Age relations and petrology of alkalic igneous rocks from Oki Dozen, Southwest Japan.

Petrology of the igneous rocks in the west and south‌west of Razan, Hamedan Province

West and south­west of Razan igneous rocks are located in the Hamedan Province in the Sanandaj- Sirjan zone, west Iran. According to petrography and chemical studies, these rock bodies are composed of diorite, gabbrodiorite, monzonite, quartz- monzonite, andesite and andesibasalt. The results of geochemical analysis show that these rocks belong to a cal- alkaline magma series. The geochemical c...

Petrology and source of Plio-Quaternary volcanic rocks in southwest of Nir, South of Yazd

In the southeast of Nir, south of Yazd Povince, several acidic volcanoes  rocks are exposed and form the youngest volcanic rocks in this region with dacite-rhyodacite composition. These rocks are composed of plagioclase, hornblende, biotite and quartz phenocrysts with trachytic and hyallomicrolithic porphyry texture. Based on geochemical data, the magmatic affinity of these rocks is calc-alkali...

Magma Composition and Igneous Rocks

Introduction In the following chapters we will find that nearly all of the varied aspects of volcanism are either directly or indirectly controlled by the chemical composition of magma and the rate at which it cools and solidifies. If you are to understand and appreciate subsequent discussions of volcanoes and related volcanic phenomena, it is essential that you have a good grasp of the basic c...

Occurrence, Texture, and Classification of Igneous Rocks

Petrology and Geochemistry of Boninite Series Volcanic Rocks, Chichi-jima, Bonin Islands, Japan

An Eocene submarine boninite series volcanic center is exposed on the island of Chichi-jima, Bonin Islands, Japan. Five rock types, boninite, bronzite andesite, dacite, quartz dacite, and rhyolite, were distinguished within the boninite volcanic sequence on the basis of petrographic and geochemical observations. Boninite lavas contain high magnesium, nickel, and chromium contents indicative of ...