volcanic ash
Noun
Meaning
volcanic ash (usually uncountable, plural volcanic ashes)
(geology) Fragments of pulverized rock, minerals and volcanic glass created during a volcanic eruption.
Synonyms
Examples
Agriculture Fava Santorinis Because of its unique ecology and climate, and especially its volcanic ash soil, Santorini is home to unique and prized produce.
Amorphous clays Amorphous clays are young, and commonly found in volcanic ash.
Dating of lava and volcanic ash layers found within a stratigraphic sequence can provide absolute age data for sedimentary rock units which do not contain radioactive isotopes and calibrate relative dating techniques.
Fortunately, in the Oman sequence, so too does a volcanic ash horizon from which zircons provide a very precise age of 541 ± 0.3 mya (calculated on the decay rate of uranium to lead).
Radioactive elements are common only in rocks with a volcanic origin, and so the only fossil-bearing rocks that can be dated radiometrically are volcanic ash layers, which may provide termini for the intervening sediments.
Potential for additional productivity from fallow land was questionable, however, because much of Honduras's soil lacks the thick volcanic ash found elsewhere in Central America.