Limestone
Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such as coral and molluscs. Its major materials are the minerals calcite and aragonite, which are different crystal forms of calcium carbonate, about 10% of sedimentary rocks are limestones. The solubility of limestone in water and weak acid solutions leads to karst landscapes, most cave systems are through limestone bedrock. The first geologist to distinguish limestone from dolomite was Belsazar Hacquet in 1778, like most other sedimentary rocks, most limestone is composed of grains. Most grains in limestone are skeletal fragments of organisms such as coral or foraminifera. Other carbonate grains comprising limestones are ooids, peloids and these organisms secrete shells made of aragonite or calcite, and leave these shells behind when they die. Limestone often contains variable amounts of silica in the form of chert or siliceous skeletal fragment, some limestones do not consist of grains at all, and are formed completely by the chemical precipitation of calcite or aragonite, i. e. travertine.
Secondary calcite may be deposited by supersaturated meteoric waters and this produces speleothems, such as stalagmites and stalactites. Another form taken by calcite is oolitic limestone, which can be recognized by its granular appearance, the primary source of the calcite in limestone is most commonly marine organisms. Some of these organisms can construct mounds of rock known as reefs, below about 3,000 meters, water pressure and temperature conditions cause the dissolution of calcite to increase nonlinearly, so limestone typically does not form in deeper waters. Limestones may form in lacustrine and evaporite depositional environments, calcite can be dissolved or precipitated by groundwater, depending on several factors, including the water temperature, pH, and dissolved ion concentrations. Calcite exhibits a characteristic called retrograde solubility, in which it becomes less soluble in water as the temperature increases. Impurities will cause limestones to exhibit different colors, especially with weathered surfaces, Limestone may be crystalline, granular, or massive, depending on the method of formation.
Crystals of calcite, dolomite or barite may line small cavities in the rock, when conditions are right for precipitation, calcite forms mineral coatings that cement the existing rock grains together, or it can fill fractures. Travertine is a banded, compact variety of limestone formed along streams, particularly there are waterfalls. Calcium carbonate is deposited where evaporation of the leaves a solution supersaturated with the chemical constituents of calcite. Tufa, a porous or cellular variety of travertine, is found near waterfalls, coquina is a poorly consolidated limestone composed of pieces of coral or shells. During regional metamorphism that occurs during the building process, limestone recrystallizes into marble
World War I
World War I, known as the First World War, the Great War, or the War to End All Wars, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. More than 70 million military personnel, including 60 million Europeans, were mobilised in one of the largest wars in history and it was one of the deadliest conflicts in history, and paved the way for major political changes, including revolutions in many of the nations involved. The war drew in all the worlds great powers, assembled in two opposing alliances, the Allies versus the Central Powers of Germany and Austria-Hungary. These alliances were reorganised and expanded as more nations entered the war, Japan, the trigger for the war was the assassination of Archduke Franz Ferdinand of Austria, heir to the throne of Austria-Hungary, by Yugoslav nationalist Gavrilo Princip in Sarajevo on 28 June 1914. This set off a crisis when Austria-Hungary delivered an ultimatum to the Kingdom of Serbia. Within weeks, the powers were at war and the conflict soon spread around the world.
On 25 July Russia began mobilisation and on 28 July, the Austro-Hungarians declared war on Serbia, Germany presented an ultimatum to Russia to demobilise, and when this was refused, declared war on Russia on 1 August. Germany invaded neutral Belgium and Luxembourg before moving towards France, after the German march on Paris was halted, what became known as the Western Front settled into a battle of attrition, with a trench line that changed little until 1917. On the Eastern Front, the Russian army was successful against the Austro-Hungarians, in November 1914, the Ottoman Empire joined the Central Powers, opening fronts in the Caucasus and the Sinai. In 1915, Italy joined the Allies and Bulgaria joined the Central Powers, Romania joined the Allies in 1916, after a stunning German offensive along the Western Front in the spring of 1918, the Allies rallied and drove back the Germans in a series of successful offensives. By the end of the war or soon after, the German Empire, Russian Empire, Austro-Hungarian Empire, national borders were redrawn, with several independent nations restored or created, and Germanys colonies were parceled out among the victors.
During the Paris Peace Conference of 1919, the Big Four imposed their terms in a series of treaties, the League of Nations was formed with the aim of preventing any repetition of such a conflict. This effort failed, and economic depression, renewed nationalism, weakened successor states, and feelings of humiliation eventually contributed to World War II. From the time of its start until the approach of World War II, at the time, it was sometimes called the war to end war or the war to end all wars due to its then-unparalleled scale and devastation. In Canada, Macleans magazine in October 1914 wrote, Some wars name themselves, during the interwar period, the war was most often called the World War and the Great War in English-speaking countries. Will become the first world war in the sense of the word. These began in 1815, with the Holy Alliance between Prussia and Austria, when Germany was united in 1871, Prussia became part of the new German nation. Soon after, in October 1873, German Chancellor Otto von Bismarck negotiated the League of the Three Emperors between the monarchs of Austria-Hungary and Germany
Hercules
Hercules is the Roman adaptation of the Greek divine hero Heracles, who was the son of Zeus and the mortal Alcmene. In classical mythology, Hercules is famous for his strength and for his numerous far-ranging adventures, the Romans adapted the Greek heros iconography and myths for their literature and art under the name Hercules. In Western art and literature and in culture, Hercules is more commonly used than Heracles as the name of the hero. Hercules was a figure with contradictory characteristics, which enabled artists and writers to pick. This article provides an introduction to representations of Hercules in the tradition, Hercules is known for his many adventures, which took him to the far reaches of the Greco-Roman world. One cycle of these adventures became canonical as the Twelve Labours, one traditional order of the labours is found in the Bibliotheca as follows, Slay the Nemean Lion. Capture the Golden Hind of Artemis, clean the Augean stables in a single day. Obtain the girdle of Hippolyta, Queen of the Amazons, obtain the cattle of the monster Geryon.
Steal the apples of the Hesperides, Hercules was a favorite subject for Etruscan art, and appears often on bronze mirrors. The Etruscan form Herceler derives from the Greek Heracles via syncope, a mild oath invoking Hercules was a common interjection in Classical Latin. Hercules had a number of myths that were distinctly Roman, one of these is Hercules defeat of Cacus, who was terrorizing the countryside of Rome. The hero was associated with the Aventine Hill through his son Aventinus, Mark Antony considered him a personal patron god, as did the emperor Commodus. Roman brides wore a belt tied with the knot of Hercules. The comic playwright Plautus presents the myth of Hercules conception as a sex comedy in his play Amphitryon, during the Roman Imperial era, Hercules was worshipped locally from Hispania through Gaul. Tacitus records a special affinity of the Germanic peoples for Hercules, in chapter 3 of his Germania, Tacitus states. They say that Hercules, once visited them, and they have those songs of theirs, by the recital of this barditus as they call it, they rouse their courage, while from the note they augur the result of the approaching conflict.
For, as their line shouts, they inspire or feel alarm, some have taken this as Tacitus equating the Germanic Þunraz with Hercules by way of interpretatio romana. In the Roman era Hercules Club amulets appear from the 2nd to 3rd century, distributed over the empire, mostly made of gold, a specimen found in Köln-Nippes bears the inscription DEO HER, confirming the association with Hercules
World War II
World War II, known as the Second World War, was a global war that lasted from 1939 to 1945, although related conflicts began earlier. It involved the vast majority of the worlds countries—including all of the great powers—eventually forming two opposing alliances, the Allies and the Axis. It was the most widespread war in history, and directly involved more than 100 million people from over 30 countries. Marked by mass deaths of civilians, including the Holocaust and the bombing of industrial and population centres. These made World War II the deadliest conflict in human history, from late 1939 to early 1941, in a series of campaigns and treaties, Germany conquered or controlled much of continental Europe, and formed the Axis alliance with Italy and Japan. Under the Molotov–Ribbentrop Pact of August 1939, Germany and the Soviet Union partitioned and annexed territories of their European neighbours, Finland and the Baltic states. In December 1941, Japan attacked the United States and European colonies in the Pacific Ocean, and quickly conquered much of the Western Pacific.
The Axis advance halted in 1942 when Japan lost the critical Battle of Midway, near Hawaii, in 1944, the Western Allies invaded German-occupied France, while the Soviet Union regained all of its territorial losses and invaded Germany and its allies. During 1944 and 1945 the Japanese suffered major reverses in mainland Asia in South Central China and Burma, while the Allies crippled the Japanese Navy, thus ended the war in Asia, cementing the total victory of the Allies. World War II altered the political alignment and social structure of the world, the United Nations was established to foster international co-operation and prevent future conflicts. The victorious great powers—the United States, the Soviet Union, the United Kingdom, the Soviet Union and the United States emerged as rival superpowers, setting the stage for the Cold War, which lasted for the next 46 years. Meanwhile, the influence of European great powers waned, while the decolonisation of Asia, most countries whose industries had been damaged moved towards economic recovery.
Political integration, especially in Europe, emerged as an effort to end pre-war enmities, the start of the war in Europe is generally held to be 1 September 1939, beginning with the German invasion of Poland and France declared war on Germany two days later. The dates for the beginning of war in the Pacific include the start of the Second Sino-Japanese War on 7 July 1937, or even the Japanese invasion of Manchuria on 19 September 1931. Others follow the British historian A. J. P. Taylor, who held that the Sino-Japanese War and war in Europe and its colonies occurred simultaneously and this article uses the conventional dating. Other starting dates sometimes used for World War II include the Italian invasion of Abyssinia on 3 October 1935. The British historian Antony Beevor views the beginning of World War II as the Battles of Khalkhin Gol fought between Japan and the forces of Mongolia and the Soviet Union from May to September 1939, the exact date of the wars end is not universally agreed upon.
It was generally accepted at the time that the war ended with the armistice of 14 August 1945, rather than the formal surrender of Japan
Aegina
Aegina is one of the Saronic Islands of Greece in the Saronic Gulf,27 kilometres from Athens. Tradition derives the name from Aegina the mother of the hero Aeacus, during ancient times Aegina was a rival of Athens, the great sea power of the era. The municipality of Aegina consists of the island of Aegina and a few offshore islets and it is part of the Islands regional unit, Attica region. The municipality is subdivided into the five communities, Aegina Kypseli Mesagros Perdika Vathy The capital is the town of Aegina. Due to its proximity to Athens, it is a vacation place during the summer months. The province of Aegina was one of the provinces of the Piraeus Prefecture and its territory corresponded with that of the current municipalities Aegina and Agkistri. Aegina is roughly triangular in shape, approximately 15 km from east to west and 10 km from north to south, with an area of 87.41 km2, an extinct volcano constitutes two thirds of Aegina. Economically, the fisheries are of notable importance.
The southern volcanic part of the island is rugged and mountainous and its highest rise is the conical Mount Oros in the south, and the Panhellenian ridge stretches northward with narrow fertile valleys on either side. The beaches are a popular tourist attraction, hydrofoil ferries from Piraeus take only forty minutes to reach Aegina, the regular ferry takes about an hour, with ticket prices for adults within the 4–15 euro range. There are regular bus services from Aegina town to destinations throughout the island such as Agia Marina, portes is a fishing village on the east coast. Aegina, according to Herodotus, was a colony of Epidaurus and its placement between Attica and the Peloponnesus made it a site of trade even earlier, and its earliest inhabitants allegedly came from Asia Minor. Minoan ceramics have been found in contexts of ca.2000 BC, the famous Aegina Treasure, now in the British Museum is estimated to date between 1700 and 1500 BC. It is probable that the island was not doricised before the 9th century BC. e. not than the half of the 7th century BC.
Its early history reveals that the importance of the island dates back to pre-Dorian times. It is usually stated on the authority of Ephorus, that Pheidon of Argos established a mint in Aegina, the first city-state to issue coins in Europe, one stamped stater can be seen in the Bibliothèque Nationale of Paris. It is an electrum stater of a turtle, a sacred to Aphrodite. The fact that the Aeginetic standard of weights and measures was one of the two standards in use in the Greek world is sufficient evidence of the early commercial importance of the island
Landslide
A landslide, known as a landslip, is a form of mass wasting that includes a wide range of ground movements, such as rockfalls, deep failure of slopes, and shallow debris flows. Landslides can occur underwater, called a submarine landslide, although the action of gravity is the primary driving force for a landslide to occur, there are other contributing factors affecting the original slope stability. Typically, pre-conditional factors build up specific sub-surface conditions that make the prone to failure. Landslides occur when the changes from a stable to an unstable condition. A change in the stability of a slope can be caused by a number of factors, slope material that becomes saturated with water may develop into a debris flow or mud flow. The resulting slurry of rock and mud may pick up trees and cars, debris flow is often mistaken for flash flood, but they are entirely different processes. Muddy-debris flows in alpine areas cause severe damage to structures and infrastructure, muddy-debris flows can start as a result of slope-related factors and shallow landslides can dam stream beds, resulting in temporary water blockage.
As the impoundments fail, an effect may be created, with a remarkable growth in the volume of the flowing mass. The solid–liquid mixture can reach densities of up to 2,000 kg/m3, for a small basin in the Italian Alps affected by a debris flow, estimated a peak discharge of 750 m3/s for a section located in the middle stretch of the main channel. At the same section, the maximum foreseeable water discharge, was 19 m3/s. Earthflows are downslope, viscous flows of saturated, fine-grained materials, they can move at speeds from 0.17 to 20 km/h. Though these are a lot like mudflows, overall they are slow moving and are covered with solid material carried along by flow from within. They are different from fluid flows which are more rapid, fine sand and silt, and fine-grained, pyroclastic material are all susceptible to earthflows. The velocity of the earthflow is all dependent on how much content is in the flow itself, if there is more water content in the flow. This thereby creates a bulging lobe which advances with a slow, as these lobes spread out, drainage of the mass increases and the margins dry out, thereby lowering the overall velocity of the flow.
This process causes the flow to thicken, the bulbous variety of earthflows are not that spectacular, but they are much more common than their rapid counterparts. They develop a sag at their heads and are derived from the slumping at the source. Earthflows occur much more during periods of precipitation, which saturates the ground
Classical Greece
Classical Greece was a period of around 200 years in Greek culture. This Classical period saw the annexation of much of modern-day Greece by the Persian Empire, Classical Greece had a powerful influence on the Roman Empire and on the foundations of western civilization. Much of modern Western politics, artistic thought, scientific thought, literature, in the context of the art and culture of Ancient Greece, the Classical period, sometimes called the Hellenic period, corresponds to most of the 5th and 4th centuries BC. The Classical period in this sense follows the Archaic period and is in turn succeeded by the Hellenistic period and this century is essentially studied from the Athenian outlook because Athens has left us more narratives and other written works than the other ancient Greek states. From the perspective of Athenian culture in Classical Greece, the period referred to as the 5th century BC extends slightly into the 4th century BC. In this context, one might consider that the first significant event of this occurs in 508 BC, with the fall of the last Athenian tyrant.
However, a view of the whole Greek world might place its beginning at the Ionian Revolt of 500 BC. The Persians were defeated in 490 BC, the Delian League formed, under Athenian hegemony and as Athens instrument. Athens excesses caused several revolts among the cities, all of which were put down by force. After both forces were spent, a brief peace came about, the war resumed to Spartas advantage, Athens was definitively defeated in 404 BC, and internal Athenian agitations mark the end of the 5th century BC in Greece. Since its beginning, Sparta had been ruled by a diarchy and this meant that Sparta had two kings ruling concurrently throughout its entire history. The two kingships were both hereditary, vested in the Agiad dynasty and the Eurypontid dynasty, according to legend, the respective hereditary lines of these two dynasties sprang from Eurysthenes and Procles, twin descendants of Hercules. They were said to have conquered Sparta two generations after the Trojan War, in 510 BC, Spartan troops helped the Athenians overthrow their king, the tyrant Hippias, son of Peisistratos.
Cleomenes I, king of Sparta, put in place a pro-Spartan oligarchy headed by Isagoras, but his rival Cleisthenes, with the support of the middle class and aided by democrats, took over. Cleomenes intervened in 508 and 506 BC, but could not stop Cleisthenes, through his reforms, the people endowed their city with isonomic institutions — i. e. with equal rights for all —and established ostracism. The isonomic and isegoric democracy was first organized into about 130 demes, the 10,000 citizens exercised their power as members of the assembly, headed by a council of 500 citizens chosen at random. The territory of the city was divided into thirty trittyes as follows, ten trittyes in the coastal region ten trittyes in the ἄστυ. A tribe consisted of three trittyes, selected at random, one each of the three groups
Republic of Venice
It was based in the lagoon communities of the historically prosperous city of Venice. It was a leading European economic and trading power during the Middle Ages, the Venetian city state was founded as a safe haven for people escaping persecution in mainland Europe after the fall of the Roman Empire. In its early years, it prospered on the salt trade, in subsequent centuries, the city state established a thalassocracy. It dominated trade on the Mediterranean Sea, including commerce between Asia and North Africa, the Venetian navy was used in the Crusades. Venice achieved territorial conquests along the Adriatic Sea, the city became home to an extremely wealthy merchant class, who patronized renowned art and architecture along the citys lagoons. Venetian merchants were influential financiers in Europe, the city was the birthplace of great European explorers, including Marco Polo, as well as the classical music composer Vivaldi. The republic was ruled by the Doge, who was elected by members of the Great Council of Venice, the ruling class was an oligarchy of merchants and aristocrats.
Venice and other Italian maritime republics played a key role in fostering capitalism, Venetian citizens generally supported the system of governance. The city-state enforced strict laws and employed ruthless tactics in its prisons, the opening of new trade routes to the Americas and the East Indies via the Atlantic Ocean marked the beginning of Venices decline as a maritime republic. The city state suffered defeats from the navy of the Ottoman Empire, in 1797, the country was colonized by Austria and France, following an invasion by Napoleon Bonaparte. Venice became a part of a unified Italy in the 19th century and it was formally known as the Most Serene Republic of Venice and is often referred to as La Serenissima, in reference to its title as one of the Most Serene Republics. He was the first historical Doge of Venice, whichever the case, the first doges had their power base in Heraclea. Ursuss successor, moved his seat from Heraclea to Malamocco in the 740s and he was the son of Ursus and represented the attempt of his father to establish a dynasty.
Such attempts were more commonplace among the doges of the first few centuries of Venetian history. They desired to remain well-connected to the Empire, another faction, republican in nature, believed in continuing along a course towards practical independence. The other main faction was pro-Frankish, supported mostly by clergy, they looked towards the new Carolingian king of the Franks, Pepin the Short, as the best provider of defence against the Lombards. A minor, pro-Lombard faction was opposed to close ties with any of these further-off powers, the successors of Obelerio inherited a united Venice. By the Pax Nicephori, the two emperors had recognised that Venice belonged to the Byzantine sphere of influence, many centuries later, the Venetians claimed that the treaty had recognised Venetian de facto independence, but the truth of this claim is doubted by modern scholars
Ottoman Empire
After 1354, the Ottomans crossed into Europe, and with the conquest of the Balkans the Ottoman Beylik was transformed into a transcontinental empire. The Ottomans ended the Byzantine Empire with the 1453 conquest of Constantinople by Mehmed the Conqueror, at the beginning of the 17th century the empire contained 32 provinces and numerous vassal states. Some of these were absorbed into the Ottoman Empire, while others were granted various types of autonomy during the course of centuries. With Constantinople as its capital and control of lands around the Mediterranean basin, while the empire was once thought to have entered a period of decline following the death of Suleiman the Magnificent, this view is no longer supported by the majority of academic historians. The empire continued to maintain a flexible and strong economy, however, during a long period of peace from 1740 to 1768, the Ottoman military system fell behind that of their European rivals, the Habsburg and Russian Empires. While the Empire was able to hold its own during the conflict, it was struggling with internal dissent.
Starting before World War I, but growing increasingly common and violent during it, major atrocities were committed by the Ottoman government against the Armenians and Pontic Greeks. The word Ottoman is an anglicisation of the name of Osman I. Osmans name in turn was the Turkish form of the Arabic name ʿUthmān, in Ottoman Turkish, the empire was referred to as Devlet-i ʿAlīye-yi ʿOsmānīye, or alternatively ʿOsmānlı Devleti. In Modern Turkish, it is known as Osmanlı İmparatorluğu or Osmanlı Devleti, the Turkish word for Ottoman originally referred to the tribal followers of Osman in the fourteenth century, and subsequently came to be used to refer to the empires military-administrative elite. In contrast, the term Turk was used to refer to the Anatolian peasant and tribal population, the term Rūmī was used to refer to Turkish-speakers by the other Muslim peoples of the empire and beyond. In Western Europe, the two names Ottoman Empire and Turkey were often used interchangeably, with Turkey being increasingly favored both in formal and informal situations and this dichotomy was officially ended in 1920–23, when the newly established Ankara-based Turkish government chose Turkey as the sole official name.
Most scholarly historians avoid the terms Turkey and Turkish when referring to the Ottomans, as the power of the Seljuk Sultanate of Rum declined in the 13th century, Anatolia was divided into a patchwork of independent Turkish principalities known as the Anatolian Beyliks. One of these beyliks, in the region of Bithynia on the frontier of the Byzantine Empire, was led by the Turkish tribal leader Osman, osmans early followers consisted both of Turkish tribal groups and Byzantine renegades, many but not all converts to Islam. Osman extended the control of his principality by conquering Byzantine towns along the Sakarya River and it is not well understood how the early Ottomans came to dominate their neighbours, due to the scarcity of the sources which survive from this period. One school of thought which was popular during the twentieth century argued that the Ottomans achieved success by rallying religious warriors to fight for them in the name of Islam, in the century after the death of Osman I, Ottoman rule began to extend over Anatolia and the Balkans.
Osmans son, captured the northwestern Anatolian city of Bursa in 1326 and this conquest meant the loss of Byzantine control over northwestern Anatolia. The important city of Thessaloniki was captured from the Venetians in 1387, the Ottoman victory at Kosovo in 1389 effectively marked the end of Serbian power in the region, paving the way for Ottoman expansion into Europe
Morean War
The Morean War is the better-known name for the Sixth Ottoman–Venetian War. The war was fought between 1684–1699, as part of the conflict known as the Great Turkish War, between the Republic of Venice and the Ottoman Empire. Military operations ranged from Dalmatia to the Aegean Sea, but the major campaign was the Venetian conquest of the Morea peninsula in southern Greece. As such, the Morean War holds the distinction of being the only Ottoman–Venetian conflict from which Venice emerged victorious, venices expansionist revival would be short-lived however, as its gains were reversed by the Ottomans in 1715. However, with the rise of the Ottomans, during the 16th and early 17th centuries, they lost most of these, such as Cyprus and Euboea to the Turks. Between 1645 and 1669, the Venetians and the Ottomans fought a long and costly war over the last major Venetian possession in the Aegean, Crete. During this war, the Venetian commander, Francesco Morosini, came into contact with the rebellious Maniots, in 1659, Morosini landed in the Morea, and together with the Maniots, he took Kalamata.
However, he was soon forced to return to Crete. In 1683, a new war broke out between Austria and the Ottomans, with a large Ottoman army advancing towards Vienna, the Ottoman siege was broken in the Battle of Vienna by the King of Poland, Jan Sobieski. As a result, an anti-Ottoman Holy League was formed at Linz on 5 March 1684 between Emperor Leopold I, and the Doge of Venice, Marcantonio Guistinian. Over the next few years, the Austrians recovered Hungary from Ottoman control, however the Austrians were now overextended, as well as being embroiled in the Nine Years War against France. The Ottomans, under another Köprülü Grand Vizier, Fazıl Mustafa Pasha, regained the initiative and pushed the Austrians back, recovering Niš and Vidin in 1690 and launching raids across the Danube. After 1696, the tide turned again, with the capture of Azov by the Russians in 1696 followed by a defeat at the hands of Eugene of Savoy at the battle of Zenta in September 1697. In its aftermath, negotiations began between the parties, leading to the signing of the Treaty of Karlowitz in 1699.
On the Venetian side, the debate in the Senate about joining the war was heated and they were complemented by a numerous and well-equipped militia, but the latter could not be used outside Italy. Revenue was scarce, at more than two million sequins a year. At the same time, the Ottoman navy is described by Chandos as being in a sore state, scarcely able to outfit ten men-of-war for operations. This left the Venetians with an uncontested supremacy at sea, while the Ottomans resorted to using light and fast galleys to evade the Venetian fleet and resupply their fortresses along the coasts
Island
An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, skerries, an island in a river or a lake island may be called an eyot or ait, and a small island off the coast may be called a holm. A grouping of geographically or geologically related islands is called an archipelago, an island may be described as such, despite the presence of an artificial land bridge. Example and its causeway, or the various Dutch delta islands, there are two main types of islands in the sea and oceanic. The word island derives from Middle English iland, from Old English igland, Old English ieg is actually a cognate of Swedish ö and German Aue, and related to Latin aqua. There is a difference between islands and continents in terms of geology, continents sit on continental lithosphere which is part of tectonic plates floating high on Earths mantle. Oceanic crust is part of tectonic plates, but it is denser than continental lithosphere, Islands are either extensions of the oceanic crust or geologically they are part of some continent sitting on continental lithosphere.
This holds true for Australia, which sits on its own continental lithosphere, continental islands are bodies of land that lie on the continental shelf of a continent. A special type of island is the microcontinental island, which is created when a continent is rifted. Examples are Madagascar and Socotra off Africa, the Kerguelen Islands, New Caledonia, New Zealand, another subtype is an island or bar formed by deposition of tiny rocks where water current loses some of its carrying capacity. While some are transitory and may disappear if the volume or speed of the current changes, others are stable, oceanic islands are islands that do not sit on continental shelves. The vast majority are volcanic in origin, such as Saint Helena in the South Atlantic Ocean, the few oceanic islands that are not volcanic are tectonic in origin and arise where plate movements have lifted up the ocean floor above the surface. Examples are Saint Peter and Paul Rocks in the Atlantic Ocean, one type of volcanic oceanic island is found in a volcanic island arc.
These islands arise from volcanoes where the subduction of one plate under another is occurring, examples are the Aleutian Islands, the Mariana Islands, and most of Tonga in the Pacific Ocean. The only examples in the Atlantic Ocean are some of the Lesser Antilles, another type of volcanic oceanic island occurs where an oceanic rift reaches the surface. There are two examples, which is the second largest volcanic island, and Jan Mayen. A third type of oceanic island is formed over volcanic hotspots. A hotspot is more or less stationary relative to the tectonic plate above it
