Geology of Jamaica: Difference between revisions
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The '''Geology of Jamaica''' is formed of rocks of [[Cretaceous]] to [[Neogene]] age. The basement consists of Cretaceous [[island arc]] and [[back-arc basin]] sequences that formed above a [[subduction|subduction zone]]. The cover is of mainly [[Eocene]] to [[Miocene]] shallow water [[limestone]]s, that have been uplifted due to the presence of a [[transpression#Restraining bend|restraining bend]] along the major [[Fault (geology)#Strike-slip faults|strike-slip faults]] that bound the southern edge of the [[Gonâve Microplate]] to the north of the island. |
The '''Geology of Jamaica''' is formed of rocks of [[Cretaceous]] to [[Neogene]] age. The basement consists of Cretaceous [[island arc]] and [[back-arc basin]] sequences that formed above a [[subduction|subduction zone]]. The cover is of mainly [[Eocene]] to [[Miocene]] shallow water [[limestone]]s, that have been uplifted due to the presence of a [[transpression#Restraining bend|restraining bend]] along the major [[Fault (geology)#Strike-slip faults|strike-slip faults]] that bound the southern edge of the [[Gonâve Microplate]] to the north of the island. |
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==Limestones== |
==Limestones== |
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During the Eocene, limestone deposition started across the whole of the Nicaraguan Rise. In Jamaica the main limestone unit is the White Limestone Group, which dominates the surface exposure of the island, particularly its central parts and consists of pure limestones and [[Dolomite (rock)|dolomite]]s. Locally the lowermost limestone is the Yellow Limestone Group, which consists of interbedded limestones and other clastic rocks.<ref name="Mitchell">{{Cite web |url=http://www.sfmgeology.com/JamaicaGeology3.html |title=The Geology of Jamaica |last=Mitchell S.F. |date=2016}}</ref> |
During the Eocene, limestone deposition started across the whole of the Nicaraguan Rise. In Jamaica the main limestone unit is the White Limestone Group, which dominates the surface exposure of the island, particularly its central parts and consists of pure limestones and [[Dolomite (rock)|dolomite]]s. Locally the lowermost limestone is the [[Yellow Limestone Group]], which consists of interbedded limestones and other clastic rocks.<ref name="Mitchell">{{Cite web |url=http://www.sfmgeology.com/JamaicaGeology3.html |title=The Geology of Jamaica |last=Mitchell S.F. |date=2016}}</ref> |
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[[File:Gonâve microplate.png|thumb|upright=1.5|The position of Jamaica relative to major strike-slip fault zones]] |
[[File:Gonâve microplate.png|thumb|upright=1.5|The position of Jamaica relative to major strike-slip fault zones]] |
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==Restraining bend== |
==Restraining bend== |
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During the [[Late Miocene]], the northeastern margin of the Caribbean Plate began to collide with the Bahamas Platform. This caused the formation of a two new strike-slip fault zones between the island of [[Hispaniola]] and the [[Mid-Cayman Rise|Mid-Cayman Spreading Center]] west of Jamaica, the [[Enriquillo-Plantain Garden fault zone]] and the [[Walton fault zone]].<ref name="Mann"> |
During the [[Late Miocene]], the northeastern margin of the Caribbean Plate began to collide with the Bahamas Platform. This caused the formation of a two new strike-slip fault zones between the island of [[Hispaniola]] and the [[Mid-Cayman Rise|Mid-Cayman Spreading Center]] west of Jamaica, the [[Enriquillo-Plantain Garden fault zone]] and the [[Walton fault zone]].<ref name="Mann"> |
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|journal=Tectonophysics |volume=246 |issue=1–3 |pages=1–69 |
|journal=Tectonophysics |volume=246 |issue=1–3 |pages=1–69 |
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|bibcode = 1995Tectp.246....1M |
|bibcode = 1995Tectp.246....1M |
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}}</ref> These fault zones now form part of the southern boundary of the Gonâve Microplate. The major right-stepping offset between the fault zones formed a restraining bend and led to transpression and uplift that is still active today and is the reason that the island of Jamaica is now well above sea level.<ref>{{Cite book |chapter-url=http://sp.lyellcollection.org/content/290/1/239.short |title=Tectonics of Strike-slip Restraining and Releasing Bends |last=Mann P. |last2=Demets C. |last3=Wiggins-Grandison M. |isbn=9781862392380 |editor-last=Cunningham W.D. & Mann P. |series=Geological Society, London, Special Publications |volume=290 |date=2007 | |
}}</ref> These fault zones now form part of the southern boundary of the Gonâve Microplate. The major right-stepping offset between the fault zones formed a restraining bend and led to transpression and uplift that is still active today and is the reason that the island of Jamaica is now well above sea level.<ref>{{Cite book |chapter-url=http://sp.lyellcollection.org/content/290/1/239.short |title=Tectonics of Strike-slip Restraining and Releasing Bends |last=Mann P. |last2=Demets C. |last3=Wiggins-Grandison M. |isbn=9781862392380 |editor-last=Cunningham W.D. & Mann P. |series=Geological Society, London, Special Publications |volume=290 |date=2007 |pages=239–253 |chapter=Toward a better understanding of the Late Neogene strike-slip restraining bend in Jamaica: geodetic, geological, and seismic constraints}}</ref> |
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==References== |
==References== |
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{{Reflist}} |
{{Reflist}} |
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{{North America topic|Geology of}} |
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[[Category:Geology of Jamaica]] |
[[Category:Geology of Jamaica| ]] |
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Latest revision as of 08:51, 14 July 2024
The Geology of Jamaica is formed of rocks of Cretaceous to Neogene age. The basement consists of Cretaceous island arc and back-arc basin sequences that formed above a subduction zone. The cover is of mainly Eocene to Miocene shallow water limestones, that have been uplifted due to the presence of a restraining bend along the major strike-slip faults that bound the southern edge of the Gonâve Microplate to the north of the island.
Cretaceous
[edit]Rocks of this age occur as a series of inliers within the younger limestones.[1]
Rift basins
[edit]Rifting during the Paleogene led to the formation of rift basins in which thick sequences of clastic rocks were deposited that are exposed at the eastern end of the island in the John Crow and Wagwater belts.[1]
Limestones
[edit]During the Eocene, limestone deposition started across the whole of the Nicaraguan Rise. In Jamaica the main limestone unit is the White Limestone Group, which dominates the surface exposure of the island, particularly its central parts and consists of pure limestones and dolomites. Locally the lowermost limestone is the Yellow Limestone Group, which consists of interbedded limestones and other clastic rocks.[1]
Restraining bend
[edit]During the Late Miocene, the northeastern margin of the Caribbean Plate began to collide with the Bahamas Platform. This caused the formation of a two new strike-slip fault zones between the island of Hispaniola and the Mid-Cayman Spreading Center west of Jamaica, the Enriquillo-Plantain Garden fault zone and the Walton fault zone.[2] These fault zones now form part of the southern boundary of the Gonâve Microplate. The major right-stepping offset between the fault zones formed a restraining bend and led to transpression and uplift that is still active today and is the reason that the island of Jamaica is now well above sea level.[3]
References
[edit]- ^ a b c Mitchell S.F. (2016). "The Geology of Jamaica".
- ^ Mann, P.; Taylor, F.W.; Edwards, R. Lawrence; Ku, Teh Lung (1995). "Actively evolving microplate formation by oblique collision and sideways motion along strike-slip faults: An example from the northeastern Caribbean plate margin". Tectonophysics. 246 (1–3): 1–69. Bibcode:1995Tectp.246....1M. doi:10.1016/0040-1951(94)00268-E.
- ^ Mann P.; Demets C.; Wiggins-Grandison M. (2007). "Toward a better understanding of the Late Neogene strike-slip restraining bend in Jamaica: geodetic, geological, and seismic constraints". In Cunningham W.D. & Mann P. (ed.). Tectonics of Strike-slip Restraining and Releasing Bends. Geological Society, London, Special Publications. Vol. 290. pp. 239–253. ISBN 9781862392380.