Changes

  | part    = Critical elements of the petroleum system

  | part    = Critical elements of the petroleum system

  | chapter = Sedimentary basin analysis

  | chapter = Sedimentary basin analysis

  | frompg  = 4-1

  | frompg  = 4-19

  | topg    = 4-123

  | topg    = 4-20

  | author  = John M. Armentrout

  | author  = John M. Armentrout

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch04/ch04.htm

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch04/ch04.htm

  | isbn    = 0-89181-602-X

  | isbn    = 0-89181-602-X

}}

}}

Models of tectonic history provide a framework for understanding the history of each phase of basin development. A tectonostratigraphic phase is a period of basin evolution during which tectonic and stratigraphic elements resulted in a specific configuration of depositional and deformational elements, many of which were critical to the evolution of the basin's [[petroleum system]]. The tectonostratigraphic history for a basin is usually portrayed in a time series of [[cross section]]s, showing the geologic elements of each phase. Because all basins are three dimensional, care must be taken to assemble enough cross sections to depict basin history accurately.

Models of tectonic history provide a framework for understanding the history of each phase of basin development. A tectonostratigraphic phase is a period of basin evolution during which tectonic and stratigraphic elements resulted in a specific configuration of depositional and [[deformation]]al elements, many of which were critical to the evolution of the basin's [[petroleum system]]. The tectonostratigraphic history for a basin is usually portrayed in a time series of [[cross section]]s, showing the geologic elements of each phase. Because all basins are three dimensional, care must be taken to assemble enough cross sections to depict basin history accurately.

==Example: the GOM basin==

==Example: the GOM basin==

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Tectonic evolution of the [[basin::Gulf of Mexico basin]] has resulted in five primary tectonostratigraphic phases (A–E), each with a different sediment accumulation and deformation history. [[:file:sedimentary-basin-analysis_fig4-11.png|Figure 1]] is a schematic diagram showing a series of cross sections representing the four phases of Late Triassic to Early Cretaceous evolution of the GOM basin (see [[:file:sedimentary-basin-analysis_fig4-6.png|Figure 2]] for the location).

Tectonic evolution of the [[Gulf of Mexico]] basin has resulted in five primary tectonostratigraphic phases (A–E), each with a different sediment accumulation and [[deformation]] history. [[:file:sedimentary-basin-analysis_fig4-11.png|Figure 1]] is a schematic diagram showing a series of cross sections representing the four phases of Late Triassic to Early Cretaceous evolution of the GOM basin (see [[:file:sedimentary-basin-analysis_fig4-6.png|Figure 2]] for the location).

===Phase A===

===Phase A===

[[:file:sedimentary-basin-analysis_fig4-11.png|Figure 1A]] consists of Late Triassic to Early Jurassic rifting along linear zones within brittle crust with deposition of synrift nonmarine sediments and volcanics within half-grabens.

[[:file:sedimentary-basin-analysis_fig4-11.png|Figure 1A]] consists of Late Triassic to Early Jurassic rifting along linear zones within [[Brittleness|brittle]] [[crust]] with deposition of synrift nonmarine sediments and volcanics within half-grabens.

===Phase B===

===Phase B===

[[:file:sedimentary-basin-analysis_fig4-11.png|Figure 1B]] of Middle Jurassic age is characterized by rifting and attenuation of the crust, with formation of transitional crust and the associated basement highs and lows that form the basic architecture. The outer periphery of the basin underwent moderate stretching and the crust remained thick, forming broad arches and basins. The central basin underwent considerable stretching and subsidence to form a large area of thin transitional crust over which thick salt was deposited. Nonmarine terrigenous sediments continued to be deposited within the peripheral grabens.

[[:file:sedimentary-basin-analysis_fig4-11.png|Figure 1B]] of Middle Jurassic age is characterized by rifting and attenuation of the crust, with formation of [[transitional crust]] and the associated [[basement]] highs and lows that form the basic architecture. The outer periphery of the basin underwent moderate stretching and the crust remained thick, forming broad arches and basins. The central basin underwent considerable stretching and subsidence to form a large area of thin transitional crust over which thick salt was deposited. Nonmarine terrigenous sediments continued to be deposited within the peripheral grabens.

===Phase C===

===Phase C===

[[:file:sedimentary-basin-analysis_fig4-11.png|Figure 1C]] of Late Jurassic age consists of emplacement of oceanic crust as mantle upwelling concentrated along the generally east–west-trending weakness in the continental crust. As the crust underlying the basin began to cool, subsidence resulted in the relative rise of sea level. The basin margins were transgressed by broad shallow-to-deep shelfal marine environments with deposition of thick carbonate successions. Locally, thick, terrigenous clastic prisms prograded into the basin. Potential and known reservoirs occur within both the carbonate and clastic depositional systems of this tectonostratigraphic phase. During the Late Jurassic maximum transgression, the deep basin was sediment starved, and thick, organic-rich shales accumulated in lowoxygen environments (source-rock types 6 and 7).

[[:file:sedimentary-basin-analysis_fig4-11.png|Figure 1C]] of Late Jurassic age consists of emplacement of oceanic crust as [[mantle]] upwelling concentrated along the generally east–west-trending weakness in the [[continental crust]]. As the crust underlying the basin began to cool, subsidence resulted in the relative rise of sea level. The basin margins were transgressed by broad shallow-to-deep shelfal marine environments with deposition of thick carbonate successions. Locally, thick, terrigenous clastic prisms [[Depocenter#Sediment_supply_rate_and_facies_patterns|prograded]] into the basin. Potential and known reservoirs occur within both the carbonate and clastic depositional systems of this tectonostratigraphic phase. During the Late Jurassic maximum transgression, the deep basin was sediment starved, and thick, organic-rich shales accumulated in lowoxygen environments (source-rock types 6 and 7).

===Phase D===

===Phase D===

===Phase E===

===Phase E===

Phase E ([[:file:sedimentary-basin-analysis_fig4-9.png|Figure 3]]) began during the mid-Cenomanian with a rapid fall and rise of sea level superimposed on a long-term rise that terminally drowned the outer margins of the carbonate platforms, causing the margins to retreat landward. Widespread submarine erosion created a prominent mid-Cretaceous unconformity. Subsequent deposition was dominated by terrigenous sedimentation as large clastic prisms prograded first from the west and northwest in the Late Cretaceous and early Cenozoic and then from the north (Mississippi River drainage) during the late Cenozoic. Most of the offshore and many onshore reservoirs occur within these Late Cretaceous and Cenozoic siliciclastic deposits. The prograding prisms of siliciclastic sediment differentially loaded the underlying salt, resulting in deformation by both salt mobility and down-to-the-basin [[growth fault]]ing along the shelf-slope break.<ref name=ch04r24>Bruce, C., H., 1973, [http://archives.datapages.com/data/bulletns/1971-73/data/pg/0057/0005/0850/0878.htm Pressured shale and related sediment deformation: mechanism for development of regional contemporaneous faults]: AAPG Bulletin, vol. 57, p. 878–886, DOI: 10.1306/819A4352-16C5-11D7-8645000102C1865D.</ref><ref name=ch04r117>Winker, C., D., Edwards, M., B., 1983, Unstable progradational clastic shelf margins: SEPM Special Publication 33, p. 139–157.</ref>

Phase E ([[:file:sedimentary-basin-analysis_fig4-9.png|Figure 3]]) began during the mid-Cenomanian with a rapid fall and rise of sea level superimposed on a long-term rise that terminally drowned the outer margins of the carbonate platforms, causing the margins to retreat landward. Widespread submarine erosion created a prominent mid-Cretaceous [[unconformity]]. Subsequent deposition was dominated by terrigenous sedimentation as large clastic prisms prograded first from the west and northwest in the Late Cretaceous and early Cenozoic and then from the north (Mississippi River drainage) during the late Cenozoic. Most of the offshore and many onshore reservoirs occur within these Late Cretaceous and Cenozoic siliciclastic deposits. The prograding prisms of siliciclastic sediment differentially loaded the underlying salt, resulting in [[deformation]] by both salt mobility and down-to-the-basin [[growth fault]]ing along the shelf-slope break.<ref name=ch04r24>Bruce, C., H., 1973, [http://archives.datapages.com/data/bulletns/1971-73/data/pg/0057/0005/0850/0878.htm Pressured shale and related sediment deformation: mechanism for development of regional contemporaneous faults]: AAPG Bulletin, vol. 57, p. 878–886, DOI: 10.1306/819A4352-16C5-11D7-8645000102C1865D.</ref><ref name=ch04r117>Winker, C., D., Edwards, M., B., 1983, Unstable progradational clastic shelf margins: SEPM Special Publication 33, p. 139–157.</ref>

==See also==

==See also==

[[Category:Critical elements of the petroleum system]]  

[[Category:Critical elements of the petroleum system]]  

[[Category:Sedimentary basin analysis]]

[[Category:Sedimentary basin analysis]]