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Tectonic Basin Classification
- 2. WHAT IS A BASIN? • A basin is a depression or low-lying area in the earth's surface that provide space for sediment accumulations. • Different types of basins are: • River Basin e.g. Amazon, Congo, Mississippi, etc. • Structural Basin e.g. The East African Rift System, Perth Basin, Williston Basin, etc. • Oceanic Basin e.g. The Atlantic ocean, Pacific Ocean basin, Indian Ocean.
- 3. BASIN FORMATION • Basins are formed due to tectonic activity likely due to processes defined by : • Plate tectonics • Continental Drift • The Wilson Cycle • Sea-level Changes • Subsidence of crust. Source: Fichtel, S., 2000 a, b
- 4. •Subsidence of the crust is induced by: • Attenuation of crust due to stretching and erosion (crustal extension). • Contraction of lithosphere during cooling. • Depression of crust and lithosphere by sedimentary or tectonic loads (supracrustal loading). Figure: Formation mechanism of basins. Source: Slideshare, Tectonics of Sedimentary basin
- 5. • The geodynamic mechanism controlling basin formation and evolution include: • lithosphericplate interactions, • sub lithosphericactions and • earth surface actions Source:Ju et.al., 2020
- 6. Source: Roberts and Bally, 2012, Ju 2020)
- 7. TECTONIC BASIN • A tectonic basin is a large low-lying area that is formed by the sinking or subsidence of the earth's crust due to tectonic forces. • Lithosphericinteraction of stretching, shortening, flexural and strike slip deformation creates different basin types of a single tectonic , thermal or gravity settings or of multistage thermal/ tectonic settings. Source: Matenco, L.C. and Haq, B.U., 2020.
- 8. Fig. 7.1. The three principal stress environments under which tectonic basins are produced (from Liu Hefu, 1986. Reprinted by permission of the American Association of Petroleum Geologists).
- 9. A schematic of sedimentary basins distributed across three continental blocks, an ocean basin (e.g. Pacific basin), and a remnant ocean basin (e.g. Juan de Fuca plate). Key tectonic elements are: subduction zones (black triangles) and associated basins, an orogenic thrust belt resulting from continent-continent or terrane-terrane collision(e.g.Alberta foreland basin) Source: modified from Ingersoll (1988) who modified from Dicinson (1980) • Tectonic basin forms primarily in convergent, divergent and transform plate settings. • Under these settings, numerous types of basin has been further classified by numerous authors. • Recent classification schemes of sedimentary basins based on plate tectonics have much in common.
- 10. BASIS OF BASIN CLASSIFICATION •Basin can be classified on general basis of : • Wilson cycle stage • The types of the crust on which basin rests • The position of the basin relative to plate margin where the basin lies close to a plate margin, • The type of plate interaction occurring during sedimentation. Source:Ju et.al., 2020
- 11. DICKINSON’S CLASSIFICATION • W.R Dickinson (1974, 1976), a pioneer who recognized that sedimentary basins evolve in concert with tectonic plates and plate boundaries and laid foundation for classification of basin governed by tectonic plate interactions. • Plate tectonics emphasizes on horizontal movements of the lithosphere, inducing vertical movements due to changes in crustal thickness, thermal character and isostatic adjustment. • These vertical movements cause formation of sedimentary basins, uplift of sediment source area and reorganizationof dispersal paths.
- 12. •Dickinson’s classification of basin depends on the position of basin in relation to: a)Type of substratum (oceanic, continental or transitional); b)Proximity of basin to plate margin (plate margin or plate boundary) and; c)Type of nearest plate boundary’s (extensional, convergent or transform)
- 13. Dickinson proposed five major basin types on this basis as, • Dickinson classification considers effects of only convergent and divergent plate motions, ignoring the transform or strike slip motion of a plate on basin formation and evolution which was later revised by Reading (1982) adding strike-slip related basins. Divergent settings Convergent settings
- 14. DIVERGENT SETTING • Under divergentsettings, two major types of basin can be distinguishedas; Types of basin Location and settings Examples Oceanic basins Proto-Oceanic Rift Basin In a narrow and newly opening ocean Red Sea, Mid- Atlantic Oceanic Ridge Dormant Ocean Basins or abyssal plains Basin floored by oceanic crust which is stable Gulf of Mexico, Ancient Tarim Basin Rifted Continental Margin Basins Terrestrial Rift Valleys within continental lithosphereon cratons Rio-Grande rift Failed rifts Inactive terrestrial rift valley that extends from passive margin towards interior of cratons. Mississippi Embayments.
- 15. Rio-Grande Rift
- 16. CONVERGENT SETTING • Under convergent settings, three major types of basin has ben distinguished as; Types of basin Location and settings Examples Arc- Trench System Trenches In the abyssal ocean, deep troughs formed by subduction of oceanic lithosphere Chile Trench Fore arc basins Basins developed between subduction complex and magmatic arcs Offshore Sumatra Inter arc basins Local basin along arc platform within magmatic arc which includes superposed & overlapping volcanoes Izu Bonin arc Lago de Nicaragua Back arc basins Basins behind either interoceanic magmatic arc or behind continental margin magmatic arc without foreland fold-thrust belt Marianas back arc, Sunda shelf Retro arc (Foreland) basins Basin on continental sides of continental-margin. Andes foothills
- 17. Peru-Chile (Atacama) trench Source: Davis and Moyer, 2005
- 18. Types of basin Location and settings Examples Suture Belts Remnant Ocean basins Shrinking ocean basins within suture zones formed by continent–continent collision Bay of Bengal Peripheral foreland basin (Compressional Basin) formed after continent–continent collisions by loading of the continental crust of the subducted plate by development of thrust sheets in the continental crust of the subducted plate directed back away from the subduction zone Persian gulf, Indo-gangetic Plain Intra Continental Margins Wrench Basin Diverse basins formed on deformed continental crust due to distant collisions under graben condition. Qaidam basin (China), Thak Khola graben.
- 19. Source:MIT OCW, chapter 11, sedimentary basin Figure: Schematic illustration for modes of different type of foreland basin.
- 20. KINGSTON CLASSIFICATION • The basins classification proposed by Kingston et al. (1983) and Exxon Group expanded Dickinson's plate tectonic method by incorporating basin-scale depositional style. • The rationale for this approach was dictated by the needs of petroleum exploration. • The system is based on the genesis and evolution of basins in the context of their geologic history.
- 21. •This classification also classify basin primarily to their plate tectonics settings as Dickinson’s (1974) but, the main elements used to classify basins are: • depositional cycles or sequences, •basin- forming tectonics and • basin-modifying tectonics
- 22. Depositional cycles or sequences: • It represents distinct tectonic episodes that are basin scale thickness and duration usually bounded by unconformities that transits from marine to non-marine and vice versa. • The minimum stratigraphic unit that can be called a cycle must have significance in the development of a basin, either in thickness or span of geologic time. Source: Kingston et al. 1983
- 23. Basin-forming tectonics are deduced by; • knowledge of the type of underlying crust, • past plate tectonic history, • basin location on the plate, and • type of primary structural movement involved in the basin formation—such as sagging or faulting.
- 25. Divergent cycle: Interior sag cycles/ basins (IS) • located entirely on continental crust in areas of divergence, not at the plate margin. • Normally circular or oval in shape. • Do not accumulate as great a thickness of sediments as continental margin basins. Source: Kingston et al. 1983
- 26. Divergent cycle: Interior fracture cycles/ basins (IF) • found on continental crust, either in the interior of present plates or at the crustal margins of old continental plates. • Interior fracture basins are caused by divergence and tension within the continental block. • Vertical horst & graben faulting and subsidence are the dominant features Source: Kingston et al. 1983
- 27. Divergent type cycle: Margin sag cycles/ basins (MS) • Located on the outer edges of continental crust blocks in areas of divergence. • The basin axes lie parallel with the continental/oceanic crust boundary, and the sediments may overlap onto oceanic crust. • Such basins are referred to as being located on "Atlantic-type" margins. • All margin sag basins have at least two basin-forming tectonic origins and are polyhistory basins.
- 28. Source: Kingston et al. 1983
- 29. • Trenches (T) are located on oceanic crust, and at the margins of two or more converging plates. • Two types of trenches i.e. • one oceanic plate riding another forming mid oceanic trench such as the Mariana, Philippine trenches • Another involve an oceanic plate overriddenby continental plate • Trench-associated (TA) basins are likely to be filled with a high percentage of volcaniclastic sediments, given the proper nearby sediment source area like fore arc basin. • Most trenches and trench-associated basins end up as fold belt. Convergent cycle: Trenches (T) and Trench Associated (TA) basins
- 30. Source: Kingston et al. 1983
- 31. • Found in area of two or more converging plates. • Most wrench couplet or shear basins are found in the areas of present-day, or Tertiary, plate convergence; • the periphery of the Pacific Ocean, including Antarctica; • southeast Asia; • the Himalayan-Alpine chain from the Solomon Islands to Spain; Convergent cycle: Wrench or shear cycles/ basins (LL) Source: Kingston et al. 1983
- 32. • Areas where oceanic crust has been formed by continental separation and the formation of a spreading center. • Subsequent cooling and subsidence of the oceanic crust have caused it to sink. • thick sediment areas are near continental blocks or island arcs and may be associated with either convergence or divergence. • The sediments consist of pelagic material, volcaniclastics, and distal turbidites Oceanic sags (OS)
- 33. • These are the mini-oceans or small ocean basins, floored by oceanic or transitional crust. • Such basins are believed to have been formed by a large divergent wrench couplet (rather than mantle upwelling and sea-floor spreading). • These basins may be filled with pelagic materials, volcaniclastics, or distal turbidites, as in oceanic sags (OS) basins. Oceanic sags- wrench couplet basins (OSLL)
- 34. Basin-modifying tectonics includes; • episodic wrenches (L), • basin-adjacent fold belts (FB), and • completely folded basins (FB3) Source: Kingston et al. 1983
- 35. Source: Kingston et al. 1983
- 36. INGERSOLL’S CLASSIFICATION • Ingersoll (1988, 2012), Busby and Ingersoll (1995) extended the classification of basin on Dickinson’s framework of plate tectonics to break down the system into five settings as ; a)Divergent b)Intraplate c)Convergent d)Transform and e)Hybrid or Miscellaneous • Further, this classification approaches 32 basin type (Ingersoll, 2012) considering subsidence mechanism of basins and their locations on a plate. • However, it does not consider the relationship between basin formation and sub lithospheric actions.
- 37. • This classification also reflects the development trends of basin classification from traditional structural locations to basin forming mechanism.
- 38. Source: after Ingersoll, 2012
- 39. Figure: 3. True-scale actualistic analog models for sedimentary basins in divergent, intraplate and miscellaneous settings. Figure: 4. True-scale actualistic analog models for sedimentary basins in convergent setiings. Source: after Ingersoll, 2012
- 40. Source: after Ingersoll, 2012
- 41. Source: after Ingersoll, 2012
- 42. Figure 5: true-scale actualistic analog models for sedimentary basins in transform and miscellaneous settings Figure 6 : True-scale actualistic analog models for sedimentary basins in continental collisional settings, resulting in hybrid basins Source: after Ingersoll, 2012
- 43. BALLY AND SNELSON’S CLASSIFICATION •The approach of Bally (1975) and Bally and Snelson’s (1980) is different from Dickinson’s framework. •The general classification is based on; •The relationship of basin formation and evolution with a giant suture zone; • Difference of basin between B- type and A- type subduction zone • Rigidity of lithosphere and • Type of plate boundaries
- 44. • Bally and Snelson’s (1980) differentiated three families of sedimentary basin as; (a) basins on rigid, stable lithosphere, (b) basins on rigid lithosphere outside contractional mega sutures,called ‘peri sutural’, and (c) basins situated within mega sutures, termed ‘episutural’. • A comprehensive system of basin classification, which groups together basins formed by different plate-margin processes. • Since all sedimentary basins are shaped by such processes, except those located on the cratonic basement. • It is perhaps not the most satisfactory approach for use by basin analysts.
- 45. Source :Bally and Snelson, 1980
- 46. • Foredeep, fore-arc and Chinese-type basins are the main basins of this type. • However, the Chinese-type basin in this scheme is ambiguous, neglecting the influence of lithospheric structure on a basin’s nature Source :Bally,1974 and Bally and Snelson1980
- 47. Source :Bally,1974 and Bally and Snelson1980 The main episutural basins are colored green and blue: (i) Forearc and backarc basin, as their names suggest, are associated with volcanic arcs ; (ii) Californian and Shear basins are associated with large lateral displacement ; (iii) in Mediterranean-type basins there is oceanization, while in a Pannonian-type there is not.
- 48. Thank You
Editor's Notes
- River basins are low-lying areas that are drained by rivers and their tributaries. River basin have multiple water sheds. Streams, ponds, wetlands and lakes are part of river basin . Sedimentary basins are areas where sediment has accumulated over time, often due to subsidence or tectonic activity. EARS, is a large tectonic basin that stretches from the Red Sea in the north to the Zambezi River in the south, and encompasses several large lakes, including Lake Victoria and Lake Tanganyika. his is a large sedimentary basin located in the northern Great Plains region of the United States and Canada. The basin was formed by subsidence related to the breaking apart of the ancient continent of Pangea. Oceanic basins are large, deep areas of the ocean floor that are surrounded by oceanic crust and often contain abyssal plains and oceanic trenches. This is the largest and deepest oceanic basin in the world, encompassing an area of over 63 million square kilometers. The Pacific Ocean Basin is defined by the Pacific Plate and includes several deep oceanic trenches, including the Mariana Trench, the deepest part of the world's oceans.
- Sedimentary basins form in response to tectonic processes, such as heating events and tectonic loading Before 1960s, formation of basins were categorized by geosynclinal theory, but after the concept of ‘Plate Tectonics’ sedimentary basins are discussed to have been formed by kinematics of plate margin processes. The sedimentary basin refers to a certain tectonic subsidence area on the Earth’s surface filled by sedimentary material and water loading. As one of the main units of global tectonics, the lifecycle of the sedimentary basin is controlled by global plate tectonics and its evolution. According to plate kinematics theory, all kinds of prototype basins can be produced through the Wilson cycle, from continental breakup, via ocean basin opening to closure, to collisional orogeny basin formation mechanism and type have a certain regularity in the Wilson cycle.
- Sedimentary or volcanic loading, tectonic loading, subcrustal loading
- Lithospheric plate interactions include plate-scale extension, compression, and shearing , sublithospheric actions include the effects of the asthenosphere and mantle plumes on the overlying lithosphere, especially crust–mantle interactions. Earth surface actions are also important, reflecting the effects of gravity, atmosphere, ocean, and biology on a basin.
- Under the action of a single tectonic setting, an extensional, a flexural or a strike–slip basin can form, such as the Great Valley Basin, the Appalachian Basin, and the North Sea Basin, respectively Superimposed (or superposed and composite) basins are formed under multistage tectonic processes (Tang et al., 2009; Alçiçek et al., 2013), as in the case of the Tarim Basin (
- Extensional rift related Compressional : Foreland basin
- Basins are classified first by geodynamic environments, including lithospheric plate interactions, sublithospheric actions, and Earth surface actions, 2. then by various geological actions and their dynamic regimes, such as tectonic settings (extension, compression and shearing), thermal actions, and gravity actions, 3. then by basin basement or crustal type, such as continental, oceanic and transitional crusts, and 4. last by sedimentary filling history and tectonic paleogeography, such as marine, lacustrine, and transitional basins. Basin classification rests on a plate tectonic foundation, highlighting lithospheric substrate, proximity to plate margin and relative motion of the nearest plate boundary.
- Reading (1982) and Miall (1990) added strike-slip or transform related basins to this list.
- Passive margins overlie rift systems that ara generally sub parallel to ocean margins.
- This category of basins is transitional between intracontinental rift basins, described above, and passive-margin basins, described below. Basins described here have opened wide enough to begin to be floored with oceanic crust but are still so narrow that the environment is either still nonmarine or, if marine, has restricted circulation. Modern examples are the Red Sea and the Gulf of Aden. In the ancient, the sediment fill of such a basin is likely to underlie passive-margin sediments deposited later in the history of ocean opening Mississipi embayments
- IBM: Izu- Bonin- Mariana Arc
- The basic unit in this classification is the cycle, which consists of the sediments deposited during one tectonic episode. Some basins have only one sedimentary or tectonic cycle. These are called simple basins. Most basins, however, contain more than one tectonic/sedimentary cycle, and are called polyhistory basins.
- A cycle is defined as the sediments deposited during one tectonic period. The minimum stratigraphic unit that can be called a cycle must have significance in the development of a basin, either in thickness or span of geologic time. This allows us to lump thin units of high-shelf or wedge-edge deposits, which may form over long periods of time, into just a few cycles and to split thick prograding deposits into identifiable units. Stage 1 of the cycle corresponds to a nonmarine wedge base. This includes primarily nonmarine floodplain, lagoonal, and beach deposits, if they can be distinguished. Sedimentary types normally present are nonmarine conglomerates, sandstones, and shales Stage 2 is the marine wedge middle. Lithologic types most commonly found here are marine shales, limestones, and sandstones. Stage 3 is the nonmarine wedge top and the associated regional unconformity Lithologically it typically resembles the wedge base with more than 50% nonmarine conglomerates, sandstones, shales, red beds, coals, fresh-water limestones, and minor evaporites
- 2. It incorporates two main plate boundary interactions : Divergence & Convergence, and The proximity of basin to boundaries i.e. plate margin or plate- interior. The result is eight single tectonic-cycle or simple basin types that are termed interior sag, margin sag, interior fracture, wrench, trench, trench associated, oceanic sag, and oceanic wrench. 3. It represents changes in plate motions that result in significant changes in basin evolution wherein; basins may become inverted (uplifted and eroded) or subside according to different mechanisms. This parameter explicitly recognizes that many sedimentary basins represent multiple tectonic histories.
- The Kingston et al. Scheme identifies 10 theoretical basin types, but for practical purposes excludes two of these (oceanic trench and oceanic fracture types) because they were deemed of little use to petroleum exploration.
- Sag or sagging: to droop, sink, bend or settle downwardby wt or pressure espe ially in middle
- Sag or sagging: to droop, sink, bend or settle downwardby wt or pressure espe ially in middle
- Sag or sagging: to droop, sink, bend or settle downwardby wt or pressure espe ially in middle
- The basin begins with the cracking of a cratonic mass by divergence. This first phase (stage 1 of cycle 1) as previously outlined is called interior fracture, and may resemble the present-day rift valleys of Africa These grabens generally are filled with nonmarine sediments. During graben formation, basal block fault structures are formed and buried by sediments. The next phase of basin formation, stage 3 of cycle 1, is the end of interior fracture basin development. Continued continental divergence and graben subsidence by block faulting are typically accompanied by nonmarine deposit and ends with a major unconformity Margin sag is initiated as the spreading center in the interior fracture grabens is activated and begins to grow. The continents separate and begin to move apart. Basement faults are no longer independently active, and basement begins to subside as one block. The entire edge of the continent sinks. Simultaneously, stage 1 of margin sag cycle 2 commonly begins with deposition of nonmarine beds and evaporites Stage 2 of margin sag includes continued subsidence and continental separation, and is identified by marine deposition. Marine waters invade the infilled graben system for the first time, depositing elastics, carbonates, or massive salt at the base of the series. As the oceanic spreading center expands, the continents separate. New layers of oceanic crust form, and the older ones cool.
- A subduction zone is formed with the trench being the "bent" portion of the lower plate, ahead figure convergent cycle. We recognize two types of trenches. The first involves one oceanic plate overriding another, forming a midocean trench such as the Mariana, Aleutian, and Philippine trenches. These features normally have little sediment fill, and the amount they do have primarily is volcanogenie and deep-water pelagic. The second type involves an oceanic plate overridden by a continental plate. This trench can receive oceanic pelagic sediments and volcanics, as well as land-derived fine elastics. These oceanmargin trenches accumulate very thick deep-water deposits.
- 1. Basins classified in this category are those formed on margins or nearby interiors of two or more plates converging toward one another. Most basins on converging plates mainly exhibit tensional features. 2.
- Wrench: a sudden violent twist or pull. These strike-slip, shear, or wrench basins are referred to here as double "L" cycles (LL), for lateral movement. These cycles are found on continental or intermediate crust. They are formed by a divergent wrench couplet with strike-slip faults along two or more sides (figure). stage 1 (basin initiation by divergent wrenching) appears similar to an interior fracture (IF) basin, with tensional block faulting and little or no evidence of wrenching. Nonmarine wedge-base sediments are deposited, unless the basin is initiated under water. Sometime after the basin is initiated in stage 1 or 2, wrench deformation of the basin begins. Wrench structures may form along the flanks or within the basin If the wrench-faulting process continues over a long enough period, it will eventually destroy the LL basin. In stage 3 of the wrench (LL) cycle, the basin is uplifted and eroded, and the continued shearing may begin to destroy the structures and parts of the basin. The term "L3FB" is used for the final stage of a basin completely wrenched to a foldbelt. Continued plate convergence may result in orogeny Sedimentary fill in wrench (LL) basins is extremely varied. Marine elastics, carbonates and evaporites, nonmarine elastics, volcaniclastics, and flysch-chert-ophiolites are all found, depending on depositional conditions.
- Episodic wrenches modify basins formed by other means and are found in basins with all ages of basement rocks. It is believed that old zones of weakness in the basement, such as old sutures, interior fracture zones, plate boundaries, etc, move periodically or episodically in response to plate movements. 2. These plate movements are manifested at the surface by plate collisions, rotations, fragmentation, and by subduction zones. the origin of an episodic wrenching or lateral L movement is fairly easy to ascertain, given good platetectonic reconstructions Foldbelts are caused by convergence of two or more plates. Basin areas caught in this convergence may be completely or only partly folded. Basins not completely folded are not considered to be foldbelts and are said to have been episodically wrenched. Basins completely folded are called foldbelts (FB3) Foldbelts represent sutures where past plates have converged or are still converging. This convergence results in compression and shearing motions that cause the rocks to be wrenched and folded.
- From a purely geodynamic perspective, the Kingston et al. scheme is less useful because the 10 basin types refer to highly generalized plate tectonic settings, for example, Trench associated basins includes the actual deep trench, trench slope basins, forearc and interarc basins. There is also some ambiguity with their placement of foreland basins that overlie continental crust, but do not seem to fit any of the convergent margin designations for either continental or oceanic crust.
- This scheme is the most concise and comprehensive classification of basins so far, not only considering subsidence mechanism of basins but also reflecting the development trends of basin classification from traditional structural locations to basin forming mechanism. However, it does not consider the relationship between basin formation and sublithospheric actions.
- .Figure 3. True-scale actualistic analog models for sedimentary basins in divergent, intraplate and miscellaneous settings. Mantle lithosphere thins during decompression melting as plates diverge; mantle lithosphere thickens during cooling, following cessation of divergence. Also shown are two miscellaneous basins (bolide and halokinetic). Placement of bolide basin is arbitrary; they may form anywhere on Earth’s surface, although preservation is more likely in cratonal areas (as shown in E). Halokinetic basins may form anywhere that salt is deeply buried; however, continental embankments (as shown in F) are the most common locations. Continental crust ¼ jackstraw pattern; oceanic crust ¼ vertical lines; mantle lithosphere and derived igneous rocks ¼ black; asthenosphere and derived melts ¼ orange; salt (halokinetic only) ¼ black True-scale actualistic analog models for sedimentary basins in convergent settings. A remnant arc is shown on the left side of (A). Trench, trench-slope and forearc basins are labeled only in (A and B), but they are associated with all types of arc-trench systems. Intra-arc basins may be associated with any magmatic arc, but they are more common andmore likely to be preserved in extensional and neutral settings (A, B, and C). Hinterland basins may form in compressional arc-trench systems (D, E), or in collisional systems (F and Figure 1.6A–B). Remnant ocean basins form between any colliding crustal margins; a compressional arc-trench system is shown converging with an intraplate margin in (E). Wedgetop basins may form in any compressional setting; a proforeland example is shown in (F). If neutral continental arc-trench systems (C) become extensional, then they may evolve into extensional oceanic systems (A). Symbols same as in Figure 1.3; slab-generated melts ¼ red
- ig. 1.5. True-scale actualistic analog models for sedimentary basins in transform and miscellaneous settings. These cross sections are based on the Miocene to Holocene evolution of southern California (Ingersoll, 2008b); many other tectonic settings are common for transtensional and transpressional basins. Transrotational basins are less common; the three-plate interactions depicted in (C) are unique on Earth today. Successor basins may form following cessation of any tectonic activity; shown in (C) is the southern Basin and Range of the USA, where undeformed Neogene to Holocene strata overlie tilted fault blocks and strata of the older extensional regime. Symbols same as in Figure 1.3.
- B-type (Benioff) subduction involves an oceanic plate plunging underneath another plate. An A-type (alpine or Ampferer) collision involves a continent-continent collision Bally (1975) and Bally and Snelson (1980) differentiated three different families of sedimentary basins based on their location in relation to megasutures, which in this context can be defined to include all the products of orogenic and igneous activity associated with predominantly compressional deformation. The boundaries of megasutures are often associated with subduction, whether it be of slabs of oceanic lithosphere (Benioff or B-type subduction) or of relatively buoyant continental lithosphere (Amferer or A-type subduction) and may also be sites of important wrench tectonism along transform faults.
- They distinguished basins on the rigid lithosphere from those occurring within mobile belts. The latter group are subdivided into those at the margins of the belt (perisutural basins) and those within the belt (episutural basins). However, the Chinese-type basin in this scheme is ambiguous, neglecting the influence of lithospheric structure on a basin’s nature.
- Continental rift, New ocean basin Mature ocean basin
- On this map only the Mesozoic-Cenozoic sedimentary basins are illustrated. To located the Paleozoic sedimentary basins, it is necessary to reconstruct the Paleozoic megasuture, which was completely distorted by the Pangea breakup and subsequent drifting of the Mesozoic-Cenozoic continents. The perisutural basins, which developed at the periphery of the megasuture, in association with a B-type (Benioff) or A-type (Ampferer), are, mainly, foredeep (foreland basins) and forearc basin (external to the volcanic arc).