Geology of the project area Cuba



I. Introduction.
The geological genesis of the Caribbean is one of the most complicated of the world. In Jurassic and Lower Cretaceous times, the break-up of Pangea occurred at an striking spreading axis which continued from the Penninic ocean into the Central Atlantic, and further into the proto-Caribbean ocean. (I refer to the 15th Caribbean Geological Conference Jamaica 1998 "Caribbean Geology into the Third Millennium, ed. Trevor A. Jackson, Kingston 2002). At this time 160 Ma. ago North Cuba (NCu) was near Dakar, Africa, South Cuba (SCu) near Venezuela (Martin Meschede, Wolfgang Frisch, S. 4). 




In the last 160 Million years the plates of North- and South America drifted some thousand kilometres  westward, while the Caribbean Plate followed with a slower motion. According to Global Positioning System (GPS) data the present-day relative lateral displacement has a magnitude of around 2 cm/yr. Along the north shore of Cuba exists a main overthrust front, while south of the island the opening of the Cayman Trough or strike -slip fault has been determined to have started with rifting in the Eocene (about 50 to 60 Ma). The Cocos Plate in the Pacific moves towards the NNE. Owing to the westward drift of the South American Plate, the Panama arc collided in the Miocene with the Western Cordillera in Colombia and caused its northward escape into the Colombian Basin. This produced the present-day northward convexity of the Panama arc These controversial movements create a very complicated geological structure of the Caribbean and Cuba.






As a result of the collided plates and terrains we get a colorful picture of geological formations in Cuba: In general 4 main structures can be distinguished in Cuba: 1. Continental units coming from the Bahamas Platform (North American margin) and the Southwestern Terrains. 2. the Oceanic units can be divided into 2 parts, a lower Tertiary fold belt, and a pre-Cenocoid basement. The latter includes 2 different terrains that were accreted to the North American continental margin during the Cretaceous:  the northern ophiolitic belt and the amphibolitic basement of the Cretaceous volcanic arc terrains. The ophilitic  represents an allochthonous belt that was transported from the south over the North American margin and Lower Tertiary foreland basin of northern Cuba and in turn overidden by the Cretaceous arc terrain. 3. the neo-authochtonous deposits are made up of slightly deformed Eocene-Quaternary sedimentary rocks. 4. palaeogene arc  of old volcanos which are the results of old subduction zones of oceanic crust diving under the Caribbean Plate.






II. The geological situation of Mayari:
With more detailed scales we get more detailed geological outcrops. For example Maastrichian/Backarc basin at the beginning of the river Mayari (brown).  These follow massive conglomerates, dominated by ophiolite pebbles (violet) and overlain by Palaeocene-early Eocene white tuffaceous rocks (brown-yellow) outcrop SE of the town Holguin where the river Mayari  is located.  The European Maastrichian is a well-known geological chalk formation with silex (flintstones). But it seems impossible, that the  the silex near Seboruco comes from the long-distance transport by the river Mayari.



The chalk-blocks and layers of the rocks round the Seboruco abri are not Cretaceous but layers of the deep ocean of Eocen/Miocene. The layers do not have fossils. But what is the origin of the silex material?  The geological formation of Ophiolite (Gabros) must be excluded. From the 480 artifacts we collected in February 2005 from one site only 3 specimens   sustain the quarzite of Ophiolithic formations. This large area of basalt (Ophiolite) is out of the question.  Can it be true, that the layers of Eocene/Miocene above of the older Ophiolite vanished by erosion and left the hard silex as a testimony?

1. photo: typical yellow-brown patinated nodule, collected from an arroyo 1 km distant from the Seboruco abris
2. photo: nucleo, white patinated edges
3. photo: point tool without cortex




III. The youngest geological formations
are the corals at the coast line of East Cuba. From the geological point of view they are like  the coral-reefs of the Franconian Swiss in Bavaria, Germany of Jurassic time. (Nearby figure is from the book:  "Medio siglo explorando a Cuba", p. 483). The rising floor of East Cuba terrain and the kinetics of the waves created terraces (terrazas costeras) and niches (nichos) with stalactites and stalagmites like the Terraza de Yara at the NE coast of the province Guantanamo. The platforms of the terraces were the living floors of the palaeoindians






PalaeoPlan - A Non-Profit-Organization by Dr.G.Elvers - Copyright 2006