Genesis of nodules and concretions in the Upper Devonian of Iberian Range (Tabuenca, Spain) (Spanish text).

摘要

This thesis shows an attempt to classify groups of nodules and concretions that there are in the geological bibliography. For it, we do the identification of the different models joining its in the principal genetic types. The three types are defined: models according to the growth's time, to the type of emplacement, and to the growth's mechanism. This models have been correlated with the different diagenetic classic stages, defined according to Faibridge (1967). This correlation will allow us established one temporal distribution in relation to the diagenetic evolution of the different models.; Anyway, the origin of the carbonate concretions and siliceous nodules of the upper Devonian in Iberian Range (Tabuenca, Spain) are described and related to the processes operating during diagenesis. These structures have been selected after consider the various alternatives depicts in one map of distribution of these structures in the Iberian Range.; For these structures are calculated the growth time for model spherical nodule or concretion, considered the existence of diffusion mechanism with diagenetic redistribution and intergranular flow. The depth of formation of these structures is assessed, through an examination of depth dependent of both the host-sediment an the cement, and is found to be less than 1000 m for concretions, and less than 10 m for nodules.; The major source of carbonate for concretions was the dissolution of aragonitic shell materials from which the host, and for nodules is doubtful, having participated several sources of silica, internals and externals.