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Igneous rock, with gray groundmass and white phenocrysts marked. Orthoclase phenocrysts within a finer-grained matrix of a granite porphyry. The matrix or groundmass of a rock is the finer-grained mass of material in which larger grains, crystals, or clasts are embedded.
Panegyris is used in three ways: A meeting of the inhabitants from one town and its vicinity, a meeting of inhabitants of an entire province, district, or of people belonging to a particular tribe, and for national meetings. The panegyreis were festivals in which prayers were made, sacrifices offered, and also processions. [4]
The degree of deformation and metamorphism along with rock type determines the kind of cleavage feature that develops. Generally, these structures are formed in fine grained rocks composed of minerals affected by pressure solution. [1] Cleavage is a type of rock foliation, a fabric element that describes the way planar features develop in a ...
The study of diagenesis in rocks is used to understand the geologic history they have undergone and the nature and type of fluids that have circulated through them. From a commercial standpoint, such studies aid in assessing the likelihood of finding various economically viable mineral and hydrocarbon deposits.
Evidence for pressure solution has been described from sedimentary rocks that have only been affected by compaction. The most common example of this is bedding plane parallel stylolites developed in carbonates. In a tectonic manner, deformed rocks also show evidence of pressure solution including stylolites at a high angle to bedding. [4]
Porphyry made the emperors unapproachable in terms of power and nature, belonging to another world, the world of the mighty gods, present for a short time on earth. [ 30 ] Porphyry also stood in for the physical purple robes Roman emperors wore to show status, because of its purple colouring.
Normative mineralogy is an estimate of the mineralogy of the rock. It usually differs from the visually observable mineralogy, at least as much as the types of mineral species, especially amongst the ferromagnesian minerals and feldspars, where it is possible to have many solid solution series of minerals, or minerals with similar Fe and Mg ratios substituting, especially with water (e.g ...
Clinozoisite is a complex calcium aluminium sorosilicate mineral with formula: Ca 2 Al 3 (Si 2 O 7)(SiO 4)O(OH).It forms a continuous solid solution series with epidote by substitution of iron(III) in the aluminium (m3 site) and is also called aluminium epidote.