The physiographic regions of the world are a means of defining the Earth's landforms into distinct regions based upon Nevin Fenneman's classic three-tiered approach of divisions, provinces and sections,^[1] in 1916,^[2] which although they date from the mid 1910s, are still considered basically valid, and were the basis for similar classifications of other continents later. ^[3] These works have been termed "Indespensible to any student of physiography are the maps and physiographic diagrams by Fenneman, Lobeck, Raisz, and Hammond". Erwin Raisz ( 1 March 1893, Levoca, Hungary &mdash 1 December 1968, Bangkok, Thailand) was a ^[4]

During the early 1900s, the study of regional-scale geomorphology was termed "physiography". Geomorphology (from Greek: γη ge, "earth" μορφή morfé, "form" and λόγος Logos, "knowledge" Unfortunately, physiography later was considered to be a contraction of "physical" and "geography", and therefore synonymous with physical geography, and the concept became embroiled in controversy surrounding the appropriate concerns of that discipline. Physical geography (also known as geosystems or physiography) is one of the three major subfields of Geography. 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. ^[5] In current usage, physiography still lends itself to confusion as to which meaning is meant, the more specialized "geomorphological" definition or the more encompassing "physical geography" definition. For the remainder of this article, emphasis will remain on the more "geomorphological" usage, which is based upon geological landforms, not on climate, vegetation, or other non-geological criteria.

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. The cycle of erosion was a model for stream erosion and landscape development proposed by William Morris Davis in the late 1800s Moraine refers to any glacially formed accumulation of unconsolidated glacial debris (soil and rock which can occur in currently glaciated and formerly glaciated regions such as those 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 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. A dissected plateau is a Plateau area that has been uplifted then severely eroded so that the relief is sharp So also, forms which are not classified together may be superficially similar; for example, a young coastal plain and a peneplain. A coastal plain is an area of flat low-lying land adjacent to a seacoast and separated from the interior by other features A peneplain is the final stage in Fluvial or stream Erosion. After the streams in an area have reached Base level, lateral erosion In a large number of cases, the boundary lines are also geologic lines, due to differences in the nature or structure of the underlying rocks. ^[2]

History of physiography

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 the distribution of plant, animals and humans. Mary Somerville' ( December 26, 1780 &ndash November 28, 1872) was a Scottish Science writer and Polymath Topography ( topo-, "place" and graphia, "writing" is the study of Earth 's Surface features or those of Planets 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 Richtofen made the study of landforms the main research field for himself and his students. Ferdinand Freiherr von Richthofen ( May 5, 1833 &ndash October 6, 1905) was a German traveller Geographer and Elsewhere, Thomas Henry Huxley's Physiography was published in 1877 in Britain. Thomas Henry Huxley PC FRS (4 May 1825 – 29 June 1895 was an English Biologist, known as "Darwin's Bulldog" for his advocacy The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located Shortly after, the field of "physical geography" itself was renamed as "physiography". Physical geography (also known as geosystems or physiography) is one of the three major subfields of Geography. 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 was now regarded as an integral, if not the most important aspect of geography. ^[6]

Block diagram of the Marathon basin, Texas

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 a balloon flight over the Alps; he is probably the first person to use aerial photography in geomorphological or physiographical research. Albert Heim ( April 12, 1849 – August 31, 1937) was a Swiss Geologist. The block diagrams of Feeneman, Raisz, Lobeck and many others were based in part upon both aerial photography and topographic maps, giving an oblique "birds-eye" view. ^[7]

By 1901, there were clear differences in the definition of the term physiography. "In England, physiography is regarded as the introduction to physical science in general. Physical science is an encompassing term for the branches of Natural science and Science that study non-living systems in contrast to the biological sciences It is made to include the elements of physics, chemistry, astronomy, physical geography, and geology, and sometimes even certain phases of botany and zoology. Physics (Greek Physis - φύσις in everyday terms is the Science of Matter and its motion. Chemistry (from Egyptian kēme (chem meaning "earth") is the Science concerned with the composition structure and properties Astronomy (from the Greek words astron (ἄστρον "star" and nomos (νόμος "law" is the scientific study Geology (from Greek γη gê, "earth" and λόγος Logos, "speech" lit Botany, plant science(s, phytology, or plant biology is a branch of Biology and is the scientific study of plant Life Zoology (from Greek ζῷον, zoon, "animal" + λόγος, " Logos " "knowledge" is the branch of In America, the term has a somewhat different meaning. It is sometimes used as a synonym for physical geography, and is sometimes defined as the science which describes and explains the physical features of the earth's surface". This article deals with the general meaning of the term "synonym" ^[8]

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 Physical meaning is better conveyed by the word physiography, a geography term which appears to have been introduced by Linnaeus, and was reinvented as a substitute for the cosmography of the Middle Ages by Professor Huxley. Carl Linnaeus (Latinized as Carolus Linnaeus, also known after his ennoblement as, May 23 new style (13 May old style 1707 who laid the foundations for 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 the fluid envelopes. In Geology, a crust is the outermost solid shell of a planet or moon 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. The lithosphere (IPA, from the Greek λίθος for "rocky" + σφαίρα for "sphere" is the solid outermost shell of a rocky Planet. Geomorphology (from Greek: γη ge, "earth" μορφή morfé, "form" and λόγος Logos, "knowledge" A hydrosphere (from Greek ύδωρ - hydor, " Water " + σφαίρα - sphaira, " Sphere " Oceanography (from the greek words Ωκεανός meaning Ocean and γράφω meaning to write also called oceanology or An atmosphere (from Greek ατμός - atmos, " Vapor " + σφαίρα - sphaira, " Sphere " Climatology (from Greek grc κλίμα klima, "region zone" and grc -λογία -logia) is the study of Climate, scientifically All these rest upon the facts of mathematical geography, and 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 a logical history of oceanic basins, and continental elevations; of mountains, plateaus and plains; of hills and valleys. A mountain is a Landform that extends above the surrounding Terrain in a limited area with a peak In Geology and Earth science, a plateau, also called a high plateau or tableland, is an area of highland, usually consisting In Geography, a plain is an area of land with relatively low relief — meaning that it is flat 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 21^st century, some confusion remains as to exactly what "physiography" is. One source states "Geomorphology includes quaternary geology, physiography and most of physical geography"^[9], treating physiography as 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"^[10], regarding physiography as synonymous with geomorphology. Yet another source states "Physiography may be viewed from two distinct angles, 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. Geodynamics is a subfield of Geophysics dealing with dynamics of the Earth masses Sediment is any particulate matter that can be transported by fluid flow and which eventually is deposited as a layer of solid particles on the bed or bottom of a body of The dynamic interlude representing the active phase of physiography weaves the basic threads of geologic history. "^[11] The U. S. Geological Survey defines physiography as a study of "Features and attributes of earth's land surface"^[12], while geomorphology is defined separately as "Branch of geology dealing with surface land features and the processes that create and change them". ^[13]

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 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 vegation and/or land use. ^[14]

Compendium table of the worlds physiographic regions

The landforms of the Earth are generally divided into physiographic divisions, consisting of physiographic provinces, which in turn consist of physiographic sections,^[15][16][17] though some others use different terminology, such as realms, regions and sub-regions. ^[18] Some areas have further categorized their respective areas into more detailed sub-sections. ^[19][20]

References

This article incorporates text from the Encyclopædia Britannica Eleventh Edition, a publication now in the public domain. The Encyclopædia Britannica Eleventh Edition (1910–1911 is a 29-volume reference work that marked the beginning of the Encyclopædia Britannica The public domain is a range of abstract materials &ndash commonly referred to as Intellectual property &ndash which are not owned or controlled by anyone