Polished stone: carbonate rock textures
Detail from a slab of decorative building stone in Calgary. The discrete horizontal layers (beds) are each about 1 cm thick.
This is a complex bit of rock -- only those who know a bit about carbonate sedimentology will be able to 'decode' the geological data recorded in this rock. Some of the white layers contain radiating clusters of elongate (bladed) calcite crystals and vague dendritic textures, and some of the round sand-size grains are concentrically layered (coated grains). Long flat grains are eroded, locally sourced (intraclastic) bits of microlaminated sediment. The best interpretation is that this probably a travertine; other very similar rock slabs at this site (same layering -- probably from the same block of quarried rock) contain more textural data consistent with a travertine origin (carbonate mound, hot or cold spring) and/or a microbial laminite origin (e.g., carbonate tidal flat).
C. J.R. Devaney
Polished stone: carbonate rock textures
Detail from a slab of decorative building stone in Calgary. The discrete horizontal layers (beds) are each about 1 cm thick.
This is a complex bit of rock -- only those who know a bit about carbonate sedimentology will be able to 'decode' the geological data recorded in this rock. Some of the white layers contain radiating clusters of elongate (bladed) calcite crystals and vague dendritic textures, and some of the round sand-size grains are concentrically layered (coated grains). Long flat grains are eroded, locally sourced (intraclastic) bits of microlaminated sediment. The best interpretation is that this probably a travertine; other very similar rock slabs at this site (same layering -- probably from the same block of quarried rock) contain more textural data consistent with a travertine origin (carbonate mound, hot or cold spring) and/or a microbial laminite origin (e.g., carbonate tidal flat).
C. J.R. Devaney