نتایج جستجو برای: alkaline rocks
تعداد نتایج: 64205 فیلتر نتایج به سال:
the etive igneous complex has intruded into dalradian and moine meta-sedimentary rocks in devonian. main rock types of the complex are granodiorite, monzodiorite, monzogranite, granite and diorite. geochemical studies show that the magmas were of high k calc-alkaline, i-type and metaluminous nature. application of discriminant diagrams to the etive rocks indicates a possible within-plate tecton...
Post-Eocene volcanic rocks of Alborz tectonic zone located in the NE of Qazvin, composed of rhyolite, trchydacite, trachyandesite, andesite, trachybasalt and basalt with porphyritic textures, pyroclastic rocks and volcanic red breccia which are settled alternatively on Eocene pyroclastics and tuffs. The volcanic rocks are enriched in LIL and depleted in HFS elements which may indicate a calc-al...
Palang Dar gabbrodioritic intrusion cropped out in about 30 Km NE of Damghan in the eastern part of the Alborz structural unit. In this area a few small-scale gabbrodioritic intrusions and diabasic dikes with Middle Jurassic age intruded into shale, sandstones and limestones of Shemshak Formation. Emplacement of this intrusion into host rocks are associated with contact metamorphism and formati...
Northeast of Meshkinshahr, Eocene igneous rocks are exposed and are composed mainly of andesite, basalt, andesitic basalt, tephrite and is sometimes analcimite. The chemical composition of the rocks are in the range of alkaline rocks with high potassium and shoshsonitic affinity. Two main hypotheses are that they are either primary analcite or replacement pseudomorphous of leucite. Analcime cr...
Palaeoproterozoic high-K I-type granites, high-level porphyry intrusions, and felsic volcanic rocks of the Whitewater Volcanics dominate the Hooper and Lamboo Complexes in the Kimberley region of northwestern Australia. The granites, porphyries and volcanic rocks are gradational into each other in the field, and they have the same mineralogy, similar major and trace element abundances, and indi...
This Special Issue aims to highlight the pivotal role of minerals found in alkaline igneous rocks tracing magmatic processes [...]
Chemical weathering indices are commonly used for characterizing weathering profiles by incorporating bulk major element oxide chemishy inlo a single metric for each sample. Generally, on homogeneous parent rocks, weathering indices change systematically with depth. However, the weathering of heterogeneous metamorphic rocks confounds the relationship between weathering index and depth. In this ...
At the base of Shemshak Formation in the south Azadshahr area, some igneous mafic rocks are discovered recently as olivine gabbro bodies and pegmatoid alkali-diorite dikes. Rock-forming minerals of olivine gabbro includes olivine, clinopyroxene and plagioclase, alkali-diorites are composed of large amphiboles and plagioclase. Major and trace elements characteristics of these rocks indicate the...
The area of study is located 120 Km north-east of Shahrood city. In terms of structure and geological classification, this area is located in the northern part of central Iran zone. Granitoids of Troud ranging from monzonite to granite. The main minerals of granitoids are quartz, plagioclase, and orthose. The accessory minerals are biotite, hornblende, sphene, and opaque minerals. Various textu...
The Neoproterozoic rocks of the Bir Madi area, south Eastern Desert, comprise a metagabbrodiorite complex (GDC) and a tonalite-granodiorite suite (TGrS). The GDC has a weak tholeiitic to strong calc-alkaline character and is made up of olivine gabbro, hornblende gabbro, diorite and monzodiorite. The olivine gabbro is characterized by abundance of augite and labradorite with pseudomorphic serpen...
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