Changes

The most striking feature about the geology of the island is the great disparity between the [http://geology.about.com/od/platetectonics/a/ophiolite.htm ophiolite]-volcanic  sequence of the basic igneous-volcanic terranes and the sedimentary sequences of the north-central and southwestern sedimentary terranes. Except for a few notable cases, essentially no relationship exists between these sedimentary and igneous terranes. There has been much argument about how the terranes came into contact and became structurally mixed, but it is generally accepted today that the [http://geology.about.com/od/platetectonics/a/ophiolite.htm ophiolite]-volcanic sequence is totally [[Allochthon|allochthonous]]. [[:file:St58OverviewFG5.JPG|Figure 3]] shows a map of Cuba's major structural features and terrane distribution, and [[:file:St58OverviewFG6.JPG|Figure 4]] shows, in cross section, the structural relations between the various terranes.

The most striking feature about the geology of the island is the great disparity between the [http://geology.about.com/od/platetectonics/a/ophiolite.htm ophiolite]-volcanic  sequence of the basic igneous-volcanic terranes and the sedimentary sequences of the north-central and southwestern sedimentary terranes. Except for a few notable cases, essentially no relationship exists between these sedimentary and igneous terranes. There has been much argument about how the terranes came into contact and became structurally mixed, but it is generally accepted today that the [http://geology.about.com/od/platetectonics/a/ophiolite.htm ophiolite]-volcanic sequence is totally [[Allochthon|allochthonous]]. [[:file:St58OverviewFG5.JPG|Figure 3]] shows a map of Cuba's major structural features and terrane distribution, and [[:file:St58OverviewFG6.JPG|Figure 4]] shows, in cross section, the structural relations between the various terranes.

Although Cuba is now part of the North American continent, it is a remnant of a [[Cretaceous]] to early [[Tertiary]] [[orogenic belt]] that has been preserved because of the local configurations of the North American and Caribbean [[plate]]s. As a consequence, Cuba exposes sequences of Upper Jurassic and Cretaceous nonvolcanic pelagic sediments that are rare, if not unique, in the Caribbean as well as in North, Central, and South America. However, Cuba has facies and faunal similarities with equivalent strata of the [[Tethys]] region, specifically the [[Alps]] and Italian [[Apennines]].

Although Cuba is now part of the North American continent, it is a remnant of a [[Cretaceous]] to early [[Tertiary]] [[Orogeny|orogenic belt]] that has been preserved because of the local configurations of the North American and Caribbean [[plate]]s. As a consequence, Cuba exposes sequences of Upper Jurassic and Cretaceous nonvolcanic pelagic sediments that are rare, if not unique, in the Caribbean as well as in North, Central, and South America. However, Cuba has facies and faunal similarities with equivalent strata of the [[Tethys]] region, specifically the [[Alps]] and Italian [[Apennines]].

Similarities and differences exist between the Jurassic–Cretaceous sedimentary sections of Cuba and other areas in the region.

Similarities and differences exist between the Jurassic–Cretaceous sedimentary sections of Cuba and other areas in the region.

===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 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] 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)===

In western Cuba, the northward-moving stack of thrust sheets did not reach the buttress of the Bahamas Platform, and the nappes came to rest on the sea floor toward the southern Gulf of Mexico. As a result, they are less deformed than they are to the east.

In western Cuba, the northward-moving stack of thrust sheets did not reach the buttress of the Bahamas Platform, and the nappes came to rest on the sea floor toward the southern Gulf of Mexico. As a result, they are less deformed than they are to the east.

It is possible that a large number of the present-day high-angle faults, some with reverse thrusting (Seibabo syncline), formed during the last phase of the orogeny.

It is possible that a large number of the present-day high-angle faults, some with reverse thrusting (Seibabo syncline), formed during the last phase of the [[orogeny]].

The intense orogenic activity ceased toward the close of the middle Eocene or early late Eocene, and the uplifted, faulted, and folded orogenic complex was subsequently eroded and [http://www.merriam-webster.com/dictionary/peneplain peneplained].

The intense orogenic activity ceased toward the close of the middle Eocene or early late Eocene, and the uplifted, faulted, and folded orogenic complex was subsequently eroded and [http://www.merriam-webster.com/dictionary/peneplain peneplained].