Model of Reef Diagenesis: Mururoa Atoll, French Polynesia

Aïssaoui, D. M.; Buigues, D.; Purser, B. H.

doi:10.1007/978-3-642-82812-6_3

Cited by 41 publications

(48 citation statements)

References 11 publications

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“…All of the reefs that he studied are less well marine cemented on their leeward side than on their windward side. Macintyre (1983) and Aissaoui et al, (1986) reported comparable conditions from the Caribbean and from Mururoa Atoll.…”

Section: Exposure and Sea Level Changesmentioning

confidence: 74%

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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Section: Exposure and Sea Level Changesmentioning

confidence: 74%

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

Vollbrecht

1990

Carbonates Evaporites

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“…In conclusion, the depositional environment of the Late Jurassic microencruster frameworks is interpreted as an upper forereef slope area with water depths estimated to be from about 10 to 20 m, down to *50 m. At these frontal, seaward margins, synsedimentary cementation was most pervasive and particularly abundant, contributing to the rigidity of reefs and helping to maintain steep slopes (e.g., Goreau and Land 1974;Focke and Gebelein 1978;Aissaoui and Purser 1985;Molenaar and Ziljstra 1997;Flügel 2004). Pumping of seawater through the sediment was facilitated by the occurrence of interconnected vugs, a prerequisite required for cement precipitation in moderate to high-energy conditions.…”

Section: Depositional Environmentmentioning

confidence: 95%

The occurrence and role of microencruster frameworks in Late Jurassic to Early Cretaceous platform margin deposits of the Northern Calcareous Alps (Austria)

Schlagintweit

Gawlick

2007

Facies

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“…The most likely reason for this is the sheltered lagoonal position in which these submerged Pleistocene deposits had been deposited, and which they repeatedly occupied during later floodings. As several studies have shown (Longman, 1980;Aissaoui et al, 1986;Marshall, 1986;Vollbrecht, 1990), marine cementation is usually negligible in the lagoonal environment.…”

Section: Discussionmentioning

confidence: 99%

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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Model of Reef Diagenesis: Mururoa Atoll, French Polynesia

Cited by 41 publications

References 11 publications

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

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

The occurrence and role of microencruster frameworks in Late Jurassic to Early Cretaceous platform margin deposits of the Northern Calcareous Alps (Austria)

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

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