Gneiss (/ naɪs / nice) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. This rock is formed under pressures ranging from 2 to 15 kbar, sometimes even more, and temperatures over 300 °C (572 °F).

2022年12月30日 · Gneiss is a high-grade metamorphic rock known for its pronounced banding and layered appearance. This banding results from the high-temperature and high-pressure conditions under which it forms, where original rock minerals recrystallize and segregate into alternating light and dark layers.

Gneiss is a type of metamorphic rock. The minerals in gneiss may come from rocks which were originally either igneous or sedimentary. They were heated and squeezed, and the minerals recrystallized. [1] Orthogneiss is gneiss got from igneous rock (such as granite). Paragneiss is gneiss got from sedimentary rock (such as sandstone).

2014年7月1日 · A diverse suite of Archaean gneisses at Huangbaiyu village in the North China Craton, includes rare fuchsite-bearing (Cr-muscovite) siliceous rocks – known as the Caozhuang quartzite. The Caozhuang quartzite is strongly deformed and locally mylonitic, with silica penetration and pegmatite veining common.

Gneisas – metamorfinė uoliena, susidariusi regioninio metamorfizmo metu iš nuosėdinių ar rūgščių magminių uolienų. Pirmuoju atveju jie vadinami paragneisais, antruoju – ortogneisais. Tačiau atskirti gneisų kilmę ne visada pavyksta. Gneisas pagal cheminę sudėtį labai artimas granitui ir molio skalūnams. Gneisas išsiskiria savo tekstūra.

The Swakane Gneiss, interpreted to represent sedimentary strata metamorphosed at 8–12 kbar, is the deepest exposed crustal levels within the exhumed North Cascades continental magmatic arc, yet the nature and age of its protolith and the mechanism by which it was transported to deep-crustal levels remains unclear.

Gneiss is a very widespread rock type, especially in the lower parts of the continental crust, but it is also a common rock on the surface in some places (Scandinavia, Canada, and other shield areas where crystalline rocks are not covered by a layer of …

Gneiss is a medium to coarse-grained banded rock formed as a result of high grade regional metamorphism. It is characterised by a layered appearance caused by the minerals from quartzo-feldspathic minerals in discontinuous layers. The ferromagnesian minerals are commonly biotite and/or hornblende with pyroxene being less common.

2015年1月1日 · REE Geochemistry and Protoliths of Gneisses of Northwest Obudu Plateau, Southeastern Nigeria. Gneisses, which include migmatitic gneiss (MG), granite gneiss (GG), garnet biotite gneiss (GBG),...

2025年3月5日 · gneiss (usually uncountable, plural gneisses) (geology) A common and widely-distributed metamorphic rock having bands or veins, but not schistose. The old towns along …