<p>Calcite-forming by bacteria has been reported in various geological environments including limestone caves, and soil. There are four natural processes by which calcite is formed: carbonic anhydrase (CA), sulphate reduction, nitrate reduction, and urea hydrolysis. ...

The Amu-Darya basin is a highly productive petroleum province in Turkmenistan and Uzbekistan (former Soviet Union), extending southwestward into Iran and southeastward into Afghanistan. This bulletin presents of an assessment of this basin.

map showingthe distribution of karst in the United States

<p>The petrographic features of the carbonate rocks from the Ionian Zone in the Etoloakarnania Prefecture are presented. They are represented by limestones with minor dolomite. The limestones include:<br />(i) wackestones (or sparse micrites), with poor presence ...