Sedimentology and paleoenvironmental interpretation of two calcareous tufas in the Guadix Basin (Betic Cordillera, Spain). / Pla Pueyo, Sila; Viseras, César; Soria, Jesús M.; García García, Fernando.

2009. 643 Poster session presented at 27th IAS Meeting of Sedimentology , Alghero (Sardinia), Italy.

Research output: Contribution to conferencePoster

Published

Abstract

Tufa deposits are good indicators of paleohydrology and paleoconditions. Current models for paludal and barrage tufas classify them in terms of cool or warm temperatures through their morphology.
In the central part of the Guadix Basin (Betic Cordillera, S. Spain), two well-preserved tufa build-ups occur associated with the fluvio-lacustrine facies of an axial system flowing towards the N and the NE during Pliocene and Pleistocene times. This system consisted of high sinuosity channels, fine siliciclastic floodplain deposits, and palustrine carbonates. This longitudinal system was fed transversally by two alluvial fan systems.
A sedimentologic and petrographic analysis of both tufa bodies will characterize the facies and morphology, aiding in the reconstruction of the depositional paleoconditions. The first calcareous tufa build-up is a macrophytic phytoherm, showing mainly autochthonous facies, with abundant plant molds in life position. The facies identified for this tufa, after Pedley (1990), are mainly framestone tufa facies, together with microdetrital tufa containing gastropod fossil remains. This body is interpreted as a paludal tufa, formed in a ponded zone of the floodplain of the Axial System.
The second tufa build-up shows mainly allochthonous facies (phytoclastic tufa and oncoidal tufa facies), although framestone tufa and boundstone tufa facies are also present. The tufa build-up is shaped as a large dome which in transverse section presents tabular to sigmoidal beds dipping towards the ENE. This body has been interpreted as a barrage tufa located in the axial valley, which would block the drainage of the main river, and whose inclined beds dip downstream.
The morphology of the build-ups for both tufas is more similar to those described for the cool-temperate models of paludal and barrage tufas than to the tufa facies of the semi-arid model. Therefore, a cool-temperate climate is proposed for the time span of tufa formation.
This interpretation is in agreement with the paleoclimatic data obtained from other sedimentologic and petrographic results in the study area for this time period, such as the carbonate textures (with features of seasonal subaerial exposure) or the nearly perennial character of the fluvial channels. An intermediate to sub-humid climate thus is interpreted for the contemporary palustrine carbonates and siliciclastic fluvial sediments deposited in the study area.
This study has been financed by research projects CGL2005-06224/BTE (MEC, FEDER), IGME 2001-016, IGME 2005-009, and the Working Group RNM-022JA.
Original languageEnglish
Pages643
Number of pages1
Publication statusPublished - 2009
Event27th IAS Meeting of Sedimentology - Alghero (Sardinia), Italy
Duration: 20 Sep 200922 Jul 2011

Conference

Conference27th IAS Meeting of Sedimentology
CountryItaly
CityAlghero (Sardinia)
Period20/09/0922/07/11

ID: 2692366