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Fig. 3 | Journal of Palaeogeography

Fig. 3

From: Computerized geochemical modeling of burial diagenesis of the Eocene turbidite reservoir elements: Urucutuca Formation, Espírito Santo Basin, southeastern Brazil passive margin

Fig. 3

Digital implicit photomicrographs (see text for explanation) resembling and representing the mineralogical and textural aspects of the turbidite sandstones under plane-polarized light. In parts f and g, the calcite cement is colored in red. The eodiagenetic and some early mesodiagenetic stages can be observed throughout. a Discontinuous growth of quartz beyond the initial detrital grain boundaries; b Growths of albite replacing fractured plagioclase grains with no twinning (thereby, healing the intragranular fractures) and also replacing lamellar-twined grains of plagioclase; c Intragranular porosity by dissolution and replacement of feldspars into kaolinite. Albitization is observed more intense at the highly angular edges, much less along the flat edges, and within fractures of the plagioclase grains without twining (grain at the top-right corner); d Plagioclase grains heterogeneously albitized; e Kaolinite replacing feldspar grains and filling the intergranular pore spaces; f Sandstone cemented with poikilotopic pre-compaction calcite; g Poikilotopic pre-compaction calcite cementing grains that were initially replaced by pyrite and microcrystalline dolomite; and h Microcrystalline pre-compaction dolomite and pyrite replacing grains and recrystallization of biotite lamellae

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