Submarine and vadose cements in Pleistocene Bermuda reef rock

Schroeder, Johannes H.

doi:10.1016/0037-0738(73)90022-5

Cited by 63 publications

(23 citation statements)

References 14 publications

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“…The primary contributor of the aragonite is pteropods, but the origin(s) of the high-Mg carbonate in the OFP traps is not known. Detrital reef-derived magnesian carbonates (Milliman et al, 1971;Schroeder, 1973;Morse, 2003) advected from the Bermuda platform and more distant coastal sediments is one possible source. In addition, unidentified pelagic source(s) also appear to contribute high-Mg carbonate to the flux.…”

Section: Pmf Factor Identification and Source Implicationmentioning

confidence: 99%

Source/process apportionment of major and trace elements in sinking particles in the Sargasso sea

Huang

Conte

2009

Geochimica et Cosmochimica Acta

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Section: Pmf Factor Identification and Source Implicationmentioning

confidence: 99%

Source/process apportionment of major and trace elements in sinking particles in the Sargasso sea

Huang

Conte

2009

Geochimica et Cosmochimica Acta

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“…He pointed out the significance of biological and biochemical processes for the course of submarine diagenesis (e.g., cements around algal filaments). Schroeder (1973Schroeder ( , 1974 and Schroeder and Zankl (1974) tried to detect equivalents of Recent submarine cements also in Pleistocene limestones. Plummer et al (1976) and Vacher (1978) analysed groundwaters of Bermuda and their respective effects on the carbonate substrate.…”

Section: Early Diagenesis -Concise History Of Investiganonmentioning

confidence: 99%

“…Within the Pleistocene carbonates, products of marine diagenesis are additionally covered by meteoric, blocky cements of low-Mgcalcite. Aragonitic cements have survived this meteoric influence unaffected (Schroeder, 1973(Schroeder, , 1974.…”

Section: Exposure and Sea Level Changesmentioning

confidence: 99%

Marine and meteoric diagenesis of submarine pleistocene carbonates from the Bermuda Carbonate Platform

Vollbrecht

1990

Carbonates Evaporites

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The tectonically stable Bermuda Carbonate Platform has undergone repeated emersions and submersions in the course of the Pleistocene sea-level changes. Shallow seismic reflection profiling and high-energy vibration coring gave access to Pleistocene carbonates that are presently situated below sea level. A study of their diagenesis was undertaken in order to document the changes occuring in various diagenetic environments, to check a, possible correlation between the state of diagenetic preservation and stratigraphic age, and to estimate the odds for a complete diagenetic imaging of a sediment's pore-water history. For the purpose of comparison, several samples from the modern Bermuda Islands were analysed as well.As indicated by their biogenic constituents, the submarine Pleistocene carbonates were chiefly composed of aragonite and high-Mg-calcite at the onset of diagenesis, whereas they now commonly appear as mixtures of aragonite and low-Mg-calcite. Marine cements (five kinds of high-Mgcalcite cement, three kinds of aragonite cement) are, as a rule, restricted to the intraparticle pore space. Meteoric influence inflicted neomorphism, cementation with low-Mg-calcite (several kinds of cement) and solution on the marine carbonates. These are characterized by patchy lithification, abundant preserved pore space and incomplete mineralogical stabilization. Furthermore, especially in lagoonal sediments, burrow or root structures have been preferentially cemented. Indicators of karst and calichification are common. High-Mg-calcite is usually the first mineral to disappear under meteoric influence; aragonite is more stable. Intensely altered carbonates consist entirely of low-Mg-calcite, whereas dolomite does not occur at all.Diagenetic indications of meteoric-phreatic alteration are generally uncommon, but support the idea of fresh-water lenses that are largely restricted to the proximity of the present islands. Most of the carbonates, however, have received their decisive diagenetic imprints in the meteoricvadose environment.The diagenetic record within the carbonates is incomplete. Only one pore-water change is recorded, from a marine to a meteoric environment. Undoubted post-meteoric marine cements are absent from the studied Pleistocene material except for some intensely Iithified littoral deposits on the present islands. Obviously, the diagenetic potential of the marine environment was too small to compete with the meteoric environment. Under these circumstances, a reconstruction of pore-water history based on diagenetic sequences is deceptive.

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“…Studies of other Bermudian localities (Ristvet, 1971;Lafon and Vacher, 1975) suggest that to reach the degree of alteration present in the Town Hill sediments under merely meteoric-vadose (non-caliche) conditions, periods longer than one glacial are needed, especially when sediments were repeatedly removed from meteoric environments by interglacial marine flooding (Vollbrecht, 1990). This line of thought is further supported by the petrographic dissimilarity between the Town Hill rocks of Whalebone Bay and the Belmont beach of Grape Bay, a well known locality of the Belmont Formation Schroeder, 1973). Unlike Town Hill sediments, the Belmont beach of that area is characterized by usually good preservation of skeletal HMC and aragonite.…”

Section: Sequence Of Eventsmentioning

confidence: 61%

Sea level and diagenesis: a case study on Pleistocene beaches, Whalebone Bay, Bermuda

Vollbrecht

Meischner

1993

Geol Rundsch

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Pleistocene fluctuations of sea level have left marine and aeolian limestones intercalated with glacial red soils on the Bermuda Carbonate Platform (Atlantic, 64°50'W, 32020 'N). Successive eustatic highstands of similar amplitude drowned the tectonically stable platform and piled up similar sets of sediments. Up to three Pleistocene beaches are stacked in shorelines sections. Post-depositional diagenetic histories of these beaches can be linked to repeated changes in sea level and pore waters.This paper presents field evidence and petrographic results (microscope, X-ray, cathodoluminescence, SEM-EDAX) for the diagenetic histories of two superimposed Pleistocene beaches in Whalebone Bay, Bermuda North Shore. The younger beach was deposited during isotopic stage 5e, about 120 ka ago. The age of the older beach may be isotopic stage 9 or older.Diagenesis drastically altered the older beach before the stage 5e transgression. Primary high-Mg calcite (HMC) and aragonite were no longer present. Marine skeletal grains were instead leached or recrystallized to low-Mg calcite (LMC). Primary and secondary pore space were largely reduced by LMC cement. Lines of needle relics reminiscent of marine aragonite cement occur as inclusions within syntaxial rim cements around echinoderm grains, indicating that a marine influence had at least once interrupted this period of freshwater alteration. Finally, before the rocks became buried by the sediments of the younger beach, a crust of marine, bladed HMC cement was precipitated throughout the pore space.The younger beach consists of skeletal grains that are, apart from the effects of non-selective dissolution, essentially unaltered. The sediments are only weakly lithified by cryptocrystalline LMC showing an alveolar texture, tangential fibres and other features characteristic of R. Vollbrecht • D. Meischner Abteilung Sediment-Geologic, Institut ffir Geologie und Palgontologie, GoldschmidtstraBe 3, D-37077 G6ttingen, Germany Correspondence to: R. Voltbrecht calichification. A younger post-depositional marine influence is not recorded.These results suggest that, under favourable conditions, diagenetic processes can document sea-level fluctuations. The recorded fluctuations, however, are difficult to assess because even major sea-level highstands may not produce a diagenetic imprint.

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Submarine and vadose cements in Pleistocene Bermuda reef rock

Cited by 63 publications

References 14 publications

Source/process apportionment of major and trace elements in sinking particles in the Sargasso sea

Source/process apportionment of major and trace elements in sinking particles in the Sargasso sea

Marine and meteoric diagenesis of submarine pleistocene carbonates from the Bermuda Carbonate Platform

Sea level and diagenesis: a case study on Pleistocene beaches, Whalebone Bay, Bermuda

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