Facturación a distintas escalas y campos de esfuerzos durante la tectogenesis alpina en el área de Mosqueruela (Teruel)

Estudios Geológicos (Impact Factor: 1.05). 01/1994; DOI: 10.3989/egeol.94501-2307
Source: DOAJ

ABSTRACT The analysis of the brittle tectonic deformation on all scales in one area of the eastern Iberian Chain (Mosqueruela, Teruel) allows us to define a fracture pattern characterized by three main sets: NNE to NE, ENE and E to ESE. Brittle structures (stylolites, tension gashes, brittle-ductile shear zones and faults) show a poliphase Alpine tectonics. From the analysis of fault populations two compressive (wrench regime) phases and a multidirectional extension regime have been inferred. Their chronological evolution is the fol1owing: 1) ENE compression; 2) ESE compression; 3) nearly multidirectional NNE extension. The study of fractures using a number of methodologies at macro-, meso- and microstructural scales allows us to suggest a model of stress distribution and relationships between different structures in sorne areas. The detailed fracture mapping on a hectometric scale shows the distribution and strike variations of fractures. These changes have been interpreted as stress deflection phenomena due to major structures which, in many cases, were identified. Examples of stress deflections have been analyzed both for strike-slip and normal fault sets.

El análisis de la deformación tectónica frágil a distintas escalas en un sector de la Cordillera Ibérica oriental ha permitido definir el patrón de fracturación, caracterizado por tres familias principales de fracturas (NNE a NE, ENE YE a ESE). Las estructuras frágiles (estilolitos, juntas de extensión, zonas de cizalla semifrágil y, fundamentalmente, fallas) registran una tectónica alpina polifásica. Del análisis poblacional de las microfal1as se infieren dos campos de esfuerzos compresivos, principalmente en régimen de desgarre, de los cuales sólo el primero tiene reflejo a nivel macroestructural, y un estado distensivo en régimen de extensión radial o multidireccional. Las relaciones de corte observadas entre las ditintas estructuras ha mostrado la evolución temporal siguiente: 1) compresión ENE; 2) compresión ESE y 3) distensión NNE tendente a radial. El estudio de la fracturación mediante distintas metodologías adaptadas a la escala macro, meso y microestructural ha permitido establecer nexos de relación entre los resultados de todas ellas y poner de relieve la influencia que las estructuras mayores tienen en aquellas de menor rango. Así, la cartografía detallada de fracturas (fundamentalmente a escala mesoestructural) ha permitido observar variaciones en la distribución y orientación de las mismas. Tales variaciones han sido interpretadas como fenómenos de perturbación de esfuerzos por estructuras mayores que, en la mayoría de los casos, han podido ser identificadas. Se han estudiado ejemplos de estas perturbaciones en relación con familias de fallas tanto de desgarre como de componente normal.

Download full-text


Available from: Carlos L. Liesa, Mar 11, 2014
1 Follower
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In the western part of the Penyagolosa subbasin (Maestrat Basin, Spain), carbonate cementation occludes fractures and infills stylolites in Tithonian-Berriasian limestones. Field relationships, petrography, cathodoluminesence and geochemical analyses (microprobe, fluid inclusions, oxygen, carbon and strontium isotopes) of the carbonate cements show that the paragenetic sequence includes (A) calcite cements in echelon tension gashes (– 11.37 δ18O VPDB). (B) Scarce isolated rhombic dolomite replacement cement. (C) Saddle dolomite replacement cement with fluid inclusions that are characterized by high salinity (21.5 to 23.5% wt. eq. NaCl), high temperatures (Th 110–155 °C) and similar negative values of oxygen isotopes (− 11.27δ18O VPDB). (D) Calcite replacing (dedolomite) saddle and rhombic dolomite ( − 8.61 to − 6.76 δ18O VPDB and −4.38 to +0.07 δ13C VPDB). (E) Calcite cement filling vertical fractures. They have the highest Th (160–260 °C), negative values of oxygen isotopes ( − 9.97 to − 13.44 δ18O VPDB). (F) Calcite cement filling bed-parallel stylolites ( − 8.81 δ18O VPDB). This paragenetic sequence reflects multiple phases of fracture-controlled carbonate cements. The first stage calcite is related to syn-sedimentary rifting of the Late Jurassic-Early Cretaceous and progressive burial depth. The later phases of dolomite and calcite in vertical veins are considered hydrothermal in origin and indicate a mix of saline waters, possibly derived from the underlying Triassic and Liassic evaporites, with deep circulating meteoric water with higher temperature than the surrounding rocks and related to the regional Alpine compression.
    Journal of Geochemical Exploration 05/2003; 78-79:33-38. DOI:10.1016/S0375-6742(03)00045-1 · 2.43 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this work we apply the study of fracturing to the characterisation of Mesozoic extensional processes in the easternmost part of the Iberian Basin (Maestrazgo basin). Faults at the macroestructural scale (many of them related with Early Cretaceous basin formation) show dominant N-S to NE-SW and E-W to NW-SE orientations. These main orientations and their relative importance change from the westernmost part of the basin (NW-SE dominated fracturing) toward the east (NNE-SSW dominated fracturing). Joints and faults at the outcrop scale in the Jurassic and Lower Cretaceous beds are arranged in two systems each consisting of two orthogonal sets: 1) a primary system with NW-SE and NE-SW fractures and 2) a secondary with N-S and E-W fractures. The origin of fracturing in the studied area is related to basin formation during the Early Cretaceous, consistent with a radial extensional regime and two main extension orientations: ESE-WNW and NNE-SSW.
  • [Show abstract] [Hide abstract]
    ABSTRACT: The stress evolution of the central-eastern Iberian Chain during the Tertiary compression has been a matter of discussion during the last decades. In particular, there is not a complete agreement on whether the tectonic evolution is controlled by different external stress fields or it is essentially related to a single stress field with multiple stress perturbations. A systematic procedure to discriminate between these two hypotheses is proposed. The procedure involves statistical computing of local compression directions, identifying and ‘filtering’ stress deviations on outcrop to map scale, and timing of paleostresses. The latter has been interpreted from both analysis of cross-cut relationships of structures and consideration of the palaeostress record through the sequence of syntectonic sedimentary units. The results suggest that a single stress field with multiple perturbations cannot explain the ensemble of compression directions inferred in the region. The final proposed model includes three different, partially superposed Intraplate Stress Fields ISF (NE–SW, ESE–WNW to SSE–NNW, and NNE–SSW ISFs), driven by genetically independent far-field tectonic forces related with the active Iberia plate margins, and showing both local and regional deflection of stress trajectories.
    Tectonophysics 09/2009; DOI:10.1016/j.tecto.2009.02.002 · 2.87 Impact Factor