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Line 7: − + − + − − [[File:IMAGEN 2.png|250px|thumbnail|right|Figure 2 : Schematic profile of the Neuquen Basin, province of Neuquen, Argentina , where you can see the site of lamellar bodies of Cenozoic age. Taken from Bermúdez & Delpino 2015.]] − + − − * Physical: the density difference between the magma (lower density) and the host rocks is a key factor. Archimedes' principle is the one who acts. The surrounding rocks exert an upward thrust that moves the crustal magma to levels where their density is equated with the host rocks. It may happen that the density remains below the rocks of the environment and that the magma is detained its vertical ascent, the factor involved here are local efforts. If the efforts of the magma pressure can not overcome the resistance of the rocks magma vertically looking for a new way of moving through a plane of weakness such as a stratigraphic unconformity, anisotropy of the medium as fault planes, hinges of folds, etc (Fig 3). − [[File:IMAGEN 3.png|300px|thumbnail|right|Figure 3: In this photograph the site of two sills can be seen in a bedrock (Vaca Muerta Fm). Right on the sector focuses it can be clearly seen intense fracturing of columnar pattern. Photo courtesy of Juan Spacapan.]] − + + + + − [[File: − [[File:IMAGEN 5.png|400px|thumbnail|left|Figure 4: Diagram relating the fluid pressure with the decrease in resistance of the country rock with increasing depth . Notice how the anisotropy of the medium magnify the value of T ( tensile stress) in the horizontal direction. Taken from Gressier et al 2010.]] − |fameless|Figure 4: Diagram relating the fluid pressure with the decrease in resistance of the country rock with increasing depth . Notice how the anisotropy of the medium magnify the value of T ( tensile stress) in the horizontal direction. Taken from Gressier et al 2010.]] − [[File:IMAGEN 6.png|fameless|Figure 5: experiment by Gressier et al 2010 made into a powder through diatomaceous saturated and unsaturated to simulate fluid through the sediment site. Magma was simulated with silicone caulk which behaves as an ideal Newtonian fluid. The conclusion of this experiment is that in a supersaturated fluid medium and the main effort horizontally oriented sill development is full.]] − − [[File:IMAGEN 7.png|thumbnail|Figure 6: Scheme of northern Neuquen basin where it can be seen as most sills are deployed in the Vaca Muerta Formation (hydrocarbon source rock).]] Line 35:
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Hydrocarbon reservoirs associated to layered intrusive bodies (view source)
Revision as of 23:59, 26 June 2015
, 23:59, 26 June 2015no edit summary
== Factors Controlling The Emplacement Of Magma ==
== Factors Controlling The Emplacement Of Magma ==
[[File:IMAGEN 2.png|250px|thumbnail|right|Figure 2 : Schematic profile of the Neuquen Basin, province of Neuquen, Argentina , where you can see the site of lamellar bodies of Cenozoic age. Taken from Bermúdez & Delpino 2015.]]
The magmatic emplacement in the crust is not a freak of nature, it is controlled by a number of physical factors. It will highlight the constraints posed by the location of sedimentary basins subvolcanic due to the importance of these as part of hydrocarbon systems.
The magmatic emplacement in the crust is not a freak of nature, it is controlled by a number of physical factors. It will highlight the constraints posed by the location of sedimentary basins subvolcanic due to the importance of these as part of hydrocarbon systems.
The focus of the article is aimed at magmatic bodies of small size (2-4 km in diameter and approximately 500 m thick) of laminar geometries and disposal consistent with available subhorizontal sedimentary rocks (Fig 2).
The focus of the article is aimed at magmatic bodies of small size (2-4 km in diameter and approximately 500 m thick) of laminar geometries and disposal consistent with available subhorizontal sedimentary rocks (Figure 2).
=== Location factors ===
=== Location factors ===
* Tectonic: the dynamics of plates associated sedimentary basin must have significant magmatic activity, with interspersed relaxation events in time and needed to climb
* Tectonic: the dynamics of plates associated sedimentary basin must have significant magmatic activity, with interspersed relaxation events in time and needed to climb it.
it.
Another important physical factor is the pore pressure. In porous sedimentary rocks saturated with fluids such as water and hydrocarbons, fracture resistance is reduced. This is why it can almost be deduced that the location of the intrusive within a sedimentary basin would be concentrated within shale formations (high porosity) with plenty of oil (Fig 4 and 5).
* Physical: the density difference between the magma (lower density) and the host rocks is a key factor. Archimedes' principle is the one who acts. The surrounding rocks exert an upward thrust that moves the crustal magma to levels where their density is equated with the host rocks. It may happen that the density remains below the rocks of the environment and that the magma is detained its vertical ascent, the factor involved here are local efforts. If the efforts of the magma pressure can not overcome the resistance of the rocks magma vertically looking for a new way of moving through a plane of weakness such as a stratigraphic unconformity, anisotropy of the medium as fault planes, hinges of folds, etc (Figure 3).
[[File:IMAGEN 3.png|300px|thumbnail|center|Figure 3: In this photograph the site of two sills can be seen in a bedrock (Vaca Muerta Fm). Right on the sector focuses it can be clearly seen intense fracturing of columnar pattern. Photo courtesy of Juan Spacapan.]]
Another important physical factor is the pore pressure. In porous sedimentary rocks saturated with fluids such as water and hydrocarbons, fracture resistance is reduced. This is why it can almost be deduced that the location of the intrusive within a sedimentary basin would be concentrated within shale formations (high porosity) with plenty of oil (Figure 4 and 5).
[[File:IMAGEN 5.png|300px|thumbnail|left|Figure 4: Diagram relating the fluid pressure with the decrease in resistance of the country rock with increasing depth . Notice how the anisotropy of the medium magnify the value of T ( tensile stress) in the horizontal direction. Taken from Gressier et al 2010.]] [[File:IMAGEN 6.png|400px|thumbnail|center|Figure 5: experiment by Gressier et al 2010 made into a powder through diatomaceous saturated and unsaturated to simulate fluid through the sediment site. Magma was simulated with silicone caulk which behaves as an ideal Newtonian fluid. The conclusion of this experiment is that in a supersaturated fluid medium and the main effort horizontally oriented sill development is full.]]
== Consequences Of Construction Sills ==
== Consequences Of Construction Sills ==
The location of magmatic sill type bodies within sedimentary lithologies has four major
The location of magmatic sill type bodies within sedimentary lithologies has four major
consequences:
consequences:
[[File:IMAGEN 7.png|500|thumbnail|right|Figure 6: Scheme of northern Neuquen basin where it can be seen as most sills are deployed in the Vaca Muerta Formation (hydrocarbon source rock).]]
* '''Location in bedrock''': has been observed in numerous world sites, site of intrusive occurs in petroleum source rocks, whose cause is still not fully understood but presumably has to do with three factors: pore pressure, level weakness is the bedrock (being shale is less competent ) and plans anisotropy generated in the shales facilitate deflection of the levees that are rising from lower levels (Fig 6).
* '''Location in bedrock''': has been observed in numerous world sites, site of intrusive occurs in petroleum source rocks, whose cause is still not fully understood but presumably has to do with three factors: pore pressure, level weakness is the bedrock (being shale is less competent ) and plans anisotropy generated in the shales facilitate deflection of the levees that are rising from lower levels (Fig 6).
* '''Columnar or polygonal fractures:''' are generated by cooling and solidification of magma, where its volume is reduced contraction columnar cells formed orthogonal to the surface through which heat is lost (Fig 7 and 8).
* '''Columnar or polygonal fractures:''' are generated by cooling and solidification of magma, where its volume is reduced contraction columnar cells formed orthogonal to the surface through which heat is lost (Fig 7 and 8).
[[File:IMAGEN 8.png|framed|center|Figure 7: Scheme of columnar fractures. Taken from Bermúdez & Delpino 2015.]]
[[File:IMAGEN 8.png|500px|thumbnail|left|Figure 7: Scheme of columnar fractures. Taken from Bermúdez & Delpino 2015]]
[[File:IMAGEN 9.png|framed|center|Figure 8: Variation of fracture patterns in a vertical section of a sill. Taken from Bermúdez & Delpino 2015.]]
[[File:IMAGEN 9.png|400px|thumbnail|center|Figure 8: Variation of fracture patterns in a vertical section of a sill. Taken from Bermúdez & Delpino 2015]]
* '''Folding:''' the movement of material not only produces fracturing but also the folding of the overlying material. These folds are important because they may constitute important reservoirs and traps, even exploited in several basins in the world (Fig 9).
* '''Folding:''' the movement of material not only produces fracturing but also the folding of the overlying material. These folds are important because they may constitute important reservoirs and traps, even exploited in several basins in the world (Fig 9).
[[File:IMAGEN 10.png|framed|center|Figure 9: 2D seismic conducted northeast of Rockall basin, North Sea Norway. Observe normal faults as a product to accommodate the deformation of the fold. Taken from Hansen & Cartwright 2006.]]
[[File:IMAGEN 10.png|400px|thumbnail|center|Figure 9: 2D seismic conducted northeast of Rockall basin, North Sea Norway. Observe normal faults as a product to accommodate the deformation of the fold. Taken from Hansen & Cartwright 2006.]]
''' Thermal Maturity:''' the intrusion of magma of high temperatures (up to 1200 ° C) has a thermal effect on the country rock can get to promote maturation of hydrocarbons when diagenetic conditions are not optima (Fig 10) .
''' Thermal Maturity:''' the intrusion of magma of high temperatures (up to 1200 ° C) has a thermal effect on the country rock can get to promote maturation of hydrocarbons when diagenetic conditions are not optima (Fig 10) .
[[File:IMAGEN 11.png|thumbnail|Figure 10: modeling of the distribution and direction of migration of oil and gas after the intrusion and cooling of a lacolito in the north of the Neuquen Basin and into the Vaca Muerta Fm province of Neuquen, Argentina ]]
[[File:IMAGEN 11.png|500|thumbnail|center|Figure 10: modeling of the distribution and direction of migration of oil and gas after the intrusion and cooling of a lacolito in the north of the Neuquen Basin and into the Vaca Muerta Fm province of Neuquen, Argentina ]]
== Conclusions ==
== Conclusions ==
[[File:CUADROS.png|framed|center|Figure 12A,12B,12C: the deformation sequence of igneous bodies in the host rock]]
[[File:CUADROS.png|framed|center|Figure 12A,12B,12C: the deformation sequence of igneous bodies in the host rock]]
== Acknowledgements ==
== Acknowledgements ==