Discovery and characterization of a struvite layer in the Chalco paleolake, Mexico

Centimeter-sized crystals of struvite (MgNH4PO4 center dot 6H(2)O) were found during the drilling of a core from Chalco paleolake, Mexico for paleoecological and paleoclimatical research. Struvite is a biogenic mineral, unstable in most geological environments. The unusual si.:e and preservation of these struvite crystals allowed us to perform a chemical and mineralogical characterization. This is the first record of struvite flans a geological locality in Mexico, and one oldie most remarkable in the world.