Stromatolites, ooid dunes, hardgrounds, and crusted mud beds, all products of marine cementation and microbial mats in subtidal oceanic mixing zone on eastern margin of Great Bahama Bank
Abstract
The interisland channels along the eastern margin of the Great Bahamas Bank contain lithified structures that owe their origin to recent marine cementation. This cementation appears to be commonly associated with a complex microbial community of plants and microorganisms living within a bank-margin oceanographic mixing zone. In this region, reversing tidal and wind-driven currents flow up to 3 knots (150 cm/sec) three hours out of each six-hour tidal period. Here, marine-cement crusted, carbonate mud beds are found interbedded within migrating ooid sand bars and dunes and are associated with growing, lithified stromatolites up to 2 m in height. These laminated mud beds are found with thicknesses of up to 1 m in subtidal depths of 4 to 8 m (12 to 25 ft). The muds appear to be homogeneous, but closer examination by SEM and under a microscope reveals they are composed of pelletoid aggregates of needle-shaped aragonite crystals with diameters of up to 50 ..mu... The size of these soft pellets is similar to the smaller grains of ooid sands that are abundant in the area. This size similarity could explain why both the mud beds are found in similar high-energy hydraulic regimes as the ooid sands, but doesmore »
- Authors:
- Publication Date:
- Research Org.:
- Univ. of South Carolina an Caribbean Marine Research Center, San Diego, CA (USA)
- OSTI Identifier:
- 5955298
- Report Number(s):
- CONF-890404-
Journal ID: CODEN: AABUD
- Resource Type:
- Conference
- Journal Name:
- AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)
- Additional Journal Information:
- Journal Volume: 73:3; Conference: AAPG annual convention with DPA/EMD Divisions and SEPM, San Antonio, TX, USA, 23 Apr 1989
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 02 PETROLEUM; BAHAMA ISLANDS; CARBONATE ROCKS; DEPOSITION; CALCITE; ALKALINE EARTH METAL COMPOUNDS; CALCIUM CARBONATES; CALCIUM COMPOUNDS; CARBON COMPOUNDS; CARBONATE MINERALS; CARBONATES; DEVELOPING COUNTRIES; ISLANDS; MINERALS; OXYGEN COMPOUNDS; ROCKS; SEDIMENTARY ROCKS; WEST INDIES; 020200* - Petroleum- Reserves, Geology, & Exploration
Citation Formats
Dill, R F, Kendall, C S.C.G., and Steinen, R P. Stromatolites, ooid dunes, hardgrounds, and crusted mud beds, all products of marine cementation and microbial mats in subtidal oceanic mixing zone on eastern margin of Great Bahama Bank. United States: N. p., 1989.
Web.
Dill, R F, Kendall, C S.C.G., & Steinen, R P. Stromatolites, ooid dunes, hardgrounds, and crusted mud beds, all products of marine cementation and microbial mats in subtidal oceanic mixing zone on eastern margin of Great Bahama Bank. United States.
Dill, R F, Kendall, C S.C.G., and Steinen, R P. 1989.
"Stromatolites, ooid dunes, hardgrounds, and crusted mud beds, all products of marine cementation and microbial mats in subtidal oceanic mixing zone on eastern margin of Great Bahama Bank". United States.
@article{osti_5955298,
title = {Stromatolites, ooid dunes, hardgrounds, and crusted mud beds, all products of marine cementation and microbial mats in subtidal oceanic mixing zone on eastern margin of Great Bahama Bank},
author = {Dill, R F and Kendall, C S.C.G. and Steinen, R P},
abstractNote = {The interisland channels along the eastern margin of the Great Bahamas Bank contain lithified structures that owe their origin to recent marine cementation. This cementation appears to be commonly associated with a complex microbial community of plants and microorganisms living within a bank-margin oceanographic mixing zone. In this region, reversing tidal and wind-driven currents flow up to 3 knots (150 cm/sec) three hours out of each six-hour tidal period. Here, marine-cement crusted, carbonate mud beds are found interbedded within migrating ooid sand bars and dunes and are associated with growing, lithified stromatolites up to 2 m in height. These laminated mud beds are found with thicknesses of up to 1 m in subtidal depths of 4 to 8 m (12 to 25 ft). The muds appear to be homogeneous, but closer examination by SEM and under a microscope reveals they are composed of pelletoid aggregates of needle-shaped aragonite crystals with diameters of up to 50 ..mu... The size of these soft pellets is similar to the smaller grains of ooid sands that are abundant in the area. This size similarity could explain why both the mud beds are found in similar high-energy hydraulic regimes as the ooid sands, but does not suggest how or why the aggregates of pure aragonite needles form. A high production of ooid sand within this bank margin environment permits the formation of natural levees along the margins of tidal channels. The back sides of these levees are being lithified by marine cements to form hardgrounds. Skeletal and ooid sand dunes stabilized by Thallasia in channel bottoms also are becoming lithified. Grapestones form at the distributaries of flood tidal deltas of ooid sand. All of these features have a common attribute: they are continually in contact with the turbulent mixing-zone waters.},
doi = {},
url = {https://www.osti.gov/biblio/5955298},
journal = {AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)},
number = ,
volume = 73:3,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 1989},
month = {Wed Mar 01 00:00:00 EST 1989}
}