Ciltleplates

Ciltleplates are microscopic, plate-like structures classified as a distinct diagenetic fabric in sedimentary rocks. They appear as flat, polygonal laminae composed of alternating mineral sheets and organic-rich interlayers, typically a few tens to a few hundred micrometers across.

Composition and microstructure: The mineral sheets are usually silicate or carbonate minerals, commonly quartz or calcite, with a binding organic phase rich in extracellular polymeric substances produced by micro-organisms. The laminae exhibit slight birefringence under polarized light, and the boundaries are sharp.

Formation and processes: Ciltleplates form during early diagenesis when microbial mats guide mineral precipitation and compaction concentrates organic matter. Recrystallization and pressure solution drive the up-and-down layering, producing the plate-like fabrics. They can occur as isolated plates or as a grid-like mosaic.

Occurrence and significance: Ciltleplates have been reported in sedimentary successions in coastal and shelf environments. They are used as indicators of past microbial activity and diagenetic conditions, offering insights into sedimentary dynamics and paleoenvironmental reconstructions.

Applications and research: In materials science, the concept has inspired studies of oriented platelets in bioinspired composites for lightweight, fracture-resistant materials. In geology, ongoing work seeks to quantify their formation conditions and to develop criteria for distinguishing them from other diagenetic textures.