Carbonate Deposition during Early Rifting: The Cambrian of Sardinia and the Triassic—Jurassic of Tuscany, Italy

  1. Maurice E. Tucker2,
  2. James Lee Wilson3,
  3. Paul D. Crevello4,
  4. J. Rick Sarg5 and
  5. J. Fred Read6
  1. T. Cocozza and
  2. A. Gandin

Published Online: 15 APR 2009

DOI: 10.1002/9781444303834.ch1

Carbonate Platforms: Facies, Sequences and Evolution

Carbonate Platforms: Facies, Sequences and Evolution

How to Cite

Cocozza, T. and Gandin, A. (1986) Carbonate Deposition during Early Rifting: The Cambrian of Sardinia and the Triassic—Jurassic of Tuscany, Italy, in Carbonate Platforms: Facies, Sequences and Evolution (eds M. E. Tucker, J. L. Wilson, P. D. Crevello, J. Rick Sarg and J. F. Read), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444303834.ch1

Editor Information

  1. 2

    Durham, UK

  2. 3

    New Braunfels, Texas, USA

  3. 4

    Littleton, Colorado, USA

  4. 5

    Midland, Texas, USA

  5. 6

    Blacksburg, Virginia, USA

Author Information

  1. Dipartimento di Science della Terra, University of Siena, Via delle Cerchia 3, 53100 Siena, Italy

Publication History

  1. Published Online: 15 APR 2009
  2. Published Print: 22 DEC 1986

ISBN Information

Print ISBN: 9780632027583

Online ISBN: 9781444303834

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Keywords:

  • carbonate deposition during early rifting – Cambrian of Sardinia and Triassic – Jurassic of Tuscany, Italy;
  • platform carbonates of early Palaeozoic age;
  • archaeocyathids;
  • laminated dolomite;
  • tectono-sedimentary evolution

Summary

The platform carbonates of early Palaeozoic age in Sardinia and of the early Mesozoic age in Tuscany were deposited in analogous tectono-sedimentary situations, the former linked to the Iapetus, the latter to the Tethyan, early stages of continental rifting. Both units represent isolated pericratonic platforms initiated and developed in an intra-cratonic rift. Deposition began with dolomites and evaporites and ended with limestones. Persistence of shallow-water deposition documents a continuous balance between carbonate production, subsidence and/or sea-level fluctuations. The synsedimentary tectonic control during deposition resulted in high rates of sedimentation and differential subsidence. Three stages of platform collapse are recognized, which terminated shallow-water deposition. During the first stage the platforms were dissected into blocks and their differential movements produced contemporaneous tilting, uplift and drowning. During the second stage of collapse marginal plateaus were formed and neritic–pelagic sediments of various lithofacies onlapped sunken platform blocks. Nodular limestones were deposited on top of the more unstable blocks. The third collapse stage resulted in general deepening of the basins. The subsequent evolution of the basins reflects the different geodynamic development of the early Palaeozoic and early Mesozoic continental rifting. The former did not reach a spreading stage whereas the latter evolved into an open ocean. Climatic changes occurred during platform growth in both cases, and they provide further evidence of divergent movements connected with continental rifting.