Changes

In the Cretaceous, when the break up of Pangaea reached South America and South Africa a huge amount of lava flowed through the fissures and cracks, creating a impermeable thick basalt cover. Later, cycles of glaciation and deglaciation created fissures and cracks in this basalt cover allowing water from ice melting and precipitation to infiltrate and, thus, form the aquifer.  The water has first to infiltrate the basalt through the fractures and through the porous until it percolates into the sandstones.

In the Cretaceous, when the break up of Pangaea reached South America and South Africa a huge amount of lava flowed through the fissures and cracks, creating a impermeable thick basalt cover. Later, cycles of glaciation and deglaciation created fissures and cracks in this basalt cover allowing water from ice melting and precipitation to infiltrate and, thus, form the aquifer.  The water has first to infiltrate the basalt through the fractures and through the porous until it percolates into the sandstones.

'''Some hydrogeologic characteristics:'''  

'''Some hydrogeologic characteristics (Betiollo, 2006)<ref name=Bertiollo_2006>Betiollo, L. M. , 2006, CARACTERIZAÇÃO ESTRUTURAL, HIDROGEOLÓGICA E HIDROQUÍMICA DOS SISTEMAS AQUIFEROS GUARANI E SERRA GERAL NO NORDESTE DO RIO GRANDE DO SUL, BRASIL, CPRM MEDIA, p.72</ref>:'''  

* A system with unconfined and confined parts

* A system with unconfined and confined parts