Geometry, evolution and facies distribution of a tufa phytoherm. La Peña del Manto (Soria, Spain)

  1. P. Huerta 1
  2. I. Armenteros 1
  3. O. Merino-Tomé 2
  4. P. G. Silva 1
  5. P. Rodríguez-Gonzálvez 1
  6. D. González-Aguilera 1
  7. P. Carrasco 1
  8. G. Martín-Merino 1
  1. 1 Universidad de Salamanca

    Universidad de Salamanca

    Salamanca, España


  2. 2 Instituto Geológico y Minero de España

    Instituto Geológico y Minero de España

    Madrid, España


IAS Meeting of Sedimentology

ISBN: 978-84-615-1755-8

Year of publication: 2011

Congress: IAS Meeting of Sedimentology

Type: Conference paper


Studies dealing with detailed palaeogeographic reconstruction of fossil tufas are rare although they could be very interesting to understand and interpret the facies, porosity distribution, the strata geometry associated with the distribution of facies and of sedimentary environments, and the geomorphological and hydrological evolution of the tufa system. The high porosity and hydraulic conductivity of these deposits could draw the attention of oil and water exploration companies in spite of the low potential preservation and the reduced extension of ancient tufas. On the contrary some tufa examples have been described in the rock record and large reservoirs with similar deposits have been recently discovered. The study case is an exceptional well preserved slope tufa (Peña del Manto), in the valley of the Henar River in Soria province. This fossil tufa was nourished by a spring, nonexistent nowadays, which formed part of the present lined springs on the southwestern side of the Ateca high, in the Iberian Chain (the same Range than the "Monasterio de Piedra" tufas, studied by the group of the University of Zaragoza). The aim of our research is to construct a 3D model with the software PETREL (Schlumberger) which reflects the geometry and the facies distribution to reconstruct the evolution and palaeogeography of this tufa body. For accomplish this objective the classic sedimentological techniques, and geomorphological analysis, with the help of terrestrial laser scanning, DGPS, and electric resistivity tomography were carried out. The preliminary results reveals the existence of at least three slope-cascades with highly dipping strata dominated by laminated bryophytes distally connected to two lower flat buildups, in turn connected more distally, with subhorizontal strata dominated by oncolitic limestones, broken encrusted plant debris and bioclastic limestones. Three tufa sequences have been recognized. In the first one, the intercalation of one siliciclastic wedge marks the suppression of carbonate tufa aggradation. Diffluence and partially downstream confluence as well as changes in the direction of cascade growth pattern have been recognized and allowed a paleogeomorphological reconstruction.