Genesis of banded iron formations: A series of experimental simulations

•A suite of self-designed glasswares to model the genesis of BIFs•Weathering–leaching of basalt by acidic meteoric water formed silica precipitates.•Weathering–leaching of basalt by CO2-rich meteoric water formed BIFs.

A series of experimental simulations of the genetic mechanism of banded iron formations has been conducted using a suite of self-designed glassware to model the hypergene circulation of surface water.The simulation process involved two parts: in the first part, the weathering and leaching of basalt by strongly acidic meteoric water during early Precambrian volcanism would have resulted in amorphous silica precipitation and strongly acidic ore-bearing solutions (pH < 1.25). And in the second part, during quiescent volcanism, the weathering and leaching of basalt by CO2-saturated meteoric water without contamination of other volcanic gases would increase the pH value of the solution. When the pH increased to 1.25–5.50, ferric hydroxides and amorphous silica would alternately precipitate owing to periodic heating and continuous addition of high-pH basalt-leaching solutions. This is a possible explanation of the genetic mechanism of the Algoma-type banded iron formations.