Roatán, (16.34°N 86.33° W) lays across the Cayman Trench at the northwestern intersection between the Caribbean and North American Plates.
Image Credit: Purdue UniversityThe easiest way to describe Roatán's formation is to say that through a process of transforming plate interaction and a parallel process of divergence between the North American Plate and Caribbean plate, magma was allowed to escape from below the earth's crust. The transform process allowed the sub-aquatic magma to cool (through an exothermic process) and form the resultant igneous rock - which eventually ended up forming the Bonacca Ridge, which resides underneath the Bay Islands, and more importantly: Roatán.
Because magma was moving from an area of high pressure to low pressure, magma moved through dikes to reach the ocean floor, and the basalt lava flows allowed centuries of compiling igneous rock to eventually form the ridge islands.
It would not be completely absurd to assume that a process of extension faulting allowed some of the material of the ridge to move in certain ways that effect its height (which would account for the fact that pats of the island are at a higher elevation than others).
Areas where the plates were convergently moving created areas of anticline folds.
Sources Consulted:
Because magma was moving from an area of high pressure to low pressure, magma moved through dikes to reach the ocean floor, and the basalt lava flows allowed centuries of compiling igneous rock to eventually form the ridge islands.
It would not be completely absurd to assume that a process of extension faulting allowed some of the material of the ridge to move in certain ways that effect its height (which would account for the fact that pats of the island are at a higher elevation than others).
Areas where the plates were convergently moving created areas of anticline folds.
Interesting Look at the trough surrounding Roatán and the Bonacca Ridge, Courtesy: Stanley Submarines
Sources Consulted:
"Island Geography." Tourism Roatan. Web. 14 Feb. 2011. http://tourismroatan.com/about-roatan/geography
Mann, Paul. Geologic and Tectonic Development of the Carribean Plate Boundary in Northern Central America. Boulder, Colo: Geological Society of America, 2007. Print.
http://books.google.com/books?id=CvmNCC0W97wC&pg=PA52&lpg=PA52&dq=bonacca+ridge+formation+site&source=bl&ots=jyciKoT7y-&sig=bXI8l-tB3FU2SjqQ9dCAzgFLuv8&hl=en&ei=rf9aTaSmB4r6sAPz_9COCg&sa=X&oi=book_result&ct=result&resnum=1&sqi=2&ved=0CBMQ6AEwAA#v=onepage&q&f=false
http://books.google.com/books?id=CvmNCC0W97wC&pg=PA52&lpg=PA52&dq=bonacca+ridge+formation+site&source=bl&ots=jyciKoT7y-&sig=bXI8l-tB3FU2SjqQ9dCAzgFLuv8&hl=en&ei=rf9aTaSmB4r6sAPz_9COCg&sa=X&oi=book_result&ct=result&resnum=1&sqi=2&ved=0CBMQ6AEwAA#v=onepage&q&f=false
Rogers, Robert. "Chapter Two Figures." Geology at CSU Stanislaus.
Web. 14 Feb. 2011. http://geology.csustan.edu/rrogers/Rogers2003/chpt2_figs.htm
Web. 14 Feb. 2011. http://geology.csustan.edu/rrogers/Rogers2003/chpt2_figs.htm
Nice choice for your blog. Roatan seems like a very nice place to visit. The pictures and video are great. I really liked how you had your geography terms in bold, however you did not really define what they are. One thing I recommend is that you spread out your text and place the images/videos you have between paragraphs. It would be nice to read the description then see a visual representation rather than seeing all of your pictures then reading about them. You might also want to reword your first sentence, it's quite long. Keep up the good work Christian!
ReplyDeleteThis is a beautiful place filled with vegetation which I am surprised considering it was formed by volcanic eruptions and the cooling of magma. Knowing that the island has vegetation, I will conclude that it has more than just igneous rocks which was made from cooling of magma, but also many other rocks and minerals that can support plant and tree life. I would think that sedimentary rocks were broken down through erosion and deterioration over time to make minerals that goes into the soil for the vegetation. I am curious if the magma that formed the island was either pahoehoe or ah-ah.
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