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  • 1
    Electronic Resource
    Electronic Resource
    Origins and development of Holocene coral reefs: a revisited model based on reef boreholes in the Seychelles, Indian Ocean (2000)
    Springer
    International journal of earth sciences 89 (2000), S. 431-445 
    Details
    ISSN: 1437-3262
    Keywords: Key words Reef structure ; Reef models ; Reef boreholes ; Influence of storms ; Seychelles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  Until recently, concepts of coral reef growth and accumulation have been predominantly based on a Darwinian model. In this, the upwards and outwards growth of a reef core (a coral framework) takes place over a foreslope consisting of reef talus, with the simultaneous filling of the back-reef lagoon by reef-derived debris. The principal adaptations of this pattern relate to the influence of relative changes in sea level and commonly ignore oceanographic factors such as storm frequency and severity. Boreholes through the outer edge of a fringing reef in the Seychelles, western Indian Ocean, reveal a record of Holocene sediment accumulation first established approximately 8 ka ago. Faunal and floral associations show that growth of this body began in relatively deep water but that this shallowed to 〈5 m within 1 ka. Subsequent accumulation was of “keep-up” style but, as the rate of sea-level rise slowed, shoaling became more frequent and aggradation was limited by reducing accommodation space. Constructional facies are characterised either by massive corals, including Leptastrea, Porites and faviids, or by branching corals, typically Acropora of the danai-robusta group. Coral surfaces may be encrusted by red algae, foraminifera and vermetids, and are commonly bored by filamentous algae, clionids and molluscs. However, detrital facies are volumetrically dominant, and the paucity of a constructional framework requires a re-evaluation of models of reef accretion. New models relate the geometry of accretion to the interplay between extreme storm events and fairweather hydrodynamic conditions. These suggest that a contiguous framework forms in areas of moderate fairweather energy without extreme storm events. Severe storms destroy the continuity of reef structures and generate increasing volumes of coarse detritus. Low storm severity, coupled with low fairweather hydrodynamic energy, may promote the accumulation of fine-grained reef-derived sediments that inhibit framework growth. While ecology reflects year-by-year sea conditions, lithology and structure are controlled by exceptional storms, with the effects of changing sea level superimposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s005310000078
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  • 2
    Electronic Resource
    Electronic Resource
    Holocene initiation and development of New Caledonian fringing reefs, SW Pacific (1995)
    Springer
    Coral reefs 14 (1995), S. 131-140 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract.  The analysis of 8 selected cores through fringing reefs in New Caledonia reveals that accretion in the Holocene has been less than 6 m. The cores exhibit three main facies: branching coral (Acropora, dominantly), massive coral heads (Porites, mainly) and coral sand/ rubble, principally made up of acroporid fragments. Subordinate facies are composed of coralline algae and alcyonarian spiculite. The initiation of growth varies according to location. The southern reefs (i.e. early settled reefs) generally began to grow first, prior to 5000 y BP. The northern structures (i.e. more recently settled reefs) are younger, occurring after 4200 y BP. This retardation could be ascribed to differences in local physical conditions (nature of substrate, wave energy). Vertical accretion rates were generally higher in areas of lower energy (3.25 – 6.4 mm·y−1) versus those exposed to higher energy conditions (1.4 –3.1 mm·y−1). Vertical development through time was accompanied by changes in composition of biological assemblages which reflect changes in hydrodynamics. The basal Acropora-dominated facies was replaced upwards by a Porites-dominated framework. The New Caledonian fringing reefs reached the sea surface generally between 5000 and 2500 y BP after the stabilization of sea level. Hence all of these reefs can be classified as catch-up reefs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00367230
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  • 3
    Electronic Resource
    Electronic Resource
    Holocene sea level changes and reef development in the southwestern Indian Ocean (1997)
    Springer
    Coral reefs 16 (1997), S. 247-259 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract.  The sedimentological and chronological study of Holocene reef sequences recovered in drill cores through modern reefs of Mauritius, Réunion Island and Mayotte allows the reconstruction of sea level changes and reef growth patterns during the Holocene. The branching-coral facies systematically predominates over coral head facies throughout the Holocene reef sequences, and Acropora is the main frame builder among the branching forms. The reconstructed sea level curves, based both on identification of coral assemblages and on radiometric U/Th ages, are characterized by a rapid rise between 10 and 7.5 ky BP, followed by a clear inflection between 7.5 and 7 ky BP. The stabilization of sea level at its present level occurred between 2000 and 3000 years ago, probably without a higher sea level stand. Rates of vertical reef accretion range between 0.9 and 7 mm. y-1. In Mauritius, and also probably in Réunion Island, the reef first tracked, then caught-up to sea level to reach an equilibrium position (“catch-up” growth), while the barrier reef margin off Mayotte has been able to keep pace with rising sea level (“keep-up” growth).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003380050080
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  • 4
    Electronic Resource
    Electronic Resource
    The significance of exposed coral conglomerates from French Polynesia (Pacific Ocean) as indicators of recent relative sea-level changes (1984)
    Springer
    Coral reefs 3 (1984), S. 29-42 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract In many Pacific islands, reef tracts possess exposed coral conglomerates ranging in age from the present to about 6,000 years B.P. These reach a maximum elevation of more than 1 metre above the present mean tide level. The outcrops occur mainly as subhorizontal rampart-platforms of poorly-sorted, cemented, skeletal detritus deposited by storm processes. With the aim of clarifying their significance as indicators of Recent sea level changes, we have attempted to determine the environments of lithification of these outcrops. To this end, rock specimens were collected from seaward vertical profiles at various levels of outcrops on French Polynesian coral and volcanic islands. For each outcrop, two sequences of marine cementation could be defined on the basis of petrological criteria: (1) a lower sequence exhibiting at least three generations of cements. The earlier generations are characterized by high amounts of high-magnesian calcite pelleted micrite normally completely occluding interparticle pore spaces. The later generation is characterized by the generalized occurrence of irregular rims of truncated aragonite fibers and pendant microstalactites. Residual interparticle porosity is relatively low; (2) an upper sequence mainly exhibiting blunted argonite needles and microstalactites; residual porosity is relatively high. The diagenetic limit between these two sequences defines the position of a former marine water table that is regarded as having been closely related to a former mean low tide level. All this seems to indicate that the lower sequence has spent time in two distinctly different diagenetic environments (phreatic overlain by vadose), whereas the upper sequence has always been within one diagenetic zone (vadose). Thus some relative fall in water table level has occurred after the deposition and early lithification of the lower deposits. Such conglomerates are believed to be useful indicators of former sea stands, particularly interesting in the case of islands devoid of other markers of Recent emergence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00306138
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  • 5
    Electronic Resource
    Electronic Resource
    Holocene initiation and development of New Caledonian fringing reefs, SW Pacific (1995)
    Springer
    Coral reefs 14 (1995), S. 131-140 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract The analysis of 8 selected cores through fringing reefs in New Caledonia reveals that accretion in the Holocene has been less than 6 m. The cores exhibit three main facies: branching coral (Acropora, dominantly), massive coral heads (Porites, mainly) and coral sand/ rubble, principally made up of acroporid fragments. Subordinate facies are composed of coralline algae and alcyonarian spiculite. The initiation of growth varies according to location. The southern reefs (i.e. early settled reefs) generally began to grow first, prior to 5000 y BP. The northern structures (i.e. more recently settled reefs) are younger, occurring after 4200 y BP. This retardation could be ascribed to differences in local physical conditions (nature of substrate, wave energy). Vertical accretion rates were generally higher in areas of lower energy (3.25–6.4 mm·y-1) versus those exposed to higher energy conditions (1.4–3.1 mm·y-1). Vertical development through time was accompanied by changes in composition of biological assemblages which reflect changes in hydrodynamics. The basal Acropora-dominated facies was replaced upwards by a Porites-dominated framework. The New Caledonian fringing reefs reached the sea surface generally between 5000 and 2500 y BP after the stabilization of sea level. Hence all of these reefs can be classified as catch-up reefs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00367230
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  • 6
    Electronic Resource
    Electronic Resource
    The modern reef complex, Jeddah area, Red Sea: a facies model for carbonate sedimentation on embryonic passive margins (1986)
    Springer
    Coral reefs 5 (1986), S. 127-150 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract The modern reef complex north of Jeddah comprises an offshore knoll platform and a fringing reef, subdivised into several depositional zones: tops and upper flanks of offshore reefs; lower flanks of offshore reefs and nearby inter-reef areas; fringing forereef, reef flat and backreef zones, and beach. Sixty-seven sediment samples were collected from the different zones and have been analysed in order to define relationships between the distribution of sedimentary facies and the depositional environments, and to furnish a reliable facies model by using multivariate analysis. Six types and subtypes have been objectively differentiated on the basis of total biogenic component and foraminiferal associations. Grain size data allowed us to discriminate three textural types, whereas five chemotypes have been recognized according to trace element concentration. Regarding the offshore reef platform, poorly sorted, medium sands of molluscan-coralline algal-Amphistegina and Cd types are restricted to the lower flanks of buildups and to the adjacent inter-reef deposits, whereas the tops and upper flanks of theses buildups are characterized by moderately sorted, coarse sands of coralline algal-Tubipora-Amphistegina-encrusting foraminiferal-bryozoan types, with a Mn chemotype. Concerning the fringing reef system, backreef areas exhibit poorly sorted, fine sands of molluscan-Ammonia-Peneroplis and Fe-Cu types. Moderately sorted, coarse sands of coralgal-Calcarina-Spiroloculina and Fe-Zn types are found on the reef flat. The forereef zone is characterized by poorly sorted, fine sand of Triloculina-encrusting foraminiferal-bryozoan and Zn-Mn types. The lateral limits of the various biotypes roughly coincide with the distribution of the relevant living organic communities. Trace elements appear to be either bound to the reef-associated silicate fractions or incorporated into the carbonate skeletons. On the basis of prevailing water conditions, physiography, biological and sedimentological attributes, the fringing reef can be regarded as an asymmetrical structure, with bidimensional (lateral and vertical) facies zonation; in contrast, the offshore platform is a symmetrical structure, with one dimensional (depth-dependent) facies zonation. This system is believed to represent a modern example of a laterally undifferentiated, offshore reef tract in a relatively enclosed basin, at an embryonic passive continental margin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298180
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  • 7
    Electronic Resource
    Electronic Resource
    Sedimentary facies from the modern coral reefs, Jordan Gulf of Aqaba, Red Sea (1982)
    Springer
    Coral reefs 1 (1982), S. 115-124 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Summary Sixty-three sediment samples collected from the modern fringing reefs off the Jordan coast (Gulf of Aqaba, Red Sea) have been analysed in order to determine variations of composition and texture by using correspondence factor analysis. From the shore seawards, the following physiographic zones are recognized: beach; shallower backreef zone; reef flat zone; forereef zone including sandy or coral-built slopes. Eight sediment facies and subfacies can be recognized on the basis of total component composition and foraminiferal assemblages and four sediment facies can be recognized using grain-size data. Wellsorted, fine to medium, quartzofeldspathic sands (terrigenous facies) occur on beaches and outer sandy slopes close to wadi mouths. Backreef areas exhibit relatively well-sorted fine sands of terrigenous-coral and Miliolidae-Soritidae facies. Poorly sorted, coarse sands of coral-coral-line algal and Homotremid facies characterize reef flats and the upper parts of coral-built forereef areas, which respecitively display an Amphistegina-Spirolina subfacies and an Acervulina one. Poorly sorted, medium sands of coralmolluscan-foraminiferal (Amphistegina-Acervulina) facies are restricted to the lower parts of the forereef zone. Latcral limits of the various biofacies coincide with the distribution of the related organic communities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00301693
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  • 8
    Electronic Resource
    Electronic Resource
    Late Holocene sea level indicators from twelve atolls in the central and eastern Tuamotus (Pacific Ocean) (1988)
    Springer
    Coral reefs 7 (1988), S. 57-68 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract New sea-level data for the late Holocene period are reported from twelve atolls of the Tuamotu archipelago: Faaite, Hikueru, Marokau, Hao, Amanu, Tatakoto, Pukarua, Nukutavake, Vairaatea, Tureia, Nukutipipi, and Hereheretue. The data come from coral conglomerate outcrops, coral colonies in growth position, in situ reef framework and marine notches; they give consistent results, and their ages are controlled by 29 radiocarbon datings. The Holocene MSL remained 0.8±0.2 m higher than at present, from before 4000 years BP until at least 1500 years BP, then dropped gradually to the present level. This pattern is very similar to that reported from the northwest Tuamotus, suggesting the absence of measurable differential vertical movements over a distance greater than 1300 km during the late Holocene. Effects of the 1983 cyclones on reef morphology are reported from some atolls and radiocarbon dates of some storm-generated reef blocks are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00301642
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  • 9
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    Holocene initiation and development of New Caledonian fringing reefs, SW Pacific (1995)
    Springer
    Details
    Publication Date: 1995-09-01
    Print ISSN: 0722-4028
    Electronic ISSN: 1432-0975
    Topics: Biology , Geosciences
    Published by Springer
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  • 10
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    Holocene sea level changes and reef development in the southwestern Indian Ocean (1997)
    Springer
    Details
    Publication Date: 1997-12-02
    Print ISSN: 0722-4028
    Electronic ISSN: 1432-0975
    Topics: Biology , Geosciences
    Published by Springer
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