Micromorphology and Classification of Secondary Calcium Carbonate Accumulations that Surround or Occur on the Undersides of Coarse Fragments in idaho (U.S.A.)

Abstract

Various micromorphological techniques were used to characterize and classify secondary calcium carbonate accumulations that surround or occur on the undersides of coarse fragments. Based on micromorphic properties, carbonate accumulations were placed into four categories. "Carbonate rinds" are thin, single-layered, micritic carbonate coatings that uniformly surround fragments. "Carbonate coats" are banded lamina of calcite spar and micrite that accumulate on the undersides of fragments. These accumulations occur where downward carbonate growth is hindered by contact with the soil matrix. "Pendants" are botryoidal to mammillary, stalactite-like, structures that emanate from carbonate coats or rock fragments. These forms occur where downward calcium carbonate growth is not hindered by the soil matrix. "Opaline pendants" are morphologically similar to pendants but have an opal component which imparts brownish-green coloration. © 1990.