Changes

The summary here of the geological history of Cuba has been strongly influenced by the geology of central Cuba. However, the timing of the events was not [[http://en.wiktionary.org/wiki/isochronous isochronous]] along the whole length of the [http://www.merriam-webster.com/dictionary/orogen orogen].

The summary here of the geological history of Cuba has been strongly influenced by the geology of central Cuba. However, the timing of the events was not [[http://en.wiktionary.org/wiki/isochronous isochronous]] along the whole length of the [http://www.merriam-webster.com/dictionary/orogen orogen].

[[Paleogeography|Paleogeographic]] maps (Figures 5-14) illustrate the possible past distribution of the most characteristic stratigraphic units. These maps are on a continental drift base modified from the [[http://www.odsn.de/ Ocean Drilling Stratigraphic Network (ODSN)] created in 2005 by the University of Bremen, with Florida occupying a fixed position. In all maps, Cuba is shown in its present position relative to Florida, although different parts of the island came from various places.  

[[Paleogeography|Paleogeographic]] maps (Figures 5-14) illustrate the possible past distribution of the most characteristic stratigraphic units. These maps are on a [[continental drift]] base modified from the [[http://www.odsn.de/ Ocean Drilling Stratigraphic Network (ODSN)] created in 2005 by the University of Bremen, with Florida occupying a fixed position. In all maps, Cuba is shown in its present position relative to Florida, although different parts of the island came from various places.  

In these maps, [[autochthon]]ous nappes, allochthonous [[nappe]]s, and [[subduction]] will be used to describe, respectively, the thrusting toward the continent of the sediments, the [[Wikipedia:Basic_rock|basic]] igneous-volcanic rocks, and the subduction. Supported by observations in Cuba and elsewhere, these maps show subduction as the main cause of the uplift of a [http://geology.com/nsta/convergent-plate-boundaries.shtml convergent continental margin] or ocean floor, whereas the nappes are the result of sedimentary or volcanic cover sliding away, under the force of gravity, from the area uplifted by subduction.

In these maps, [[autochthon]]ous nappes, allochthonous [[nappe]]s, and [[subduction]] will be used to describe, respectively, the thrusting toward the continent of the sediments, the [[Wikipedia:Basic_rock|basic]] igneous-volcanic rocks, and the subduction. Supported by observations in Cuba and elsewhere, these maps show subduction as the main cause of the uplift of a [http://geology.com/nsta/convergent-plate-boundaries.shtml convergent continental margin] or ocean floor, whereas the nappes are the result of sedimentary or volcanic cover sliding away, under the force of gravity, from the area uplifted by subduction.

===Early(?)-Middle Jurassic===

===Early(?)-Middle Jurassic===

Very little is known about the pre-Late Jurassic history of the island except that the lower part of the San Cayetano clastics might be Lower Jurassic (163 Ma; [[:file:St58OverviewFG25.JPG|Figure 5]]). The San Cayetano must have been deposited over an initially [[rift]]ing [[basement]] that probably included fragments of continental crust as well as [http://geology.com/rocks/basalt.shtml basaltic] flows. This is supported by the sub-Neocomian [https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?gID=00000000073 granodioritic] [[klippe]]n of La Rana, Tres Guanos, and Rancho Veloz and the occurrences of the El Sabalo and Nueva Maria [https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?Term=tholeiite tholeitic basalt]s underlying the sedimentary section of the northern Rosario belt and Cifuentes* belt of the Sierra de Camajan.

Very little is known about the pre-Late Jurassic history of the island except that the lower part of the San Cayetano clastics might be Lower Jurassic (163 Ma; [[:file:St58OverviewFG25.JPG|Figure 5]]). The San Cayetano must have been deposited over an initially [[rift]]ing [[basement]] that probably included fragments of [[continental crust]] as well as [http://geology.com/rocks/basalt.shtml basaltic] flows. This is supported by the sub-Neocomian [https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?gID=00000000073 granodioritic] [[klippe]]n of La Rana, Tres Guanos, and Rancho Veloz and the occurrences of the El Sabalo and Nueva Maria [https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?Term=tholeiite tholeitic basalt]s underlying the sedimentary section of the northern Rosario belt and Cifuentes* belt of the Sierra de Camajan.

It can also be assumed that, prior to the deposition of the Upper Jurassic rocks, a large area of basement was exposed to the northwest, extending from Florida's Sarasota arch to the Maya Mountains. The nature of this basement is generally unknown, but it must have been of [http://geology.about.com/od/more_igrocks/a/granite.htm granitic] to [https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?gID=00000000073 granodioritic] composition as indicated by the [[Arkose|arkosic]] nature of the San Cayetano Formation. In south Florida, several wells have penetrated an undifferentiated Jurassic–Triassic volcanic section and Paleozoic granite. The basement must also have included Paleozoic sediments known to outcrop in the Maya Mountains, present as fragments in San Cayetano [[conglomerate]]s, and, perhaps, as exotics in the Cayo Coco Formation. The bulk of the San Cayetano Formation accumulated south of this basement high.

It can also be assumed that, prior to the deposition of the Upper Jurassic rocks, a large area of basement was exposed to the northwest, extending from Florida's Sarasota arch to the Maya Mountains. The nature of this basement is generally unknown, but it must have been of [http://geology.about.com/od/more_igrocks/a/granite.htm granitic] to [https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?gID=00000000073 granodioritic] composition as indicated by the [[Arkose|arkosic]] nature of the San Cayetano Formation. In south Florida, several wells have penetrated an undifferentiated Jurassic–Triassic volcanic section and Paleozoic granite. The basement must also have included Paleozoic sediments known to outcrop in the Maya Mountains, present as fragments in San Cayetano [[conglomerate]]s, and, perhaps, as exotics in the Cayo Coco Formation. The bulk of the San Cayetano Formation accumulated south of this basement high.

Toward the northeast, sub-Upper Jurassic sediments have not been observed in situ, but the Cunagua salt suggests the presence of an [[evaporite basin]] correlating with the [[Louann Salt]] and [[Maraval]] [[evaporite]]s and, possibly, as suggested by the San Adrian Formation, interfingering with the San Cayetano.

Toward the northeast, sub-Upper Jurassic sediments have not been observed in situ, but the Cunagua salt suggests the presence of an [[evaporite basin]] correlating with the [[Louann Salt]] and [[Maraval]] [[evaporite]]s and, possibly, as suggested by the San Adrian Formation, interfingering with the San Cayetano.

As rifting continued, new oceanic crust formed with outpouring of basalts (El Sabalo) and [http://jersey.uoregon.edu/~mstrick/AskGeoMan/geoQuerry45.html serpentinization] of the upper [[mantle]].

As rifting continued, new [[oceanic crust]] formed with outpouring of basalts (El Sabalo) and [http://jersey.uoregon.edu/~mstrick/AskGeoMan/geoQuerry45.html serpentinization] of the upper [[mantle]].

===Tithonian===

===Tithonian===

In the [[Tithonian]] (144 Ma; [[:file:St58OverviewFG26.JPG|Figure 6]]) section, sediments vary from the shallow-water carbonate and evaporite deposits of Wood River, Punta Alegre*, and Guani* in the north, toward Florida and the Bahamas, to shallow-water normal marine limestones of the [[Trocha Group|Trocha* Group]] to the south in the Las Villas* belt. Toward Pinar del Rio, thick, massive, shallow-water limestone of the [[Guasasa Formation]] accumulated over a northward-thinning wedge of San Cayetano, [[Jagua]], and possibly, basement. Farther south, the thin-bedded limestones of Cobrito, Sauco, and Isla de la Juventud marbles were deposited over the lower [[Oxfordian]] thin quartzose sandstones of [[La Lamagua Formation|La Llamagua]], [[Loma la Gloria Formation|Loma la Gloria]], and [[Agua Santa Formation]]s. The outpouring of [http://geology.com/rocks/basalt.shtml basalt] continued forming the slightly younger [[Nueva Maria Formation]] in the southern Loma Camajan. Farther south, rifting produced [https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?gID=00000000012 ultrabasic] oceanic crust.

In the [[Tithonian]] (144 Ma; [[:file:St58OverviewFG26.JPG|Figure 6]]) section, sediments vary from the shallow-water carbonate and evaporite deposits of Wood River, Punta Alegre*, and Guani* in the north, toward Florida and the Bahamas, to shallow-water normal marine limestones of the [[Trocha Group|Trocha* Group]] to the south in the Las Villas* belt. Toward Pinar del Rio, thick, massive, shallow-water limestone of the [[Guasasa Formation]] accumulated over a northward-thinning wedge of San Cayetano, [[Jagua]], and possibly, basement. Farther south, the thin-bedded limestones of Cobrito, Sauco, and Isla de la Juventud marbles were deposited over the lower [[Oxfordian]] thin quartzose sandstones of [[La Lamagua Formation|La Llamagua]], [[Loma la Gloria Formation|Loma la Gloria]], and [[Agua Santa Formation]]s. The outpouring of [http://geology.com/rocks/basalt.shtml basalt] continued forming the slightly younger [[Nueva Maria Formation]] in the southern Loma Camajan. Farther south, rifting produced [https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?gID=00000000012 ultrabasic] [[oceanic crust]].

===Neocomian===

===Neocomian===

In central Cuba, the Upper Jurassic and Neocomian beds were only partially eroded. In western Cuba, shallow-bank carbonates, similar to those of the [[Vinas Group|Vinas* Group]], accumulated atop the La Rana [https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?gID=00000000073 granodiorite] [http://en.wikipedia.org/wiki/Horst_%28geology%29 horst] and formed the Guajaibon–Sierra Azul belt. South of the La Rana basement horst, deep-water limestones of the Mayari, Collantes, and Cobrito Formations were deposited and preserved.

In central Cuba, the Upper Jurassic and Neocomian beds were only partially eroded. In western Cuba, shallow-bank carbonates, similar to those of the [[Vinas Group|Vinas* Group]], accumulated atop the La Rana [https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?gID=00000000073 granodiorite] [http://en.wikipedia.org/wiki/Horst_%28geology%29 horst] and formed the Guajaibon–Sierra Azul belt. South of the La Rana basement horst, deep-water limestones of the Mayari, Collantes, and Cobrito Formations were deposited and preserved.

Farther south, rifting continued, accompanied by outpouring of tholeites and other [[Wikipedia:Basic_rock|basic]] to [https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?gID=00000000012 ultrabasic] material forming a layered [[Oceanic crust|oceanic basement]] consisting of [http://geology.about.com/od/rocks/ig/igrockindex/rocpicperidotite.htm peridotite], [http://www.britannica.com/EBchecked/topic/223075/gabbro gabbro], sheeted [http://www.britannica.com/EBchecked/topic/163476/dike dikes], [[Wikipedia:Pillow lava|pillow basalts]] (old volcanics of the Domingo* sequence), and associated sediments. Although some genetic relationship exists between the [[Domingo*]] sequence and the El Sabalo–Nueva Maria lithologies, these belong to two entirely different provinces. [[El Sabalo Formation|El Sabalo]] and the [[Nueva Maria Formation]]s, like the granodiorites, belong to the autochthonous nappes and were at the continental margin, whereas the Domingo* sequence forms the base of the allochthonous nappe and is entirely oceanic.

Farther south, rifting continued, accompanied by outpouring of tholeites and other [[Wikipedia:Basic_rock|basic]] to [https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?gID=00000000012 ultrabasic] material forming a layered [[Oceanic crust|oceanic basement]] consisting of [http://geology.about.com/od/rocks/ig/igrockindex/rocpicperidotite.htm peridotite], [http://www.britannica.com/EBchecked/topic/223075/gabbro gabbro], sheeted [http://www.britannica.com/EBchecked/topic/163476/dike dikes], [[Wikipedia:Pillow lava|pillow basalts]] (old volcanics of the Domingo* sequence), and associated sediments. Although some genetic relationship exists between the [[Domingo*]] sequence and the El Sabalo–Nueva Maria lithologies, these belong to two entirely different provinces. [[El Sabalo Formation|El Sabalo]] and the [[Nueva Maria Formation]]s, like the granodiorites, belong to the autochthonous nappes and were at the [[continental margin]], whereas the Domingo* sequence forms the base of the allochthonous nappe and is entirely oceanic.

===Barremian===

===Barremian===

Shallow-marine conditions prevailed during most of this time interval, and mostly limestones, marls, and shales accumulated, accompanied by some coarse clastic sediment (present; [[:file:St58OverviewFG34.JPG|Figure 14]]). There was very little tectonic activity. In the northern basins, a strong angular [[unconformity]] separates the upper Eocene strata from the older rocks. In the southern basins, sedimentation was essentially continuous from the [[Cretaceous]] through the [[Tertiary]], with no major unconformity. Some local basins may have formed as gentle deformation of the old [[Orogeny|orogenic belt]] occurred. This deformation consisted mostly of large-scale folds (Habana-Matanzas) and high-angle [[fault]]s (Pinar). This type of deformation is still active today and is largely responsible for Cuba's present physiography.

Shallow-marine conditions prevailed during most of this time interval, and mostly limestones, marls, and shales accumulated, accompanied by some coarse clastic sediment (present; [[:file:St58OverviewFG34.JPG|Figure 14]]). There was very little tectonic activity. In the northern basins, a strong angular [[unconformity]] separates the upper Eocene strata from the older rocks. In the southern basins, sedimentation was essentially continuous from the [[Cretaceous]] through the [[Tertiary]], with no major unconformity. Some local basins may have formed as gentle deformation of the old [[Orogeny|orogenic belt]] occurred. This deformation consisted mostly of large-scale folds (Habana-Matanzas) and high-angle [[fault]]s (Pinar). This type of deformation is still active today and is largely responsible for Cuba's present physiography.

Cuba is an example of [[subduction]] generating an orogenic belt. The subduction progressed from an oceanic environment through a region of relatively recent [[oceanic crust]] between North and South America and, finally, became inactive at the southern margin of the North American continent. The main difference relative to most of the well-known marginal orogenic belts is that the [[Thrust fault|thrust]] sheets that accompanied the subduction rode onto and over a much depressed and fragmented continental margin (with fragments now in the Bahamas Basin, Gulf of Mexico, Yucatan) relatively far away from a fully continental craton.

Cuba is an example of [[subduction]] generating an orogenic belt. The subduction progressed from an oceanic environment through a region of relatively recent [[oceanic crust]] between North and South America and, finally, became inactive at the southern margin of the North American continent. The main difference relative to most of the well-known marginal orogenic belts is that the [[Thrust fault|thrust]] sheets that accompanied the subduction rode onto and over a much depressed and fragmented [[continental margin]] (with fragments now in the Bahamas Basin, Gulf of Mexico, Yucatan) relatively far away from a fully continental craton.

The orogeny was characterized by a scarcity of detrital sediments on its continental side and by the rapidity of the entire orogenic process that started during the Late Cretaceous and culminated within the early to middle Eocene. It also shows clearly that when the thrusting occurred, the continental margin was not contiguous with the subduction, but was separated from it by an arch, which mostly exposed [https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?gID=00000000073 granodioritic] basement rocks. The Alps show similar geology. The northward displacement of the visible thrusting was on the order of several hundred kilometers.

The orogeny was characterized by a scarcity of detrital sediments on its continental side and by the rapidity of the entire orogenic process that started during the Late Cretaceous and culminated within the early to middle Eocene. It also shows clearly that when the thrusting occurred, the continental margin was not contiguous with the subduction, but was separated from it by an arch, which mostly exposed [https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?gID=00000000073 granodioritic] basement rocks. The Alps show similar geology. The northward displacement of the visible thrusting was on the order of several hundred kilometers.