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Sandstone pseudomorphs of aragonite fossils in an Ordovician vadose zone
Author(s) -
HANKEN NILSMARTIN
Publication year - 1979
Publication title -
sedimentology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.494
H-Index - 108
eISSN - 1365-3091
pISSN - 0037-0746
DOI - 10.1111/j.1365-3091.1979.tb00343.x
Subject(s) - geology , vadose zone , aragonite , calcite , pseudomorph , clastic rock , geochemistry , diagenesis , ordovician , meteoric water , paleontology , sedimentary rock , quartz , groundwater , hydrothermal circulation , geotechnical engineering
Moulds after aragonite fossils from two Upper Ordovician limestones in the Oslo Region are filled with well sorted clastic fine sand. The fossil moulds are thought to have been formed by selective dissolution of aragonite shell material by fresh water in the vadose zone. Internal sedimentation post‐dates precipitation of a thin veneer of iron poor drusy calcite cement, but predates precipitation of ferroan blocky calcite cement. These age relationships and the texture of the fine sand suggests sedimentation in semiconsolidated sediment in the vadose zone of an island during early emergence.