Topic
Granulite
About: Granulite is a research topic. Over the lifetime, 6763 publications have been published within this topic receiving 268925 citations.
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TL;DR: In this article, a detailed study on chemical and isotopic zonation of monazite in Lewisian granulites has been carried out, which is of particular relevance for the interpretation of the chemical and age information from any zoned monazites.
190 citations
TL;DR: In this article, the authors presented an analysis of C-O-H fluid composition for conditions of granulite facies metamorphism and showed that the addition of CO2-rich fluid causes graphite to precipitate.
Abstract: Pervasive flooding of CO2 has been proposed as the cause of granulite facies metamorphism that is capable of producing many distinctive characteristics of the deep continental crust: reduced water activity, orthopyroxene-bearing assemblages, depletion of large-ion lithophile (LIL) elements, and dehydration1–6. The calculations presented here of C–O–H fluid composition for conditions of granulite facies metamorphism show that oxygen fugacity (f O2) estimates from many terranes are sufficiently low that the addition of CO2-rich fluid causes graphite to precipitate. For values of pressure (P) and temperature (T) common to granulites, and with f O2 slightly below the quartz–fayalite–magnetite buffer (QFM), the addition of CO2 sufficient to grow 10 vol. % orthopyroxene requires the precipitation of 1.5 vol. % graphite. As 0.1 vol. % graphite is readily recognizable, but is not reported in most low f O2 granulites, these rocks have not been flooded by CO2, and low f H2O is probably due to extraction of a magma or recrystallization of an already dry rock7,8. Granulite terranes may thus result from a combination of these three processes and the dominance of any one cannot now be demonstrated on a regional basis.
188 citations
TL;DR: In this paper, high pressure rocks from the Caledonian root zone in Norway provide analogues for processes occurring today under southern Tibet, allowing large-scale geophysical observations, from gravity and earthquakes, to be linked with the mechanical properties of metastable rocks under high mountains.
Abstract: Exhumed high-pressure rocks from the Caledonian root zone in Norway provide analogues for processes occurring today under southern Tibet, allowing large-scale geophysical observations, from gravity and earthquakes, to be linked with the mechanical properties of metastable rocks under high mountains. Metastability is essential for the survival of thick mountain roots and, hence, of high mountains and is in turn controlled by water. If water is absent, dry granulite, formed from earlier melting episodes, is both stable and strong and likely to survive in the eclogite stability field of deep root zones for hundreds of million years. But if hydrous fluid is introduced, the transformation of granulite to eclogite is relatively rapid and accompanied by a dramatic loss of strength. In Norway, this transformation was initiated by water infiltration along fractures formed by earthquakes. The same process, as marked by deep earthquakes, may be occurring today beneath southern Tibet.
186 citations
TL;DR: In this article, the Mohe Complex of the Erguna block was analyzed for metamorphism in the form of discrete zircon grains or metamorphic rims around detrital cores and they record remarkably consistent 206 Pb/ 238 U ages between 495-±2-Ma and 497-±6-Ma.
185 citations
TL;DR: Using Pb stepwise leaching of metamorphic silicates, the Central Zone (CZ) of the Limpopo Belt has been studied in this paper, where three distinct high grade events at about 3.2−3.1 Ga, 2.65−2.52 Ga and 2.0−0.05 Ga are recognized.
184 citations