Albian Carbonate Mounds: Comparative Study in the Context of Sea-Level Variations (Soba, Northern Spain)

  1. C. L. V. Monty,
  2. D. W. J. Bosence,
  3. P. H. Bridges and
  4. B. R. Pratt
  1. J. García-Mondéjar and
  2. P. A. Fernández-Mendiola

Published Online: 14 APR 2009

DOI: 10.1002/9781444304114.ch12

Carbonate Mud-Mounds: Their Origin and Evolution

Carbonate Mud-Mounds: Their Origin and Evolution

How to Cite

García-Mondéjar, J. and Fernández-Mendiola, P. A. (1995) Albian Carbonate Mounds: Comparative Study in the Context of Sea-Level Variations (Soba, Northern Spain), in Carbonate Mud-Mounds: Their Origin and Evolution (eds C. L. V. Monty, D. W. J. Bosence, P. H. Bridges and B. R. Pratt), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304114.ch12

Author Information

  1. Universidad del País Vasco, Dpto Estratigrafía y Paleontología, Apartado 644, 48080 Bilbao, Spain

Publication History

  1. Published Online: 14 APR 2009
  2. Published Print: 17 JUL 1995

ISBN Information

Print ISBN: 9780865429338

Online ISBN: 9781444304114

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Keywords:

  • Albian carbonate mounds;
  • phase corresponding to a highstand systems tract (HST);
  • transgressive systems tract (TST);
  • lowstand systems tract (LST);
  • An ‘empty bucket’ morphology

Summary

The sedimentary characteristics of three carbonate mounds from the Albian of Soba (Basque-Cantabrian region, northern Spain) can be related to the local curve of relative sea-level change. The lower Albian La Gándara mound complex is about 250 m wide and 150 m thick. Three growth phases have been identified: (i) a shoaling-upward lower phase corresponding to a highstand systems tract (HST) and culminating with a major discontinuity surface; (ii) a deepening-upward intermediate phase related to a transgressive systems tract (TST); and (iii) a new shoaling-upward phase related to an HST topped by a major unconformity. Core facies from this complex mound are mainly coral and rudist wackestones with peloidal micrite, whereas the flanks consist of skeletal packstones and grainstones with shallow-water fossils. The middle Albian Casas del Carrascal mound is about 45 m wide and 15 m thick and contains a single deepening-upward cycle. Its core is mainly made up of coral and rudist wackestones and its flanks consist of fine-grained calcarenites and marly micritic limestones. Its top is overlain unconformably by deeper-water sediments. It is attributed to a TST. Finally, the upper Albian La Muela-1 mound is about 200 m wide and 8 m thick, and corresponds to a lowstand systems tract (LST). It shows a small core composed of red algal bafflestones and extensively developed flanks consisting of grainstones and packstones of skeletal red algae. It represents shallowing-upward conditions that were followed by a sudden drowning corresponding to the first transgressive surface (TS). This is the first Albian red-algal mound reported in the region.

In the Soba valley mid-Cretaceous series, it is suggested that mounds from LST and HST are characterized by shoaling-upward trends, while mounds from TST show deepening-upward trends. Shoaling trends lead to increased production of flank deposits and deepening trends favour reduced production of flank deposits. Shoaling trends are often accompanied by progradational geometries. However, HST mounds culminate with an exposure surface related to a sequence boundary, whereas TST mounds are topped by a drowning surface.