Accumulation of carbonates

 

 

RECRYSTALLIZATION

Soil carbonates, once precipitated, are very frequently subject to recrystallization as can be deduced from following microscopic characteristics:

Interwoven acicular crystals The intersecting acicular crystals can recrystallize as micritic masses.
     
A more heterogeneous size of the grains

Crystals of very heterogeneous size with gradual transition between zones of sparite crystals with distinct sizes, without detectable boundary. The crystals occur clustered in domains which vary in a very irregular way at short distances, with clusters of microsparite (Ø= 4 - 10 microns), pseudosparite (Ø=10 - 50 microns) and sparite (>50 microns).

     
Starlike masses

Starlike masses with a central zone of microsparite or pseudosparite, surrounded by sparite crystals. The sparite crystals are frequently elongated and radially arranged.
     
Sparitic crystals with radial fibrous fabric Elongated parallel arranged sparite crystals with a radial fibrous habit and frequently with undulating extinction, forming coatings.
     
Curved contact Sometimes the recrystallization is expressed by the presence of curved or undulating contacts between sparite grains.

 

 

 

Index | Processes | Previous | Next