Changes

During the [[Aptian]] (110 Ma; [[:file:St58OverviewFG28.JPG|Figure 8]]), deposition continued to be shallow-water marine along the north coast (Yaguajay* belt) with, farther to the north (Cayo Coco area) and as far as Oriente (Gibara area), some [http://www.merriam-webster.com/dictionary/pelagic pelagic] influence (Casablanca Group). Toward central and western Cuba, conditions continued to be pelagic. The pelagic and shallow-water conditions were separated by a [[Conglomerate|conglomeratic]] [[breccia]] zone (Sagua la Chica* belt) representing a [[forereef]] facies, although reefs themselves are not common in outcrops.

During the [[Aptian]] (110 Ma; [[:file:St58OverviewFG28.JPG|Figure 8]]), deposition continued to be shallow-water marine along the north coast (Yaguajay* belt) with, farther to the north (Cayo Coco area) and as far as Oriente (Gibara area), some [http://www.merriam-webster.com/dictionary/pelagic pelagic] influence (Casablanca Group). Toward central and western Cuba, conditions continued to be pelagic. The pelagic and shallow-water conditions were separated by a [[Conglomerate|conglomeratic]] [[breccia]] zone (Sagua la Chica* belt) representing a [[forereef]] facies, although reefs themselves are not common in outcrops.

There was an influx of quartz- and mica-rich [[Turbidite|turbiditic]] detritus, possibly from the erosion of the previously formed basement high, which formed the La Esperanza, Polier, and Constancia* Formations. A southern Guajaibon–Sierra Azul carbonate bank may have been deposited.

There was an influx of quartz- and mica-rich [[Turbidite|turbiditic]] [http://dictionary.reference.com/browse/detrital detritus], possibly from the erosion of the previously formed basement high, which formed the La Esperanza, Polier, and Constancia* Formations. A southern Guajaibon–Sierra Azul carbonate bank may have been deposited.

Toward the south, the close of the Early Cretaceous was characterized by a great outpouring of [http://geology.com/rocks/basalt.shtml basaltic] flows (Matagua* Formation) over rifted basement. This activity was accompanied toward the north and west (Cifuentes*, southern Rosario, northern Rosario, and La Esperanza belts) by abundant and extensive [[chert]] deposits (Calabazar*, Carmita*, and Santa Teresa* Formations).

Toward the south, the close of the Early Cretaceous was characterized by a great outpouring of [http://geology.com/rocks/basalt.shtml basaltic] flows (Matagua* Formation) over rifted basement. This activity was accompanied toward the north and west (Cifuentes*, southern Rosario, northern Rosario, and La Esperanza belts) by abundant and extensive [[chert]] deposits (Calabazar*, Carmita*, and Santa Teresa* Formations).

===Albian-Cenomanian===

===Albian-Cenomanian===

Except for the Yaguajay* belt along the north coast where platform carbonates accumulated, deep-water [http://www.merriam-webster.com/dictionary/pelagic pelagic] deposition continued during the [[Albian]] to [[Cenomanian]] (93 Ma; [[:file:St58OverviewFG29.JPG|Figure 9]]). In the south, volcanic activity contributed silica to the seawater, which led to the deposition of primary radiolarian [[chert]]s (Calabazar*, Carmita, and Santa Teresa) below the carbonate compensation depth. Whereas noncalcareous detritus was absent over most of the northern area, volcanic-derived clays became increasingly abundant toward the south (Santa Teresa* Formation). The Rana [https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?gID=00000000073 granodiorite] high was still active, providing material for the Chaco Azul Formation. The position of the Vinas* type carbonates of the Guajaibon–Sierra Azul belt is problematic.

Except for the Yaguajay* belt along the north coast where platform carbonates accumulated, deep-water [http://www.merriam-webster.com/dictionary/pelagic pelagic] deposition continued during the [[Albian]] to [[Cenomanian]] (93 Ma; [[:file:St58OverviewFG29.JPG|Figure 9]]). In the south, volcanic activity contributed silica to the seawater, which led to the deposition of primary radiolarian [[chert]]s (Calabazar*, Carmita, and Santa Teresa) below the carbonate compensation depth. Whereas noncalcareous [http://dictionary.reference.com/browse/detrital detritus] was absent over most of the northern area, volcanic-derived clays became increasingly abundant toward the south (Santa Teresa* Formation). The Rana [https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?gID=00000000073 granodiorite] high was still active, providing material for the Chaco Azul Formation. The position of the Vinas* type carbonates of the Guajaibon–Sierra Azul belt is problematic.

To the north, as during the Aptian–Albian, the shallow carbonate banks continued to be separated from the pelagic, deep-water sediments to the south by a zone of carbonate-derived clastics, which shifted progressively southward; carbonate [[turbidite]]s became increasingly abundant (Calabazar* and Mata* formations). In the Florida Straits, carbonate deposition did not keep up with subsidence as indicated by the increase in pelagic deposits, including [[chert]] (upper Casablanca Group).

To the north, as during the Aptian–Albian, the shallow carbonate banks continued to be separated from the pelagic, deep-water sediments to the south by a zone of carbonate-derived clastics, which shifted progressively southward; carbonate [[turbidite]]s became increasingly abundant (Calabazar* and Mata* formations). In the Florida Straits, carbonate deposition did not keep up with subsidence as indicated by the increase in pelagic deposits, including [[chert]] (upper Casablanca Group).

Toward the south, the volcanic activity that formed the lower Cabaiguan* sequence decreased markedly, and argillaceous, calcareous sedimentation became predominant, whereas conditions remained pelagic. The detrital limestones in the southernmost outcrops of the volcanic sequence (Cristobal* Formation) that contain abundant Upper Jurassic reworked carbonates (including [[oolite]]s) indicate an unknown southern source, possibly the Yucatan Platform.

Toward the south, the volcanic activity that formed the lower Cabaiguan* sequence decreased markedly, and argillaceous, calcareous sedimentation became predominant, whereas conditions remained pelagic. The [http://dictionary.reference.com/browse/detrital detrital] limestones in the southernmost outcrops of the volcanic sequence (Cristobal* Formation) that contain abundant Upper Jurassic reworked carbonates (including [[oolite]]s) indicate an unknown southern source, possibly the Yucatan Platform.

With the exception of the thick carbonate banks, the Cenomanian sediments are mostly uniformly thin.

With the exception of the thick carbonate banks, the Cenomanian sediments are mostly uniformly thin.

===Campanian-Maastrichtian===

===Campanian-Maastrichtian===

After the period of the [[Unconformity|disconformity]], [http://www.merriam-webster.com/dictionary/pelagic pelagic] conditions characterized the platform to deep-water province, which received massive, dominantly carbonate [[turbidite]] flows from the north (Lutgarda* Formation) and from the south (Amaro* and Cacarajicara formations) (67 Ma; [[:file:St58OverviewFG31.JPG|Figure 11]]). Over the [[Wikipedia:Basic_rock|basic]] igneous-volcanic province, local [http://www.merriam-webster.com/dictionary/provenance provenance] resulted in an abundance of fragmental rocks; that is, limestones toward the north (Penalver Formation) and volcanics toward the south. In the south, sedimentation was accompanied during the Maastrichtian by an outpouring of late [[Orogeny|orogenic]] [http://geology.com/rocks/basalt.shtml basaltic] flows and flow breccias (the Maastrichtian age of these flows disagrees with the current interpretation of most Cuban geologists, including Iturralde-Vinent, 1996). Toward the north, along the present outer line of clays, deposition of coarse [[Maastrichtian]] limestone [[conglomerate]] (Mayajigua* Formation) graded into fine-grained pelagic rocks. The basic igneous-volcanic province began its initial northward movement as indicated by [http://www.galleries.com/serpentine serpentine] detritus in the turbidites, by basic [http://www.geolsoc.org.uk/ks3/gsl/education/resources/rockcycle/page3598.html intrusive]-derived clastics (Miguel Formation) associated with the Domingo* thrust, as well as by the presence of large Maastrichtian [[Thrust fault|thrust]] sheets of [https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?gID=00000000012 ultrabasics] in Oriente. Thrusting (and metamorphism) of ultrabasics began in the Escambray, and thrust sheets began to stack into the former basin that is today represented by the Guaniguanico Mountains. Northward-[[dip]]ping subduction to the south produced uplift of the [http://geology.com/nsta/convergent-plate-boundaries.shtml convergent margins]. The northward-moving thrust sheets or [[nappe]]s formed as the result of the sedimentary or volcanic cover sliding away from the uplifted areas.

After the period of the [[Unconformity|disconformity]], [http://www.merriam-webster.com/dictionary/pelagic pelagic] conditions characterized the platform to deep-water province, which received massive, dominantly carbonate [[turbidite]] flows from the north (Lutgarda* Formation) and from the south (Amaro* and Cacarajicara formations) (67 Ma; [[:file:St58OverviewFG31.JPG|Figure 11]]). Over the [[Wikipedia:Basic_rock|basic]] igneous-volcanic province, local [http://www.merriam-webster.com/dictionary/provenance provenance] resulted in an abundance of fragmental rocks; that is, limestones toward the north (Penalver Formation) and volcanics toward the south. In the south, sedimentation was accompanied during the Maastrichtian by an outpouring of late [[Orogeny|orogenic]] [http://geology.com/rocks/basalt.shtml basaltic] flows and flow breccias (the Maastrichtian age of these flows disagrees with the current interpretation of most Cuban geologists, including Iturralde-Vinent, 1996). Toward the north, along the present outer line of clays, deposition of coarse [[Maastrichtian]] limestone [[conglomerate]] (Mayajigua* Formation) graded into fine-grained pelagic rocks. The basic igneous-volcanic province began its initial northward movement as indicated by [http://www.galleries.com/serpentine serpentine] [http://dictionary.reference.com/browse/detrital detritus] in the turbidites, by basic [http://www.geolsoc.org.uk/ks3/gsl/education/resources/rockcycle/page3598.html intrusive]-derived clastics (Miguel Formation) associated with the Domingo* thrust, as well as by the presence of large Maastrichtian [[Thrust fault|thrust]] sheets of [https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?gID=00000000012 ultrabasics] in Oriente. Thrusting (and metamorphism) of ultrabasics began in the Escambray, and thrust sheets began to stack into the former basin that is today represented by the Guaniguanico Mountains. Northward-[[dip]]ping subduction to the south produced uplift of the [http://geology.com/nsta/convergent-plate-boundaries.shtml convergent margins]. The northward-moving thrust sheets or [[nappe]]s formed as the result of the sedimentary or volcanic cover sliding away from the uplifted areas.

===Paleocene (Danian)===

===Paleocene (Danian)===

The early to middle [[Eocene]] was characterized by intense [[Orogeny|orogenic]] activity (50 Ma; [[:file:St58OverviewFG32.JPG|Figure 12]]). Early in the Eocene, the large-scale low-angle [[Thrust fault|thrust sheets]], or gravity [[nappe]]s, that first moved in the Maastrichtian began to move at a greater rate. The volcanic section, along with the [[Oceanic crust|oceanic basement]], rode over the platform to deep water province, probably along the line separating the [[Wikipedia:Basic_rock|basic]] igneous-volcanic province from the platform to deep basin province. As thrusting proceeded, additional thrusts formed within the carbonate section in front of and north of the basic igneous-volcanic front. As a result, the thrust sheets were generally arranged from older and more southerly sourced at the top of the stack to younger and more northerly sourced at the base.

The early to middle [[Eocene]] was characterized by intense [[Orogeny|orogenic]] activity (50 Ma; [[:file:St58OverviewFG32.JPG|Figure 12]]). Early in the Eocene, the large-scale low-angle [[Thrust fault|thrust sheets]], or gravity [[nappe]]s, that first moved in the Maastrichtian began to move at a greater rate. The volcanic section, along with the [[Oceanic crust|oceanic basement]], rode over the platform to deep water province, probably along the line separating the [[Wikipedia:Basic_rock|basic]] igneous-volcanic province from the platform to deep basin province. As thrusting proceeded, additional thrusts formed within the carbonate section in front of and north of the basic igneous-volcanic front. As a result, the thrust sheets were generally arranged from older and more southerly sourced at the top of the stack to younger and more northerly sourced at the base.

A large trough-shaped basin formed in front of the thrust sheets, deeper near the thrust front and shallower northward. Early to middle Eocene [[flysch]] deposition in the trough began with sediments derived from limestones, such as the Sagua* and San Martin* formations, followed by an increase in volcanic and [http://www.geolsoc.org.uk/ks3/gsl/education/resources/rockcycle/page3598.html intrusive]-derived detritus, such as the lower Vega* and lower Manacas (Pica Pica) formations, and finally, capped by the intrusive and volcanic-derived coarse [[conglomerate]]s and [http://www.encyclopedia.com/doc/1O13-wildflysch.html wildflysch] of the upper Vega* (Rosas*) and upper Manacas (Vieja) Formations. In central Cuba, the rocks of the deep-water Vega* Formation became coarser grained through time. In western Cuba, the fine-grained clastics and other [http://www.merriam-webster.com/dictionary/pelagic pelagic] sediments of the Manacas Formation changed abruptly to the coarse [[breccia]]s of the Vieja Member. The breccia clasts reflect the lithology of the associated fault blocks. This suggests some subaerial [[erosion]] in central Cuba, whereas western Cuba was largely submarine.

A large trough-shaped basin formed in front of the thrust sheets, deeper near the thrust front and shallower northward. Early to middle Eocene [[flysch]] deposition in the trough began with sediments derived from limestones, such as the Sagua* and San Martin* formations, followed by an increase in volcanic and [http://www.geolsoc.org.uk/ks3/gsl/education/resources/rockcycle/page3598.html intrusive]-derived [http://dictionary.reference.com/browse/detrital detritus], such as the lower Vega* and lower Manacas (Pica Pica) formations, and finally, capped by the intrusive and volcanic-derived coarse [[conglomerate]]s and [http://www.encyclopedia.com/doc/1O13-wildflysch.html wildflysch] of the upper Vega* (Rosas*) and upper Manacas (Vieja) Formations. In central Cuba, the rocks of the deep-water Vega* Formation became coarser grained through time. In western Cuba, the fine-grained clastics and other [http://www.merriam-webster.com/dictionary/pelagic pelagic] sediments of the Manacas Formation changed abruptly to the coarse [[breccia]]s of the Vieja Member. The breccia clasts reflect the lithology of the associated fault blocks. This suggests some subaerial [[erosion]] in central Cuba, whereas western Cuba was largely submarine.

South of the front of the advancing volcanic and basic intrusive-rock thrust plate, a second series of basins developed parallel to the northern trough. Within these basins, which were carried piggyback by the thrust plate, lower Eocene [[Igneous rock|igneous]]-derived sediments accumulated, but under quieter tectonic conditions (the Taguasco*, Bijabo*, Santa Clara*, Alkazar, Bacunayagua, Capdevila, and Universidad Formations, for example).

South of the front of the advancing volcanic and basic intrusive-rock thrust plate, a second series of basins developed parallel to the northern trough. Within these basins, which were carried piggyback by the thrust plate, lower Eocene [[Igneous rock|igneous]]-derived sediments accumulated, but under quieter tectonic conditions (the Taguasco*, Bijabo*, Santa Clara*, Alkazar, Bacunayagua, Capdevila, and Universidad Formations, for example).

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 [http://dictionary.reference.com/browse/detrital 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.

==References==

==References==

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