The interpretation of granitic textures from serial thin sectioning, image analysis and three-dimensional reconstruction

Abstract

Textural development of the felsic phases in two granodioritic rocks from the zoned Linga superunit of the Peruvian Coastal Batholith has been characterized using serial thin sectioning, image analysis and three-dimensional reconstruction. The study has shown how each mineral phase contributed to the texture during the formation and development of a contiguous crystal framework and during subsequent restriction, isolation and occlusion of the melt-filled porosity. The work highlights the important factors and potential problems in the use of serial thin sections and imaging in the analysis of complex polyphase rock textures.

Melt movement and the occlusion of porosity in crystallizing granitic systems

“…This distinction becomes even more evident when the texture is studied in three dimensions using serial thin-sectioning, image analysis, and threedimensional reconstruction (described in Bryon et al, 1995). The large anhedral plates can invariably be traced through consecutive sections (Fig.…”

“…2), with plagioclase, quartz, alkali feldspar, amphibole and biotite as the major phases, and clinopyroxene, magnetite, apatite and zircon appearing as accessories. The plagioclase crystals are mainly subhedral, and lorm a touching framework in three dimensions (Bryon et al, 1995). Alkali feldspar forms large anhedral poikilitic plates up to 8 mm in diameter (Fig.…”

“…7a in Bryon et al, 1995) indicates that the Yauca granodiorite evolved to the cotectic during stage 1 of the crystallization interval, i.e. before the development of a continuous crystal framework.…”

“…Variation in the geometry and location of the alkali feldspar plates (shaded grey) and pockets (shown as black dots) through six serial sections from the Yauca granodiorite. The sectioning and digitizing technique is described at length in Bryon et al (1995). The distance between each of the sections is approximately 500 i.tm.…”

Complex evaluation of the Kiskunhalas-NE fractured metamorphic hydrocarbon reservoir

“…Although there were some circumstantial and time-consuming methods to get 3D information about the structural or textural features of a sample, like using successive digitised images acquired by serial thin sectioning or lapping (Bryon et al 1995;Cooper and Hunter 1995;Marschallinger 1998), or by partial melting experiments (Philpotts et al 1998), these were not applicable to all rock types (Ikeda et al 2000). The propagation of the CT method in geology provided the opportunity for visualisation and quantitative textural analysis of igneous (e.g., Carlson et al 2000;Ikeda et al 2000) and metamorphic rocks (e.g., Ikeda et al 2000;Ketcham 2005; Huddlestone-Holmes and Ketcham 2010).…”