1.
United States
–
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, climate 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
United States
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Native Americans meeting with Europeans, 1764
United States
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Flag
United States
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The signing of the
Mayflower Compact, 1620.
United States
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The
Declaration of Independence: the
Committee of Five presenting their draft to the
Second Continental Congress in 1776
2.
Texas
–
Texas is the second largest state in the United States by both area and population. Other major cities include Austin, the second most populous state capital in the U. S. Texas is nicknamed the Lone Star State to signify its former status as an independent republic, and as a reminder of the states struggle for independence from Mexico. The Lone Star can be found on the Texan state flag, the origin of Texass name is from the word Tejas, which means friends in the Caddo language. Due to its size and geologic features such as the Balcones Fault, although Texas is popularly associated with the U. S. southwestern deserts, less than 10 percent of Texas land area is desert. Most of the centers are located in areas of former prairies, grasslands, forests. Traveling from east to west, one can observe terrain that ranges from coastal swamps and piney woods, to rolling plains and rugged hills, the term six flags over Texas refers to several nations that have ruled over the territory. Spain was the first European country to claim the area of Texas, Mexico controlled the territory until 1836 when Texas won its independence, becoming an independent Republic. In 1845, Texas joined the United States as the 28th state, the states annexation set off a chain of events that caused the Mexican–American War in 1846. A slave state before the American Civil War, Texas declared its secession from the U. S. in early 1861, after the Civil War and the restoration of its representation in the federal government, Texas entered a long period of economic stagnation. One Texan industry that thrived after the Civil War was cattle, due to its long history as a center of the industry, Texas is associated with the image of the cowboy. The states economic fortunes changed in the early 20th century, when oil discoveries initiated a boom in the state. With strong investments in universities, Texas developed a diversified economy, as of 2010 it shares the top of the list of the most Fortune 500 companies with California at 57. With a growing base of industry, the leads in many industries, including agriculture, petrochemicals, energy, computers and electronics, aerospace. Texas has led the nation in export revenue since 2002 and has the second-highest gross state product. The name Texas, based on the Caddo word tejas meaning friends or allies, was applied by the Spanish to the Caddo themselves, during Spanish colonial rule, the area was officially known as the Nuevo Reino de Filipinas, La Provincia de Texas. Texas is the second largest U. S. state, behind Alaska, though 10 percent larger than France and almost twice as large as Germany or Japan, it ranks only 27th worldwide amongst country subdivisions by size. If it were an independent country, Texas would be the 40th largest behind Chile, Texas is in the south central part of the United States of America. Three of its borders are defined by rivers, the Rio Grande forms a natural border with the Mexican states of Chihuahua, Coahuila, Nuevo León, and Tamaulipas to the south
Texas
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Sam Rayburn Reservoir
Texas
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Flag
Texas
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Texas Hill Country
Texas
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Big Bend National Park.
3.
Central Texas
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Central Texas is a region in the U. S. state of Texas surrounding Austin and roughly bordered by Brady to Kerrville to La Grange to Waco. Central Texas contains the Texas Hill Country and corresponds to a physiographic section designation within the Edwards Plateau, Central Texas includes the Austin–Round Rock, Killeen-Temple-Fort Hood, Bryan–College Station, and Waco metropolitan areas. The Austin–Round Rock and Killeen-Temple-Fort Hood areas are among the metropolitan areas in the state. Some of the largest cities in the region are Austin, College Station, Killeen, Round Rock, Bridge City, Mansfield, the United States Armys Fort Hood, a large military installation, is located in this region. Fredericksburg, Texas Chamber of Commerce Celebrate Diversity in Central Texas
Central Texas
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Hamilton Pool Preserve - one of the many lush areas in Central Texas
Central Texas
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Central Texas counties in red; counties sometimes included in Central Texas in pink
Central Texas
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The Texas Capital -
Austin
Central Texas
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Alamo Mission -
San Antonio
4.
Geographic coordinate system
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A geographic coordinate system is a coordinate system used in geography that enables every location on Earth to be specified by a set of numbers, letters or symbols. The coordinates are chosen such that one of the numbers represents a vertical position. A common choice of coordinates is latitude, longitude and elevation, to specify a location on a two-dimensional map requires a map projection. The invention of a coordinate system is generally credited to Eratosthenes of Cyrene. Ptolemy credited him with the adoption of longitude and latitude. Ptolemys 2nd-century Geography used the prime meridian but measured latitude from the equator instead. Mathematical cartography resumed in Europe following Maximus Planudes recovery of Ptolemys text a little before 1300, in 1884, the United States hosted the International Meridian Conference, attended by representatives from twenty-five nations. Twenty-two of them agreed to adopt the longitude of the Royal Observatory in Greenwich, the Dominican Republic voted against the motion, while France and Brazil abstained. France adopted Greenwich Mean Time in place of local determinations by the Paris Observatory in 1911, the latitude of a point on Earths surface is the angle between the equatorial plane and the straight line that passes through that point and through the center of the Earth. Lines joining points of the same latitude trace circles on the surface of Earth called parallels, as they are parallel to the equator, the north pole is 90° N, the south pole is 90° S. The 0° parallel of latitude is designated the equator, the plane of all geographic coordinate systems. The equator divides the globe into Northern and Southern Hemispheres, the longitude of a point on Earths surface is the angle east or west of a reference meridian to another meridian that passes through that point. All meridians are halves of great ellipses, which converge at the north and south poles, the prime meridian determines the proper Eastern and Western Hemispheres, although maps often divide these hemispheres further west in order to keep the Old World on a single side. The antipodal meridian of Greenwich is both 180°W and 180°E, the combination of these two components specifies the position of any location on the surface of Earth, without consideration of altitude or depth. The grid formed by lines of latitude and longitude is known as a graticule, the origin/zero point of this system is located in the Gulf of Guinea about 625 km south of Tema, Ghana. To completely specify a location of a feature on, in, or above Earth. Earth is not a sphere, but a shape approximating a biaxial ellipsoid. It is nearly spherical, but has an equatorial bulge making the radius at the equator about 0. 3% larger than the radius measured through the poles, the shorter axis approximately coincides with the axis of rotation
Geographic coordinate system
–
Longitude lines are perpendicular and latitude lines are parallel to the equator.
5.
Edwards Plateau
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San Angelo, Austin, San Antonio and Del Rio roughly outline the area. The eastern portion of the plateau is known as the Texas Hill Country, the landscape of the plateau is mostly savanna scattered with trees. It mostly lacks deep soil suitable for farming, though the soil is fertile mollisols and some cotton, grain sorghum, for the most part, though, the thin soil and rough terrain areas are primarily grazing regions, with cattle, sheep and Angora goats predominant. The area is drained, rainwater flows into the Edwards Aquifer recharge zone at the south of the plateau to feed rivers to the south. Rainfall varies from 15 to 33 inches per year, on average, from northwest to southeast, and the area has a moderate temperature and a reasonably long growing season. Flora Trees of the include a juniper-oak mix and a mesquite-acacia mix scattered over fairly short grasses. Some pecan trees are found near the springs and rivers, the Balcones Fault is associated with the Edwards Plateau formation. This fault line is a demarcation for the range definition of a number of species. Fauna Caves of the Edwards Plateau are important habitats for a deal of wildlife. The area is home to some of the largest colonies of bats in the world, there are also large numbers of reptiles and birds, including breeding populations of the Texan endemic golden-cheeked warbler. Further alteration to the savanna has incurred though the encroachment of shrubs now that grassland fires are carefully controlled, small areas of intact habitat remain, particularly around Austin, where areas are protected, such as the Balcones Canyonlands National Wildlife Refuge. Another important area for wildlife is Fort Hood military base, earliest human settlement of this area was by Native Americans. First it was used and wandered about by Jumano and Coahuiltecan groups, then the Apacheria extended into the Southern Plains by the forerunners of the Lipan and Mescalero Apaches. After the expulsion of the Apachean groups from the Plains by the Comanche, Texas Hill Country Balcones Canyonlands National Wildlife Refuge Colorado River Mount Bonnell List of ecoregions in the United States Johnson, E. H. Edwards Plateau. Texas counties map showing the ecoregion
Edwards Plateau
–
A photograph taken by NASA of the Edwards Plateau and Balcones Escarpment
Edwards Plateau
–
Edwards Plateau terrain as seen from
U.S. Route 277 between
Del Rio and
Sonora.
Edwards Plateau
–
Biogeography
6.
West Texas
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West Texas is a loosely defined part of the U. S. state of Texas, generally encompassing the arid and semiarid lands west of a line drawn between the cities of Fort Worth and Del Rio. There is no consensus on the boundary between eastern and western Texas, West Texas is often subdivided according to distinct physiographic features. The portion of West Texas that lies west of the Pecos River is often referred to as Far West Texas or the Trans-Pecos, the Trans-Pecos lies within the Chihuahuan Desert, the most arid portion of the state. Another part of West Texas is the Llano Estacado, a vast region of high, level plains extending into Eastern New Mexico, to the east of the Llano Estacado lies the “redbed country” of the Rolling Plains and to the south of the Llano Estacado lies the Edwards Plateau. The Rolling Plains and the Edwards Plateau subregions act as transitional zones between eastern and western Texas, the counties included in the West Texas region vary depending on the organization. West Texas has a lower population density than the rest of the state. It was once inhabited by nomadic Native American tribes, such as the Apache, Comanche, and Kiowa. This period was marked with savage war waged between the US Army, frontier Texans, and the Texas Rangers on one side and native peoples on the other. During the later 19th century, the population of Americans. This period was marked by the mapping and geographical intelligence collection of a denied area held by hostile Indian tribes. In turn, the Comanche way of war reached its zenith, having either subjugated or defeated the other Indian clans. In contrast, the support by the US government of Americans settlement. By the end of the 19th century, West Texas had been pacified of hostile Indians, leaving its turbulent history to what remained of outlaw Texans and people such as Judge Roy Bean. With the defeat of the Comanche and their allies and their removal upon demand by Texas from the state, the area was settled by Texans. These decades marked the last great cattle drives, the zenith of American cowboys, small farmers and ranchers battling sheepherders. This continuing socioeconomic trends resulted in the region having a mix of Mexican American and American communities of the modern day. As a result of historical development, many Mexican Americans still have close family ties in Mexico. Of American settlers, during the migration era, the vast majority were either East Texans or other Southerners going west for new opportunities
West Texas
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West of
Notrees
West Texas
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Map of Texas
West Texas
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El Paso
West Texas
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Lubbock
7.
South Texas
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South Texas is a region of the U. S. state of Texas that lies roughly south of -- and sometimes including -- San Antonio. The southern and western boundary is the Rio Grande, and to the east it is the Gulf of Mexico, the population of this region is about 4.67 million according to the 2013 census estimates. The southern portion of region is often referred to as the Rio Grande Valley. The eastern portion along the Gulf of Mexico is also referred to as the Coastal Bend, many South Texas residents Exclude San Antonio, as San Antonio is southern Central Texas. The Rio Grande serves as the western and southern boundaries and separates Texas from Mexico, the eastern portion of South Texas is bordered by the Gulf of Mexico. This region of Texas consist of 41 counties, South Texas terrain is flat, lying on the coastal plain. South Texas is so vast, there are even subregions, the very southern tip of South Texas, called the Rio Grande Valley, has fertile soils and is known for its citrus production. The eastern portion of South Texas is often referred to as the Coastal Bend, here, coastal marshes, estuaries. The western and central parts are known as the South Texas Plains or the brush country, mesquite trees and crop fields dominate the land. The fastest growing county in South Texas is Guadalupe County, growing by 5. 64% from 2010 to 2012, the United States District Court for the Southern District of Texas includes the Houston division. However, Houston is most accurately classified as being within Southeast Texas, the area along the Mexican border is generally semi-arid, while the area from the coast inland to just west of San Antonio has a humid subtropical climate. South Texas weather is affected by the Sierra Madre Oriental mountains to the west, the Gulf of Mexico to the east, moisture from the Pacific is cut off by the Mexican Sierra Madre Occidental and Oriental mountain ranges. Temperatures reach freezing only a few times in the winter and snowfall is rare, summers in this zone are hot and humid, with daily averages above 90 °F. Night-time temperatures are around 85 °F in summer. The region of South Texas includes the ranch country and the wetter Rio Grande Valley. Considered to be the southernmost tip of the American Great Plains region, the coastal areas are warm most of the year due to currents of the Gulf of Mexico, but can get cold in winter if a strong front comes in, occasionally causing snow at sea level. Rain in the region is more abundant than in the inland region. Inland, where it is drier, ranches dominate the landscape, characterized by thick, spiny brush, the winters in the inland region are cooler and drier, as Arctic air can make it into the region, but snow is rare due to the lack of humidity. Summers are for the most part hot and dry, but at times can be humid if winds come off the warmer Gulf of Mexico, tornadoes can occur in this region, but less frequently than in other parts of the state
South Texas
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San Antonio is the largest city and the fastest growing city in South Texas.
South Texas
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Corpus Christi is the second largest city in South Texas.
South Texas
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Laredo is the third largest city in South Texas. The
San Agustin Cathedral was built during the
Spanish Texas period.
South Texas
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Brownsville is the fourth largest city in South Texas.
8.
Southwestern United States
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The population of the area is around 11 million people, with over half that in Arizona, the most populous cities are Phoenix, El Paso, Las Vegas, Albuquerque, and Tucson. Most of the area was part of the Viceroyalty of New Spain in the Spanish Empire before becoming part of Mexico and it became part of the United States through the Treaty of Guadalupe Hidalgo and the Gadsden Purchase. The deserts dominate the southern and western reaches of the area, the two major rivers of the region are the Colorado River, running in the northern and western areas, and the Rio Grande, running in the south. Formed approximately 8000 years ago, the Chihuahuan Desert is a dry desert. The Chihuahuan Desert spreads across the portion of the region, covering from southeastern Arizona, across southern New Mexico. While it is the second largest desert in the United States, only a third of the desert is within the United States, El Paso is the major city in this desert, with other smaller cities being Las Cruces and Roswell in New Mexico. The Chihuahuan is a rain shadow desert, formed two mountain ranges which block oceanic precipitation from reaching the area. The most prolific plants in this region are agave, yucca and creosote bushes, when people think of the desert southwest, the landscape of the Sonoran Desert is what mostly comes to mind. Rainfall averages between 4–12 inches per year, and the deserts most widely known inhabitant is the saguaro cactus and it is bounded on the northwest by the Mojave Desert, to the north by the Colorado Plateau and to the east by the Arizona Mountains forests and the Chihuahuan Desert. The portion of the Sonora Desert which lies in the Southwestern United States is the most populated area within the region. Six of the top ten major population centers of the region are found within its borders, Phoenix, Tucson, Mesa, Chandler, Glendale, also within its borders are Yuma and Prescott Arizona. The most northwest portion of the American Southwest is covered by the Mojave Desert, bordered on the south by the Sonoran Desert and the east by the Colorado Plateau, its range within the region makes up the southeast tip of Nevada, and the northwestern corner of Arizona. In terms of topography, the Mojave is very similar to the Great Basin Desert, the Mojave is the smallest, driest and hottest desert within the United States. The Mojave gets less than six inches of rain annually, the most prolific vegetation is the tall Joshua tree, which grow as tall as 40 feet, and are thought to live almost 1000 years. Other major vegetation includes the Parry saltbush and the Mojave sage, the Colorado Plateau varies from the large stands of forests in the west, including the largest stand of ponderosa pine trees in the world, to the Mesas to the east. Although not called a desert, the Colorado Plateau is mostly made up of high desert, the Plateau is characterized by a series of plateaus and mesas, interspersed with canyons. The most dramatic example is the Grand Canyon, but that is one of many dramatic vistas included within the Plateau, which includes spectacular lava formations, painted deserts, sand dunes, and badlands. One of the most distinctive features of the Plateau is its longevity, the Plateau can be divided into six sections, three of which fall into the Southwest region
Southwestern United States
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Panoramic view of the southwestern United States.
Southwestern United States
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Approximate map of the Southwestern U.S. using the definition of Reed, Meinig, and others.
Southwestern United States
–
Saguaro cactus in the Sonoran Desert
Southwestern United States
–
The Delicate Arch at
Arches National Park
9.
Karst topography
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Karst topography is a landscape formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves and it has also been documented for more weathering-resistant rocks, such as quartzite, given the right conditions. Subterranean drainage may limit surface water, with few to no rivers or lakes, the English word karst was borrowed from German Karst in the late 19th century. The German word came into use before the 19th century, according to the prevalent interpretation, the term is derived from the German name for the Karst region, a limestone plateau above the city of Trieste in the northern Adriatic. Scholars disagree, however, on whether the German word was borrowed from Slovene, the Slovene common noun kras was first attested in the 18th century, and the adjective form kraški in the 16th century. The Slovene words arose through metathesis from the reconstructed form *korsъ, ultimately, the word is of Mediterranean origin, believed to derive from some Romanized Illyrian base. It has been suggested that the word may derive from the Proto-Indo-European root karra- rock, the name may also be connected to the oronym Karsádios oros cited by Ptolemy, and perhaps also to Latin Carusardius. The development of karst occurs whenever acidic water starts to break down the surface of bedrock near its cracks, as the bedrock continues to degrade, its cracks tend to get bigger. As time goes on, these fractures will become wider, if this underground drainage system does form, it will speed up the development of karst formations there because more water will be able to flow through the region, giving it more erosive power. The carbonic acid that causes karstic features is formed as rain passes through the atmosphere picking up carbon dioxide, once the rain reaches the ground, it may pass through soil that can provide much more CO2 to form a weak carbonic acid solution, which dissolves calcium carbonate. The oxidation of sulfides leading to the formation of acid can also be one of the corrosion factors in karst formation. As oxygen -rich surface waters seep into deep anoxic karst systems, they bring oxygen, sulfuric acid then reacts with calcium carbonate, causing increased erosion within the limestone formation. This chain of reactions is, This reaction chain forms gypsum, the karstification of a landscape may result in a variety of large- or small-scale features both on the surface and beneath. On exposed surfaces, small features may include solution flutes, runnels, limestone pavement, medium-sized surface features may include sinkholes or cenotes, vertical shafts, foibe, disappearing streams, and reappearing springs. Large-scale features may include limestone pavements, poljes, and karst valleys, mature karst landscapes, where more bedrock has been removed than remains, may result in karst towers, or haystack/eggbox landscapes. Beneath the surface, complex underground systems and extensive caves. Some of the most dramatic of these formations can be seen in Thailands Phangnga Bay, calcium carbonate dissolved into water may precipitate out where the water discharges some of its dissolved carbon dioxide. Rivers which emerge from springs may produce tufa terraces, consisting of layers of calcite deposited over extended periods of time, in caves, a variety of features collectively called speleothems are formed by deposition of calcium carbonate and other dissolved minerals
Karst topography
–
Škocjan Caves,
Slovenia
Karst topography
–
A karst landscape in
Minerve, Hérault,
France
Karst topography
–
The
Puerto Princesa Underground River,
Philippines.
Karst topography
–
Global distribution of major outcrops of carbonate rocks (mainly
limestone, except
evaporites)
10.
Limestone
–
Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such as coral, forams 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, intraclasts 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 also 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, clastic, granular, or massive, depending on the method of formation. Crystals of calcite, quartz, 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
Limestone
–
Limestone outcrop in the
Torcal de Antequera nature reserve of
Málaga, Spain
Limestone
–
Limestone quarry at
Cedar Creek, Virginia, USA
Limestone
–
Cutting the limestone blocks at a quarry in
Gozo,
Malta
Limestone
–
Limestone as building material
11.
Granite
–
Granite is a common type of felsic intrusive igneous rock that is granular and phaneritic in texture. Granites can be white, pink, or gray in color. The word granite comes from the Latin granum, a grain, in reference to the structure of such a holocrystalline rock. By definition, granite is a rock with at least 20% quartz. The term granitic means granite-like and is applied to granite and a group of igneous rocks with similar textures and slight variations in composition. Occasionally some individual crystals are larger than the groundmass, in case the texture is known as porphyritic. A granitic rock with a texture is known as a granite porphyry. Granitoid is a general, descriptive field term for lighter-colored, coarse-grained igneous rocks, petrographic examination is required for identification of specific types of granitoids. The extrusive igneous rock equivalent of granite is rhyolite, Granite is nearly always massive, hard and tough, and therefore it has gained widespread use throughout human history, and more recently as a construction stone. The average density of granite is between 2.65 and 2.75 g/cm3, its compressive strength usually lies above 200 MPa, and its viscosity near STP is 3–6 •1019 Pa·s. The melting temperature of dry granite at ambient pressure is 1215–1260 °C, it is reduced in the presence of water. Granite has poor primary permeability, but strong secondary permeability, true granite according to modern petrologic convention contains both plagioclase and alkali feldspars. When a granitoid is devoid or nearly devoid of plagioclase, the rock is referred to as alkali feldspar granite, when a granitoid contains less than 10% orthoclase, it is called tonalite, pyroxene and amphibole are common in tonalite. A granite containing both muscovite and biotite micas is called a binary or two-mica granite, two-mica granites are typically high in potassium and low in plagioclase, and are usually S-type granites or A-type granites. A worldwide average of the composition of granite, by weight percent, based on 2485 analyses. Much of it was intruded during the Precambrian age, it is the most abundant basement rock that underlies the relatively thin veneer of the continents. Outcrops of granite tend to form tors and rounded massifs, granites sometimes occur in circular depressions surrounded by a range of hills, formed by the metamorphic aureole or hornfels. Granite often occurs as small, less than 100 km² stock masses
Granite
–
Granite containing
potassium feldspar,
plagioclase feldspar,
quartz, and
biotite and/or
amphibole
Granite
–
Close-up of granite exposed in
Chennai,
India
Granite
–
The
Cheesewring, a granite
tor
Granite
–
A granite peak at
Huangshan, China
12.
Packsaddle Mountain (Llano County, Texas)
–
In 1873 it was the site of the Packsaddle Mountain Fight, the last major Native American battle in the area. The mountain is now part of a ranch called Packsaddle Ranch. It is thought that the Spanish mined the mountain for gold prior to the Texas Revolution, prospecting on Packsaddle Mountain renewed interest in gold mining in Llano County in the 1920s, but with no lasting result. The mountain was the site of the Packsaddle Mountain Fight with Texas Native Americans on August 4,1873 and was the last major Native american battle in the area. The fight on Packsaddle Mountain was precipitated when a woman from the Moss Ranch came into the house with an arrow sticking out of her side. A party of eight ranchers, including W. B. Moss and they found some twenty-one Native Americans encamped on Packsaddle Mountain. In the ensuing fight at least three Native Americans were killed and three ranchers wounded, the Texas state historical marker reads Two and one half miles east on the Packsaddle Mountain, in a battle fought August 4,1873, Captain J. R. Moss, Stephen B. Moss, Eli Lloyd, Arch Martin, Pink Ayers, E. D. Harrington, the last Native American battle in this region. At an elevation of 1,628 feet, the higher of the two summits rises 650 feet above Highway 71, local topography ranges from flat to rolling to steep, with local escarpments, covered with soils ranging from shallow and stony to deep, fine, sandy loam. Vegetation consists primarily of stands of live oak and Ashe juniper
Packsaddle Mountain (Llano County, Texas)
–
Packsaddle Mountain Cliff Face
Packsaddle Mountain (Llano County, Texas)
–
Packsaddle - Mountain Historical Monument
Packsaddle Mountain (Llano County, Texas)
–
Packsaddle - Mountain View from CR 309
Packsaddle Mountain (Llano County, Texas)
–
Packsaddle - Close View of Cliff
13.
Kingsland, Texas
–
Kingsland is a census-designated place in Llano County, Texas, United States. The population was 6,030 at the 2010 census, Texas Ranch to Market Road 1431 runs through the community. Kingsland is located at 30°40′02″N 98°26′41″W, the town is at the confluence of the Colorado and the Llano rivers, which combine to form Lake Lyndon B. Johnson. According to the United States Census Bureau, the CDP has an area of 9.8 sq mi. As of the census of 2000,4,584 people,2,103 households, the population density was 509.4 people per square mile. There were 2,803 housing units at a density of 311. 5/sq mi. The racial makeup of the CDP was 95. 66% White,0. 13% African American,0. 31% Native American,0. 52% Asian,0. 02% Pacific Islander,2. 31% from other races, and 1. 05% from two or more races. Hispanics or Latinos of any race were 5. 89% of the population, about 32. 4% of all households were made up of individuals, and 20. 8% had someone living alone who was 65 years of age or older. The average household size was 2.13 and the family size was 2.64. In the CDP, the population was distributed as 17. 4% under the age of 18,5. 3% from 18 to 24,19. 6% from 25 to 44,24. 9% from 45 to 64, the median age was 51 years. For every 100 females, there were 91.0 males, for every 100 females age 18 and over, there were 87.4 males. The median income for a household in the CDP was $29,615, males had a median income of $27,264 versus $19,255 for females. The per capita income for the CDP was $18,220, about 6. 8% of families and 12. 2% of the population were below the poverty line, including 21. 5% of those under age 18 and 9. 6% of those age 65 or over. The house where The Texas Chain Saw Massacre was filmed is located here and has been restored as a restaurant, also a favorite location is The Slab, where the road traverses the clear Llano River as it crosses over granite slabs and boulders. Both residents and tourists come to the slab to bask in the warm sun, Kingsland is served by the Llano Independent School District, and is the location of Packsaddle Elementary School. High and High-school aged youth are bussed to Llano Jr, High and Llano High School,18 miles away in Llano, TX. Central Texas Electric Cooperative Kingsland from the Handbook of Texas Online Kingsland Current newspaper Kingsland Masonic Lodge #1424 Newsletter Kingsland Chamber of Commerce City-Data. com
Kingsland, Texas
–
As part of the
Antlers Hotel, the Grand Central Cafe Restaurant and Club Car Bar in Kingsland is built in the style of
Queen Anne architecture. Before the structure was moved from
Round Rock, Texas to Kingsland, it had been used as part of the set for the 1974 film
The Texas Chain Saw Massacre. For additional information see:
Texas Chainsaw House.
Kingsland, Texas
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Part of the railroad district in Kingsland associated with the
Antlers Hotel
Kingsland, Texas
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Kingsland Library
Kingsland, Texas
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The tourist information office off
Texas Ranch to Market Road 1431 in Kingsland celebrated its fiftieth anniversary in 2011.
14.
Llano Uplift
–
The Llano Uplift is a roughly circular geologic dome of Precambrian rock, primarily granite, in Central Texas in the United States. It is located in the region of the Edwards Plateau. The region is characterized by a central exposure of Precambrian granite, surrounded by a ring of gneiss and schist and this area is rimmed by limestone ridges. The Llano Uplift is best known for its large, protruding rock formations, the area includes several major quarries like Granite Mountain that mine the distinctive pink granite. Further, the contains the only known deposits of llanite. However, the exposures of Precambrian rock are located at the lowest surface elevations of the region. The origin of the Town Mountain granite--tightly-dated to late Mesoproterozoic times--is a minor mystery, the ancient faulting that produced the Llano Uplift is believed to be related to that which produced the Marathon Uplift in West Texas. Both may have formed around the time of the Ouachita orogeny. The Llano Uplift is ancient, with parts being over a billion years old. Several gold mines operated in this area, the most famous of which is the Heath mine, some minerals that have come out of the mines include quartz, pyrite, and schorl. Road cuts and creeks provide more samples of found in this area, with Texas renowned blue topaz. Various iron and copper minerals have been found, especially hematite and malachite
Llano Uplift
–
Exposed igneous core of the Llano Uplift
Llano Uplift
Llano Uplift
Llano Uplift
15.
Granite dome
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Granite domes are domical hills composed of granite with bare rock exposed over most of the surface. Generally, domical features such as these are known as bornhardts, bornhardts can form in any type of plutonic rock but are typically composed of granite and granitic gneiss. As granitic plutons cool kilometers below the earth’s surface minerals in the rock crystallize under uniform confining pressure, erosion brings the rock closer to earth’s surface and the pressure from above the rock decreases, as a result the rock fractures. These fractures are known as joints, or sheet fractures. These sheets of rock peel off the surface and in certain conditions develop domical structures. Additional theories on the origin of granite domes involve scarp-retreat and tectonic uplift, sheet fractures are arcuate fractures defining slabs of rock that range from 0.5 to 10 meters thick. They normally form in parallel to the Earth’s surface but may form in convex-upward or concave-upward sets. There are several explanations for the formation of sheet fractures. The most popular hypothesis is that they are the result of expansion, there is evidence that supports this hypothesis when looking at granitic landforms that have sheet fractures. Granite forms deep in the Earth’s crust under conditions of ambient or lithostatic pressure. In order for the granite to be exposed at the Earth’s surface a considerable thickness of rock must be eroded and this unloading allows the granite to expand radially and sheet fractures form tangentially to the radial stress. This indicates that the shape of the land surface determines the geometry of the sheet fractures. One hypothesis is that granite domes are uplifted blocks and this is the case with some granite domes but the fracture related exfoliation joints are what controls the steep slopes. Another theory that regards isolated bornhardts is that they remain after long-distance scarp recession, moisture related weathering is what causes scarp recession. In the case of granite in a dissected landscape the dry granite high on a slope remains stable, granite below this is more easily weathered and eroded because it has been exposed to moisture and has weathered
Granite dome
–
Half Dome,
Yosemite, a classic granite dome (though not, contrary to popular belief, "
Glacier -sliced")
Granite dome
–
Granite domes in
Rio de Janeiro
Granite dome
–
Liberty Cap Yosemite, by
Nevada Fall
Granite dome
–
A number of domes are clustered at the upper end of
Tenaya Lake,
Yosemite.
16.
Enchanted Rock
–
Enchanted Rock is an enormous pink granite pluton batholith located in the Llano Uplift approximately 17 miles north of Fredericksburg, Texas and 24 miles south of Llano, Texas, United States. Enchanted Rock State Natural Area, which includes Enchanted Rock and surrounding land, Enchanted Rock covers approximately 640 acres and rises approximately 425 feet above the surrounding terrain to elevation of 1,825 feet above sea level. It is the largest such pink granite monadnock in the United States, Enchanted Rock State Natural Area, a part of the Texas state park system, includes 1,644 acres. Designated a Recorded Texas Historic Landmark in 1936, the prominent granite dome is visible for many miles in the surrounding basin of the Llano Uplift. The weathered dome, standing above the plain is known to geologists as a monadnock. Archaeological evidence indicates human visitation at the going back at least 11,000 years. According to the book The Enchanted Rock published in 1999 by Ira Kennedy These hunter-gatherers had flint-tipped spears, fire, with these resources, some twelve thousand years ago, the first Texans became the wellspring of Plains Indian culture. On the basis of evidence, human habitation at Enchanted Rock can be traced back at least 10,000 years. Paleo-Indian projectile points, or arrowheads, 11–12,000 years old have been found in the upstream and downstream from The Rock. The oldest authenticated projectile point found within the present day park is a Plainview point type, the rock has been the subject of numerous geological surveys and paintings. Folklore of local Tonkawa, Apache and Comanche tribes ascribes magical and spiritual powers to the rock, while attempting to hide from Anglo settlers in the area, the natives would hide on the top two tiers of the rock, where they were invisible from the ground below. The first European to visit the area was probably Álvar Núñez Cabeza de Vaca in 1536, the Tonkawa, who inhabited the area in the 16th century, believed that ghost fires flickered at the top of the dome. In particular they heard unexplained creaking and groaning, which attribute to the rocks night-time contraction after being heated by the sun during the day. The name Enchanted Rock derives from Spanish and Anglo-Texan interpretations of such legends and related folklore, a plaque formerly embedded in Enchanted Rock near the top, but now removed to a kiosk below, reads, From its summit in 1841, Captain John C. Hays, while surrounded by Comanche Indians who cut him off from his ranging company repulsed the whole band, vernal pools, ecologically threatened depressions of flora and fauna adapted to harsh environments, contain fragile invertebrate fairy shrimp. Other wildlife includes bats, ringtails, squirrels, and fox, a wide variety of lizards, including the Texas horned lizard also make the Enchanted Rock area their home. Park activities include caving, hiking, primitive camping, rock climbing and picnicking. The Summit Trail is the most popular hiking path, the Granite Gripper is an annual rock climbing competition that acts as a fund raiser for park conservation through the Friends of Enchanted Rock
Enchanted Rock
–
Enchanted Rock, as seen from the trail leading to its summit on a busy
hiking day.
Enchanted Rock
–
Enchanted Rock panorama
Enchanted Rock
–
Geological
exfoliation at Enchanted Rock State Natural Area
Enchanted Rock
–
Sedum growing on top of Enchanted Rock near a vernal pool.
17.
Rock (geology)
–
Rock or stone is a natural substance, a solid aggregate of one or more minerals or mineraloids. For example, granite, a rock, is a combination of the minerals quartz, feldspar. The Earths outer solid layer, the lithosphere, is made of rock, rock has been used by mankind throughout history. The minerals and metals found in rocks have been essential to human civilization, three major groups of rocks are defined, igneous, sedimentary, and metamorphic. The scientific study of rocks is called petrology, which is a component of geology. At a granular level, rocks are composed of grains of minerals, the aggregate minerals forming the rock are held together by chemical bonds. The types and abundance of minerals in a rock are determined by the manner in which the rock was formed, many rocks contain silica, a compound of silicon and oxygen that forms 74. 3% of the Earths crust. This material forms crystals with other compounds in the rock, the proportion of silica in rocks and minerals is a major factor in determining their name and properties. Rocks are geologically classified according to such as mineral and chemical composition, permeability, the texture of the constituent particles. These physical properties are the end result of the processes that formed the rocks, over the course of time, rocks can transform from one type into another, as described by the geological model called the rock cycle. These events produce three general classes of rock, igneous, sedimentary, and metamorphic, the three classes of rocks are subdivided into many groups. However, there are no hard and fast boundaries between allied rocks, hence the definitions adopted in establishing rock nomenclature merely correspond to more or less arbitrary selected points in a continuously graduated series. Igneous rock forms through the cooling and solidification of magma or lava and this magma can be derived from partial melts of pre-existing rocks in either a planets mantle or crust. Typically, the melting of rocks is caused by one or more of three processes, an increase in temperature, a decrease in pressure, or a change in composition, igneous rocks are divided into two main categories, plutonic rock and volcanic. Plutonic or intrusive rocks result when magma cools and crystallizes slowly within the Earths crust, a common example of this type is granite. Volcanic or extrusive rocks result from magma reaching the surface either as lava or fragmental ejecta, the chemical abundance and the rate of cooling of magma typically forms a sequence known as Bowens reaction series. Most major igneous rocks are found along this scale, about 64. 7% of the Earths crust by volume consists of igneous rocks, making it the most plentiful category. Of these, 66% are basalts and gabbros, 16% are granite, only 0. 6% are syenites and 0. 3% peridotites and dunites
Rock (geology)
–
Balanced Rock stands in the
Garden of the Gods park in
Colorado Springs
Rock (geology)
–
Rock outcrop along a mountain creek near
Orosí,
Costa Rica.
Rock (geology)
–
Sample of igneous
gabbro
Rock (geology)
–
Sedimentary sandstone with iron oxide bands
18.
Flash flood
–
A flash flood is a rapid flooding of geomorphic low-lying areas, washes, rivers, dry lakes and basins. It may be caused by heavy rain associated with a thunderstorm, hurricane, tropical storm. Flash floods may occur after the collapse of an ice or debris dam, or a human structure such as a man-made dam. Flash floods are distinguished from regular floods by a timescale of less than six hours, the water that is temporarily available is often used by foliage with rapid germination and short growth cycles, and by specially adapted animal life. Flash floods can occur under several types of conditions, Flash flooding occurs when it rains rapidly on saturated soil or dry soil that has poor absorption ability. The runoff collects in gullies and streams and, as they join to form larger volumes, often forms a fast flowing front of water, in areas on or near volcanoes, flash floods have also occurred after eruptions, when glaciers have been melted by the intense heat. Flash floods are known to occur in the highest mountain ranges of the United States and are common in the arid plains of the Southwestern United States. Flash flooding can also be caused by extensive rainfall released by hurricanes and other tropical storms, human activities can also cause flash floods to occur. When dams fail, a quantity of water can be released. Many people tend to underestimate the dangers of flash floods, what makes flash floods most dangerous is their sudden nature and fast-moving water. A vehicle provides little to no protection against being swept away, it may make people overconfident, more than half of the fatalities attributed to flash floods are people swept away in vehicles when trying to cross flooded intersections. As little as 2 feet of water is enough to carry away most SUV-sized vehicles. The U. S. National Weather Service reported in 2005 that, using a national 30-year average, more people die yearly in floods,127 on average, than by lightning, tornadoes, in deserts, flash floods can be particularly deadly for several reasons. First, storms in arid regions are infrequent, but they can deliver an enormous amount of water in a short time. Second, these rains often fall on poorly absorbent and often clay-like soil, in fact, in some areas, desert roads frequently cross dry river and creek beds without bridges. From the drivers perspective, there may be clear weather, when a river unexpectedly forms ahead of or around the vehicle in a matter of seconds. Finally, the lack of rain to clear water channels may cause flash floods in deserts to be headed by large amounts of debris, such as rocks, branches. 1889, Johnstown Flood, Pennsylvania, U. S. more than 2,200 people dead 1903, Heppner Flood of 1903, Oregon, United States,247 dead, 25% of the city 1938, Los Angeles Flood of 1938, California, U. S. S
Flash flood
–
Driving through a flash-flooded road
Flash flood
–
Nepal Monsoon
Flash flood
–
A flash flood after a thunderstorm in the
Gobi, Mongolia
19.
Yucca
–
Yucca is a genus of perennial shrubs and trees in the family Asparagaceae, subfamily Agavoideae. Its 40-50 species are notable for their rosettes of evergreen, tough, sword-shaped leaves and they are native to the hot and dry parts of the Americas and the Caribbean. Early reports of the species were confused with the cassava, consequently, Linnaeus mistakenly derived the generic name from the Taíno word for the latter, yuca. It is commonly found growing in rural graveyards and when in bloom the cluster of flowers on a thin stalk appear as floating apparitions, the natural distribution range of the genus Yucca covers a vast area of the Americas. The genus is represented throughout Mexico and extends into Guatemala and it also extends to the north through Baja California in the west, northwards into the southwestern United States, through the drier central states as far north as southern Alberta in Canada. Yucca is also native to the lowlands and dry scrub of the Gulf. Yuccas have adapted to an equally vast range of climatic and ecological conditions, Yucca species are the host plants for the caterpillars of the yucca giant-skipper, ursine giant-skipper, and Streckers giant-skipper. Species of yucca have adapted to a variety of climates in mountains, coastal sand, grasslands and prairies as well as rocky badlands. Most species of yucca have thick, waxy skins to prevent loss of water through evaporation and they frequently store water in thick roots. Some yuccas store water in thick, fleshy leaves, some desert plants have an oily coating on their leaves or pads that traps moisture, thereby reducing water loss. Some species drop their leaves during drought to prevent the loss of water through transpiration, dead leaves of yucca collecting against the trunk of the trees help protect it from the sun. The channeled leaves of a yucca direct dew and rainfall water to their roots, yuccas are said to be fire adapted, that is, they grow and spread vigorously after wildfires. Yuccas are widely grown as ornamental plants in gardens, many species also bear edible parts, including fruits, seeds, flowers, flowering stems, and more rarely roots. References to yucca root as food often arise from confusion with the similarly pronounced, roots of soaptree yucca are high in saponins and are used as a shampoo in Native American rituals. Dried yucca leaves and trunk fibers have a low ignition temperature, in rural Appalachian areas, species such as Yucca filamentosa are referred to as meat hangers. The tough, fibrous leaves with their tips were used to puncture meat. Yuccas are widely grown as architectural plants providing a dramatic accent to landscape design and they tolerate a range of conditions, but are best grown in full sun in subtropical or mild temperate areas. In gardening centres and horticultural catalogues they are grouped with other architectural plants such as cordylines
Yucca
–
Yucca
Yucca
–
Distribution of the capsular fruited species in southwest, midwest USA, Mexico's Baja California and Canada, overview
Yucca
–
Yucca aloifolia L. (Type species) (syn. Yucca yucatana)
Yucca
–
Yucca angustissima Engelm. ex Trel. (including Yucca kanabensis)
20.
Opuntia
–
Opuntia is a genus in the cactus family, Cactaceae. The most common species is the Indian fig opuntia. Most culinary uses of the prickly pear refer to this species. Prickly pears are also known as tuna, sabra, nopal from the Nahuatl word nōpalli for the pads, or nostle, from the Nahuatl word nōchtli for the fruit, or paddle cactus. The genus is named for the Ancient Greek city of Opus, where, according to Theophrastus, like all true cactus species, prickly pears are native only to the Americas, but they have been introduced to other parts of the globe. Prickly pear species are found in abundance in Mexico, especially in the central and western regions, Prickly pear cactus is also native to coastal beach scrub environments and low open areas of the East Coast from Florida to Connecticut/Long Island. Prickly pears also produce a fruit, commonly eaten in Mexico and in the Mediterranean region, known as tuna, the fruit can be red, wine-red, green, or yellow-orange. The first introduction of prickly pears into Australia is ascribed to Governor Philip, brought from Brazil to Sydney, prickly pear grew in Sydney, New South Wales, where they were rediscovered in a farmers garden in 1839. They appear to have spread from New South Wales and caused great damage in the eastern states. In the Galápagos Islands, six different species are found, O. echios, O. galapageia, O. helleri, O. insularis, O. saxicola and these species are divided into 14 different varieties, most of these are confined to one or a few islands. For this reason, they have described as an excellent example of adaptive radiation. On the whole, islands with tall, trunked varieties have giant tortoises, Prickly pears are a prime source of food for the common giant tortoises in the Galápagos islands so they are important in the food web. Charles Darwin was the first to note that these cacti have thigmotactic anthers and this movement can be seen by gently poking the anthers of an open Opuntia flower. The same trait has evolved convergently in other cacti, chollas, now recognized to belong to the distinct genus Cylindropuntia, are distinguished by having cylindrical, rather than flattened, stem segments with large barbed spines. The barbed spines can remain embedded in the skin, causing discomfort, collectively, opuntias, chollas, and related plants are sometimes called opuntiads. When Carl Linnaeus published Species Plantarum in 1753 – the starting point for botanical nomenclature – he placed all the species of cactus known to him in one genus, Cactus. In 1754, the Scottish botanist Philip Miller divided cacti into several genera and he distinguished the genus largely on the form of its flowers and fruits. Also, not all species listed here may actually belong in this genus, – quipá Opuntia insularis Opuntia invicta syn. O. leptocarpa MacKensen, O. tenuispina Engelm
Opuntia
–
Opuntia
Opuntia
–
Typical
habitus of an Opuntia with fruit
Opuntia
–
Bud appears ►
Opuntia
21.
Dasylirion wheeleri
–
Dasylirion wheeleri is a moderate to slow-growing evergreen shrub with a single unbranched trunk up to 40 cm thick growing to 1.5 m tall, though often recumbent on the ground. The leaf blade is slender, 35-100 cm long, gray-green, the leaves radiate from the center of the plants apex in all directions. The flowering stem grows above the foliage, to a height of 5 m tall, the stem is topped by a long plume of straw-colored small flowers about 2.5 cm long with six tepals. The color of the flower determinate the gender of the plant, being mostly white colored for males, the fruit is an oval dry capsule 5-8 mm long, containing a single seed. D. wheeleri is grown as a plant, valued in xeriscaping. As it does not tolerate extended frosts, in regions it is usually grown under glass. It has gained the Royal Horticultural Societys Award of Garden Merit, the alcoholic drink sotol, the northern cousin to tequila and mezcal, is made from the fermented inner cores of the desert spoon. It is the drink of the Mexican states of Chihuahua, Durango. It was also used by the natives of the region for food and its flower stalk can be used as a fire plow. The Tarahumara and Pima Bajo peoples of the Sierra Madre Occidental of Chihuahua weave baskets from the leaves after they strip off the spines from the leaf margins and they also employ the expanded leaf bases in making large artificial flowers as holiday decorations. Flora of North America, Dasylirion wheeleri, Range Map USDA Plant Profile, Dasylirion wheeleri Pictures of Dasylirion wheeleri
Dasylirion wheeleri
–
Dasylirion wheeleri
Dasylirion wheeleri
–
Flower stem of the Desert Spoon plant
Dasylirion wheeleri
–
Decorative flowers made from leaf bases of sotol, Darylirion wheeleri, Yepachi, Chihuahua
22.
Juniperus ashei
–
It grows up to 10 metres tall, rarely 15 metres, and provides erosion control and year-round shade for wildlife and livestock. The feathery foliage grows in dense sprays, bright green in color, the leaves are scale-like,2 to 5 millimetres long, and produced on rounded shoots. It is a species, with separate male and female plants. The seed cones are round,3 to 5 millimetres long and they contain 1-2 seeds, which are dispersed when birds eat the cones and pass the seeds in their droppings. The male cones are 3–5 mm long, yellow, turning brown after pollen release in December to February, the pollen causes a severe allergic reaction for some people in the winter, and people who are allergic to Ashe juniper are also often allergic to the related Juniperus virginiana. Consequently, what begins as an allergy in the winter may extend into spring since the pollination of J. virginiana follows that of J. ashei, Ashe juniper is sometimes known in the area as mountain cedar, and locals usually refer to the allergy as cedar fever. Left untreated, symptoms of cedar fever may develop into a severe infection such as pneumonia. The wood is naturally rot resistant and provides raw material for fence posts, posts cut from old-growth Ashe junipers have been known to last in the ground for more than 50 years. Over one hundred years ago, most old-growth Ashe junipers were cut and used not only for fence posts, although Ashe Juniper is native to central Texas, it is considered a weed by many landowners. Some believe that it captures large amounts of water, denying it to plants, thus causing them to die out and allowing the Ashe Juniper to take over. Since with a constant water supply they are fast growing, this causes the land to become more valuable due to its improved nature. Ranchers also consider it to be a pest plant because overgrazing by cattle selectively removes competition when they avoid the bitter-tasting juniper seedlings and this allows for a high rate of juniper establishment and reduces ranch yields. Ashe juniper does not resprout when cut, but its cousin, the junipers that establish in overgrazed lands are young and vigorous, dense and multi-trunked, and shallow rooted. This makes it difficult for remaining grasses to compete for water, especially if they are still being grazed, the presence of these dense, shallow-rooted shrubs also means less water reaches the soil, subsurface flows and deep drainage. However, their dense canopies and thick litter do reduce overland flows compared to grazed grasses, old-growth Ashe junipers are different in that they have true trunks, use less water, are slow growing, less foliated and have very deep roots. Wilcox and Keith Owens are currently studying how these deeper roots may facilitate the drainage of water down trunk stemflows. Dr. Owens reports that for one inch of rain. IUCN Red List of Threatened Species, international Union for Conservation of Nature
Juniperus ashei
–
Juniperus ashei
23.
Quercus fusiformis
–
Quercus fusiformis, commonly known as escarpment live oak, plateau live oak, or plateau oak, is an evergreen or nearly evergreen tree. Its native range includes the Quartz Mountains and Wichita Mountains in southwestern Oklahoma, through Texas, to the Mexican states of Coahuila, Tamaulipas, Quercus fusiformis is an evergreen tree in the white oak section of the genus Quercus. It is distinguished from Quercus virginiana most easily by the acorns and it is also a smaller tree, not exceeding 1 meter in trunk diameter, with more erect branching and a less wide crown. Like Q. virginiana, its magnificent, stately form and unparalleled longevity has endeared it to generations of residents where it is native, escarpment live oak is typically found on dry sites, unlike southern live oak, which prefers moister conditions. The tree, especially the Quartz Mountains variety, is accepted to be the hardiest evergreen oak. For this reason the tree has become popular within the industry for its beauty, ability to endure urban conditions. It is prevalently used for purposes in Texas and southern Oklahoma. United States Department of Agriculture Plants Profile of Quercus fusiformis Texas Native Plants Database, Texas A&M University, lady Bird Johnson Wildflower Center, University of Texas at Austin photo of herbarium specimen collected in Nuevo León in 2003
Quercus fusiformis
–
Texas live oak
Quercus fusiformis
24.
Balcones Fault
–
The Balcones Fault zone is made up of many smaller features, including normal faults, grabens, and horsts. One of the features is the Mount Bonnell Fault. The location of the zone may be related to the Ouachita Mountains. Although long since eroded away in Texas, the roots of ancient mountains still exist. These buried Ouachita Mountains may still be an area of weakness that becomes a site for faulting when stress exists in the Earths crust. The Balcones Fault has remained inactive for nearly 15 million years and this activity was related to subsidence of the Texas Coastal Plain, most likely from the large amount of sediment deposited on it by Texas rivers. The Balcones Fault is in one of the zones for earthquakes in the United States. Subterranean features such as Wonder Cave and numerous other caves are found along the fault zone. Many cities are located along this fault zone
Balcones Fault
–
Escarpment formed by the Balcones Fault at
Mount Bonnell
Balcones Fault
–
Central city
25.
San Antonio
–
San Antonio, officially the City of San Antonio, is the seventh-most populated city in the United States and the second-most populous city in the state of Texas, with a population of 1,409,019. It was the fastest growing of the top 10 largest cities in the United States from 2000 to 2010, the city straddles South Texas and Central Texas and is on the southwestern corner of an urban megaregion known as the Texas Triangle. San Antonio serves as the seat of Bexar County, recent annexations have extended the citys boundaries into Medina County and, though for only a very tiny area near the city of Garden Ridge, into Comal County. Due to its placement, the city has characteristics of other urban centers in which there are sparsely populated areas. San Antonio is the center of the San Antonio–New Braunfels Metropolitan Statistical Area, growth along the Interstate 35 and Interstate 10 corridors to the north, west and east make it likely that the metropolitan area will continue to expand. San Antonio was named for Saint Anthony of Padua, whose feast day is on June 13, the city contains five 18th-century Spanish frontier missions, including The Alamo and San Antonio Missions National Historical Park, which were designated UNESCO World Heritage Sites in 2015. Other notable attractions include the River Walk, the Tower of the Americas, the Alamo Bowl, the city is home to the five-time NBA champion San Antonio Spurs and hosts the annual San Antonio Stock Show & Rodeo, one of the largest such events in the country. The U. S. Kelly Air Force Base operated out of San Antonio until 2001, the remaining portions of the base were developed as Port San Antonio, an industrial/business park and aerospace complex. San Antonio is home to six Fortune 500 companies and the South Texas Medical Center, at the time of European encounter, Payaya Indians lived near the San Antonio River Valley in the San Pedro Springs area, calling the vicinity Yanaguana, meaning refreshing waters. In 1691, a group of Spanish Catholic explorers and missionaries came upon the river and Payaya settlement on June 13 and they named the place and river San Antonio in his honor. It was years before any Spanish settlement took place, father Antonio de Olivares visited the site in 1709, and he was determined to found a mission and civilian settlement there. He directed Martin de Alarcón, the governor of Coahuila and Texas, differences between Alarcón and Olivares resulted in delays, and construction did not start until 1718. The families who clustered around the presidio and mission formed the beginnings of Villa de Béjar, on May 1, the governor transferred ownership of the Mission San Antonio de Valero to Fray Antonio de Olivares. On May 5,1718 he commissioned the Presidio San Antonio de Béxar on the west side of the San Antonio River, one-fourth league from the mission. On February 14,1719, the Marquis of San Miguel de Aguayo proposed to the king of Spain that 400 families be transported from the Canary Islands, Galicia, or Havana to populate the province of Texas. By June 1730,25 families had reached Cuba, and 10 families had sent to Veracruz before orders from Spain came to stop the re-settlement. Under the leadership of Juan Leal Goraz, the group marched overland from Veracruz to the Presidio San Antonio de Béxar, due to marriages along the way, the party now included 15 families, a total of 56 persons. They joined the community established in 1718
San Antonio
–
From top to bottom and Left to Right: 1. San Antonio downtown from the Tower of The Americas at night. 2. The Riverwalk 3. The McNay Museum of Art 4. The Tower Life Building 5. Bexar County courthouse 6. San Antonio Public Library 7. The Tower of the Americas at night 8. The Alamo
San Antonio
–
Seal
San Antonio
–
Lithograph of San Antonio in 1886
San Antonio
–
Memorial to the
Alamo defenders
26.
Austin, Texas
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Austin is the capital of the U. S. state of Texas and the seat of Travis County. It is the 11th-most populous city in the U. S. and it is the fastest growing large city in the United States and the second most populous capital city after Phoenix, Arizona. As of the U. S. Census Bureaus July 1,2015 estimate and it is the cultural and economic center of the Austin–Round Rock metropolitan area, which had an estimated population of 2,056,405 as of July 1,2016. In the 1830s, pioneers began to settle the area in central Austin along the Colorado River, in 1839, the site was officially chosen to replace Houston as the new capital of the Republic of Texas and was incorporated under the name Waterloo. Shortly thereafter, the name was changed to Austin in honor of Stephen F. Austin, the Father of Texas and the republics first secretary of state. The city subsequently grew throughout the 19th century and became a center for government and education with the construction of the Texas State Capitol and the University of Texas at Austin. After a lull in growth from the Great Depression, Austin resumed its development into a city and, by the 1980s, it emerged as a center for technology. A number of Fortune 500 companies have headquarters or regional offices in Austin, including Amazon. com, cisco, eBay, Google, IBM, Intel, Oracle Corporation, Texas Instruments, 3M, and Whole Foods Market. Dells worldwide headquarters is located in nearby Round Rock, a suburb of Austin, residents of Austin are known as Austinites. They include a mix of government employees, college students, musicians, high-tech workers, blue-collar workers. The city also adopted Silicon Hills as a nickname in the 1990s due to an influx of technology. In the late 1800s, Austin was known as the City of the Violet Crown because of the glow of light across the hills just after sunset. Even today, many Austin businesses use the term Violet Crown in their name, Austin is known as a clean-air city for its stringent no-smoking ordinances that apply to all public places and buildings, including restaurants and bars. The FBI ranked Austin as the second-safest major city in the U. S. for the year 2012, U. S. News & World Report named Austin the best place to live in the U. S. in 2017. Austin, Travis County and Williamson County have been the site of habitation since at least 9200 BC. When settlers arrived from Europe, the Tonkawa tribe inhabited the area, the Comanches and Lipan Apaches were also known to travel through the area. Spanish colonists, including the Espinosa-Olivares-Aguirre expedition, traveled through the area for centuries, in 1730, three missions from East Texas were combined and reestablished as one mission on the south side of the Colorado River, in what is now Zilker Park, in Austin. The mission was in area for only about seven months
Austin, Texas
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Downtown skyline as seen from
Lady Bird Lake
Austin, Texas
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An 1873 illustration of Edwin Waller's layout for Austin
Austin, Texas
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Statue of the Goddess of Liberty on the
Texas State Capitol Grounds prior to installation on top of the rotunda
Austin, Texas
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Bob Bullock Texas History Museum in Austin. Its mission is to "tell The Story of Texas".
27.
Spring (hydrosphere)
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A spring is any natural situation where water flows from an aquifer to the Earths surface. It is a component of the hydrosphere, a spring may be the result of karst topography where surface water has infiltrated the Earths surface, becoming part of the area groundwater. The groundwater then travels through a network of cracks and fissure—openings ranging from intergranular spaces to large caves, the water eventually emerges from below the surface, in the form of a karst spring. The forcing of the spring to the surface can be the result of an aquifer in which the recharge area of the spring water table rests at a higher elevation than that of the outlet. Spring water forced to the surface by elevated sources are artesian wells and this is possible even if the outlet is in the form of a 300-foot-deep cave. In this case the cave is used like a hose by the higher elevated area of groundwater to exit through the lower elevation opening. Non-artesian springs may simply flow from a higher elevation through the earth to a lower elevation, still other springs are the result of pressure from an underground source in the earth, in the form of volcanic activity. The result can be water at elevated temperature such as a hot spring, the action of the groundwater continually dissolves permeable bedrock such as limestone and dolomite, creating vast cave systems. The term seep refers to springs with small flow rates in which the water has filtered through permeable earth. Fracture springs, discharge from faults, joints, or fissures in the earth, tubular springs, in which the water flows from underground caverns. Spring discharge, or resurgence, is determined by the springs recharge basin, factors that affect the recharge include the size of the area in which groundwater is captured, the amount of precipitation, the size of capture points, and the size of the spring outlet. Water may leak into the system from many sources including permeable earth, sinkholes. In some cases entire creeks seemingly disappear as the water sinks into the ground via the stream bed, grand Gulf State Park in Missouri is an example of an entire creek vanishing into the groundwater system. The water emerges 9 miles away, forming some of the discharge of Mammoth Spring in Arkansas, human activity may also affect a springs discharge--withdrawal of groundwater reduces the water pressure in an aquifer, decreasing the volume of flow. Springs are often classified by the volume of the water they discharge, the largest springs are called first-magnitude, defined as springs that discharge water at a rate of at least 2800 liters or 100 cubic feet of water per second. The scale for spring flow is as follows, Minerals become dissolved in the water as it moves through the underground rocks and this may give the water flavor and even carbon dioxide bubbles, depending on the nature of the geology through which it passes. This is why spring water is bottled and sold as mineral water. Springs that contain significant amounts of minerals are sometimes called mineral springs, Springs that contain large amounts of dissolved sodium salts, mostly sodium carbonate, are called soda springs
Spring (hydrosphere)
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On an average day nearly 303 million US gallons (1,150,000 m 3) of water flow from
Big Spring in
Missouri at a rate of 469 cubic feet per second (13.3 m 3 /s).
Spring (hydrosphere)
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A natural spring on
Mackinac Island in
Michigan
Spring (hydrosphere)
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Sunrise at Middle Spring,
Fish Springs National Wildlife Refuge, Utah
Spring (hydrosphere)
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Fontaine de Vaucluse or Spring of Vaucluse in France discharges about 470 million US gallons (1,800,000 m 3) of water per day at a rate of 727 cubic feet (21 m 3) per second.
28.
Edwards Aquifer
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The Edwards Aquifer is one of the most prolific artesian aquifers in the world. Although between 25 and 55 million acre-feet of water may be present in the Edwards aquifer, only a portion of this water is practically or legally available for use. Storage is the difference between recharge and discharge from the Edwards Aquifer, annual storage can be negative during dry years with high water use and positive during wet years with relatively low water use. A long-term negative imbalance between recharge and discharge in an aquifer may lead to the depletion of the water in the aquifer. The average storage during this period was 37,000 acre-feet per year, Water enters the Edwards Aquifer in two ways, it either falls as precipitation and percolates directly into the aquifer, or it enters as streamflow flowing through the Recharge Zone. The Recharge Zone occurs along the Balcones Fault Zone where the Edwards Plateau drops steeply, here, highly fractured limestones are exposed at the Earths surface, which allow rain and streamflow to infiltrate directly into the aquifer. The Contributing Zone, which occurs on 5,400 mi2 of the Edwards Plateau, collects precipitation, major streams draining the Contributing Zone include Cibolo Creek, Helotes Creek, Barton Creek, and Onion Creek. Water is unable to percolate into the aquifer in the Contributing Zone because much of the geology is impermeable. Average precipitation in the region is around 30 inches per year, only precipitation that falls on the contributing area is available for infiltration. The average annual rate between 1934 and 2013 is estimated to be 699,000 acre-feet, or only 6% of the total inputs to the system. Water from the Edwards Aquifer is discharged in two ways, it is pumped from wells or it leaves as stream outflow. The Edwards Aquifer Authority and the United States Geological Survey have monitored annual well, annual well discharge - the sum of all well discharges in a year - ranged from 219,300 acre-feet to 542,500 acre-feet between 1955 and 2012. The average well discharge for this period was approximately 371,667 acre-feet, annual spring discharge ranged from 69,800 acre-feet to 802,800 acre-feet between 1955 and 2012. The average spring discharge for this period was approximately 392,991 acre-feet, during dry years, more water is discharged from wells while during wet years, more water is discharged from springs. These are used to estimate the levels of groundwater withdrawal throughout the aquifer. Aquifer storage is correlated with water levels recorded in the J-17 Bexar index well which serves as the official monitoring well in the Edwards Aquifer. The J-17 well, is located in the artisanal confined Edwards Aquifer at a location AY-68-37-203 based on the latitude and longitude, Water levels have been recorded in the J-17 well since the 1910s, and is used to generalize the entire aquifer system. Changes in aquifer storage are used to estimate recharge rates, in the Edwards aquifer, groundwater flow models have been developed for the San Antonio and Barton Springs aquifer segments in the San Antonio region of Texas
Edwards Aquifer
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Karst formation from Segovia, Spain.
Edwards Aquifer
Edwards Aquifer
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Main Barton Spring in Austin, Texas, a prominent fracture (visible here) in limestone rock. Through this artesian karst spring water emerges to the surface from the karstic Edwards Aquifer. This spring is situated near the diving board in Barton Springs Pool. Photo provided by US Geological Survey.
Edwards Aquifer
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Central city
29.
San Marcos, Texas
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San Marcos is a city in the U. S. state of Texas, within the Austin–Round Rock–San Marcos metropolitan area. The city is on the Interstate 35 corridor between Austin and San Antonio and is the seat of Hays County, the city limits extend into Caldwell and Guadalupe Counties, as well. Its population was 44,894 in 2010, in 2015 the U. S. Census Bureau estimated the population at 60,684 Founded on the banks of the San Marcos River, the area is thought to be among the oldest continuously inhabited sites in the Americas. San Marcos is home to Texas State University and the Meadows Center for Water, in 2010, San Marcos was listed in Business Weeks fourth annual survey of the Best Places to Raise your Kids. In 2013 and 2014, the United States Census Bureau named San Marcos the fastest-growing city in the United States, in December 2013, San Marcos was named #9 on Business Insiders list of the 10 Most Exciting Small Cities In America. San Marcos is in Central Texas and it is 30 miles southwest of Austin and 51 miles northeast of San Antonio. According to the United States Census Bureau, in 2010, the city had an area of 30.3 square miles, of which 30.2 square miles was land and 0.1 square miles. Interstate 35 is the highway through the city, with access from Exits 199 through 208. The city is situated on the Balcones Fault, the boundary between the Hill Country to the west and the Coastal Plains to the east. Along the fault, many springs emerge, such as San Marcos Springs, the eastern part of the city is blackland prairie. The western part consists of forested or grassy rolling hills, often marked with cacti, the San Marcos River and the Blanco River, part of the Guadalupe watershed, flow through the city, along with Cottonwood Creek, Purgatory Creek, Sink Creek, and Willow Springs Creek. The climate in this area is characterized by hot, humid summers and generally mild to cool winters, annual precipitation is about 34 inches, almost all is rain. According to the Köppen climate classification system, San Marcos has a subtropical climate. For primary and secondary education, San Marcos is served by the San Marcos Consolidated Independent School District, San Marcos High School is the districts sole high school. San Marcos Baptist Academy, a high school, is in the city. Texas State University is a four year university in town, the Forensic Anthropology Center at Texas State is one of the four extant body farms in the United States and the largest such forensics research facility in the world. Along with its access to air travel, the city has ready access to several freight routes and IH-35 and IH-10. The access points of the area provide a route to major cities in Texas such as Austin, San Antonio, Dallas
San Marcos, Texas
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Hays County Courthouse Historic District
San Marcos, Texas
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Seal
San Marcos, Texas
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Old Main academic building at
Texas State University
San Marcos, Texas
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San Marcos Premium Outlets located to the east of
Interstate 35
