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[ 4] lyell had a clear perception of the regional diagenesis sequence in sedimentary rocks that remains valid today. Information and translations of migmatite in the most comprehensive dictionary definitions resource on the web. These composite rocks sederholm ( 1907, p. Meaning of migmatite. The rock derived its name from a greek word which means “ mixed rock”. A migmatite is a megascopically composite rock comprising alternating layers or lenses of granitoid and schist or gneiss. Until now, many geologists have been deterred from working with migmatites because of their complex appearance and an unhelpful non- genetic nomenclature. Migmatite outcrop ( width of field - ca. Metatexis will produce a migmatite, diatexis will not. Migmatites are produced by partial melting; to aid the reader in the identification of migmatites, the author describes and illustrates microstructures that can be used to infer the presence of melt or a melt- producing reaction.
Download pdf copy request quote aprmigmatite is a rock composed of both igneous and metamorphic rocks. What does migmatite mean? Pdf) migmatites february authors: ajay kumar atomic minerals directorate for exploration and research, jamshedpur, india abstract and figures petromineralogical studies with the help of. Heat- induced melting occurs at the mantle plumes or hotspots. Many migmatites probably. Migmatites and migmatite terranes 1 1. However, as you have access to this content, a full pdf is available via the ‘ save pdf’ action button. Download reference work entry pdf over wide areas of cratons and high- grade mobile belts, highly metamorphosed rocks are intimately mixed with granitic rocks. ( photo by ed. An early geological cross- section of the earth' s crust.
Illustrative examples from the massif armoricain, central bohemia, the pyrenees and the canadian shield are discussed. Department for manufacturing, innovation, trade, resources and energy, south australia, adelaide. Migmatites represent the transition from metamorphic to igneous rocks in the rock cycle. Bookpdf available a user' s guide to migmatites publisher: report book / 00016. Migmatites represent the. Sederholm in connection with his life- long study of the finnish migmatites. ( source: peter davis) heat- induced melting, transforming solid mantle into liquid magma by simply applying heat, is the least common process for generating magma ( see figure: graph c, label y). Agmatite was one of the new descriptive terms introduced by the late professor j.
It typically consists of darker and lighter parts. It was first discovered by jakob johannes sederholm in 1907. A migmatite is a rock produced under high- grade metamorphic conditions by melting or partial melting of a pre- existing rock in the continental or oceanic crust, irrespective of proportion of melt. 4 cm) from type locality in southern finland. A migmatite is a metamorphic rock formed by anatexis that is generally heterogeneous and preserves evidence of partial melting at the microscopic to macroscopic scale.
Migmatite: a composite silicate metamorphic rock, pervasively heterogeneous on a meso- to megascopic scale. Ptygma ( " ptygmatic folds" of some petrologists) ( width directly below stamp - 11. The resulting rock, which includes both metamorphosed and igneous material, is known as migmatite ( figure \ ( \ pageindex{ 5} \ ) ). Migmatite, in geology, rock composed of a metamorphic ( altered) host material that is streaked or veined with granite rock; the name means “ mixed rock. In this study, we investigated migmatite associated leucogranite and pegmatite from the exhumed > 1000- km- long ailao shan- red river left- lateral strike- slip shear zone in southeast asia that was active during india- eurasia plate convergence. 110, see sederholm, 1967) called migmatites ( from the greek migma, mixture). Publication date: janu. Figure \ ( \ pageindex{ 1} \ ) : migmatite is a partially molten metamorphic rock. 1 introduction structures and structural relationships result ing from superimposed deformation have long been recognized by geologists, and references to this perception can be found in the literature at least as far back as the late nineteenth century ( clough, the geology of cowal ( gunn.
Migmatite is the penultimate member of a sequence of lithology transformations first identified by lyell, 1837. Access- restricted- item true addeddate: 20: 45 bookplateleaf 0006 boxid ia1256114 camera sony alpha- a6300 ( control) collection_ set trent external- identifier. Migmatites - download as a pdf or view online for free. Most zircons from the migmatites and leucogranitic intrusions present inherited core- rim structure. The darker parts usually exhibit features of metamorphic rocks whereas the lighter parts are of igneous- looking appearance ( see also leucosome, melanosome, mesosome, neosome, palaeosome). He also describes how geochemical data can be used to infer petrological processes involved in migmatite development. Figure \ ( \ pageindex{ 5} \ ) migmatite from prague, czech republic as already noted, the nature of the parent rock controls the types of metamorphic rocks that can form from it under differing metamorphic conditions. Migmatites are highly heterogeneous rocks found in high- grade metamorphic environments; they are commonly encountered in the continental crust. Volume 2 chris yakymchuk, in encyclopedia of geology ( second edition), abstract a migmatite is a metamorphic rock formed by anatexis that is generally heterogeneous and preserves evidence of partial melting at the microscopic to macroscopic scale. Such rocks are usually gneissic ( banded) and felsic rather than mafic in composition; they may occur on a regional scale in areas of high- grade metamorphism.
