Azoic


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Related to Azoic: Azoic Age

Azoic

[ā′zō·ik]
(geology)
That portion of the earlier Precambrian time in which there is no trace of life.
References in periodicals archive ?
The European Commission has adopted a new Directive prohibiting chromium-based azoic colours for dying textiles (more commonly known as azo-dyes), a ban that must take effect no later than June 30, 2004.
The lack of light, the extremely high pressure even at moderate depths (hydrostatic pressure increases by 1 atmosphere with every 33 ft [10 m] depth) and the predictable lack of food due to the absence of primary producers, led the English naturalist Edward Forbes to formulate the azoic theory at the middle of the last century.
Only about 150 years ago, biologists were convinced that the deep ocean was an "azoic zone" where crushing pressure made life impossible.
The Ministry of Environment and Forests is imposing a ban on the manufacture in India of the 190 prohibited dyes, including 84 direct dyes, 30 acid dyes, 16 disperse dyes, 11 basic dyes, 11 azoic dyes and 38 pigments.
Since the oyster shell used in this study was azoic, it is likely that megalopae were responding more to a tactile stimulus (physical and hydrodynamic) rather than a chemical one in their choice of shell over mud.
It is used for the synthesis of reactive, direct, azoic, acidic, vat, anthraquinone, indigo, phthalocyanine, carbonium, polymethine, and nitro dye.
Dyes may also be classified according to their solubility into soluble dyes like acid, basic, metal complex, direct, mordant, and reactive dyes or insoluble dyes including sulfur, azoic, vat, and disperse dyes.