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111-878: Geologically separated from the Greater Antilles island of Hispaniola by the Mona Passage and from the Lesser Antilles island arc by the Anegada Passage , the main island of Puerto Rico, the Spanish Virgin Islands of Vieques and Culebra, the British Virgin Islands , and the U.S. Virgin Islands except for the southernmost island of Saint Croix , all lie on the same carbonate platform and insular shelf ,

222-577: A cause célèbre , and local protesters were joined by sympathetic groups and prominent individuals from the mainland United States and abroad, including political leaders Rubén Berríos , Robert F. Kennedy Jr. , Al Sharpton and Jesse Jackson , singers Danny Rivera , Willie Colón and Ricky Martin , actors Edward James Olmos and Jimmy Smits , boxer Félix 'Tito' Trinidad , baseball superstar Carlos Delgado , writers Ana Lydia Vega and Giannina Braschi , and Guatemala's Nobel Prize winner Rigoberta Menchú . Kennedy's son, Aidan Caohman "Vieques" Kennedy,

333-535: A characteristic fabric . All three types may melt again, and when this happens, new magma is formed, from which an igneous rock may once again solidify. Organic matter, such as coal, bitumen, oil, and natural gas, is linked mainly to organic-rich sedimentary rocks. To study all three types of rock, geologists evaluate the minerals of which they are composed and their other physical properties, such as texture and fabric . Geologists also study unlithified materials (referred to as superficial deposits ) that lie above

444-485: A petrographic microscope , where the minerals can be identified through their different properties in plane-polarized and cross-polarized light, including their birefringence , pleochroism , twinning , and interference properties with a conoscopic lens . In the electron microprobe, individual locations are analyzed for their exact chemical compositions and variation in composition within individual crystals. Stable and radioactive isotope studies provide insight into

555-630: A certain amount of social exclusion . A map shows these communities occur in nearly every municipality of the commonwealth. Of the 742 places that were on the list in 2014, the following barrios, communities, sectors, or neighborhoods were in Vieques: Sector Gobeo in Barrio Florida, Bravos de Boston, Jagüeyes, Monte Carmelo, Pozo Prieto (Monte Santo) and Villa Borinquén. Vieques measures about 21 miles (34 km) east-west, and three to four miles (6.4 km) north-south. It has

666-434: A definite homogeneous chemical composition and an ordered atomic arrangement. Each mineral has distinct physical properties, and there are many tests to determine each of them. Minerals are often identified through these tests. The specimens can be tested for: A rock is any naturally occurring solid mass or aggregate of minerals or mineraloids . Most research in geology is associated with the study of rocks, as they provide

777-598: A friend of White House Deputy Chief of Staff Josh Lyman ; the character was modeled on future West Wing star Jimmy Smits , a native of Puerto Rico who was repeatedly arrested for leading protests there. As a result of this pressure, in May 2003 the Navy withdrew from Vieques, and much of the island was designated a National Wildlife Refuge under the control of the United States Fish and Wildlife Service . The island

888-718: A land area of 52 square miles (130 km ) and is located about ten miles (16 km) to the east of Puerto Rico. To the north of Vieques is the Atlantic Ocean, and to the south, the Caribbean . The island of Culebra is about 10 miles (16 km) north of Vieques, and the United States Virgin Islands lie to the east. Vieques and Culebra, together with various small islets, make up the Spanish Virgin Islands , sometimes known as

999-595: A lawless outpost, frequented by pirates and outlaws. As European powers fought for control in the region, a series of attempts by the French , English and Danish to colonize the island in the 17th and 18th centuries were repulsed by the Spanish. At the beginning of the 19th century, the Spanish took steps to permanently settle and secure the island. In 1811, Don Salvador Meléndez, then governor of Puerto Rico, sent military commander Juan Rosselló to begin what would become

1110-627: A length of less than a meter. Rocks at the depth to be ductilely stretched are often also metamorphosed. These stretched rocks can also pinch into lenses, known as boudins , after the French word for "sausage" because of their visual similarity. Where rock units slide past one another, strike-slip faults develop in shallow regions, and become shear zones at deeper depths where the rocks deform ductilely. The addition of new rock units, both depositionally and intrusively, often occurs during deformation. Faulting and other deformational processes result in

1221-452: A means to provide information about geological history and the timing of geological events. The principle of uniformitarianism states that the geological processes observed in operation that modify the Earth's crust at present have worked in much the same way over geological time. A fundamental principle of geology advanced by the 18th-century Scottish physician and geologist James Hutton

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1332-608: A number of fields, laboratory, and numerical modeling methods to decipher Earth history and to understand the processes that occur on and inside the Earth. In typical geological investigations, geologists use primary information related to petrology (the study of rocks), stratigraphy (the study of sedimentary layers), and structural geology (the study of positions of rock units and their deformation). In many cases, geologists also study modern soils, rivers , landscapes , and glaciers ; investigate past and current life and biogeochemical pathways, and use geophysical methods to investigate

1443-570: A population of 8,249. 8.0% of the population is of non-Hispanic origin, making it the second-least Hispanic municipality in Puerto Rico after Culebra . This represents an increase from 2010, when only 5.7% of the population was non-Hispanic. The 2010 US census, showed the total population of Vieques was 9,301. 94.3% of the population are Hispanic or Latino (of any race). Natives of Vieques are known as Viequenses . Both Spanish and English are recognized as official languages. Spanish

1554-451: A sedimentary rock. Sedimentary rocks are mainly divided into four categories: sandstone, shale, carbonate, and evaporite. This group of classifications focuses partly on the size of sedimentary particles (sandstone and shale), and partly on mineralogy and formation processes (carbonation and evaporation). Igneous and sedimentary rocks can then be turned into metamorphic rocks by heat and pressure that change its mineral content, resulting in

1665-499: A single environment and do not necessarily occur in a single order. The Hawaiian Islands , for example, consist almost entirely of layered basaltic lava flows. The sedimentary sequences of the mid-continental United States and the Grand Canyon in the southwestern United States contain almost-undeformed stacks of sedimentary rocks that have remained in place since Cambrian time. Other areas are much more geologically complex. In

1776-400: A variety of applications. Dating of lava and volcanic ash layers found within a stratigraphic sequence can provide absolute age data for sedimentary rock units that do not contain radioactive isotopes and calibrate relative dating techniques. These methods can also be used to determine ages of pluton emplacement. Thermochemical techniques can be used to determine temperature profiles within

1887-523: A warm, relatively dry, tropical climate. Temperatures vary little throughout the year, with average daily maxima ranging from 84.7 °F (29.3 °C) in January to 89.9 °F (32.2 °C) in September. Average daily minima are about 18 °F or 6 °C lower. Rainfall averages around 40 to 45 inches (1,000 to 1,100 millimetres) per year, with the month of September being the wettest. The west of

1998-419: Is a branch of natural science concerned with the Earth and other astronomical objects , the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth sciences , including hydrology . It is integrated with Earth system science and planetary science . Geology describes the structure of the Earth on and beneath its surface and

2109-422: Is accomplished in two primary ways: through faulting and folding . In the shallow crust, where brittle deformation can occur, thrust faults form, which causes the deeper rock to move on top of the shallower rock. Because deeper rock is often older, as noted by the principle of superposition , this can result in older rocks moving on top of younger ones. Movement along faults can result in folding, either because

2220-460: Is an intimate coupling between the movement of the plates on the surface and the convection of the mantle (that is, the heat transfer caused by the slow movement of ductile mantle rock). Thus, oceanic parts of plates and the adjoining mantle convection currents always move in the same direction – because the oceanic lithosphere is actually the rigid upper thermal boundary layer of the convecting mantle. This coupling between rigid plates moving on

2331-828: Is characterized by an irregular topography resulting in an intricate coastline. The island is approximately 11 by 8 kilometers (7 by 5 mi). The coast is marked by cliffs, coral sand beaches, and mangroves . The highest elevation on the island is Mount Resaca , which is about 190 meters (623 ft). Its hydrography is based on lagoons (Laguna Flamenco, Laguna Zoní, Laguna de Cornelio, and Laguna de Molino, among others), bays (Ensenada Honda [including Ensenada del Coronel, Ensenada Fulladoza, Ensenada del Cementerio, Ensenada Dákity, Bahía Mosquito, and Ensenada Malena], Puerto Manglar, and Bahía de Tamarindo, among others), and small creeks. Geology Geology (from Ancient Greek γῆ ( gê )  'earth' and λoγία ( -logía )  'study of, discourse')

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2442-475: Is geographically part of the Spanish Virgin Islands . Vieques lies about 8 miles (13 km) east of the mainland of Puerto Rico , measuring about 20 miles (32 km) long and 4.5 miles (7 km) wide. Its most populated barrio is the town of Isabel Segunda (or "Isabel the Second", sometimes written "Isabel II"), the administrative center located on the northern side of the island. The population of Vieques

2553-433: Is horizontal). The principle of superposition states that a sedimentary rock layer in a tectonically undisturbed sequence is younger than the one beneath it and older than the one above it. Logically a younger layer cannot slip beneath a layer previously deposited. This principle allows sedimentary layers to be viewed as a form of the vertical timeline, a partial or complete record of the time elapsed from deposition of

2664-616: Is important for mineral and hydrocarbon exploration and exploitation, evaluating water resources , understanding natural hazards , remediating environmental problems, and providing insights into past climate change . Geology is a major academic discipline , and it is central to geological engineering and plays an important role in geotechnical engineering . The majority of geological data comes from research on solid Earth materials. Meteorites and other extraterrestrial natural materials are also studied by geological methods. Minerals are naturally occurring elements and compounds with

2775-526: Is now called the Taíno culture. This culture flourished in the region from around 1000 AD until the arrival of Europeans in the late 15th century. The European discovery of Vieques is sometimes credited to Christopher Columbus , who landed in Puerto Rico in 1493. It does not seem to be certain whether Columbus personally visited Vieques, but in any case the island was soon claimed by the Spanish. During

2886-484: Is primarily accomplished through normal faulting and through the ductile stretching and thinning. Normal faults drop rock units that are higher below those that are lower. This typically results in younger units ending up below older units. Stretching of units can result in their thinning. In fact, at one location within the Maria Fold and Thrust Belt , the entire sedimentary sequence of the Grand Canyon appears over

2997-568: Is that "the present is the key to the past." In Hutton's words: "the past history of our globe must be explained by what can be seen to be happening now." The principle of intrusive relationships concerns crosscutting intrusions. In geology, when an igneous intrusion cuts across a formation of sedimentary rock , it can be determined that the igneous intrusion is younger than the sedimentary rock. Different types of intrusions include stocks, laccoliths , batholiths , sills and dikes . The principle of cross-cutting relationships pertains to

3108-519: Is the primary language of most inhabitants. The sugar industry , once the mainstay of the island's economy, declined during the early 20th century, and finally collapsed in the 1940s when the US Navy took over much of the land on which the sugar cane plantations stood. After an initial naval construction phase, opportunities to make a living on the island were increased to include not only fishing or subsistence farming, but also Naval jobs. Crops grown on

3219-901: Is under the leadership of a mayor, presently Junito Corcino. Vieques belongs to the Puerto Rico Senatorial district VIII , which is represented by two Senators. In 2012, Pedro A. Rodríguez and Luis Daniel Rivera were elected as District Senators. Vieques is divided into eight barrios , including the downtown barrio called Isabel Segunda. Barrios (which are like minor civil divisions ) are further subdivided into smaller areas called sectores ( sectors in English). The types of sectores may vary, from normally sector to urbanización to reparto to barriada to residencial , among others. Comunidades Especiales de Puerto Rico (Special Communities of Puerto Rico) are marginalized communities whose citizens are experiencing

3330-523: Is used for geologically young materials containing organic carbon . The geology of an area changes through time as rock units are deposited and inserted, and deformational processes alter their shapes and locations. Rock units are first emplaced either by deposition onto the surface or intrusion into the overlying rock . Deposition can occur when sediments settle onto the surface of the Earth and later lithify into sedimentary rock, or when as volcanic material such as volcanic ash or lava flows blanket

3441-645: The Bioluminescent Bay . Linear arrays of smaller stones radiating from the central boulders are apparent at the site today, but their age and reason for placement are unknown. Further waves of settlement by Native Americans followed over many centuries. The Arawak -speaking Saladoid (or Igneri ) people, thought to have originated in modern-day Venezuela , arrived in the region perhaps around 200 BC (estimates vary). These tribes, noted for their pottery, stone carving, and other artifacts, eventually merged with groups from Hispaniola and Cuba to form what

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3552-801: The Islas Vírgenes Puertorriqueñas (Puerto Rican Virgin Islands) or the Islas Vírgenes de Puerto Rico (Virgin Islands of Puerto Rico). Archaeological works in Vieques indicate that the island of Vieques was inhabited by indigenous groups from South America around 1,500 years before the arrival of Christopher Columbus in 1493 . The inhabitants of Vieques, brothers of the Taínos of the Big Island of Puerto Rico, resisted

3663-466: The Puerto Ferro site by Luis Chanlatte and Yvonne Narganes uncovered a fragmented human skeleton in a large hearth area. Radiocarbon dating of shells found in the hearth indicate a burial date of c. 1900 BCE. This skeleton, popularly known as El Hombre de Puerto Ferro , was buried at the center of a group of large boulders near Vieques's south-central coast, approximately one kilometer northwest of

3774-733: The Puerto Rico Bank , between the North Atlantic Ocean and the Caribbean Sea . The archipelagos of Puerto Rico and the Virgin Islands except for Saint Croix also lie on the same tectonic plate , the Puerto Rico–Virgin Islands microplate . Historically, the islands of Vieques and Culebra were included in maps and chronicles as part of the archipelago of the Virgin Islands , which

3885-506: The bedrock . This study is often known as Quaternary geology , after the Quaternary period of geologic history, which is the most recent period of geologic time. Magma is the original unlithified source of all igneous rocks . The active flow of molten rock is closely studied in volcanology , and igneous petrology aims to determine the history of igneous rocks from their original molten source to their final crystallization. In

3996-461: The founder of Vieques (though this title is also sometimes conferred on Francisco Saínz, governor from 1843 to 1852, who founded Isabel Segunda , the main town in Vieques, named after Queen Isabel II of Spain). Vieques was formally annexed to Puerto Rico in 1854. In 1816, Vieques was briefly visited by Simón Bolívar when his ship ran aground there while fleeing defeat in Venezuela. During

4107-512: The geochemical evolution of rock units. Petrologists can also use fluid inclusion data and perform high temperature and pressure physical experiments to understand the temperatures and pressures at which different mineral phases appear, and how they change through igneous and metamorphic processes. This research can be extrapolated to the field to understand metamorphic processes and the conditions of crystallization of igneous rocks. This work can also help to explain processes that occur within

4218-402: The mantle below (separated within itself by seismic discontinuities at 410 and 660 kilometers), and the outer core and inner core below that. More recently, seismologists have been able to create detailed images of wave speeds inside the earth in the same way a doctor images a body in a CT scan . These images have led to a much more detailed view of the interior of the Earth, and have replaced

4329-536: The 17th and 18th centuries. In 1688, and later in 1717, these English tried to colonize Vieques, establishing hamlets, a military fort, an English government, and extensive farming. In both cases the Spanish governor in Puerto Rico sent strong military expeditions and successfully evicted the English invaders and thus assured Spanish domination over Vieques. In 1875, the Spanish Crown made an effort to populate

4440-583: The 1920s and 1930s, the sugar industry , on which Vieques was dependent, went into decline due to falling prices and industrial unrest. Many locals were forced to move to mainland Puerto Rico or Saint Croix to look for work. In 1941, while Europe was in the midst of World War II , the United States Navy purchased or seized almost eighty percent of Vieques as an extension to the Roosevelt Roads Naval Station nearby on

4551-440: The 1960s, it was discovered that the Earth's lithosphere , which includes the crust and rigid uppermost portion of the upper mantle , is separated into tectonic plates that move across the plastically deforming, solid, upper mantle, which is called the asthenosphere . This theory is supported by several types of observations, including seafloor spreading and the global distribution of mountain terrain and seismicity. There

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4662-720: The American virgin islands from the neighboring British virgin islands, the islands under the control of the British Empire began to be known as the British Virgin Islands . As part of the Virgin Islands archipelago, the islands of Vieques and Culebra , which along with the main island of Puerto Rico , remained under the control of the Spanish Empire throughout the European colonization of

4773-711: The Americas until the Spanish-American War in 1898, are known as the Spanish Virgin Islands, distinguishing them from the other islands in the archipelago: the United States Virgin Islands and the British Virgin Islands . As island- municipalities of Puerto Rico , Vieques and Culebra are mostly known as islas municipio (island municipality) , with Vieques being also popularly known among residents of Puerto Rico as Isla Nena (“girl island”) . As such, they are also known as

4884-424: The Earth, such as subduction and magma chamber evolution. Structural geologists use microscopic analysis of oriented thin sections of geological samples to observe the fabric within the rocks, which gives information about strain within the crystalline structure of the rocks. They also plot and combine measurements of geological structures to better understand the orientations of faults and folds to reconstruct

4995-581: The English name Crab Island came from. Puerto Rico was ceded by Spain in the aftermath of the Spanish–American War under the terms of the Treaty of Paris of 1898 and became a territory of the United States. In 1899, the United States conducted its first census of Puerto Rico finding that the population of Vieques was 6,642 (but this included 704 residents from a nearby island, Culebra ). In

5106-484: The Grand Canyon in the southwestern United States being a very visible example, the lower rock units were metamorphosed and deformed, and then deformation ended and the upper, undeformed units were deposited. Although any amount of rock emplacement and rock deformation can occur, and they can occur any number of times, these concepts provide a guide to understanding the geological history of an area. Geologists use

5217-498: The Passage Islands. The former US Navy lands, now wildlife reserves, occupy the entire eastern and western ends of Vieques, with the former live weapons testing site (known as the "LIA", or "Live Impact Area") at the extreme eastern tip. These areas are unpopulated. The former civilian area occupies very roughly the central third of the island and contains the towns of Isabel Segunda on the north coast, and Esperanza on

5328-642: The Puerto Rican mainland. It is said that the original purpose of the base (never implemented) was to provide a safe haven for the British fleet and the British royal family should Great Britain fall to Nazi Germany . This assertion does not match U.S. Navy documents and the obvious fact that Canada's Halifax harbor would have been a more likely fallback position for the British fleet, with British King George VI already reigning as King of Canada. The base

5439-737: The Spaniards' plans of colonization and slavery. It has been documented that Christopher Columbus discovered the island of Culebra on his second trip to America in 1493. It is believed that the first known inhabitants of the island were the Taíno Indians and then the Caribs . Culebra Island served as a refuge for many defeated Taíno Indians during the rebellion against the Spanish in 1511 . English from Vieques's neighboring British colonies— Tortola , Anguilla , Saint Kitts and Nevis —established themselves in Vieques on several occasions throughout

5550-521: The Spanish, Dutch , French , English , and Danish jostled for control of the islands. The Dutch established a permanent settlement on the island of Tortola by 1648, frequently clashing with the Spanish who were based on nearby main island of Puerto Rico . In 1672, the English captured Tortola from the Dutch, and the English annexation of Anegada and Virgin Gorda followed in 1680. Meanwhile, over

5661-512: The Susan Centeno community health center based on its "replacement value." The family of Jaideliz Moreno Ventura, 13, whose 2020 death was blamed on the lack of a functioning hospital and lifesaving medical equipment in Vieques, is suing the government for violation of human and civil rights. Funds for rebuilding the hospital were approved two weeks after Jaideliz's death. While Governor Pedro Pierluisi expected construction to begin on

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5772-598: The U.S. Navy to take immediate possession of the lands to be expropriated in Vieques. Thus began the process of military expropriation that left the Navy in control of 26,000 acres (11,000 ha) of the 33,000 acres (13,000 ha) of Vieques territory by the end of the 1940s. With the outbreak of World War II , Vieques Island became the main artillery- and bombing-practice area for the U.S. Navy and continued to be used for this purpose until 2003. The larger islands are Culebra and Vieques, with multiple associated smaller islands and islets . Other islands that are close to

5883-523: The US military used the island (with a population of over 9000 inhabitants in 1950 ) as a live munitions target practice. According to internal Navy documents, bombardments occurred on 180 days out of a year on average. The US military used the highest possible contaminant depleted uranium (DU) munitions since 1972 on the populated (and full of exotic wildlife) island, at a rate of over 80 live bombs daily for decades. The health consequences are felt to this day as

5994-534: The annexation of Vieques by the Puerto Ricans. In 1832, under an agreement with the Spanish Puerto Rican administration, Frenchman Teófilo José Jaime María Le Guillou became Governor of Vieques, and undertook to impose order on the anarchic province. He was instrumental in the establishment of large plantations, marking a period of social and economic change. Le Guillou is now remembered as

6105-439: The bay from the ocean. The Spanish believed that the bioluminescence they encountered there while first exploring the area was the work of the devil and tried to block ocean water from entering the bay by dropping huge boulders in the channel. The Spanish only succeeded in preserving and increasing the luminescence in the now isolated bay. Kayaking is permitted in the bay and may be arranged through local vendors. Vieques has

6216-537: The beginning of the 20th century, advancement in geological science was facilitated by the ability to obtain accurate absolute dates to geological events using radioactive isotopes and other methods. This changed the understanding of geological time. Previously, geologists could only use fossils and stratigraphic correlation to date sections of rock relative to one another. With isotopic dates, it became possible to assign absolute ages to rock units, and these absolute dates could be applied to fossil sequences in which there

6327-490: The cancer rates are ostensibly higher for the population of Vieques, especially children, than for those on the main island. After the war, the US Navy continued to use the island for military exercises, and as a firing range and testing ground for munitions . The continuing postwar presence in Vieques of the United States Navy drew protests from the local community, angry at the expropriation of their land and

6438-443: The central region, the island is largely covered by brush and subtropical dry forest . Around the coast lie palm-fringed sandy beaches interspersed with lagoons, mangrove swamps , salt flats and coral reefs . A series of nearshore islets and rocks are part of the municipality of Vieques, clockwise starting at the northernmost: The Vieques Bioluminescent Bay (also known as Puerto Mosquito , Mosquito Bay , or "The Bio Bay" ),

6549-612: The community of San Ildefonso de la Culebra, expelling its residents, and huddled in a small area of Bahía Sardinas , which they called Dewey in honor of an outstanding American admiral during the Spanish-American War. On March 17, 1941, Public Law 13 was passed in Washington, allocating $ 35 million for the construction of the Vieques Base. On August 25 of the same year, Public Law 247 allowed

6660-515: The creation of topographic gradients, causing material on the rock unit that is increasing in elevation to be eroded by hillslopes and channels. These sediments are deposited on the rock unit that is going down. Continual motion along the fault maintains the topographic gradient in spite of the movement of sediment and continues to create accommodation space for the material to deposit. Deformational events are often also associated with volcanism and igneous activity. Volcanic ashes and lavas accumulate on

6771-437: The crust, the uplift of mountain ranges, and paleo-topography. Fractionation of the lanthanide series elements is used to compute ages since rocks were removed from the mantle. Other methods are used for more recent events. Optically stimulated luminescence and cosmogenic radionuclide dating are used to date surfaces and/or erosion rates. Dendrochronology can also be used for the dating of landscapes. Radiocarbon dating

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6882-461: The early 16th century Vieques became a center of Taíno rebellion against the European invaders, prompting the Spanish to send armed forces to the island to quell the resistance. The native Taíno population was decimated, and its people either killed, imprisoned or enslaved by the Spanish. The Spanish did not, however, permanently colonize Vieques at this time, and for the next 300 years it remained

6993-405: The environmental impact of weapons testing. The locals' discontent was exacerbated by the island's perilous economic condition. Protests came to a head in 1999 when Vieques native David Sanes , a civilian employee of the United States Navy, was killed by a jet bomb that the Navy said misfired. Sanes had been working as a security guard. A popular campaign of civil disobedience resurged; not since

7104-570: The fault is a normal fault or a thrust fault . The principle of inclusions and components states that, with sedimentary rocks, if inclusions (or clasts ) are found in a formation, then the inclusions must be older than the formation that contains them. For example, in sedimentary rocks, it is common for gravel from an older formation to be ripped up and included in a newer layer. A similar situation with igneous rocks occurs when xenoliths are found. These foreign bodies are picked up as magma or lava flows, and are incorporated, later to cool in

7215-403: The faults are not planar or because rock layers are dragged along, forming drag folds as slip occurs along the fault. Deeper in the Earth, rocks behave plastically and fold instead of faulting. These folds can either be those where the material in the center of the fold buckles upwards, creating " antiforms ", or where it buckles downwards, creating " synforms ". If the tops of the rock units within

7326-483: The folds remain pointing upwards, they are called anticlines and synclines , respectively. If some of the units in the fold are facing downward, the structure is called an overturned anticline or syncline, and if all of the rock units are overturned or the correct up-direction is unknown, they are simply called by the most general terms, antiforms, and synforms. Even higher pressures and temperatures during horizontal shortening can cause both folding and metamorphism of

7437-404: The formation of faults and the age of the sequences through which they cut. Faults are younger than the rocks they cut; accordingly, if a fault is found that penetrates some formations but not those on top of it, then the formations that were cut are older than the fault, and the ones that are not cut must be younger than the fault. Finding the key bed in these situations may help determine whether

7548-579: The geological history of the Earth as a whole. One aspect is to demonstrate the age of the Earth . Geology provides evidence for plate tectonics , the evolutionary history of life , and the Earth's past climates . Geologists broadly study the properties and processes of Earth and other terrestrial planets. Geologists use a wide variety of methods to understand the Earth's structure and evolution, including fieldwork , rock description , geophysical techniques , chemical analysis , physical experiments , and numerical modelling . In practical terms, geology

7659-415: The history of rock deformation in the area. In addition, they perform analog and numerical experiments of rock deformation in large and small settings. Vieques, Puerto Rico Vieques ( / v i ˈ eɪ k ə s / ; Spanish pronunciation: [ˈbjekes] ), officially Isla de Vieques , is an island, town and municipality of Puerto Rico , and together with Culebra , it

7770-435: The hospital rebuild in 2022, it was delayed until 2023 with the holdup blamed on both construction complications on the island and further bureaucratic proceduress by FEMA . As of November 2024, construction was not yet complete. Vieques is a municipio of Puerto Rico , translated as "municipality" and in this context roughly equivalent to "township". It is in the Puerto Rican electoral district of Carolina. Local government

7881-423: The internal composition and structure of the Earth. Seismologists can use the arrival times of seismic waves to image the interior of the Earth. Early advances in this field showed the existence of a liquid outer core (where shear waves were not able to propagate) and a dense solid inner core . These advances led to the development of a layered model of the Earth, with a lithosphere (including crust) on top,

7992-411: The island include avocados , bananas, coconuts , grains, papayas and sweet potatoes . A number of permanent local jobs were provided by the US Navy, and their economy benefited. Starting in the 1970s General Electric had employed a few hundred workers at a manufacturing plant but that plant subsequently closed. Unemployment was widespread, with consequent social problems. The 2000 US census reported

8103-406: The island of Culebra. But it was not until 1880 that the colonization of Culebra began with the founding of the town of San Idelfonso de la Culebra . Like Puerto Rico, the islands belonged to Spain until 1898. On September 19, 1898, the United States took possession of the islands after the signing of the armistice that ended military operations in the Spanish–American War . The islands, along with

8214-556: The island proved unsuccessful, the Scottish fleet, en route to Darien in 1698, made landfall and took possession of the island in the name of the Company of Scotland Trading to Africa and The Indies . Scottish sovereignty of the island proved short-lived, as a Danish ship arrived shortly afterward and claimed the island. From 1689 to 1693, the island was controlled by Brandenburg-Prussia as Krabbeninsel ( German crab island ), where

8325-431: The island receives significantly more rainfall than the east. Prevailing winds are easterly. Vieques is prone to tropical storms and at risk from hurricanes from June to November. In 1989, Hurricane Hugo caused considerable damage to the island, and in 2017, Hurricane Maria also caused major damage. According to the 2020 Census, Vieques is the third-least populous municipality (after Maricao and Culebra ) with

8436-504: The islands of Puerto Rico, Mona , Monito , Desecheo , and other smaller islands adjacent to the island of Puerto Rico, were formally ceded by Spain to the United States with the signing of the Treaty of Paris on December 10, 1898. In 1903 the U.S. government reserved all public lands belonging to the Spanish Crown on the island of Culebra for the use of the U.S. Navy . At that time the U.S. military took complete control of

8547-464: The later end of the scale, it is marked by the present day (in the Holocene epoch ). The following five timelines show the geologic time scale to scale. The first shows the entire time from the formation of the Earth to the present, but this gives little space for the most recent eon. The second timeline shows an expanded view of the most recent eon. In a similar way, the most recent era is expanded in

8658-589: The local population who had lived and worked there for centuries and protested the expropriations, the decision to turn it into a bombing range was made in Washington. In a similar way as the former population of the Chagos Islands , who were displaced to make way for an Air Force Base in the Indian Ocean in the 1960s, many agricultural workers, who had no formal title to the land they occupied, were evicted and forced to migrate. For over sixty years,

8769-454: The lowest layer to deposition of the highest bed. The principle of faunal succession is based on the appearance of fossils in sedimentary rocks. As organisms exist during the same period throughout the world, their presence or (sometimes) absence provides a relative age of the formations where they appear. Based on principles that William Smith laid out almost a hundred years before the publication of Charles Darwin 's theory of evolution ,

8880-607: The main island of Puerto Rico to give birth. People needing dialysis had to travel to the main island. In November 2018, a mobile dialysis machine was delivered to a temporary clinic. On January 21, 2020, the Federal Emergency Management Agency (FEMA) approved $ 39.5 million to help rebuild its only hospital after damage caused by Hurricane Maria. FEMA approved the funding after the Office of Management and Budget agreed to provide money to rebuild

8991-497: The mantle and show the crystallographic structures expected in the inner core of the Earth. The geological time scale encompasses the history of the Earth. It is bracketed at the earliest by the dates of the first Solar System material at 4.567 Ga (or 4.567 billion years ago) and the formation of the Earth at 4.54 Ga (4.54 billion years), which is the beginning of the Hadean eon  – a division of geological time. At

9102-405: The matrix. As a result, xenoliths are older than the rock that contains them. The principle of original horizontality states that the deposition of sediments occurs as essentially horizontal beds. Observation of modern marine and non-marine sediments in a wide variety of environments supports this generalization (although cross-bedding is inclined, the overall orientation of cross-bedded units

9213-532: The mid-1970s had Viequenses come together en masse to protest the target practices. The locals took to the ocean in their small fishing boats and successfully stopped the US Navy's military exercises for a short period, until the US Navy and two US Coast Guard cutters began controlling access to the island and escorting boaters away from Vieques. On April 27, 2001, the Navy resumed operations and protesting resumed. At this point over 600 protesters had already been detained. The Vieques issue became something of

9324-517: The military is, slowly, cleaning up. Some of the most beautiful beaches on the island are on the eastern end (former site of the Marine Base) that the Navy named Red Beach, Blue Beach , Caracas Beach , Pata Prieta Beach, La Chiva Beach, and Plata Beach. At the far western tip (formerly the Navy Base) is Punta Arenas , which the Navy named 'Green Beach'. The beaches are commonly listed among

9435-693: The period between 1672 and 1733, the Danish gained control of the nearby islands of Saint Thomas , Saint John , and Saint Croix . The islands under English control were known as the Virgin Islands , while the ones under Danish control were known as the Danish West Indies or Danish Virgin Islands . When the United States purchased the Danish islands in 1917, they became known as the United States Virgin Islands . To distinguish

9546-413: The primary record of the majority of the geological history of the Earth. There are three major types of rock: igneous , sedimentary , and metamorphic . The rock cycle illustrates the relationships among them (see diagram). When a rock solidifies or crystallizes from melt ( magma or lava ), it is an igneous rock . This rock can be weathered and eroded , then redeposited and lithified into

9657-569: The principles of succession developed independently of evolutionary thought. The principle becomes quite complex, however, given the uncertainties of fossilization, localization of fossil types due to lateral changes in habitat ( facies change in sedimentary strata), and that not all fossils formed globally at the same time. Geologists also use methods to determine the absolute age of rock samples and geological events. These dates are useful on their own and may also be used in conjunction with relative dating methods or to calibrate relative methods. At

9768-423: The processes that have shaped that structure. Geologists study the mineralogical composition of rocks in order to get insight into their history of formation. Geology determines the relative ages of rocks found at a given location; geochemistry (a branch of geology) determines their absolute ages . By combining various petrological, crystallographic, and paleontological tools, geologists are able to chronicle

9879-428: The rocks. This metamorphism causes changes in the mineral composition of the rocks; creates a foliation , or planar surface, that is related to mineral growth under stress. This can remove signs of the original textures of the rocks, such as bedding in sedimentary rocks, flow features of lavas , and crystal patterns in crystalline rocks . Extension causes the rock units as a whole to become longer and thinner. This

9990-454: The second part of the 19th century, thousands of slaves of African descent were brought to Vieques to work the sugarcane plantations . They arrived from mainland Puerto Rico and nearby islands of St. Thomas , Nevis , Saint Kitts , Saint Croix , and many other Caribbean islands. Slavery was abolished in Puerto Rico in 1873. The island also received considerable attention as a possible colony from Scotland , and after numerous attempts to buy

10101-590: The shore of the main island of Puerto Rico include Icacos Island, Cayo Lobo, Cayo Diablo, Palomino Island , Palominito Island, Isla de Ramos, and Isla Pineiro. Near Culebra is Cayo Luis Peña . Much of Vieques is part of the Vieques National Wildlife Refuge , formerly a U.S. Navy training facility. Culebra's offshore islet, known as Culebrita , is part of the Culebra National Wildlife Refuge . Culebra

10212-433: The simplified layered model with a much more dynamic model. Mineralogists have been able to use the pressure and temperature data from the seismic and modeling studies alongside knowledge of the elemental composition of the Earth to reproduce these conditions in experimental settings and measure changes within the crystal structure. These studies explain the chemical changes associated with the major seismic discontinuities in

10323-512: The south. Vieques has a terrain of rolling hills, with a central ridge running east–west. The highest point is Monte Pirata at 987 feet (301 m). Geologically the island is composed of a mixture of volcanic bedrock , sedimentary rocks such as limestone and sandstone , and alluvial deposits of gravel, sand, silt, and clay. There are no permanent rivers or streams. Much former agricultural land has been reclaimed by nature due to prolonged disuse, and, apart from some small-scale farming in

10434-532: The southwestern United States, sedimentary, volcanic, and intrusive rocks have been metamorphosed, faulted, foliated, and folded. Even older rocks, such as the Acasta gneiss of the Slave craton in northwestern Canada , the oldest known rock in the world have been metamorphosed to the point where their origin is indiscernible without laboratory analysis. In addition, these processes can occur in stages. In many places,

10545-492: The storm caused widespread devastation and a near-total shutdown of the island's tourism-based economy. The largest hotel on the island, The W, has not reopened since the storm, but most smaller hotels, bed and breakfasts, and Airbnb operators have resumed operations. As of December 2019, the Susana Centeno Hospital in Vieques had not been repaired and remained shuttered. Expectant mothers had to travel to

10656-550: The subsurface. Sub-specialities of geology may distinguish endogenous and exogenous geology. Geological field work varies depending on the task at hand. Typical fieldwork could consist of: In addition to identifying rocks in the field ( lithology ), petrologists identify rock samples in the laboratory. Two of the primary methods for identifying rocks in the laboratory are through optical microscopy and by using an electron microprobe . In an optical mineralogy analysis, petrologists analyze thin sections of rock samples using

10767-407: The surface of the Earth and the convecting mantle is called plate tectonics . The development of plate tectonics has provided a physical basis for many observations of the solid Earth . Long linear regions of geological features are explained as plate boundaries: Plate tectonics has provided a mechanism for Alfred Wegener 's theory of continental drift , in which the continents move across

10878-488: The surface of the Earth over geological time. They also provided a driving force for crustal deformation, and a new setting for the observations of structural geology. The power of the theory of plate tectonics lies in its ability to combine all of these observations into a single theory of how the lithosphere moves over the convecting mantle. Advances in seismology , computer modeling , and mineralogy and crystallography at high temperatures and pressures give insights into

10989-479: The surface, and igneous intrusions enter from below. Dikes , long, planar igneous intrusions, enter along cracks, and therefore often form in large numbers in areas that are being actively deformed. This can result in the emplacement of dike swarms , such as those that are observable across the Canadian shield, or rings of dikes around the lava tube of a volcano. All of these processes do not necessarily occur in

11100-742: The surface. Igneous intrusions such as batholiths , laccoliths , dikes , and sills , push upwards into the overlying rock, and crystallize as they intrude. After the initial sequence of rocks has been deposited, the rock units can be deformed and/or metamorphosed . Deformation typically occurs as a result of horizontal shortening, horizontal extension , or side-to-side ( strike-slip ) motion. These structural regimes broadly relate to convergent boundaries , divergent boundaries , and transform boundaries, respectively, between tectonic plates. When rock units are placed under horizontal compression , they shorten and become thicker. Because rock units, other than muds, do not significantly change in volume , this

11211-407: The third timeline, the most recent period is expanded in the fourth timeline, and the most recent epoch is expanded in the fifth timeline. Horizontal scale is Millions of years (above timelines) / Thousands of years (below timeline) Epochs: Methods for relative dating were developed when geology first emerged as a natural science . Geologists still use the following principles today as

11322-433: The top in the Caribbean for their azure waters and white sands. Archaeological evidence suggests that Vieques was first inhabited by ancient Indigenous peoples of the Americas who traveled mostly from South America perhaps between 3000 BCE and 2000 BCE. Estimates of these prehistoric dates of inhabitation vary widely. These tribes had a Stone Age culture and were probably fishermen and hunter-gatherers . Excavations at

11433-416: The water (the organisms have been related to mangrove forests although mangrove is not necessarily associated with this species ); a complete lack of modern development around the bay; the water is warm enough and deep enough; and a small channel to the ocean keeps the dinoflagellates in the bay. This small channel was created artificially, the result of attempts by the occupants of Spanish ships to choke off

11544-437: Was Crab Island . Vieques is best known internationally as the site of a series of protests , held against the United States Navy 's use of the island as a bombing range and testing-ground, leading to the Navy's departure in 2003. Today, the former navy lands are a national wildlife refuge ; some of it is open to the public, but much remains closed off due to biological or chemical contamination or unexploded ordnance that

11655-418: Was 8,249 at the 2020 Census. The island's name is a Spanish spelling of a Taíno word said to mean "small island" or "small land". It also has the nickname Isla Nena , usually translated as "girl island" or "little girl island", alluding to its perception as Puerto Rico's little sister. The island was given this name by the Puerto Rican poet Luís Lloréns Torres . During the British colonial period, its name

11766-576: Was also placed on the National Priorities List (NPL), the list of hazardous waste sites in the United States eligible for long-term remedial action (cleanup) financed by the federal Superfund program. Closure of Roosevelt Roads Naval Station followed in 2004, and prior to Hurricane Maria the Roosevelt Roads Naval Station was reopened. Puerto Rico was struck by Hurricane Maria on September 20, 2017, and

11877-423: Was born while his father served jail time in Puerto Rico for his role in the protests. The problems arising from the US Navy base have also featured in songs by various musicians, including Puerto Rican rock band Puya , rapper Immortal Technique and reggaeton artist Tego Calderón . In popular culture, one subplot of " The Two Bartlets " episode of The West Wing dealt with a protest on the bombing range led by

11988-615: Was datable material, converting the old relative ages into new absolute ages. For many geological applications, isotope ratios of radioactive elements are measured in minerals that give the amount of time that has passed since a rock passed through its particular closure temperature , the point at which different radiometric isotopes stop diffusing into and out of the crystal lattice . These are used in geochronologic and thermochronologic studies. Common methods include uranium–lead dating , potassium–argon dating , argon–argon dating and uranium–thorium dating . These methods are used for

12099-469: Was declared the "Brightest bioluminescent bay" in the world by Guinness World Records in 2006, and is listed as a national natural landmark , one of five in Puerto Rico . The luminescence in the bay is caused by a microorganism , the dinoflagellate Pyrodinium bahamense , which glows whenever the water is disturbed, leaving a trail of neon blue. A combination of factors creates the necessary conditions for bioluminescence: red mangrove trees surround

12210-581: Was however seen as the Atlantic's counterpart of Pearl Harbor in the Pacific due to its strategic location. The Naval Station at Roosevelt Roads was a perfect location to defend the strategic approaches to the Panama Canal . Much of the land was bought from the owners of large farms and sugar cane plantations, and the expropriations triggered the final demise of the sugar industry. Without consulting

12321-406: Was named Santa Úrsula y las Once Mil Vírgenes by Christopher Columbus after the legend of Saint Ursula and the 11,000 virgins. The name was shortened to Islas Vírgenes (Virgins Islands). Having been discovered during the second voyage of Columbus in 1493, the archipelago of the Virgin Islands was claimed by the Spanish Empire , but the Spaniards never settled them. Over the 17th century,

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