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Oxfordian (Upper Jurassic) coral reefs in Western Europe: reef types and conceptual depositional model
Author(s) -
INSALACO E.,
HALLAM A.,
ROSEN B.
Publication year - 1997
Publication title -
sedimentology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.494
H-Index - 108
eISSN - 1365-3091
pISSN - 0037-0746
DOI - 10.1046/j.1365-3091.1997.d01-44.x
Subject(s) - reef , geology , facies , sedimentary depositional environment , sedimentology , shoal , coral reef , coral , paleontology , carbonate , siliciclastic , oceanography , structural basin , materials science , metallurgy
Comparative sedimentology and palaeoecology of Oxfordian (Upper Jurassic) coral‐dominated reefs of England, France, Italy and Switzerland has been used to: (1) identify and characterize different types of Late Jurassic coral reefs with regard to their litho‐ and biofacies; and (2) develop a depositional model for these reefs relating different reef types to each other within a palaeoenvironmental framework. Eight generic reef types and one associated reef facies are recognized. These are: (I) biostromal units dominated by platy microsolenids developed within clean limestone facies; (II) biostromal units dominated by platy microsolenids developed within marly facies; (III) reefal thickets dominated by tall dense phaceloid colonies developed within pure carbonate muds; (IV) microbial‐coral reefs dominated by massive, branching ramose and phaceloid colonies; (V) large high diversity reefal units associated with large volumes of bioclastic material; (VI) small species‐poor reefs developed within mixed carbonate/siliciclastic facies; (VII) microbial‐coral reefs dominated by massive colonies; (VIII) reefal thickets dominated by branching ramose colonies with widely spaced branches developed amongst sand shoals and coral debris channels; and (IX) conglomerates rich in rounded coral fragments (the reef associated facies). The development of these different constructional and compositional reef types is interpreted as being primarily a function of light intensity, hydrodynamic energy levels and sediment balance. A conceptual depositional model based on these parameters can be used to predict the spatial and temporal distribution of different reefal carbonates and highlight sedimentological and palaeoecological trends in reef development.