Bahamian Oölitic Sand

Newell, Norman D.; Purdy, Edward G.; Imbrie, John

doi:10.1086/626683

Cited by 188 publications

(77 citation statements)

References 2 publications

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“…Newell et al, 1960;Simone, 1981;Richter, 1983) agree that conditions required for optimal production of tangentialaragonitic ooids are: (1) a flat topography where particles can remain in their formation locus; (2) a very shallow and potentially turbulent environment; (3) a mixture of cool, CO 2 -rich, oceanic water and warm bank-water supersaturated with respect to aragonite. Factors favouring reef growth, and thus indirectly bioclast production, are: (1) a hard substrate, (2) a high-energy setting, (3) shallow to moderate depths (up to 20 m), (4) normal-salinity, low-turbidity waters and (5) water temperatures between 20 and 30 C (Newell & Rigby, 1957;Voss, 1988).…”

Section: Petrography Of Bahamian Stratigraphic Unitsmentioning

confidence: 91%

Carbonate petrography as an indicator of climate and sea‐level changes: new data from Bahamian Quaternary units

Kindler

Hearty

1996

Sedimentology

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Coeval stratigraphic units of similar petrology occur throughout the northern Bahamas islands. The petrographic composition of these limestones provides clues about regional sea level and climate changes during the late Quaternary. At least eight fossil shoreline units, which are linked to transgressive episodes between the middle Pleistocene and the late Holocene, are recognized in the Bahamas. The petrographic composition of these units is either dominated by ooids and peloids or by bioclasts. Sedimentological observations demonstrate that oolitic-peloidal units were formed when sea level was higher than today, whereas skeletal units were deposited at or below modern ordnance datum. Skeletal units may reflect times of partial, or modest platform flooding, when the bulk of sediments brought to islands originates from bank-margin reefs. In contrast, oolitic-peloidal units correspond to major flooding events and active water circulation on the bank top. Cement fabrics further show that the early diagenesis of oolitic units took place during warm and humid climatic conditions, whereas skeletal rock bodies underwent subaerial diagenesis during drier climatic conditions characterized by marked seasonal changes. This example from the Bahamas suggests that compositional analysis of limestone from fossil carbonate platforms could be used for resolving ancient climate and sea-level changes.

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Section: Petrography Of Bahamian Stratigraphic Unitsmentioning

confidence: 91%

Carbonate petrography as an indicator of climate and sea‐level changes: new data from Bahamian Quaternary units

Kindler

Hearty

1996

Sedimentology

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“…Contemporary ooids form in warm, shallow water where they are continuously moved by waves and (or) tidal currents (Illing, 1954;Newell et al, 1960;Loreau and Purser, 1973;Bathurst, 1971;Lees and Buller, 1972). Jenkyns (1972) pointed out that certain types of micritic ooids with pelagic fossils may actually form below several tens of meters of water.…”

Section: Shallow-water and Deep-water Grain Assemblagesmentioning

confidence: 99%

Mesozoic Calciturbidites in Deep Sea Drilling Project Hole 416ARecognition of a Drowned Carbonate Platform

Schlager¹

1980

Initial Reports of the Deep Sea Drilling Project

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The Tithonian-Hauterivian section of Site 416 contains about 10 per cent limestone and marlstone in well-defined beds between shale and sandstone. Depositional structures, grain composition, and diagenetic fabrics of the limestone beds as well as their association with graded sandstone and brown shale suggest their deposition by turbidity currents below calcite-compensation depth. Carbonate material was initially shed from a shallow-water platform with ooid shoals and peloidal sands. Soft clasts of deep-water carbonate muds were ripped up during downslope sediment transport. Shallow-water mud of metastable aragonite and magnesium calcite was deposited on top of the graded sands, forming the fine tail of the turbidite; it has been subsequently altered to tight micritic limestone that is harder and less porous than Coccolith sediment under similar overburden. Abnormally high strontium contents are attributed to high aragonite contents in the original sediment. This suggests that the limestone beds behaved virtually as closed systems during diagenesis.Drowning of the platform during the Valanginian is inferred from the disappearance of the micritic limestones, the increase in abundance of phosphorite, of ooids with quartz nuclei, and of the quartz content in the calciturbidites. In Hauterivian time, the carbonate supply disappeared completely. The last limestone layers are lithoclastic breccias which indicate that erosion has cut into well-lithified and dolomitized deeper parts of the platform rather than sweeping off loose sediment from its top.Of all Tithonian sections recovered from the Atlantic, only the one at Site 416 contains abundant shallow-water debris and was deposited below the calcite-compensation depth. It is probably located on mid-Jurassic or older crust that had already deeply subsided and was close to the continental slope by Tithonian time. The other sites, located on younger crust, stood high on the flank of the mid-ocean ridge, and were consequently above the compensation level and beyond reach of shallow-water detritus shed down the continental slope.

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“…Compositionally, modem ooids may consist of low-Mg calcite, high-Mg calcite, and aragonite with more than one phase commonly occurring within an individual cortex (Land et al, 1979;Medwedeff and Wilkinson, 1983). However normal marine ooids are composed of aragonite (Newell et al, 1960;Purdy, 1963;Friedman et al, 1973); calcite ooids are much less abundant in modem environments (Popp and Wilkinson, 1983). Mechanisms invoked to explain the mineralogy of ooids are highly dependent on Mg/Ca ratio, hydrodynamic parameters (Given and Wilkinson, 1985), and the tectonically induced changes in Pco2 (Mackanzie And Pigott, 1981).…”

Section: Carbonate Mineralogymentioning

confidence: 99%

Diagenetic trends of the Pleistocene calcareous ridges, Mersa Matruh area, Egypt

Holail

1993

Chemical Geology

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Bahamian Oölitic Sand

Cited by 188 publications

References 2 publications

Carbonate petrography as an indicator of climate and sea‐level changes: new data from Bahamian Quaternary units

Carbonate petrography as an indicator of climate and sea‐level changes: new data from Bahamian Quaternary units

Mesozoic Calciturbidites in Deep Sea Drilling Project Hole 416ARecognition of a Drowned Carbonate Platform

Diagenetic trends of the Pleistocene calcareous ridges, Mersa Matruh area, Egypt

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Bahamian Oölitic Sand

Cited by 188 publications

References 2 publications

Carbonate petrography as an indicator of climate and sea‐level changes: new data from Bahamian Quaternary units

Carbonate petrography as an indicator of climate and sea‐level changes: new data from Bahamian Quaternary units

Mesozoic Calciturbidites in Deep Sea Drilling Project Hole 416ARecognition of a Drowned Carbonate Platform

Diagenetic trends of the Pleistocene calcareous ridges, Mersa Matruh area, Egypt

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Mesozoic Calciturbidites in Deep Sea Drilling Project Hole 416ARecognition of a Drowned Carbonate Platform