{"id":1123,"date":"2014-10-13T09:42:34","date_gmt":"2014-10-13T09:42:34","guid":{"rendered":"https:\/\/valmargstone.com\/?p=1123"},"modified":"2014-12-01T14:10:32","modified_gmt":"2014-12-01T14:10:32","slug":"%d0%bc%d0%b5%d1%82%d0%b0%d0%bc%d0%be%d1%80%d1%84%d0%bd%d0%b8%d1%82%d0%b5-%d1%81%d0%ba%d0%b0%d0%bb%d0%b8-%d0%b2-%d0%b1%d1%8a%d0%bb%d0%b3%d0%b0%d1%80%d0%b8%d1%8f","status":"publish","type":"post","link":"https:\/\/valmargstone.com\/en\/%d0%b3%d0%bd%d0%b0%d0%b9%d1%81\/%d0%bc%d0%b5%d1%82%d0%b0%d0%bc%d0%be%d1%80%d1%84%d0%bd%d0%b8%d1%82%d0%b5-%d1%81%d0%ba%d0%b0%d0%bb%d0%b8-%d0%b2-%d0%b1%d1%8a%d0%bb%d0%b3%d0%b0%d1%80%d0%b8%d1%8f\/","title":{"rendered":"Metamorphic Rocks in Bulgaria"},"content":{"rendered":"

Formation of metamorphic rocks<\/a> is a long and complex process. It includes the wide range of temperature amplitudes and pressure in the bowels of the Earth.<\/p>\n

\"\u043c\u0435\u0442\u0430\u043c\u043e\u0440\u0444\u043d\u0438<\/a><\/p>\n

Metamorphism<\/strong><\/p>\n

This is a set of endogenous modifications of the mineral composition and structure of the rocks, which is needed for their successful adaptation to the already-existing conditions in the deep layers under the Earth’s crust.<\/p>\n

It plays an important role in the alteration of the mineral composition of the rocks. This reflects on the composition of the rock structure itself. With the increase of the depth, the temperature usually rises, but this also depends on:
\n\u2022\u00a0\u00a0 \u00a0the heat, which is transferred from the deep fluids and solutions;
\n\u2022\u00a0\u00a0 \u00a0the energy of the radioactive decay in the Earth’s crust;
\n\u2022\u00a0\u00a0 \u00a0the thermal effect of chemical reactions in the crust of the planet
\n\u2022\u00a0\u00a0 \u00a0the heat that is generated due to magma rising from beneath Earth\u2019s mantle<\/p>\n

Pressure<\/strong><\/p>\n

There is hydrostatic pressure or stagnation pressure. Hydrostatic pressure is equal on all sides as a result of the weight of the top rock masses. Stagnation pressure is caused by tectonic movements and is dependent on their intensity.<\/p>\n

Types of Metamorphism:<\/strong><\/p>\n

\u2022\u00a0\u00a0 \u00a0Contact metamorphism;
\n\u2022\u00a0\u00a0 \u00a0Dislocational (cataclastic) metamorphism;
\n\u2022\u00a0\u00a0 \u00a0Regional (deep-crustal) metamorphism.<\/p>\n

Metamorphic Rocks<\/strong><\/p>\n

Minerals that make up the metamorphic rocks are:
\n\u2022\u00a0\u00a0 \u00a0minerals that are often found in igneous and metamorphic rocks: quartz<\/a>, feldspars, mica, amphibole, olivine, peridot, etc.;
\n\u2022\u00a0\u00a0 \u00a0minerals that are often found in sedimentary and metamorphic rocks: dolomite, calcite, etc.;
\n\u2022\u00a0\u00a0 \u00a0minerals that are\u00a0 primary in the composition of metamorphic rocks and secondary in the composition of igneous rocks: serpentine, sericit, chlorite, actinolite, , etc.;
\n\u2022\u00a0\u00a0 \u00a0minerals which are found only in metamorphic rocks: wollastonite, distin, sillimanite,\u00a0 stavrolit, andalusite, staurolit, grenades, cordierit, and others.<\/p>\n

Orto-metamorphic and Para-metamorphic Rocks:<\/strong><\/p>\n

\u2022\u00a0\u00a0 \u00a0Clay schist rocks;
\n\u2022\u00a0\u00a0 \u00a0Phyllite
\n\u2022\u00a0\u00a0 \u00a0Cristalline
\n\u2022\u00a0\u00a0 \u00a0Gneiss<\/a>;
\n\u2022\u00a0\u00a0 \u00a0Amphibolite rocks;
\n\u2022\u00a0\u00a0 \u00a0Granulites;
\n\u2022\u00a0\u00a0 \u00a0Eclogite rocks
\n\u2022\u00a0\u00a0 \u00a0Hornfels
\n\u2022\u00a0\u00a0 \u00a0Marbles;
\n\u2022\u00a0\u00a0 \u00a0Quartz rocks
\n\u2022\u00a0\u00a0 \u00a0Cataclastic rocks
\n\u2022\u00a0\u00a0 \u00a0Mylonite
\n\u2022\u00a0\u00a0 \u00a0Phylonite<\/p>\n

Gneiss is a metamorphic stone<\/a>, distinguished by its exceptional strength and high durability during environmental changes; its surface is rough and non-slippery. Therefore, it provides stable, aesthetic and long-lasting results in the construction, tiling, flooring and decoration of interior and exterior spaces. The gneissic pavements and facings can give a natural and beautiful finishing touch to any space. Gneiss is available for usage both in its naturally occurring form and shaped (after processing). The different mineral composition of the gneissic stones cause variety of colors in its texture: white, yellow, gray, green, metallic, brown etc.<\/p>\n

Structure of Gneiss<\/strong><\/p>\n

Metamorphic gneiss is also called shale gneiss. Its geological structure<\/a> is similar to that of granite. Its hardness is great and thus, the stone can easily replace granite.<\/p>\n

Gneiss Formation<\/strong><\/p>\n

Metamorphic rocks such as gneiss are most likely to be found at sites, located deep beneath the Earth’s surface. The collision of plates in the lithosphere causes high pressure which in turn leads to the clustering of several minerals in a rock.<\/p>\n

Useful Characteristics of gneiss rock<\/strong><\/p>\n

Shale gneiss has beautiful patterns and loops that make it perfect for polished marble countertops and tiling<\/a>. Due to its great hardness, things created by gneiss can endure for centuries. It is also a good insulator, so houses or buildings lined with gneiss, besides being beautiful and cozy, remain cool in the summer and warm in the winter.<\/p>\n

Structure and texture of gneiss stone<\/strong><\/p>\n

The structure can be divided into three basic types:
\n\u2022\u00a0\u00a0 \u00a0crystal structure
\n\u2022\u00a0\u00a0 \u00a0cataclastic structure
\n\u2022\u00a0\u00a0 \u00a0relic rock structure<\/p>\n

The texture of the gneiss can be:
\n\u2022\u00a0\u00a0 \u00a0relic rock texture \u2013 when it retains part of the texture features, inherent to the source rock;
\n\u2022\u00a0\u00a0 \u00a0massive marble texture –\u00a0 formed without direct pressure;
\n\u2022\u00a0\u00a0 \u00a0oriented texture – formed under the impact of direct pressure and spread quite widely It varies: lenticular, linear, striped, etc.<\/p>","protected":false},"excerpt":{"rendered":"

Formation of metamorphic rocks is a long and complex process. It includes the wide range of temperature amplitudes and pressure in the bowels of the Earth. Metamorphism This is a set of endogenous modifications of the mineral composition and structure of the rocks, which is needed for their successful adaptation to the already-existing conditions in […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0,"footnotes":""},"categories":[25],"tags":[],"_links":{"self":[{"href":"https:\/\/valmargstone.com\/en\/wp-json\/wp\/v2\/posts\/1123"}],"collection":[{"href":"https:\/\/valmargstone.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/valmargstone.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/valmargstone.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/valmargstone.com\/en\/wp-json\/wp\/v2\/comments?post=1123"}],"version-history":[{"count":9,"href":"https:\/\/valmargstone.com\/en\/wp-json\/wp\/v2\/posts\/1123\/revisions"}],"predecessor-version":[{"id":1126,"href":"https:\/\/valmargstone.com\/en\/wp-json\/wp\/v2\/posts\/1123\/revisions\/1126"}],"wp:attachment":[{"href":"https:\/\/valmargstone.com\/en\/wp-json\/wp\/v2\/media?parent=1123"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/valmargstone.com\/en\/wp-json\/wp\/v2\/categories?post=1123"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/valmargstone.com\/en\/wp-json\/wp\/v2\/tags?post=1123"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}