ABSTRACT
Caliche developed on the Holocene surface and at two Pleistocene horizons on Big Pine Key occurs primarily in two modes: distinctly laminated crusts and irregular, unlaminated alteration zones. Both fabrics are part of a spectrum of textures that result from subaerial exposure of carbonate sediments. Components of caliche include micrite, equant spar, fibrous Mg-calcite, random needle fibres, peloids, calcified filaments and microborings. The formation of distinctively laminated caliche crusts is a common phenomenon, but such horizons are not always developed or may subsequently be eroded. Consequently, it is important to recognize the more subtle, often thicker, underlying alteration zone. Comparison of Quaternary caliches with ancient caliches illustrates that they share common fabrics and probably a common origin.
