Deformed Ooid and Pressure Shadow

Thin section (crossed polars, quartz plate) of deformed oolitic limestone, Wales. The structure of the originally concentric ooid has been truncated by pressure solution (e.g., red arrow), and the ooid shells have been extended due to the fibrous growth of quartz and calcite (e.g., blue arrow) in the principal extension direction. Photo credit: John Ramsay.