The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The increasing recognition of high P-T metamorphic conditions in crustal rocks has lead to a major reappraisal of the processes inherent to continental collision. Within high-grade regions in orogenic belts, a particular problem is that bodies of high P-T rocks are often found preserved within an apparently lower grade gneissose matrix. Resolving the true extent of high P-T conditions in such situations...
Mafic to intermediate dykes are spatially and temporally closely associated with major post-tectonic granitic complexes in the western Lachlan Orogen of SE Australia. These dykes, which range petrographically from basaltic to andesitic, are concentrated within several, north- to northwest-trending zones and were emplaced during two broad intervals of extensive magmatic activity during the Silurian-Devonian...
Prograde evolution of minerals in Fe- and Al-rich graphitic metapelites in the Ayakhtinsk aureole, Siberia, produced the unusual contact metamorphic mineral assemblages: chloritoid+biotite, chloritoid+biotite+andalusite and cordierite+garnet+muscovite. Field-petrologic observations show that: (1) the grade of contact metamorphism ranges from chloritoid to sillimanite-alkali feldspar zone; (2) chloritoid+biotite...
Several types of xenoliths occur in a Permian basanite sill in Fidra, eastern central Scotland. One group consists of spinel lherzolites, which have geochemical and isotopic characteristics similar to those of lithospheric upper mantle from elsewhere in western Europe, with both LREE-depleted and LREE-enriched compositions. A separate group comprises pyroxenites and wehrlites, some of which contain...
The evolution of the pre-Alpine Corio and Monastero metagabbros points to strong chemical and mineralogical similarities with that of other Permian gabbro bodies of the Alps, which are concentrated in the Southalpine and Austroalpine domains. The structural and metamorphic pre-Alpine evolution of these gabbros records a re-equilibration following the emplacement in the deep crust (P=0.6-0.9 GPa and...
The Tarcouate pluton (Anti-Atlas, Morocco) is an inversely zoned laccolith emplaced 583 Ma ago into low-grade metasediments, with the following succession: leucocratic granites, biotite-granodiorites (+/-monzodiorites), hornblende-granodiorites (+/-monzodiorites) and monzodiorites syn-plutonic dykes. These rocks form two distinct, chemically coherent, units:(1) A main unit consists of layered (57<SiO...
The Emeishan flood basalt is a large igneous province erupted during the Permian-Triassic period in southwestern China. Based on petrographic, major and trace element, and Sr-Nd isotope data, the Emeishan basalts can be classified into two major magma types. These are: (1) a low-Ti (LT) type that exhibits low Ti/Y (<500), Fe 2 O 3 * (<12%), Nb/La (0.6-1.4), Nd (t)...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.