A cave is a hollow place in the ground, specifically a natural underground space large enough for a human to enter. Caves form naturally by the weathering of rock and often extend deep underground, the word cave can refer to much smaller openings such as sea caves, rock shelters, and grottos. A cavern is a type of cave, naturally formed in soluble rock with the ability to grow speleothems. Speleology is the science of exploration and study of all aspects of caves, visiting or exploring caves for recreation may be called caving, potholing, or spelunking. The formation and development of caves is known as speleogenesis, which can occur over the course of millions of years, caves are formed by various geologic processes and can be variable sizes. These may involve a combination of processes, erosion from water, tectonic forces, pressure. Isotopic dating techniques can be applied to cave sediments, in order to determine the timescale when geologic events may have occurred to help form and it is estimated that the maximum depth of a cave cannot be more than 3,000 metres due to the pressure of overlying rocks.
For karst caves the maximum depth is determined on the basis of the limit of karst forming processes. Most caves are formed in limestone by dissolution, solutional caves or karst caves are the most frequently occurring caves and such caves form in rock that is soluble. Most occur in limestone, but they can form in other rocks including chalk, marble, salt. Rock is dissolved by acid in groundwater that seeps through bedding planes, joints. Over geological epochs cracks expand to become caves and cave systems, the largest and most abundant solutional caves are located in limestone. Limestone dissolves under the action of rainwater and groundwater charged with H2CO3, the dissolution process produces a distinctive landform known as karst, characterized by sinkholes and underground drainage. Limestone caves are often adorned with calcium carbonate formations produced through slow precipitation and these include flowstones, stalagmites, soda straws and columns. These secondary mineral deposits in caves are called speleothems, the portions of a solutional cave that are below the water table or the local level of the groundwater will be flooded.
Lechuguilla Cave in New Mexico and nearby Carlsbad Cavern are now believed to be examples of type of solutional cave. They were formed by H2S gas rising from below, where reservoirs of oil give off sulfurous fumes and this gas mixes with ground water and forms H2SO4. The acid dissolves the limestone from below, rather than from above, caves formed at the same time as the surrounding rock are called primary caves
Forty-eight of the fifty states and the federal district are contiguous and located in North America between Canada and Mexico. The state of Alaska is in the northwest corner of North America, bordered by Canada to the east, the state of Hawaii is an archipelago in the mid-Pacific Ocean. The U. S. territories are scattered about the Pacific Ocean, the geography and wildlife of the country are extremely diverse. At 3.8 million square miles and with over 324 million people, the United States is the worlds third- or fourth-largest country by area, third-largest by land area. It is one of the worlds most ethnically diverse and multicultural nations, paleo-Indians migrated from Asia to the North American mainland at least 15,000 years ago. European colonization began in the 16th century, the United States emerged from 13 British colonies along the East Coast. Numerous disputes between Great Britain and the following the Seven Years War led to the American Revolution. On July 4,1776, during the course of the American Revolutionary War, the war ended in 1783 with recognition of the independence of the United States by Great Britain, representing the first successful war of independence against a European power.
The current constitution was adopted in 1788, after the Articles of Confederation, the first ten amendments, collectively named the Bill of Rights, were ratified in 1791 and designed to guarantee many fundamental civil liberties. During the second half of the 19th century, the American Civil War led to the end of slavery in the country. By the end of century, the United States extended into the Pacific Ocean. The Spanish–American War and World War I confirmed the status as a global military power. The end of the Cold War and the dissolution of the Soviet Union in 1991 left the United States as the sole superpower. The U. S. is a member of the United Nations, World Bank, International Monetary Fund, Organization of American States. The United States is a developed country, with the worlds largest economy by nominal GDP. It ranks highly in several measures of performance, including average wage, human development, per capita GDP. While the U. S. economy is considered post-industrial, characterized by the dominance of services and knowledge economy, the United States is a prominent political and cultural force internationally, and a leader in scientific research and technological innovations.
In 1507, the German cartographer Martin Waldseemüller produced a map on which he named the lands of the Western Hemisphere America after the Italian explorer and cartographer Amerigo Vespucci
Spalling and spallation both describe the process of surface failure in which spall is shed. The terms spall and spalling have been adopted by particle physicists, in neutron scattering instruments, the neutrons that are ejected from the target are known as spall. Mechanical spalling occurs at high stress contact points, for example, spalling occurs in preference to brinelling where the maximal shear stress occurs not at the surface, but just below, shearing the spall off. When such bubbles collapse, a high pressure can cause spalling on adjacent surfaces. The resulting spall is dangerous to crew and equipment, and may result in a partial or complete disablement of a vehicle and/or its crew, many AFVs are equipped with spall liners inside their armor for protection. A kinetic energy penetrator, if it can defeat the armor, generally causes spalling within the target as well, spalling is a common mechanism of rock weathering, and occurs at the surface of a rock when there are large shear stresses under the surface.
This form of mechanical weathering can be caused by freezing and thawing, thermal expansion and contraction, unloading is the release of pressure due to the removal of an overburden. When the pressure is reduced rapidly, the expansion of the rock causes high surface stress. Freeze thaw weathering is caused by moisture freezing inside cracks in rock, upon freezing its volume expands, causing large forces which cracks spall off the outer surface. As this cycle repeats the outer surface repeatedly undergoes spalling, resulting in weathering, some stone and masonry surfaces used as building surfaces will absorb moisture at their surface. If exposed to freezing conditions the surface may flake off due to the expansion of the water. This effect can be seen in terra-cotta surfaces if there is an entrance for water at the edges, exfoliation is the gradual removing of spall due to the cyclic increase and decrease in the temperature of the surface layers of the rock. Rocks do not conduct heat well, so when they are exposed to heat the outermost layer becomes much hotter than the rock underneath causing differential thermal expansion.
This differential expansion causes sub-surface shear stress, in turn causing spalling, extreme temperature change, such as forest fires, can cause spalling of rock. This mechanism of weathering causes the surface of the rock to fall off in thin fragments, sheets or flakes. Salt spalling is a type of weathering which occurs in porous building materials, such as brick, natural stone, tiles. Dissolved salt is carried through the material in water and crystallizes inside the material near the surface as the water evaporates, as the salt crystals expand this builds up shear stresses which break away spall from the surface. Great care and expert advice must be consulted, however, to ensure that any coating is compatible with the substrate in terms of breathability, chimneys show spalling damage before other portions of buildings because they are more exposed to the elements
Belgium, officially the Kingdom of Belgium, is a sovereign state in Western Europe bordered by France, the Netherlands, Germany and the North Sea. It is a small, densely populated country which covers an area of 30,528 square kilometres and has a population of about 11 million people. Additionally, there is a group of German-speakers who live in the East Cantons located around the High Fens area. Historically, the Netherlands and Luxembourg were known as the Low Countries, the region was called Belgica in Latin, after the Roman province of Gallia Belgica. From the end of the Middle Ages until the 17th century, Belgium is a federal constitutional monarchy with a parliamentary system of governance. It is divided into three regions and three communities, that exist next to each other and its two largest regions are the Dutch-speaking region of Flanders in the north and the French-speaking southern region of Wallonia. The Brussels-Capital Region is a bilingual enclave within the Flemish Region. A German-speaking Community exists in eastern Wallonia, Belgiums linguistic diversity and related political conflicts are reflected in its political history and complex system of governance, made up of six different governments.
Upon its independence, declared in 1830, Belgium participated in the Industrial Revolution and, during the course of the 20th century, possessed a number of colonies in Africa. This continuing antagonism has led to several far-reaching reforms, resulting in a transition from a unitary to a federal arrangement during the period from 1970 to 1993. Belgium is a member of the Eurozone, NATO, OECD and WTO. Its capital, hosts several of the EUs official seats as well as the headquarters of major international organizations such as NATO. Belgium is a part of the Schengen Area, Belgium is a developed country, with an advanced high-income economy and is categorized as very high in the Human Development Index. A gradual immigration by Germanic Frankish tribes during the 5th century brought the area under the rule of the Merovingian kings, a gradual shift of power during the 8th century led the kingdom of the Franks to evolve into the Carolingian Empire. Many of these fiefdoms were united in the Burgundian Netherlands of the 14th and 15th centuries, the Eighty Years War divided the Low Countries into the northern United Provinces and the Southern Netherlands.
The latter were ruled successively by the Spanish and the Austrian Habsburgs and this was the theatre of most Franco-Spanish and Franco-Austrian wars during the 17th and 18th centuries. The reunification of the Low Countries as the United Kingdom of the Netherlands occurred at the dissolution of the First French Empire in 1815, although the franchise was initially restricted, universal suffrage for men was introduced after the general strike of 1893 and for women in 1949. The main political parties of the 19th century were the Catholic Party, French was originally the single official language adopted by the nobility and the bourgeoisie
Charcoal is a lightweight, black residue, consisting of carbon and any remaining ash, obtained by removing water and other volatile constituents from animal and vegetation substances. Charcoal is usually produced by slow pyrolysis- the heating of wood or other substances in the absence of oxygen, the whole pile is covered with turf or moistened clay. The firing is begun at the bottom of the flue, the success of the operation depends upon the rate of the combustion. The operation is so delicate that it was left to colliers. They often lived alone in small huts in order to tend their wood piles, for example, in the Harz Mountains of Germany, charcoal burners lived in conical huts called Köten which are still much in evidence today. The massive production of charcoal was a cause of deforestation. The increasing scarcity of easily harvested wood was a factor behind the switch to fossil fuel equivalents, mainly coal. Charcoal made at 300 °C is brown and friable, and readily inflames at 380 °C, made at higher temperatures it is hard and brittle, in Finland and Scandinavia, the charcoal was considered the by-product of wood tar production.
The best tar came from pine, thus pinewoods were cut down for tar pyrolysis, the residual charcoal was widely used as substitute for metallurgical coke in blast furnaces for smelting. Tar production led to deforestation, it has been estimated all Finnish forests are younger than 300 years. The end of tar production at the end of the 19th century resulted in rapid re-forestation, the charcoal briquette was first invented and patented by Ellsworth B. A. Zwoyer of Pennsylvania in 1897 and was produced by the Zwoyer Fuel Company. The process was popularized by Henry Ford, who used wood. Ford Charcoal went on to become the Kingsford Company, Charcoal has been made by various methods. The traditional method in Britain used a clamp and this is essentially a pile of wooden logs leaning against a chimney. The chimney consists of 4 wooden stakes held up by some rope, the logs are completely covered with soil and straw allowing no air to enter. It must be lit by introducing some burning fuel into the chimney, if the soil covering gets torn by the fire, additional soil is placed on the cracks.
Once the burn is complete, the chimney is plugged to prevent air from entering, the true art of this production method is in managing the sufficient generation of heat, and its transfer to wood parts in the process of being carbonised. A strong disadvantage of this method is the huge amount of emissions that are harmful to human health
Sites may range from those with few or no remains visible above ground, to buildings and other structures still in use. Beyond this, the definition and geographical extent of a site can vary widely, depending on the period studied and it is almost invariably difficult to delimit a site. It is sometimes taken to indicate a settlement of some sort although the archaeologist must define the limits of human activity around the settlement, any episode of deposition such as a hoard or burial can form a site as well. Development-led archaeology undertaken as cultural resources management has the disadvantage of having its sites defined by the limits of the intended development, even in this case however, in describing and interpreting the site, the archaeologist will have to look outside the boundaries of the building site. According to Jess Beck in “How Do Archaeologists find sites. ”The areas with a number of artifacts are good targets for future excavation. The most common person to have found artifacts are farmers who are plowing their fields or just cleaning them up often find archaeological artifacts, many people who are out hiking and even pilots find artifacts they usually end up reporting them to archaeologist to do further investigation.
When they find sites, they have to first record the area and if they have the money, there are many ways to find sites, one example can be through surveys. Surveys involve walking around analyzing the land looking for artifacts. ”This helps archaeologists in the future. In case there was no time, or money during the finding of the site, archaeologists can come back, archaeologist can sample randomly within a given area of land as another form of conducting surveys. Surveys are very useful, according to Jess Beck, “it can tell you where people were living at different points in the past. ”Geophysics is a branch of survey becoming more and more popular in archaeology, because it uses different types of instruments to investigate features below the ground surface. It is not as reliable, because although they can see what is under the surface of the ground it does not produce the best picture, Archaeologists have to still dig up the area in order to uncover the truth. There are two most common types of survey, which is, magnetometer and ground penetrating radar.
Magnetometry is the technique of measuring and mapping patterns of magnetism in the soil and it uses an instrument called a magnetometer which is required to measure and map traces of soil magnetism. The ground penetrating radar is a method that uses radar pulses to image the subsurface and it uses electro magnetic radiation in the microwave band of the radio spectrum, and detects the reflected signals from subsurface structures. There are many tools that can be used to find artifacts. This tool is helpful to archaeologists who want to explore in a different area. They can use this tool to see what has already been discovered, with this information available, archaeologists can expand their research and add more to what has already been found. Traditionally, sites are distinguished by the presence of artifacts and features
Bosnia and Herzegovina
Bosnia and Herzegovina, sometimes called Bosnia-Herzegovina, and, in short, often known informally as Bosnia, is a country in Southeastern Europe located on the Balkan Peninsula. Sarajevo is the capital and largest city, in the central and eastern interior of the country the geography is mountainous, in the northwest it is moderately hilly, and the northeast is predominantly flatland. The inland is a larger region and has a moderate continental climate, with hot summers and cold. The southern tip of the country has a Mediterranean climate and plain topography and Herzegovina is a region that traces permanent human settlement back to the Neolithic age and after which it was populated by several Illyrian and Celtic civilizations. Culturally and socially, the country has a rich history, the Ottomans brought Islam to the region, and altered much of the cultural and social outlook of the country. This was followed by annexation into the Austro-Hungarian Monarchy, which lasted up until World War I.
In the interwar period, Bosnia was part of the Kingdom of Yugoslavia and after World War II, following the dissolution of Yugoslavia, the country proclaimed independence in 1992, which was followed by the Bosnian War, lasting until late 1995. The country is home to three ethnic groups or, constituent peoples, as specified in the constitution. Bosniaks are the largest group of the three, with Serbs second and Croats third, a native of Bosnia and Herzegovina, regardless of ethnicity, is identified in English as a Bosnian. The terms Herzegovinian and Bosnian are maintained as a rather than ethnic distinction. Moreover, the country was simply called Bosnia until the Austro-Hungarian occupation at the end of the 19th century and Herzegovina has a bicameral legislature and a three-member Presidency composed of a member of each major ethnic group. The Federation of Bosnia and Herzegovina is itself complex and consists of 10 cantons, the country has been a member of the Council of Europe since April 2002 and a founding member of the Mediterranean Union upon its establishment in July 2008.
The name is believed to have derived from the hydronym of the river Bosna coursing through the Bosnian heartland. According to philologist Anton Mayer the name Bosna could be derived from Illyrian Bass-an-as which would be a diversion of the Proto-Indo-European root bos or bogh, meaning the running water. According to English medievalist William Miller the Slavic settlers in Bosnia adapted the Latin designation Basante, to their own idiom by calling the stream Bosna, the name Herzegovina originates from Bosnian magnate Stephen Vukčić Kosačas title, Herceg of Hum and the Coast. Hum, formerly Zahumlje, was a medieval principality that was conquered by the Bosnian Banate in the first half of the 14th century. Bosnia is located in the western Balkans, bordering Croatia to the north and west, Serbia to the east and it has a coastline about 20 kilometres long surrounding the city of Neum. It lies between latitudes 42° and 46° N, and longitudes 15° and 20° E, the countrys name comes from the two regions Bosnia and Herzegovina, which have a very vaguely defined border between them
Kozarnika or Peshtera Kozarnika is a cave in northwestern Bulgaria that was used as a hunters’ shelter as early as the Lower Paleolithic. It marks an older route of human migration from Africa to Europe via the Balkans. The cave probably keeps the earliest evidence of symbolic behaviour. Kozarnika cave is located 6 km from the town of Belogradchik in northwestern Bulgaria, on the slopes of the Balkan Mountains. It is opened to the south, at 85 m above the valley, with its length of 210 m, the cave is among the small-sized in the Belogradchick karst region. The Kozarnika cave project started in 1984, since 1996, it has been headed by Dr. Prof. Nikolay Sirakov and Dr. Jean-Luc Guadelli. In the ground layers, dated to 1. 6–1, the findings from Middle Paleolithic layers, rather bifacial points, dating from 300, 000–50,000 BP prove presence of hunters’ groups possibly of Homo neanderthalensis. Upper Paleolithic layers consist flint assemblages from the earliest European Gravette complex dating from 43,000 up to 39,000 BP belonging to Homo sapiens sapiens, magura Cave Bacho Kiro cave Sićevo Gorge Peștera cu Oase Vértesszőlős Proto-Indo-Europeans Campanian Ignimbrite Eruption Rincon, Paul
In other words, a floodplain is an area near a river or a stream which floods when the water level reaches flood stage. Flood plains are made by a meander eroding sideways as it travels downstream, when a river breaks its banks and floods, it leaves behind layers of alluvium. These gradually build up to create the floor of the flood plain, floodplains generally contain unconsolidated sediments, often extending below the bed of the stream. These are accumulations of sand, loam, and/or clay, and are often important aquifers, geologically ancient floodplains are often represented in the landscape by fluvial terraces. These are old floodplains that remain relatively high above the present floodplain and it is probable that any section of such an alluvial plain would show deposits of a similar character. The floodplain during its formation is marked by meandering or anastomotic streams, oxbow lakes and bayous, marshes or stagnant pools, and is occasionally completely covered with water. When the drainage system has ceased to act or is diverted for any reason.
The floodplain differs, because it is not altogether flat and it has a gentle slope downstream, and often, for a distance, from the side towards the center. The floodplain is the place for a river to dissipate its energy. Meanders form over the floodplain to slow down the flow of water, in terms of flood management the upper part of the floodplain is crucial as this is where the flood water control starts. Artificial canalisation of the river here will have a impact on wider flooding. This is the basis of flood management. Floodplains can support particularly rich ecosystems, both in quantity and diversity, tugay forests form an ecosystem associated with floodplains, especially in Central Asia. They are a category of riparian zones or systems, a floodplain can contain 100 or even 1,000 times as many species as a river. Microscopic organisms thrive and larger species enter a rapid breeding cycle, opportunistic feeders move in to take advantage. The production of nutrients peaks and falls away quickly, however the surge of new growth endures for some time and this makes floodplains particularly valuable for agriculture.
River flow rates are undergoing change following suit with climate change and this change is a threat to the riparian zones and other flood plain forests. These forests have over time synced their seedling deposits after the peaks in flow to best take advantage of the nutrient rich soil generated by peak flow
Cave paintings are painted drawings on cave walls or ceilings, mainly of prehistoric origin, to some 40,000 years ago in Eurasia. The exact purpose of the Paleolithic cave paintings is not known, evidence suggests that they were not merely decorations of living areas since the caves in which they have been found do not have signs of ongoing habitation. They are located in areas of caves that are not easily accessible. Some theories hold that cave paintings may have been a way of communicating with others, the paintings are remarkably similar around the world, with animals being common subjects that give the most impressive images. Humans mainly appear as images of hands, mostly hand stencils made by blowing pigment on a hand held to the wall. The earliest known cave paintings/drawings of animals are at least 35,000 years old and are found in Pettakere cave on the island of Sulawesi in Indonesia, previously it was believed that the earliest paintings were in Europe. The earliest non-figurative rock art dates back to approximately 40,000 years ago, nearly 340 caves have now been discovered in France and Spain that contain art from prehistoric times.
But subsequent technology has made it possible to date the paintings by sampling the pigment itself, the choice of subject matter can indicate chronology. For instance, the reindeer depicted in the Spanish cave of Cueva de las Monedas places the drawings in the last Ice Age. The oldest date given to a cave painting is now a pig that has a minimum age of 35,400 years old at Pettakere cave in Sulawesi. Indonesian and Australian scientists have dated other non-figurative paintings on the walls to be approximately 40,000 years old, the method they used to confirm this was dating the age of the stalactites that formed over the top of the paintings. The art is similar in style and method to that of the Indonesian caves as there were hand stencils and this date coincides with the earliest known evidence for Homo sapiens in Europe. Because of the cave arts age, some scientists have conjectured that the paintings may have made by Neanderthals. The earliest known European figurative cave paintings are those of Chauvet Cave in France and these paintings date to earlier than 30,000 BCE according to radiocarbon dating.
Some researchers believe the drawings are too advanced for this era, the radiocarbon dates from these samples show that there were two periods of creation in Chauvet,35,000 years ago and 30,000 years ago. In 2009, cavers discovered drawings in Coliboaia Cave in Romania, an initial dating puts the age of an image in the same range as Chauvet, about 32,000 years old. Some caves probably continued to be painted over a period of thousands of years. This was created roughly between 10,000 and 5,500 years ago, and painted in rock shelters under cliffs or shallow caves, though individual figures are less naturalistic, they are grouped in coherent grouped compositions to a much greater degree
The Areni-1 cave complex is located near the Areni village in southern Armenia along the Arpa River. In 2010, it was announced that the earliest known shoe was found at the site, in January 2011, the earliest known winery in the world was announced to have been found. Also in 2011, the discovery of a straw skirt dating to 3900 BC was reported, in 2009, the oldest brain was discovered