530 feet long with lateral terminations forty feet in each direction and was charged with 8000 pounds of gunpowder. Burnside was to rush into the breach and seize Cemetery Hill, commanding the town. A crater 200 feet long by sixty wide was formed by the explosion, and one Confederate regiment was blown up, but the rest poured such a murderous fire upon the advancing Federals that 4000 men were lost, and the attempt failed.
After this things remained comparatively quiet around Petersburg until February, 1865. Then Robert E Lee, having been appointed commander-in-chief of the entire Confederate force, perceiving that his situation was becoming desperate, determined to evacuate Richmond and Petersburg and join Edward Johnston in the south. To cover his retreat, he sent a strong force on the night of March the 24th, 1865, to assault Fort Steedman. The fort was carried at the first assault, but reinforcements failed to come, and the Federals under Parke quickly repelled the assault. Of 5000 Confederates, 3000 were killed, and Robert E Lee's retreat was prevented. The National line then extended without a break from the Appomattox to Dinwiddie Court House.
Abbreviations
Research Crater
