50 Years of Plate Tectonics and its impact on understanding the tectonic evolution of Cuba
8/15 50 Years of Plate Tectonics & its impact on understanding the tectonic evolution of Cuba” Presented by Larry Lawver, Institute for Geophysics, Jackson School of Geosciences, Univ. of Texas.
Plate tectonics was a hotly debated topic just 50 years ago and remained contentious in some universities well into the late 1970s. While continental drift (an early descriptor of plate tectonics) dates back to the early 20th century, concepts such as vertical tectonics, miogeosynclines and eugeosynclines, were still being taught exclusively in the early 1960s. By the end of that decade a number of demonstrable facts led to the unifying theory of plate tectonics – that the surface of the earth consists of discrete plates that are all in motion, are all interacting. Examples of the critical data include physical evidence of the magnetic reversal timescale, measured transform offset on the San Andreas Fault and on both sides of the Mendocino Fracture Zone – but these studies were only published in the early 1960s. Such information coupled with the understanding of subduction zones and the recognition of the obduction of material onto continental margins, eventually produced a coherent theory: Plate Tectonics.
An example of the importance of plate tectonics to understanding our earth’s history can be found on the island of Cuba. Not until scientists realized that plates, the different pieces of the surface of the earth, were essentially in constant motion could the truly complex tectonic history of Cuba be fully appreciated and explained.
The geology of Cuba can be divided into a Space-Time summary that separates the Pre-Cuban geology into a pre-orogenic phase that ended in the Late Cretaceous followed by an orogenic phase (mountain building phase) that ended in the Eocene. There are at least five significant, geological components of Cuba, including the northern foldbelt, believed to be part of the Bahamas passive margin, relatively in place where it was formed. It was overthrust by oceanic formations from the Proto-Caribbean Ocean that were obducted onto the Bahamas passive margin. To the south in Cuba is the Cretaceous Caribbean volcanic belt that originated far to the southwest near where Panama is today. On the southern margin of Cuba are the Caribeana metamorphic terranes that may have in fact originated off northwestern-most South America.
We have put together an animation starting at 200 Ma that illustrates a possible scenario for the plate tectonic evolution of the various Cuban and pre-Cuba blocks that now form Cuba. Video