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50-698: The Maya Block , also known as the Maya Terrane , Yucatan Block , or Yucatan–Chiapas Block , is a physiographic or geomorphic region and tectonic or crustal block in the southernmost portion of the North American Plate . The Block is commonly delimited by the continental margin in the Gulf of Mexico to the north, in the Caribbean Sea to the east, and in the Pacific Ocean to the southwest, and further, by

100-464: A balloon flight over the Alps; he is probably the first person to use aerial photography in geomorphological or physiographical research. The block diagrams of Fenneman, Raisz, Lobeck and many others were based in part upon both aerial photography and topographic maps, giving an oblique "birds-eye" view. By 1901, there were clear differences in the definition of the term physiography. "In England, physiography

150-678: A further nine were located near it (in the Motagua–Polochic Faults or the portion of the Middle America Trench bordering the Block). Middle America, including the Maya Block, is thought to have taken shape sometime after 170 million years ago. Its formation is thought to have 'involved [the] complex movement of [various] crustal blocks and terranes between the two pre-existing continental masses [ie North and South America].' Details of

200-593: A logical history of oceanic basins, and continental elevations; of mountains , plateaus and plains ; of hills and valleys. Physical geography is used loosely as a synonym, but the term is more properly applied to the borderland between geography and physiography; dealing, as it does, largely with the human element as influenced by its physiographic surroundings". Even in the 21st century, some confusion remains as to exactly what "physiography" is. One source states "Geomorphology includes quaternary geology, physiography and most of physical geography", treating physiography as

250-463: A portmanteau of " physi cal" and "ge ography ", and therefore synonymous with physical geography , and the concept became embroiled in controversy surrounding the appropriate concerns of that discipline. Some geomorphologists held to a geological basis for physiography and emphasized a concept of physiographic regions while a conflicting trend among geographers was to equate physiography with "pure morphology," separated from its geological heritage. In

300-482: A separate field, but subservient to geomorphology. Another source states "Geomorphology (or physiography) refers to the study of the surface features of the earth. It involves looking at the distribution of land, water, soil and rock material that forms the land surface. Land is closely linked to the geomorphology of a particular landscape", regarding physiography as synonymous with geomorphology. Yet another source states "Physiography may be viewed from two distinct angles,

350-403: A study of "Features and attributes of earth's land surface", while geomorphology is defined separately as "Branch of geology dealing with surface land features and the processes that create and change them". Partly due to this confusion over what "physiography" actually means, some scientists have refrained from using the term physiography (and instead use the similar term geomorphology) because

400-460: A thick sedimentary cover of Upper Palaeozoic clasts and carbonates, Upper Jurassic continental redbeds, and Cretaceous–Eocene carbonates and evaporites. It has been suggested that the Block's continental basement is stretched, since its sedimentary cover reaches a thickness of up to 6 kilometres (3.7 mi), this being considered impossible on an unstretched basement at isostatic equilibrium. The Block

450-651: Is believed to have opened around 590 Ma with the emplacement of the Central Iapetus Magmatic Province between Laurentia and Baltica. The southern Iapetus Ocean opened between Laurentia and southwestern Gondwana (now South America) about 550 Ma, close to the end of the Ediacaran period. At the time it did so the Adamastor Ocean further east closed . The opening of the Iapetus Ocean probably postdates

500-412: Is regarded as the introduction to physical science in general. It is made to include the elements of physics , chemistry , astronomy , physical geography, and geology , and sometimes even certain phases of botany and zoology . In America, the term has a somewhat different meaning. It is sometimes used as a synonym for physical geography, and is sometimes as the science which describes and explains

550-534: Is thought to fully or partially incorporate between two and thirteen geologic provinces. The Block is believed to fully or partially comprehend some four or five sedimentary basins. A number of faults or fault zones have been identified within the Block, the most prominent of which include various boundary faults abutting the Maya Mountains, various offshore faults east of the Yucatán Peninsula–Belize,

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600-582: The Famatinian and Taconic orogenies, meaning a collision between Western Gondwana and Laurentia. Because the Iapetus Ocean was positioned between continental masses that would at a much later time roughly form the opposite shores of the Atlantic Ocean , it can be seen as a sort of precursor of the Atlantic, and the process by which it opened shares many similarities with that of the Atlantic's initial opening in

650-701: The Jurassic . The Iapetus Ocean was therefore named for the titan Iapetus , who in Greek mythology was the father of Atlas , after whom the Atlantic Ocean was named. At the start of the 20th century, American paleontologist Charles Walcott noticed differences in early Paleozoic benthic trilobites of Laurentia (such as Olenellidae , the so-called "Pacific fauna"), as found in Scotland and western Newfoundland , and those of Baltica (such as Paradoxididae , often called

700-823: The Motagua–Polochic Faults to the south-southeast, and by the Isthmus of Tehuantepec to the west. The Motagua–Polochic Faults divide the Maya Block from the Chortis Block , while the Isthmus of Tehuantepec divides it from the Oaxaquia Block (i.e. the Juarez, Cuicateco, or Oaxaquia Block, Terrane, or microcontinent). The Block's precise subaerial limits are not widely agreed upon, in contrast to its relatively exact submarine borders. Furthermore, it has been recently suggested that

750-523: The continental shelves of Baltica and Laurentia are still very different in the Ordovician, but Silurian faunas show progressive mixing of species from both sides, because the continents moved closer together. In the west, the Iapetus Ocean closed with the Taconic orogeny (480-430 million years ago), when the volcanic island arc collided with Laurentia. Some authors consider the oceanic basin south of

800-451: The geologic timescale (between 600 and 400 million years ago). It was in the southern hemisphere , between the paleocontinents of Laurentia , Baltica and Avalonia . The ocean disappeared with the Acadian , Caledonian and Taconic orogenies , when these three continents joined to form one big landmass called Euramerica . The "southern" Iapetus Ocean has been proposed to have closed with

850-481: The "Atlantic fauna"), as found in the southern parts of the British Isles and eastern Newfoundland. Geologists of the early 20th century presumed that a large trough, a so-called geosyncline , had existed between Scotland and England in the early Paleozoic, keeping the two sides separated. With the development of plate tectonics in the 1960s, geologists such as Arthur Holmes and John Tuzo Wilson concluded that

900-614: The Appalachian–Caledonian or Ouachita–Marathon–Appalachian orogeny (that is, during the formation of Pangaea from the collision of Gondwana and Laurentia ). It is thought to have been displaced away from the Laurentian craton by clockwise rotation, translation, or anticlockwise rotation, during the Middle Jurassic opening of the Gulf of Mexico and subsequent northwesterly drift of North America away from Pangaea. Details of

950-485: The Atlantic Ocean must have had a precursor before the time of Pangaea . Wilson also noticed that the Atlantic had opened at roughly the same place where its precursor ocean had closed. This led him to his Wilson cycle hypothesis. In many spots in Scandinavia basaltic dikes are found with ages between 670 and 650 million years. These are interpreted as evidence that by that time, rifting had started that would form

1000-613: The Belize Barrier Reef, the Lacandon Range, the Cuchumatanes Range, and various formations to the north and south of the Maya Mountains. The most prominent topographic features of the Block's Caribbean coast are extensive seagrass beds and coral reefs, with the Belize Barrier Reef forming a notable example of the latter. Its Pacific coast, in contrast, is predominated by extensive mangrove forests. The terrestrial portion of

1050-474: The Block encompasses all six districts of Belize , five northerly departments of Guatemala (Huehuetenango, Quiche, Alta Verapaz, Izabal, Peten), and five southeasterly states of Mexico (Chiapas, Tabasco, Campeche, Yucatán, and Quintana Roo). Its submarine portion encompasses the continental shelf which abuts the coastal districts. Mean thickness of the continental crust constituting the Block increases southwards, ranging from 20–25 kilometres (12–16 mi) in

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1100-537: The Block's western extreme may rather extend past the Isthmus of Tehuantepec, along the Gulf of Mexico, and into Louisiana. A broad arching fold belt of 'morphological distinct mountain ranges separated by deep fault-controlled canyons and occasional broad alluvial valleys' extends along the south-southeasterly limit of the Block. The most prominent of said mountain ranges are the Northern Chiapas Mountains and

1150-710: The Cenozoic (66–0 million years ago) geologic history of Middle America, including that of the Maya Block, are relatively more widely agreed upon. In broad strokes, the Chortis Block is thought to have reached its present-day position by at least 20 million years ago. The northern and eastern coasts of the Block are not thought to have been fully subaerially exposed until some 5–2 million years ago. The Block's coastlines, which were initially more expansive than its present-day ones, are thought to have reached modern dimensions due to rising sea levels some 11–8 thousand years ago. The Block

1200-669: The Iapetus Ocean. In Newfoundland and Labrador , the Long Range dikes are also thought to have formed during the formation of the Iapetus Ocean. It has been proposed that both the Fen Complex in Norway and the Alnö Complex in Sweden formed as consequence to mild extensional tectonics in the ancient continent of Baltica that followed the opening of the Iapetus Ocean. The eastern Iapetus Ocean

1250-622: The North and South America show that no rotation has occurred. Restoration of the blocks along the Cayman trend by re-aligning their eastern faulted margins also results in line-up the Río Hondo-Guayape systems. Physiographic regions of the world The classification mechanism has become a popular geographical tool in the United States, indicated by the publication of a USGS shapefile that maps

1300-881: The Sierra Madre de Chiapas in Mexico, the Cuchumatanes, Chama, Santa Cruz, and Lacandon Ranges in Guatemala, and the Maya Mountains in Belize. The 'most extensive karstlands of the North American continent' extend northwards from the Block's southern extreme. The Block's most prominent karstic landform is the Yucatán Platform to its north. Relatively less prominent karstic formations occur in the Block's southern portion, including an unnamed formation in northwestern Peten to northeastern Belize,

1350-636: The Ticul Fault, the Malpaso Faults, and the Rio Hondo Faults. The Block is thought to experience significant counterclockwise rotation and a north-northwest down tilt, which gradually lowers the northern portion of the Yucatán Platform, thereby lifting its southern extreme in the Maya Mountains. It is nonetheless tectonically rigid or stable, experiencing an absolute west-southwest motion of 1.8 centimetres (0.71 in) per annum. Central America, including

1400-420: The casual observer, but this is not always the case. A maturely dissected plateau may grade without a break from rugged mountains on the one hand to mildly rolling farm lands on the other. So also, forms which are not classified together may be superficially similar; for example, a young coastal plain and a peneplain . In a large number of cases, the boundary lines are also geologic lines, due to differences in

1450-521: The definitions vary from the American Geological Institute's "the study and classification of the surface features of Earth on the basis of similarities in geologic structure and the history of geologic changes" to descriptions that also include vegetation and/or land use. Iapetus Ocean The Iapetus Ocean ( / aɪ ˈ æ p ɪ t ə s / ; eye- AP -ih-təs ) existed in the late Neoproterozoic and early Paleozoic eras of

1500-499: The distribution of plant, animals and humans. This work gave impetus to further works along the field. In Germany, Oscar Peschel in 1870, proposed that geographers should study the morphology of the Earth's surface, having an interest in the study of landforms for the development of human beings. As the chair of geography (and a geologist by training) in Bonn, Germany, Ferdinand von Richthofen made

1550-621: The eastern parts had closed too: the Tornquist Sea between Avalonia and Baltica already during the late Ordovician, the main branch between Baltica-Avalonia and Laurentia during the Grampian and Scandian phases of the Caledonian orogeny (440–420 million years ago). At the end of the Silurian period (c. 420 million years ago) the Iapetus Ocean had completely disappeared and the combined mass of

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1600-413: The fluid envelopes. It thus draws upon physics for the explanation of the phenomena with the space-relations of which it is specially concerned. Physical geography naturally falls into three divisions, dealing respectively with the surface of the lithosphere – geomorphology; the hydrosphere – oceanography ; and the atmosphere – climatology . All these rest upon the facts of mathematical geography, and

1650-527: The island arc also a part of the Iapetus, this branch closed during the later Acadian orogeny , when Avalonia collided with Laurentia. It has been suggested that the southern Iapetus Ocean closed during a continental collision between Laurentia and Western Gondwana (South America). If factual the Taconic orogen would be the northward continuation of the Famatinian orogen exposed in Argentina. Meanwhile,

1700-627: The more encompassing "physical geography" definition. For the purposes of physiographic mapping, landforms are classified according to both their geologic structures and histories. Distinctions based on geologic age also correspond to physiographic distinctions where the forms are so recent as to be in their first erosion cycle , as is generally the case with sheets of glacial drift . Generally, forms which result from similar histories are characterized by certain similar features, and differences in history result in corresponding differences of form, usually resulting in distinctive features which are obvious to

1750-418: The nature or structure of the underlying rocks. The history of "physiography" itself is at best a complicated effort. Much of the complications arise from how the term has evolved over time, both as its own 'science' and as a synonym for other branches of science. In 1848, Mary Somerville published her book Physical Geography which gave detailed descriptions of the topography of each continent, along with

1800-569: The northern Yucatán Peninsula to 30–40 kilometres (19–25 mi) in the Peninsula's south. The crust's i.e. Block's crystalline basement is composed mainly of Silurian–Triassic metamorphic and igneous rocks, and is exposed in at least five formations, namely, the Mixtequita Massif, Chiapas Massif, Cuchumatanes Dome, Tucuru–Teleman, and the Maya Mountains . Elsewhere, the basement is overlain by

1850-411: The one dynamic, the other passive". The same source continues by stating "In a large fashion geodynamics is intimately associated with certain branches of geology, as sedimentation , while geomorphology connects physiography with geography. The dynamic interlude representing the active phase of physiography weaves the basic threads of geologic history." The U.S. Geological Survey defines physiography as

1900-567: The opening of the Puncoviscana Ocean , which is believed to have opened around 700 Ma as Laurentia drifted away from Amazonia, with the Iapetus Ocean being separated from the Puncoviscana Ocean by the ribbon-shaped Arequipa-Antofalla terrane . However, the formation of both oceans seems unrelated. Southwest of the Iapetus, a volcanic island arc evolved from the early Cambrian (540 million years ago) onward. This volcanic arc

1950-405: The period following World War II, the emergence of process, climatic, and quantitative studies led to a preference by many Earth scientists for the term "geomorphology" in order to suggest an analytical approach to landscapes rather than a descriptive one. In current usage, physiography still lends itself to confusion as to which meaning is meant, the more specialized "geomorphological" definition or

2000-494: The physical features of the earth's surface". By 1911, the definition of physiography in Encyclopædia Britannica had evolved to be "In popular usage the words 'physical geography' have come to mean geography viewed from a particular standpoint rather than any special department of the subject. The popular meaning is better conveyed by the word physiography, a term which appears to have been introduced by Linnaeus , and

2050-516: The pre-Cenozoic portion of this process (170–67 million years ago), however, are not widely agreed upon. Nonetheless, it has been proposed that the Block formed before or during the opening of the Iapetus Ocean . It, together with the Oaxaquia, Suwannee, and Carolina Blocks, are thought to have constituted a peri-Gondwanan terrane on that continent's western, northwestern, northern, or eastern edge during

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2100-523: The regions of the original work and the National Park Services's use of the terminology to describe the regions in which its parks are located. Originally used in North America , the model became the basis for similar classifications of other continents. During the early 1900s, the study of regional-scale geomorphology was termed "physiography". Physiography later was considered to be

2150-544: The southern portion of the Maya Block, 'is very well-known and characterised by numerous, medium size earthquakes preceded and followed by damaging shocks,' with the Middle America Trench in the Pacific deemed the main source of such quakes. Of thirty-three earthquakes of M s ≥ 7.0 in Central America during 1900–1993, the epicentres of at least two of these were located within the Block (in its southwestern quadrant), though

2200-528: The study of landforms the main research field for himself and his students. Elsewhere, Thomas Henry Huxley 's Physiography was published in 1877 in Britain . Shortly after, the field of "physical geography" itself was renamed as "physiography". Afterwards, physiography became a very popular school subject in Britain, accounting for roughly 10% of all examination papers in both English and Welsh schools, and physiography

2250-431: The three are so closely inter-related that they cannot be rigidly separated in any discussion". The 1919 edition of The Encyclopedia Americana: A Library of Universal Knowledge further adjusted the definition to be "Physiography (geomorphology), now generally recognized as a science distinct from geology, deals with the origins and development of land forms, traces out the topographic expression of structure, and embodies

2300-563: The two. Models should not deny stratigraphy. The two blocks have similar tectonic origins and similar structure. They are continental remnants of Pangean breakup, left at the western end of the Caribbean. [The] Maya [block] was sinistrally offset from [the] Chortis [block] when [the] early Cayman offset developed. Neither block is a terrane rotated into place form another location. The major Jurassic faults on [the] Maya and Chortis [blocks] (Río Hondo and Guayape) that remain parallel to coeval faults in

2350-811: Was discovered in 1969 by Gabriel Dengo, a Guatemalan geographer. It was quickly adopted in scholarship, and remains 'accepted by many as a valid subdivision of Central America's geology, especially of its crystalline basement.' Numerous illustrations/models show the Maya and Chortis blocks originating in the Gulf of Mexico or [show the] Maya [block originating] in the Gulf and [the] Chortis [block elsewhere]. They are shown to have rotated clockwise or anticlockwise by as much as 80º about various poles or migrating poles to their present locations. The variety and complexity of interpretations reflects dominance of models over data. Similarity of basement, Jurassic and Cretaceous sections on [the] Maya and Chortis [blocks] should be reason to relate

2400-524: Was formed above a subduction zone where the oceanic lithosphere of the Iapetus Ocean subducted southward under other oceanic lithosphere . From Cambrian times (about 550 million years ago) the western Iapetus Ocean began to grow progressively narrower due to this subduction. The same happened further north and east, where Avalonia and Baltica began to move towards Laurentia from the Ordovician (488–444 million years ago) onward. Trilobite faunas of

2450-436: Was now regarded as an integral, if not the most important aspect of geography. In conjunction with these 'advances' in physiography, physically and visually mapping these descriptive areas was underway as well. The early photographers and balloonists, Nadar and Triboulet, experimented with aerial photography and the view it provided of the landscape. In 1899, Albert Heim published his photographs and observations made during

2500-458: Was reinvented as a substitute for the cosmography of the Middle Ages by Professor Huxley. Although the term has since been limited by some writers to one particular part of the subject, it seems best to maintain the original and literal meaning. In the stricter sense, physical geography is that part of geography which involves the processes of contemporary change in the crust and the circulation of

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