Gneiss - Wikipedia
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).
灰色片麻岩 - 百度百科
灰色片麻岩（grey gneiss）又称长英质片麻岩（felsic gneiss），是主要由长石和石英组成的片麻状岩石。 灰色片麻岩呈大面积出现在太古宙的高级变质区，其中常有大小不等的各种变质岩的夹层或包裹体。 岩石外表为灰白色，矿物成分主要为中酸性斜长石和石英，不含或含很少量钾长石，常含有少量黑云母和角闪石，有时含少量辉石和石榴子石。 一般为中粗粒变晶结构，片麻状或条带状构造。 变质作用为角闪岩相至麻粒岩相，构造变形作用十分强烈。 长石以富钠质斜长石为 …
Gneiss: Identification, Characteristics, and More
Gneiss is a coarse-grained foliated metamorphic rock that displays alternating bands of light and dark minerals, formed from high-grade metamorphism. The light minerals are typically interlocking crystals of quartz and feldspar, while the dark bands are made of mafic minerals and often display a preferred orientation.
Gneiss: Metamorphic Rock - Pictures, Definition & More - Geology.com
Gneiss is a foliated metamorphic rock identified by its bands and lenses of varying mineral composition. Some of these bands (or lenses) contain granular minerals that are bound together in an interlocking texture. Other bands contain platy or elongated minerals that show a preferred orientation that parallels the overall banding in the rock.
Geochronology and petrogenesis of gray gneisses from the …
2012年3月1日 · In this study, we present whole rock geochemical and Nd isotopes, and in-situ zircon U–Pb age and Hf isotope data for the gray gneisses from the Taihua Complex in the Xiong'er area in order to: (1) document the emplacement ages of these rocks, (2) investigate their magma sources and petrogenetic processes, and (3) evaluate the Early Paleoprotero...
Generation of early Archaean grey gneisses through melting of …
2014年12月1日 · We report zircon ages, Hf-in-zircon isotopes as well as whole-rock geochemistry and Hf–Nd isotopic systematics for Palaeoarchaean grey gneisses of the Ancient Gneiss Complex of Swaziland, the oldest components of the Kaapvaal craton, southern Africa.
Common dioritic gneiss and Qeqertaussaq diorite The grey gneiss covers a large range of compositions from dioritic rocks with less than 55 wt.% SiO 2 to trond-hjemitic rocks with over 75% SiO 2; the presentation of geochemical data follows these two large field groups: dioritic gneiss (with less than c. 65% SiO 2) and tonalitic-
Gneiss Rock Type, Color, Texture, and Uses (Expert Guide)
2023年9月1日 · Dark-colored bands in Gneiss are caused by mafic minerals like pyroxene, hornblende, or biotite. These minerals are generally dark gray or black, which is why there isn’t as much variation in the color of dark bands. The ratio of dark to light bands significantly impacts Gneisses’ appearance.
The composite Archaean grey gneisses: Petrological significance…
2011年4月1日 · Archaean Grey Gneiss complexes are composite units made of many distinct lithologies. Only a portion of grey gneisses is actually TTG. TTGs can be subdivided in three groups reflecting different pressures of melting. TTGs form along a range of geothermal gradients in contrasting tectonic settings.
GNEISS中文(简体)翻译：剑桥词典 - Cambridge Dictionary
gneiss翻译：片麻岩（由长石﹑石英组成﹐中粗粒变晶结构和片麻状或条带状构造的变质岩）。了解更多。
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