File:Altar Cave - main chamber (San Salvador Island, Bahamas) 3 (16204647750).jpg
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[edit]DescriptionAltar Cave - main chamber (San Salvador Island, Bahamas) 3 (16204647750).jpg |
Altar Cave (looking ~NE), southwestern San Salvador Island, eastern Bahamas. Altar Cave is hosted in aragonitic, oolitic calcarenite limestones of the Cockburn Town Member of the Grotto Beach Formation (Upper Pleistocene). This cave is nearly intact, breached flank margin cave. Flank margin caves form at the flanks of carbonate islands and at the margins of fresh-groundwater lenses. As such, flank margin caves are phreatic features. In the vicinity of the seawater-freshwater mixing zone (halocline) of a groundwater lens (see diagram - www.carbonatecreek.com/caves/images/carbisland.gif), relatively rapid dissolution of limestone occurs due to the high aggressivity of the water. Limestone dissolution at Altar Cave occurred during the MIS 5e highstand (early Late Pleistocene ~119-131 ka). Flank margin caves have no surface entrances. Access to them occurs only after surficial erosion intercepts chambers or passages. Altar Cave was erosionally intercepted by the development of a wave-cut, paleo-sea cliff formed during the mid-Holocene, at about 5000 years ago. The cave entrance is low and requires crawling. The entrance passage has a sand-covered floor. The bedrock floor occurs at up to 2 meters below the present sediment-covered cave floor. Altar Cave consists of one main chamber (see above). A large mound of travertine speleothem occurs near the northeastern corner of the main chamber - it somewhat resembles a ceremonial altar. |
Date | |
Source | Altar Cave - main chamber (San Salvador Island, Bahamas) 3 |
Author | James St. John |
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This image was originally posted to Flickr by jsj1771 at https://www.flickr.com/photos/47445767@N05/16204647750. It was reviewed on 2 March 2015 by FlickreviewR and was confirmed to be licensed under the terms of the cc-by-2.0. |
2 March 2015
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Date and time of data generation | 10:24, 13 March 2013 |
Lens focal length | 6.2 mm |
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Software used | Adobe Photoshop CS2 Macintosh |
File change date and time | 22:09, 27 January 2015 |
Y and C positioning | Co-sited |
Exif version | 2.21 |
Date and time of digitizing | 10:24, 13 March 2013 |
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Date metadata was last modified | 17:09, 27 January 2015 |
IIM version | 2 |