Guilds, Cycles and Episodic Vertical Aggradation of a Reef (Late Barremian to Early Aptian, Dinaric Carbonate Platform, Slovenia)

  1. P. L. de Boer3 and
  2. D. G. Smith4
  1. J. Grötsch

Published Online: 29 APR 2009

DOI: 10.1002/9781444304039.ch17

Orbital Forcing and Cyclic Sequences

Orbital Forcing and Cyclic Sequences

How to Cite

Grötsch, J. (1994) Guilds, Cycles and Episodic Vertical Aggradation of a Reef (Late Barremian to Early Aptian, Dinaric Carbonate Platform, Slovenia), in Orbital Forcing and Cyclic Sequences (eds P. L. de Boer and D. G. Smith), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304039.ch17

Editor Information

  1. 3

    Utrecht, The Netherlands

  2. 4

    London, UK

Author Information

  1. Institut für Paläontologie, Universität Erlangen-Nürnberg, Loewenichstr. 28, D-8520 Erlangen, Germany

  1. Shell Research B.V., Volmerlaan 6, 2288 GD Rijswijk, The Netherlands

Publication History

  1. Published Online: 29 APR 2009
  2. Published Print: 28 JAN 1994

ISBN Information

Print ISBN: 9780632037360

Online ISBN: 9781444304039

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Keywords:

  • guilds, cycles and episodic vertical aggradation of reef;
  • Dinaric carbonate platform;
  • relative index for in-place framework production (RIEF);
  • Baffler facies;
  • reefs and sea-level

Summary

A new approach to high-resolution stratigraphy of massive reef limestones is presented. On the northern edge of the Dinaric carbonate platform next to the Slovenian trough (Kanalski Vrh, Slovenia), an ‘Urgonian’ type reef of late Barremian to early Aptian age has been investigated. The section comprises a reef flat to back reef environment. Guilds of reef organisms (constructor, binder, baffler, dweller, destroyer) in 267 samples spaced at equal distances have been quantified together with sediment parameters (primary content of biogenic aragonite, facies). The first component of a principal component analysis of the data set, which is controlled by the process of construction in the reef, reveals cyclic changes in the variables. Cycles are composed of an alternation of baffler and detrital framework facies. The shallow subtidal baffler facies is characterized by fine-grained packstones or wackestones with Tubiphytes as the main baffling organism. Other components are miliolid foraminifera, debris of molluscs, bryozoans, sponges, echinoderms and dasyclads. In contrast, the intertidal detrital, rarely inplace framework facies contains grainstones, rudstones and framestones with reef-building organisms (scleractinian corals, hydrozoans, calcisponges), molluscs, agglutinating and miliolid foraminifera, algae and, less important, bryozoans and echinoderms.

Even though rhythmic sedimentation cannot be traced directly in the field, cycles do show up in the spectral analysis. The periodogram of the time series shows that the reef has been built up by the stacking of episodic, vertical, aggradational cycles with an average thickness of about 3.2 m, representing the 20-ka period of the Milankovitch band. Cyclostratigraphic results suggest that the 133.5-m section was built up during roughly 800 ka. The high-frequency, low-amplitude Milankovitch cycles are superimposed on a third-order rise of sea level which took place during the latest Barremian to early Aptian.