In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers. The stratum is the unit in a stratigraphic column and forms the basis of the study of stratigraphy. Each layer is one of a number of parallel layers that lie one upon another. They may extend over hundreds of thousands of kilometers of the Earths surface. Strata are typically seen as bands of different colored or differently structured material exposed in cliffs, road cuts, individual bands may vary in thickness from a few millimeters to a kilometer or more. Each band represents a mode of deposition, river silt, beach sand, coal swamp, sand dune, lava bed. Geologists study rock strata and categorize them by the material of beds, each distinct layer is typically assigned to the name of sheet, usually based on a town, mountain, or region where the formation is exposed and available for study. For example, the Burgess Shale is an exposure of dark, occasionally fossiliferous.
Slight distinctions in material in a formation may be described as members, formations are collected into groups while groups may be collected into supergroups. Archaeological horizon Geologic formation Geologic map Geologic unit Law of superposition Bed GeoWhen Database
Sandstone is a clastic sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz or feldspar because these are the most common minerals in the Earths crust, like sand, sandstone may be any color, but the most common colors are tan, yellow, grey, pink and black. Since sandstone beds often form highly visible cliffs and other topographic features, quartz-bearing sandstone is converted into quartzite through heating and pressure, usually related to tectonic compression within orogenic belts. They are formed from cemented grains that may either be fragments of a rock or be mono-minerallic crystals. The cements binding these grains together are typically calcite, grain sizes in sands are defined within the range of 0.0625 mm to 2 mm. The formation of sandstone involves two principal stages, first, a layer or layers of sand accumulates as the result of sedimentation, either from water or from air. Typically, sedimentation occurs by the settling out from suspension.
The most common cementing materials are silica and calcium carbonate, which are derived either from dissolution or from alteration of the sand after it was buried. Colours will usually be tan or yellow, a predominant additional colourant in the southwestern United States is iron oxide, which imparts reddish tints ranging from pink to dark red, with additional manganese imparting a purplish hue. Red sandstones are seen in the Southwest and West of Britain, as well as central Europe. The regularity of the latter favours use as a source for masonry, either as a building material or as a facing stone. These physical properties allow the grains to survive multiple recycling events. Quartz grains evolve from rock, which are felsic in origin. Feldspathic framework grains are commonly the second most abundant mineral in sandstones, Feldspar can be divided into two smaller subdivisions, alkali feldspars and plagioclase feldspars. The different types of feldspar can be distinguished under a petrographic microscope, below is a description of the different types of feldspar.
Alkali feldspar is a group of minerals in which the composition of the mineral can range from KAlSi3O8 to NaAlSi3O8. Plagioclase feldspar is a group of solid solution minerals that range in composition from NaAlSi3O8 to CaAl2Si2O8. Lithic framework grains are pieces of ancient source rock that have yet to weather away to individual mineral grains, accessory minerals are all other mineral grains in a sandstone, commonly these minerals make up just a small percentage of the grains in a sandstone
Groundwater is the water present beneath Earths surface in soil pore spaces and in the fractures of rock formations. A unit of rock or a deposit is called an aquifer when it can yield a usable quantity of water. The depth at which pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from, and eventually flows to, the naturally, natural discharge often occurs at springs and seeps. Groundwater is withdrawn for agricultural and industrial use by constructing and operating extraction wells. The study of the distribution and movement of groundwater is hydrogeology, Groundwater is hypothesized to provide lubrication that can possibly influence the movement of faults. It is likely that much of Earths subsurface contains some water, Groundwater may not be confined only to Earth. The formation of some of the landforms observed on Mars may have influenced by groundwater. There is evidence that water may exist in the subsurface of Jupiters moon Europa.
Groundwater is often cheaper, more convenient and less vulnerable to pollution than surface water, therefore, it is commonly used for public water supplies. For example, groundwater provides the largest source of water storage in the United States. Underground reservoirs contain far more water than the capacity of all surface reservoirs and lakes in the US, many municipal water supplies are derived solely from groundwater. Polluted groundwater is less visible, but more difficult to clean up, than pollution in rivers, Groundwater pollution most often results from improper disposal of wastes on land. An aquifer is a layer of substrate that contains and transmits groundwater. When water can flow directly between the surface and the zone of an aquifer, the aquifer is unconfined. The deeper parts of unconfined aquifers are more saturated since gravity causes water to flow downward. The upper level of this layer of an unconfined aquifer is called the water table or phreatic surface. Below the water table, where in general all pore spaces are saturated with water, is the phreatic zone, substrate with low porosity that permits limited transmission of groundwater is known as an aquitard
United States Naval Construction Battalions - better known as Seabees, a heterograph of the first initials - C. B. comprise US Naval Construction Forces. International law made it illegal for civilians to resist enemy attack, doing so would classify them as guerrillas, the Seabees would consist of skilled workers that would be trained to drop their tools if necessary and take up their weapons at a moments notice to defend themselves. The concept model, A USMC trained Battalion of construction tradesmen that would be capable of, any type of construction, anywhere needed and it was quickly realized that this model could be utilized in every theater of operations as it was seen to be flexible and adaptable. The use of USMC organization allowed for smooth co-ordination, integration or interface of both the NCF and the Marine Corps elements, in addition, Seabee Battalions could be deployed individually or in multiples as the project scope and scale dictated. What distinguishes Seabees from Combat Engineers are the skill sets, Combat Engineering is but a sub-set in the Seabee toolbox.
They have a legacy of creative field ingenuity stretching from Normandy and Okinawa to Iraq. Seabees believe that anything they are tasked with they Can Do and they were unique at conception and remain so today. In 2017, the Seabees celebrated 75 years of service and have not changed from Admiral Ben Moreells conceptual model, as far back as the War of 1812, US Navy seamen were employed in large numbers for major shore construction. In 1813, under command of Captain David Porter, rounded Cape Horn from the Atlantic Ocean, after capturing several British ships he discovered that a British naval squadron had been sent to search for him. Needing to repair and prepare Essex and his squadron, he sailed for the Marquesas Islands to find a suitable site for him to build the US Navys first advanced base. During construction they were attacked by unfriendly natives, during which they would have to lay down their tools. It wasnt until World War I that Navy craftsmen would be employed in large number again, in 1917, the Twelfth Regiment was organized at Naval Training Station Great Lakes.
This allowed the Public Works Department to grow to nearly 600 men by July 1917 and they were organized into the Twelfth Regiment, which was essentially the Public Works Department because staff officers could not exercise military command. Lieutenant William C. Davis was appointed commanding officer of the regiment, he exercised military control, in October 1917, the regiment began building Camp Paul Jones. With its completion, on 30 December 1917, the regiment became operational with 1,500 men organized into three battalions. By April 1918, the regiment consisted of 2,400 in five battalions, men were withdrawn for assignments in the US and abroad. In spring of 1918,100 men were given special mechanics and ordnance training before being sent to St. Nazaire, they would join the gun crews and perform combat duties along the railway lines in proximity to the German lines. The Twelfth Regiment reached its peak strength 5 November 1918,55 officers and 6,211 enlisted men formed into 11 battalions, with the end of the war on 11 November 1918, the regiment gradually faded away by the end of 1918
Artois is a region of northern France. Its territory has an area of around 4,000 km² and its principal cities are Arras, Saint-Omer, Lens and Béthune. Artois occupies the interior of the Pas-de-Calais département, the part of which constitutes the former Boulonnais. Artois roughly corresponds to the arrondissements of Arras, Béthune, Saint Omer, and Lens, and it occupies the western end of the coalfield which stretches eastward through the neighbouring Nord département and across central Belgium. Originally a feudal county itself, Artois was annexed by the county of Flanders and it came to France in 1180 as a dowry of a Flemish princess, Isabelle of Hainaut, and was again made a separate county in 1237 for Robert, a grandson of Isabelle. Through inheritance, Artois came under the rule of the dukes of Burgundy in 1384, at the death of the fourth duke, Charles the Bold, Artois was inherited by the Habsburgs and passed to the dynastys Spanish line. After the religious revolts of 1566 in the Netherlands, Artois briefly entered the Dutch Revolt in 1576, after the Union of Atrecht and Hainaut reached a separate agreement with Philip II.
Artois remained with the Spanish Netherlands until it was conquered by the French during the Thirty Years War, the annexation was acknowledged during the Treaty of the Pyrenees in 1659, and it became a French province. Artois had already been largely French-speaking, but it was part of the Southern Netherlands until the French annexation, Artois experienced rapid industrial development during the second half of the 19th century, fueled by its rich coal resources. During World War I, the front line between the opposing Entente and Allied armies in France ran through the province, resulting in physical damage. Since the second half of the 20th century, Artois has suffered along with nearby areas because of the decline of the coal industry, pierre-Charles Le Sueur, born in Artois, noted explorer and trader
France, officially the French Republic, is a country with territory in western Europe and several overseas regions and territories. The European, or metropolitan, area of France extends from the Mediterranean Sea to the English Channel and the North Sea, Overseas France include French Guiana on the South American continent and several island territories in the Atlantic and Indian oceans. France spans 643,801 square kilometres and had a population of almost 67 million people as of January 2017. It is a unitary republic with the capital in Paris. Other major urban centres include Marseille, Lille, Toulouse, during the Iron Age, what is now metropolitan France was inhabited by the Gauls, a Celtic people. The area was annexed in 51 BC by Rome, which held Gaul until 486, France emerged as a major European power in the Late Middle Ages, with its victory in the Hundred Years War strengthening state-building and political centralisation. During the Renaissance, French culture flourished and a colonial empire was established.
The 16th century was dominated by civil wars between Catholics and Protestants. France became Europes dominant cultural and military power under Louis XIV, in the 19th century Napoleon took power and established the First French Empire, whose subsequent Napoleonic Wars shaped the course of continental Europe. Following the collapse of the Empire, France endured a succession of governments culminating with the establishment of the French Third Republic in 1870. Following liberation in 1944, a Fourth Republic was established and dissolved in the course of the Algerian War, the Fifth Republic, led by Charles de Gaulle, was formed in 1958 and remains to this day. Algeria and nearly all the colonies became independent in the 1960s with minimal controversy and typically retained close economic. France has long been a centre of art, science. It hosts Europes fourth-largest number of cultural UNESCO World Heritage Sites and receives around 83 million foreign tourists annually, France is a developed country with the worlds sixth-largest economy by nominal GDP and ninth-largest by purchasing power parity.
In terms of household wealth, it ranks fourth in the world. France performs well in international rankings of education, health care, life expectancy, France remains a great power in the world, being one of the five permanent members of the United Nations Security Council with the power to veto and an official nuclear-weapon state. It is a member state of the European Union and the Eurozone. It is a member of the Group of 7, North Atlantic Treaty Organization, Organisation for Economic Co-operation and Development, the World Trade Organization, originally applied to the whole Frankish Empire, the name France comes from the Latin Francia, or country of the Franks
GIS or geographic information system is a computer system that allows for visualizing, manipulating and storage of data with associated attributes. GIS offers better understanding of patterns and relationships of the landscape at different scales, tools inside the GIS allow for manipulation of data for spatial analysis or cartography. A topographical map is the type of map used to depict elevation. In a Geographic Information System, digital models are commonly used to represent the surface of a place. Digital terrain models are another way to represent terrain in GIS, USGS is developing a 3D Elevation Program to keep up with growing needs for high quality topographic data. 3DEP is a collection of enhanced elevation data in the form of high quality LiDAR data over the conterminous United States, there are three bare earth DEM layers in 3DEP which are nationally seamless at the resolution of 1/3,1, and 2 arcseconds. This map is derived from GTOPO30 data that describes the elevation of Earths terrain at intervals of 30 arcseconds and it uses color and shading instead of contour lines to indicate elevation.
Hypsography is the study of the distribution of elevations on the surface of the Earth, the term originates from the Greek word ὕψος hypsos meaning height. Most often it is used only in reference to elevation of land, related to the term hypsometry, the measurement of these elevations of a planets solid surface are taken relative to mean datum, except for Earth which is taken relative to the sea level. In the troposphere, temperatures decrease with altitude and this lapse rate is approximately 6.5 °C/km. S
Hydrogeology is the area of geology that deals with the distribution and movement of groundwater in the soil and rocks of the Earths crust. The term geohydrology is often used interchangeably, some make the minor distinction between a hydrologist or engineer applying themselves to geology, and a geologist applying themselves to hydrology. Hydrogeology is a subject, it can be difficult to account fully for the chemical, biological. The study of the interaction between groundwater movement and geology can be quite complex, Groundwater does not always follow the surface topography, groundwater follows pressure gradients, often through fractures and conduits in circuitous paths. Taking into account the interplay of the different facets of a multi-component system often requires knowledge in diverse fields at both the experimental and theoretical levels. The following is a more traditional introduction to the methods and nomenclature of saturated subsurface hydrology, hydrogeology, as stated above, is a branch of the earth sciences dealing with the flow of water through aquifers and other shallow porous media.
The very shallow flow of water in the subsurface is pertinent to the fields of science and civil engineering. The general flow of fluids in deeper formations is a concern of geologists, Groundwater is a slow-moving, viscous fluid, many of the empirically derived laws of groundwater flow can be alternately derived in fluid mechanics from the special case of Stokes flow. The mathematical relationships used to describe the flow of water through porous media are the diffusion and Laplace equations, steady groundwater flow has been simulated using electrical and heat conduction analogies. Transient groundwater flow is analogous to the diffusion of heat in a solid, the movement of groundwater has been studied separately from surface water and even the chemical and microbiological aspects of hydrogeology. As the field of hydrogeology matures, the interactions between groundwater, surface water, water chemistry, soil moisture and even climate are becoming more clear. For example, aquifer drawdown or overdrafting and the pumping of water may be a contributing factor to sea-level rise.
One of the tasks a hydrogeologist typically performs is the prediction of future behavior of an aquifer system, based on analysis of past. Some hypothetical, but characteristic questions asked would be, Can the aquifer support another subdivision, will the river dry up if the farmer doubles his irrigation. Did the chemicals from the dry cleaning facility travel through the aquifer to my well, will the plume of effluent leaving my neighbors septic system flow to my drinking water well. Most of these questions can be addressed through simulation of the hydrologic system, accurate simulation of the aquifer system requires knowledge of the aquifer properties and boundary conditions. Therefore, a task of the hydrogeologist is determining aquifer properties using aquifer tests. In order to further characterize aquifers and aquitards some primary and derived physical properties are introduced below, aquifers are broadly classified as being either confined or unconfined, and either saturated or unsaturated, the type of aquifer affects what properties control the flow of water in that medium
Helmand or Hillmand The ancient names of of Helmand were is one of the 34 provinces of Afghanistan, in the south of the country. It is the largest province by area, covering 58,584 square kilometres area, the province contains 13 districts, encompassing over 1,000 villages, and roughly 879,500 settled people. Lashkar Gah serves as the provincial capital, Helmand was part of the Greater Kandahar region until made into a separate province by the Afghan government in the 20th century. The province has an airport, in the city of Lashkar Gah. The British Camp Bastion and U. S, Camp Leatherneck are a short distance southwest of Lashkar Gah. The Helmand River flows through the desert region of the province. The Kajaki Dam, which is one of Afghanistans major reservoirs, is located in the Kajaki district, Helmand is believed to be one of the worlds largest opium-producing regions, responsible for around 42% of the worlds total production. This is believed to be more than the whole of Burma, which is the second largest producing nation after Afghanistan.
The region produces tobacco, sugar beets, sesame, mung beans, nuts, onions, tomato, peanut, apricot and melon. Helmand culture of western Afghanistan was a Bronze Age culture of the 3rd millennium BC and it is exemplified by such major sites as Shahr-i Sokhta and Bampur. The term Helmand civilization was proposed by M. Tosi and this civilization flourished between 2500 BC and 1900 BC, and may have coincided with the great flourishing of the Indus Valley Civilisation. This was the phase of Periods III and IV of Shahr-i Sokhta. Jiroft culture is related to Helmand culture. Jiroft culture flourished in the eastern Iran, and the Helmand culture in western Afghanistan at the same time, in fact, they may represent the same cultural area. Mehrgarh culture, on the hand, is far earlier. Some Vedic scholars believe the Helmand valley corresponds to the Sarasvati area mentioned in the Rig Veda as the homeland for the Indo-Aryan migrations into India, helmland was inhabited by ancient peoples and governed by the Medes before falling to the Achaemenids.
Later, the area was part of the ancient Arachosia polity, and a frequent target for conquest because of its location in Asia. The Helmand river valley is mentioned by name in the Avesta as Haetumant, one of the centers of the Zoroastrian faith
Great Artesian Basin
The Great Artesian Basin, located in Australia, is the largest and deepest artesian basin in the world, stretching over 1,700,000 square kilometres, with measured temperatures ranging from 30–100 °C. The basin provides the source of fresh water through much of inland Australia. The Basin underlies 23% of the continent, including the states and territories of Queensland, the Northern Territory, South Australia, the basin is 3,000 metres deep in places and is estimated to contain 64,900 cubic kilometres of groundwater. The Great Artesian Basin Coordinating Committee coordinates activity between the levels of government and community organisations. This area is one of the physiographic provinces of the larger East Australian Basins division. The water of the GAB is held in a sandstone laid down by continental erosion of higher ground during the Triassic, Jurassic. The eastern edge of the basin was uplifted when the Great Dividing Range formed, the other side was created from the landforms of the Central Eastern Lowlands and the Great Western Plateau to the west.
Most recharge water enters the rock formations from relatively high ground near the edge of the basin and very gradually flows toward the south. A much smaller amount enters along the margin in arid central Australia, flowing to the south. Because the sandstones are permeable, water makes its way through the pores between the sand grains, flowing at a rate of one to five metres per year. Discharge water eventually exits through a number of springs and seeps, prior to European occupation, waters of the GAB discharged through mound springs, many in arid South Australia. These springs supported a variety of invertebrates, and supported extensive Aboriginal communities. After the arrival of Europeans, they enabled early exploration and faster communications between southeastern Australia and Europe via the Australian Overland Telegraph Line. The Great Artesian Basin became an important water supply for cattle stations and livestock and domestic usage, to tap it, water wells are drilled down to a suitable rock layer, where the pressure of the water forces it up, mostly without pumping.
European discovery of the dates from 1878 when a shallow bore near Bourke produced flowing water. There were similar discoveries in 1886 at Back Creek east of Barcaldine, in essence, water extraction from the GAB is a mining operation, with recharge much less than current extraction rates. In 1915, there were 1,500 bores providing 2,000 megalitres of water per day and this included just under 2000 freely flowing bores and more than 9000 that required mechanical power to bring water to the surface. Many bores are unregulated or abandoned, resulting in considerable water wastage and these problems have existed for many decades, and in January 2007 the Australian Commonwealth Government announced additional funding in an attempt to bring them under control
Fossil water or paleowater is a somewhat broadly-used term to describe water that has been contained in some undisturbed space, usually groundwater in an aquifer, for millennia. Fossil water could describe ancient water on planets, or water sealed in subglacial lakes such as Antarcticas Lake Vostok. Fossil groundwater can be defined as water infiltrated usually millennia ago and often under climatic conditions different from the present. Determining the time since water infiltrated usually involves analyzing isotopic signatures, some aquifers are hundreds of meters deep and underlie vast areas of land. Research techniques in the field are developing quickly and the knowledge base is growing. In the cases of many aquifers, research is lacking or disputed as to the age of the water, prolific aquifers containing fossil water are of significant socio-economic value. Fossil water is extracted from these aquifers for many purposes, agriculture, industry. In arid regions, some aquifers containing available and usable water receive little to no significant recharge, extraction rates greater than recharge rates result in lowering of the water table and can lead to groundwater depletion.
Extraction of non-renewable groundwater resources is referred to as groundwater mining because of their finite nature, aquifers are typically composed of semi-porous rock or unconsolidated material whose pore space has been filled with water. In the relatively rare cases of confined aquifers, a geologic layer encloses an aquifer, isolating the water within. More commonly, fossil water is found in arid or semi-arid regions where the climate was more humid in recent geologic history. In some semi-arid regions, the majority of precipitation evaporates before it can infiltrate, most fossil groundwater has been estimated to have originally infiltrated within the Holocene and Pleistocene. Some fossil groundwater is associated with the melting of ice in the time since the last glacial maximum, dating of groundwater relies on measuring concentrations of certain stable isotopes, including 3H and 18O, and comparing values with known concentrations of the geologic past. Fossil water can dissolve and absorb a number of ions from its host rock.
Salinity in groundwater can be higher than seawater, in some cases, some form of treatment is required to make these waters suitable for human use. Saline fossil aquifers can store significant quantities of oil and natural gas, the Ogallala or High Plains Aquifer sits under 450,000 km2 of 8 states of the United States of America. It is one of the largest freshwater deposits in the world, the aquifer is composed of unconsolidated alluvial deposits. Groundwater in this aquifer has been dated to have deposited in the humid time following the last glacial maximum
A Qanāt or karez/kariz is a gently sloping underground channel to transport water from an aquifer or water well to surface for irrigation and drinking. The qanat technology is known to have developed in Iran by the Persian people sometime in the early 1st millennium BC. Qanat is the Arabic word for channel, Qanats in Persian called kārīz, Kahn, kahriz/kəhriz, Canal, falaj or foggara/fughara. Alternative terms for qanats in Asia and North Africa are kakuriz, chin-avulz, common variants of qanat in English include kanat, kunut, konait, ghundat. Qanats are constructed as a series of vertical shafts, connected by gently sloping tunnels. Qanats efficiently deliver large amounts of water to the surface without need for pumping. The water drains by gravity, typically from an upland aquifer, Qanats allow water to be transported over long distances in hot dry climates without much water loss to evaporation. The qanat should not be confused with the spring-flow tunnel typical to the area around Jerusalem.
Although both are excavated tunnels designed to extract water by gravity flow, there are crucial differences, the origin of the qanat was a well that was turned into an artificial spring. In contrast, the origin of the tunnel was the development of a natural spring to renew or increase flow following a recession of the water table. Secondly, the shafts essential for the construction of qanats are not essential to spring-flow tunnels and it is very common for a qanat to start below the foothills of mountains, where the water table is closest to the surface. From this source, the tunnel slopes gently downward, slowly converging with the steeper slope of the land surface above. To connect a populated or agricultural area with an aquifer, qanats must often extend for long distances, Qanats are sometimes split into an underground distribution network of smaller canals called kariz. Like qanats, these canals are below ground to avoid contamination and evaporation. In some cases water from a qanat is stored in a reservoir, an ab anbar is an example of a traditional Persian qanat-fed reservoir for drinking water.
The qanat system has the advantage of being resistant to disasters such as earthquakes and floods. Furthermore, it is almost insensitive to the levels of precipitation, from a sustainability perspective, qanats are powered only by gravity, and thus have low operation & maintenance costs once built. Qanats transfer freshwater from the plateau to the lower-lying plains with saltier soil