KLAUS F. PRÖSSL, JOACHIM R. GRÖSSER; Pyritized microfossils in palynological slides from the Late Cretaceous of Colombia. Journal of Micropalaeontology ; 28 (1): 45–52. doi: https://doi.org/10.1144/jm.28.1.45
Palynological investigations of Late Cretaceous to Tertiary sediments of the Andes in Colombia yielded some distinct groups of palynoclasts recovered as pyritized remains of diatoms, radiolaria and foraminifera. The different processes of pyritization are illustrated and the palaeontological use of these fossils is discussed. Techniques for investigating such opaque microfossils are also suggested.