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   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Plate tectonic processes in the Pacific and Atlantic during the   
   Cretaceous period have shaped the Caribbean region to this day    
      
     Date:   
         April 19, 2023   
     Source:   
         Johannes Gutenberg Universitaet Mainz   
     Summary:   
         Earthquakes and volcanism occur as a result of plate tectonics. The   
         movement of tectonic plates themselves is largely driven by the   
         process known as subduction. The question of how new active   
         subduction zones come into being, however, is still under   
         debate. An example of this is the volcanic Lesser Antilles arc   
         in the Caribbean. A research team recently developed models that   
         simulated the occurrences in the Caribbean region during the   
         Cretaceous, when a subduction event in the Eastern Pacific led   
         to the formation of a new subduction zone in the Atlantic. The   
         computer simulations show how the collision of the old Caribbean   
         plateau with the Greater Antilles arc contributed to the creation   
         of this new Atlantic subduction zone. Some 86 million years ago,   
         the triggered processes subsequently resulted in a major mantle flow   
         and thus to the development of the Caribbean large igneous province.   
      
      
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   FULL STORY   
   ==========================================================================   
   Earthquakes and volcanism occur as a result of plate tectonics. The   
   movement of tectonic plates themselves is largely driven by the process   
   known as subduction. The question of how new active subduction zones   
   come into being, however, is still under debate. An example of this   
   is the volcanic Lesser Antilles arc in the Caribbean. A research team   
   including geophysicists Dr.   
      
   Nicolas Riel and Professor Boris Kaus of Johannes Gutenberg University   
   Mainz (JGU) as well as researchers from Universidade de Lisboa   
   (ULisboa) recently developed models that simulated the occurrences in   
   the Caribbean region during the Cretaceous, when a subduction event in   
   the Eastern Pacific led to the formation of a new subduction zone in   
   the Atlantic. The computer simulations show how the collision of the   
   old Caribbean plateau with the Greater Antilles arc contributed to the   
   creation of this new Atlantic subduction zone. Some 86 million years   
   ago, the triggered processes subsequently resulted in a major mantle   
   flow and thus to the development of the Caribbean large igneous province.   
      
      
   ==========================================================================   
   Subduction as a driving force of plate tectonics Subduction is a   
   geological process in which the cold oceanic lithosphere, which is part   
   of the rocky and about 100 kilometer thick outermost layer of the planet,   
   runs into the edge of a continental plate and slides beneath it to be   
   recycled back into the Earth's mantle. Together with the release of   
   hot mantle material in the form of mantle plumes and new oceanic floor   
   generation at mid- ocean ridges, subduction events form the backbone of   
   plate tectonics. However, it is largely unknown how active subduction   
   zones form mainly because there are very few examples of ongoing   
   subduction initiation currently here on Earth.   
      
   With this in view, Dr. Nicolas Riel and Professor Boris Kaus of the   
   JGU Institute of Geosciences decided to investigate the geodynamic   
   conditions that would have predominated in the Caribbean region in the   
   late Cretaceous period.   
      
   "In terms of its plate tectonics, the Caribbean is a particularly   
   interesting location," said Professor Boris Kaus, head of the Geodynamics   
   & Geophysics group at Mainz University. The Caribbean region can be seen   
   as a kind of natural laboratory in which, over millions of years, plate   
   tectonics resulted in the transfer of a subduction zone from the Pacific   
   to the Atlantic. This was associated with very extensive magmatic activity   
   that accounted for the origin of the Caribbean large igneous province   
   (or CLIP for short). This structure of magmatic rock is now the center   
   of the Caribbean plate.   
      
   For their computer simulations, the researchers selected a point in time   
   140 million years ago when the so-called Farallon plate, an ancient major   
   plate in the Eastern Pacific, began to move east and subduct beneath the   
   South American margin, thus shifting the old Caribbean plateau in the   
   direction of the Farallon trench. About 135 million years ago, the old   
   Caribbean plateau came into collision with the proto-Caribbean plate. As   
   the simulations showed, the subduction of the Farallon plate was then   
   temporarily interrupted while the subduction of the proto-Caribbean   
   plate was initiated. Several subsequent phases follow over a period of   
   some 50 million years, including the renewed subduction of the Farallon   
   plate at the western end of the old plateau, the formation of a mantle   
   plume, and the transfer of the Greater Antilles arc onto the retreating   
   proto-Caribbean plate.   
      
   Simultaneous subduction of two plates forced part of the mantle upwards   
   "With the help of our computer simulations, we can better understand   
   the physical process," added Dr. Nicolas Riel, the lead author of the   
   corresponding article recently published in Nature Communications. "We   
   were all surprised by the results showing that 90 to 86 million years   
   ago the renewal of the Farallon plate subduction led to a major mantle   
   flow, triggering the formation of a plume. This produced a huge amount   
   of magma." This molten rock material added to the thickness of the crust   
   of the Caribbean plate, making it up to 22 kilometers in depth, thus   
   8 to 10 kilometers thicker than the standard for the oceanic crust. It   
   was previously assumed that the mantle plume induced the renewal of the   
   Farallon plate subduction.   
      
   "We are in the unique situation of being able to carry out very realistic   
   simulations," said Boris Kaus. His team is one of the few groups worldwide   
   that can use supercomputer modeling to test to the plausibility of their   
   physical assumptions and thus to analyze what plate tectonic events   
   actually occurred in the Caribbean. For their complex calculations,   
   the researchers had access to the MOGON II supercomputer operated by   
   Johannes Gutenberg University Mainz and the Helmholtz Institute Mainz   
   (HIM), one of the fastest high-performance computers in the world.   
      
   Research under the aegis of TeMaS The geophysical research was undertaken   
   under the aegis of the Terrestrial Magmatic Systems (TeMaS) research   
   platform, a joint project of the universities of Mainz, Frankfurt, and   
   Heidelberg. TeMaS coordinates interdisciplinary research on magmatic   
   processes in the broadest sense, from the generation of magma in the   
   Earth's mantle through to its eruption in volcanoes and how this impacts   
   the atmosphere and climate. TeMaS is a High-potential Research Area at   
   JGU, funded by the Ministry of Science and Health of Rhineland-Palatinate.   
      
   Boris Kaus is Head of the Geodynamics & Geophysics group at the JGU   
   Institute of Geosciences. In 2018, he was granted an ERC Consolidator   
   Grant, one of the most richly endowed EU funding awards, to support   
   his research into magmatic processes. As part of the ERC project MAGMA,   
   short for "Melting And Geodynamic Models of Ascent," Kaus and his team   
   developed numerical models that enabled them to simulate magmatic   
   events. The geophysicist is also a Fellow of the Gutenberg Research   
   College (GRC) of JGU.   
      
       * RELATED_TOPICS   
             o Earth_&_Climate   
                   # Earthquakes # Geology # Natural_Disasters # Tsunamis   
             o Fossils_&_Ruins   
                   # Fossils # Origin_of_Life # Early_Climate # Evolution   
       * RELATED_TERMS   
             o Mid-ocean_ridge o Earthquake o Great_Hurricane_of_1780   
             o Volcano o Oceanic_trench o Plate_tectonics o Ocean o   
             Geologic_fault   
      
   ==========================================================================   
   Story Source: Materials provided by   
   Johannes_Gutenberg_Universitaet_Mainz. Note: Content may be edited for   
   style and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Nicolas Riel, Joa~o C. Duarte, Jaime Almeida, Boris J. P. Kaus,   
      Filipe   
         Rosas, Yamirka Rojas-Agramonte, Anton Popov. Subduction   
         initiation triggered the Caribbean large igneous province. Nature   
         Communications, 2023; 14 (1) DOI: 10.1038/s41467-023-36419-x   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2023/04/230419125108.htm   
      
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