restite造句

• When chunks of restite are caught up within the granite it is known as a " restite inclusion " or enclave.
• When chunks of restite are caught up within the granite it is known as a " restite inclusion " or enclave.
• Cordierite in restite inclusions is unstable at low pressures; this reverts to textured inclusion of biotite-muscovite-feldspar-quartz.
• Generally, restite is not present within magmas in large amounts and thus the effects of the above processes are not usually profound.
• Generally, restite is composed of a predominance of mafic minerals because these are harder to melt ( see Bowen's reaction series ).
• Since HREEs and Eu are readily accommodated in garnet and plagioclase, respectively, their depletion suggests the presence of these minerals in the restite.
• Restite can, in large enough amounts, retard the compositional changes of a magma either via providing more reagents or physically trapping crystals within the magma.
• This process is envisaged as, for instance, pyroxene-bearing restite inclusions'soaking up'water and being converted to hydrous hornblende-bearing inclusions.
• Secondly, restite acts as a compositional buffer, providing elements to the surrounding magma as it is melted and ground up by erosive forces within the ascending magma.
• Restite acts as a form of buffer within magma, acting as a reservoir primarily of water and water-adsorbent minerals, which may prevent or retard a granitic magma from attaining water saturation.
• If the restite minerals are carried with the magma, as the minerals become thermo-barometrically unstable during ascent, they will react back with the magma to form biotite from orthopyroxene, and feldspar or mica from cordierite.
• However, it is likely that, particularly for S-type granite which is formed by wholesale anatexis ( melting ) of metasedimentary rocks, restite mediated melting and fractionation is crucial to the composition and behaviour of these magmas.
• In magmas which do not have a restite component, such as most M-type granites, some A-type granites, and most basaltic magmas, it is much easier for these magmas to achieve more dramatic fractional crystallization effects.