Editing The Bahamas (section)

===Geology===
{{main|Bahama Banks}}
[[File:Dean Blue Hole Long Island Bahamas 20110210.JPG|thumb|[[Dean's Blue Hole]] in [[Clarence Town]] on [[Long Island, Bahamas]]]]
[[File:Blue Lagoon.JPG|thumb|The [[Blue Lagoon Island]], Bahamas]]

It was generally believed that the Bahamas were formed approximately 200 million years ago, when Pangaea started to break apart. In current times, it endures as an archipelago containing over 700 islands and cays, fringed around different [[coral reef]]s. The [[limestone]] that comprises the Banks has been accumulating since at least the [[Cretaceous]] period, and perhaps as early as the [[Jurassic]]; today the total thickness under the Great Bahama Bank is over 4.5 kilometres (2.8 miles).<ref name=NASA>{{cite web|url=http://geoinfo.amu.edu.pl/wpk/geos/GEO_6/GEO_PLATE_C-16.HTML|title=Geomorphology from Space, Chapter 6: Coastal Landforms. Plate C-16, 'Great Bahama Bank'|author=<!--Not stated-->|website=geoinfo.amu.edu.pl|access-date=9 March 2006|archive-date=25 March 2005|archive-url=https://web.archive.org/web/20050325012629/http://geoinfo.amu.edu.pl/wpk/geos/GEO_6/GEO_PLATE_C-16.HTML|url-status=live}}</ref> As the limestone was deposited in shallow water, the only way to explain this massive column is to estimate that the entire platform has [[subsidence|subsided]] under its own weight at a rate of roughly 3.6 centimetres (2 inches) per 1,000 years.<ref name=NASA/>
The Bahamas is part of the [[Lucayan Archipelago]], which continues into the Turks and Caicos Islands, the [[Mouchoir Bank]], the [[Silver Bank]], and the [[Navidad Bank]].<ref name=Carew/> The Bahamas Platform, which includes the Bahamas, Southern Florida, Northern Cuba, the Turks and Caicos, and the [[Blake Plateau]], formed about 150 [[megaannum|Ma]], not long after the formation of the North Atlantic. The {{cvt|6.4|km||adj=on}} thick [[limestone]]s, which predominate in the Bahamas, date back to the [[Cretaceous]]. These limestones would have been deposited in shallow seas, assumed to be a stretched and thinned portion of the [[North American Plate|North American continental crust]]. Sediments were forming at about the same rate as the crust below was sinking due to the added weight. Thus, the entire area consisted of a large marine plain with some islands. Then, at about 80&nbsp;Ma, the area became flooded by the [[Gulf Stream]]. This resulted in the drowning of the Blake Plateau, the separation of the Bahamas from Cuba and Florida, the separation of the southeastern Bahamas into separate banks, the creation of the [[Cay Sal Bank]], plus the [[Bahama Banks|Little and Great Bahama Banks]]. Sedimentation from the "carbonate factory" of each bank, or [[atoll]], continues today at the rate of about {{cvt|20|mm}} per [[kyr]]. [[Coral reef]]s form the "retaining walls" of these atolls, within which [[oolite]]s and [[pellets (petrology)|pellets]] form.<ref name="Sealey">{{cite book|last1=Sealey|first1=Neil|title=Bahamian Landscapes; An Introduction to the Geology and Physical Geography of The Bahamas|date=2006|publisher=Macmillan Education|location=Oxford|isbn=9781405064064|pages=1–24}}</ref>

Coral growth was greater through the [[Tertiary (geology)|Tertiary]], until the start of the [[ice ages]], and hence those deposits are more abundant below a depth of {{cvt|36|m}}. In fact, an ancient extinct reef exists half a kilometre seaward of the present one, {{cvt|30|m}} below sea level. Oolites form when oceanic water penetrate the shallow banks, increasing the temperature about {{cvt|3|C-change}} and the salinity by 0.5 per cent. [[Cementation (geology)|Cemented]] [[ooid]]s are referred to as grapestone. Additionally, giant [[stromatolite]]s are found off the [[Exuma Cays]].<ref name=Sealey/>{{rp|22,29–30}}

[[Sea level change]]s resulted in a drop in sea level, causing wind blown oolite to form [[sand dune]]s with distinct [[cross-bedding]]. Overlapping dunes form oolitic ridges, which become rapidly [[lithified]] through the action of rainwater, called [[eolianite]]. Most islands have ridges ranging from {{cvt|30|to|45|m}}, though Cat Island has a ridge {{cvt|60|m}} in height. The land between ridges is conducive to the formation of lakes and swamps.<ref name=Sealey/>{{rp|41–59,61–64}}

[[Solution weathering]] of the limestone results in a "Bahamian [[Karst]]" topography. This includes [[pothole (geology)|potholes]], [[blue hole]]s such as [[Dean's Blue Hole]], [[sinkhole]]s, [[beachrock]] such as the [[Bimini Road]] ("pavements of Atlantis"), [[caliche|limestone crust]], caves due to the lack of rivers, and [[sea caves]]. Several blue holes are aligned along the South Andros [[fault (geology)|Fault]] line. [[Tidal flat]]s and [[tidal creek]]s are common, but the more impressive drainage patterns are formed by troughs and canyons such as [[Great Bahama Canyon]] with the evidence of [[turbidity current]]s and [[turbidite]] deposition.<ref name=Sealey/>{{rp|33–40,65,72–84,86}}

The [[stratigraphy]] of the islands consists of the [[Middle Pleistocene]] Owl's Hole [[formation (geology)|Formation]], overlain by the [[Late Pleistocene]] Grotto Beach Formation, and then the [[Holocene]] Rice Bay Formation. However, these units are not necessarily stacked on top of each other but can be located laterally. The oldest formation, Owl's Hole, is capped by a [[terra rossa (soil)|terra rosa]] [[paleosoil]], as is the Grotto Beach, unless [[eroded]]. The Grotto Beach Formation is the most widespread.<ref name=Carew>{{cite book|last1=Carew|first1=James|last2=Mylroie|first2=John|editor1-last=Vacher|editor1-first=H.L.|editor2-last=Quinn|editor2-first=T.|title=Geology of Bahamas, in Geology and Hydrology of Carbonate Islands, Developments in Sedimentology 54|url=https://archive.org/details/geologyhydrogeol00vach_559|url-access=limited|date=1997|publisher=Elsevier Science B.V.|location=Amsterdam|isbn=9780444516442|pages=[https://archive.org/details/geologyhydrogeol00vach_559/page/n109 91]–139}}</ref>