Trachyandesite is an extrusive igneous rock with a composition between trachyte and andesite. It has little or no free quartz, but is dominated by sodic...

targets – Basaltic lava with a flowing, often ropy appearance Basaltic trachyandesite – Naming system for volcanic rocksPages displaying short descriptions...

rock. More specifically, it is a potassium-rich variety of basaltic trachyandesite, composed of olivine, augite and plagioclase phenocrysts in a groundmass...

Trachybasalt. S2 (Basaltic trachyandesite)—*Sodic and potassic variants are Mugearite and Shoshonite. S3 (Trachyandesite—*Sodic and potassic variants...

mafic compositions. Typical intermediate rocks include andesite and trachyandesite among volcanic rocks and diorite and granodiorite among plutonic rocks...

example in the intrusive dioritic pluton of El Teniente, Chile and in trachyandesite pumice erupted by El Chichón volcano, Mexico. The name anhydrite was...

basalt-trachybasalt-trachyandesite volcanoes (Ngorongoro also contains trachydacite) and the 1.6-1.5 Ma Oldeani basalt-trachyandesite volcano. The highlands...

intermediate composition. It is a silica-undersaturated sodium-rich variety of trachyandesite (the other kind is latite) and belongs to the alkaline suite of igneous...

sediments and volcanic rocks. The volcanics consist of rhyolite, basalt, trachyandesite, and trachyrhyolite. Uranium ore bodies are found in the Dornod, consisting...

alkaline rocks atypical for oceanic islands, ranging from basalt through trachyandesite and trachyte to rhyolite. Ascension has a hot desert climate (BWh, according...

fields, such as the trachyandesite field, are further classified by the ratio of potassium to sodium (so that potassic trachyandesites are latites and sodic...

phonolite Jabal Arknu Libya Tertiary Otoge Japan Miocene alkali basalt, trachyandesite Zarza Mexico Cretaceous gabbro Houshihushan China Cretaceous granite...

material used: it is the locally-cut volcanic "pierre de Volvic" (of the Trachyandesite type) that gives the building its dark colour and whose strength allows...

plagioclase-bearing basaltic trachyandesite flows Hog Pen Formation: interbedded debris flows and basalt to basaltic trachyandesite flows These rest on the...

is the tephra of Deception Island, which is of trachyte and basaltic trachyandesite, richer in potassium and sodium. Quaternary volcanic products of the...

along ring faults associated with caldera collapse. Rock types include trachyandesite, trachyte, syenite and amphibole - biotite granite. They are commonly...

identified as plagioclase basalt, but now reclassified as basaltic trachyandesite to trachyandesite. The third phase, from 2.75 to 2.52 million years ago, completed...

Pozzolana containing significantly less volcanic glass, such as a trachyandesite from Volvic (France) with only 25 wt% are less reactive. Apart from...

million years ago, above an accumulation of several layers of pyroclastic trachyandesite. The summit is accessible from the ski resort of Super Lioran by a cable...

drying in the sun in many places. The island consists primarily of trachyandesite rock. A major explosive eruption about 9,350 years ago reached a Volcanic...

lava plateaus are left. The lavas erupted from the cone are porphyric trachyandesite-basalt of shoshonitic composition. They contain pyroxene and olivine...

trachyandesite was interpreted as lacustrine, likely the result of ponding against the volcanic flows. The high relative abundance of trachyandesite and...

have calderas. Ngorongoro Volcano (2.5–1.9 Ma) is primarily basaltic trachyandesite. The caldera is fed by the Munge and Oljoro Nyuki Rivers, while the...

descended over steep slopes. Tambora has produced trachybasalt and trachyandesite rocks which are rich in potassium. The volcanics contain phenocrysts...

an estimated VEI of 7. An estimated 41 km3 (10 cu mi) of pyroclastic trachyandesite were ejected, weighing about 10 billion tonnes. This left a caldera...

million years before present. The volcano's rock type is principally trachyandesite. K-Ar dating of about 1.14 million years was obtained from the Amorong...

deposited dacite, rhyolite and ignimbrite, as well as trachyte and trachyandesite. This trend towards the production of more felsic, viscous lavas could...

olivine phenocrysts. This first cone is lengthened to the north by the trachyandesite tuff ring which caused its obstruction. These projections are dark and...

volcanic rocks are exposed in valleys. Emi Koussi has erupted phonolite, trachyandesite and trachyte, as well as mafic rocks like basanite and tephrite. The...

various rock types are distinguished in the Kiruna porphyry such as trachyandesite lava and quartz-bearing porphyry of rhyolitic composition. These two...