Search results
Results from the WOW.Com Content Network
The types of minerals present in volcanic ash are dependent on the chemistry of the magma from which it erupted. Considering that the most abundant elements found in silicate magma are silicon and oxygen, the various types of magma (and therefore ash) produced during volcanic eruptions are most commonly explained in terms of their silica content.
In the deep ocean, another 26.2 Tmol Si Year −1 is dissolved before being deposited to the sediments as opal silica. [20] At the sediment water interface, over 90% of the silica is recycled and upwelled for use again in the photic zone. [20] Biogenic silica production in the photic zone is estimated to be 240 ± 40 Tmol si year −1. [36]
High-silica rhyolite (HSR), with a silica content of 75 to 77·8% SiO 2, forms a distinctive subgroup within the rhyolites. HSRs are the most evolved of all igneous rocks, with a composition very close to the water-saturated granite eutectic and with extreme enrichment in most incompatible elements .
Volcanic rocks are named according to both their chemical composition and texture. Basalt is a very common volcanic rock with low silica content. Rhyolite is a volcanic rock with high silica content. Rhyolite has silica content similar to that of granite while basalt is compositionally equal to gabbro.
Pozzolana from Mount Vesuvius volcano, Italy. Pozzolana or pozzuolana (/ ˌ p ɒ t s (w) ə ˈ l ɑː n ə / POT-s(w)ə-LAH-nə, Italian: [potts(w)oˈlaːna]), also known as pozzolanic ash (Latin: pulvis puteolanus), is a natural siliceous or siliceous-aluminous material which reacts with calcium hydroxide in the presence of water at room temperature (cf. pozzolanic reaction).
This figure describes the geological aspects and processes of the carbonate silicate cycle, within the long-term carbon cycle. The carbonate–silicate geochemical cycle, also known as the inorganic carbon cycle, describes the long-term transformation of silicate rocks to carbonate rocks by weathering and sedimentation, and the transformation of carbonate rocks back into silicate rocks by ...
A volcanic eruption is essentially the only natural way for short-lived – less than a few years – gases like sulfur dioxide and water vapor to make it into the stratosphere.
LSi can either be accumulated "directly" in marine sediments as clastic particles or be transferred into dissolved silica (DSi) in the water column. Within living marine systems, DSi is the most important form of silica [4] Forms of DSi, such as silicic acid (Si(OH) 4), are utilized by silicoflagellates and radiolarians to create their mineral skeletons, and by diatoms to develop their ...