Bahama Banks

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Above Little Bahama Bank , below Great Bahama Bank . At the left edge of the picture Cay Sal Bank , at the bottom Cuba . MODIS , NASA

The Bahama Banks are a group of carbonate platforms that form the subsurface for most of the Bahamas archipelago . They consist of the Great Bahama Bank around Andros Island in the north, the Little Bahama Bank around Grand Bahama and Abaco, and the Cay Sal Bank in the west, immediately north of Cuba . The islands of these platforms are politically part of the Bahamas. Further to the southeast, outside of the closed distribution of the platform, there are isolated deposits, such as around the Turks and Caicos Islands - here especially the Caicos Bank , the Turks Islands Bank and the completely submerged Mouchoir Bank - and even further to the southwest the also completely underwater lying Silver Bank and Navidad Bank north of Hispaniola .

Geological history and structure

The limestone from which the benches are built has been deposited at least since the Cretaceous , and possibly since the Jurassic . Today the limestone beneath the Great Bahama Bank is more than 4,500 meters thick . Since the limestone was deposited in shallow water, this great thickness can only be explained by constant sinking. From the thickness and age of the limestone, a mean subsidence of 3.6 centimeters per 1,000 years can be calculated.

The waters of the Bahama Banks are very shallow, generally no deeper than 25 meters on the Great Bahama Bank. The slopes at its edges, such as around the Tongue of the Ocean , the sea ditch in the Great Bahama Bank, are very steep. During the last ice ages , the Bahama Banks fell completely dry because of lower sea levels around the world. So today's Bahamas are only a part of the islands that existed back then. When the banks were exposed to the earth's atmosphere , the limestones were subject to the chemical weathering that is typical for them , which led to karst forms such as caves and sinkholes . Similar to today's Central America, cenotes were also created here .

Web links

Individual evidence

  1. ↑ a b c Geomorphology from Space, Chapter 6: Coastal Landforms. Panel C-16, Great Bahama Bank. Retrieved October 25, 2008
  2. ↑ a b Stephen K. Boss: Geological Research on the Great Bahama Bank. ( Memento of the original from February 5, 2006 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved October 25, 2008  @1@ 2Template: Webachiv / IABot / comp.uark.edu

Coordinates: 24 ° 3 ′  N , 77 ° 39 ′  W