Facies Architecture and Cyclicity of an Upper Carboniferous Carbonate Ramp Developed in a Variscan Piggy-Back Basin (Cantabrian Mountains, Northwest Spain)

  1. Gary Nichols,
  2. Ed Williams and
  3. Chris Paola
  1. Oscar Merino-Tomé1,
  2. Juan R. Bahamonde2,
  3. Luis P. Fernández2 and
  4. Juan R. Colmenero1

Published Online: 30 MAR 2009

DOI: 10.1002/9781444304411.ch9

Sedimentary Processes, Environments and Basins: A Tribute to Peter Friend

Sedimentary Processes, Environments and Basins: A Tribute to Peter Friend

How to Cite

Merino-Tomé, O., Bahamonde, J. R., Fernández, L. P. and Colmenero, J. R. (2007) Facies Architecture and Cyclicity of an Upper Carboniferous Carbonate Ramp Developed in a Variscan Piggy-Back Basin (Cantabrian Mountains, Northwest Spain), in Sedimentary Processes, Environments and Basins: A Tribute to Peter Friend (eds G. Nichols, E. Williams and C. Paola), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304411.ch9

Author Information

  1. 1

    Department of Geology, Salamanca University, 37008 Salamanca, Spain

  2. 2

    Department of Geology, Oviedo University, 33005 Oviedo, Spain

Publication History

  1. Published Online: 30 MAR 2009
  2. Published Print: 7 DEC 2007

Book Series:

  1. Special Publication Number 38 of the International Association of Sedimentologists

Book Series Editors:

  1. Ian Jarvis

Series Editor Information

  1. School of Earth Sciences & Geography, Centre for Earth & Environmental Science Research, Kingston University, Penrhyn Road, Kingston upon Thames KT1 2EE, UK

ISBN Information

Print ISBN: 9781405179225

Online ISBN: 9781444304411

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Keywords:

  • facies architecture and cyclicity of Upper Carboniferous carbonate ramp developed in Variscan piggy-back basin;
  • latest Moscovian (late Myachkovsky) to Gzhelian succession in northern sector of Picos de Europa Province;
  • conceptual model explaining expression of 4th–5th-order cycles - sequences or as parasequences;
  • integration of biostratigraphical and lithostratigraphic data and field mapping;
  • Dorogomilovsky–Gzhelian synorogenic basin structured into domains

Summary

The latest Moscovian (late Myachkovsky) to Gzhelian succession in the northern sector of the Picos de Europa Province (Cantabrian Mountains, northwest Spain) was deposited in a rapidly subsiding piggy-back basin. The succession has been subdivided into 11 mappable depositional sequences (3rd–4th order), which have in turn been grouped into two sequence sets, and they are formed of several higher order cycles (4th–5th order). This work focuses on the study of a carbonate ramp system (Puentellés Formation, northern proximal deposits of Sequences 8–10), where the cyclicity is best developed. Each of the three depositional sequences forming the Puentellés Formation comprises a fining upward lower part, which consists of several higher order (metric to decimetric) cycles with similar internal organization, and an upper part mainly arranged in metric to decametric shallowing upward parasequences. The results of this study suggest that tectonic activity controlled the configuration and long-term development of the latest Moscovian (late Myachkovsky) to Gzhelian basins, being responsible for the large-scale stratigraphical architecture (sequence sets). Eustasy, on the other hand, was the driving mechanism for the higher frequency architecture (3rd–5th-order cyclicity).

The subsidence curves are similar for both sequence sets, showing a maximum subsidence rate in the beginning that gradually decreased, reflecting the tectonic load during two major phases of thrust-sheet emplacement. The unconformity between both sequence sets records an intense phase of erosion linked to uplift of the northern sector of the Picos de Europa Province due to the onset of the emplacement of the Picos de Europa thrust sheets. The tectonic deformation was also responsible for the angular unconformities and the syntectonic unconformities that bound the depositional sequences, but the unconformities in themselves were a consequence of eustatic sea-level falls. The lower part of each sequence in the Puentellés Formation records late lowstand clastic sedimentation in flood-dominated deltas and fan-deltas, which co-existed with a reduced carbonate production in a narrow shallow-water ramp. The minor unconformities that bound the 4th–5th-order cycles are only present in the lower part of the 3rd-order sequences, and are interpreted to have developed when minor tectonic uplift was enhanced during lowstand stages. The upper part, mainly composed of autochthonous carbonates (including microbial and algal boundstones, among others), represents the abandonment of the previous clastic systems and the encroachment and aggradation of the carbonate ramps during rising and highstand stages.

The development of the Puentellés carbonate ramp was exceptional in that, normally, terrigenous influx typical of active tectonic regimes adversely affects carbonate production, preventing the development of carbonate depositional systems. In this case, the clastic supply was mainly calcareous, due to the composition of the source area, and as a consequence, almost no terrigenous clay was shed into the basin to inhibit carbonate production.