Changes

===Late Eocene to Present===

===Late Eocene to Present===

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 orogenic belt occurred. This deformation consisted mostly of large-scale folds (Habana-Matanzas) and high-angle faults (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 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 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 granodioritic basement rocks. The Alps show similar geology. The northward displacement of the visible thrusting was on the order of several hundred kilometers.