Authigenic 2 : A clay or other mineral that was formed within the pore spaces of the rock. The material is most often formed by reaction or precipitation from connate fluids
George E. King Engineering, 5000 Oilfield Terms: A Glossary of Petroleum Engineering Terms, Abbreviations and Acronyms, US 2010. http://gekengineering.com/Downloads/Free_Downloads /Glossary_of_Petroleum_Engineering_Terms_25_August _2010.pdf, (Oil - Amer) {593}