Slab of algal limestone from base of Worland Limestone

View close-ups of Section A
View close-ups of Section B
View close-ups of Section C

Polished slab of limestone containing encrusting calcareous algae from
the base of the Worland Limestone. The matrix consists of algal fragments,
small articulated brachiopods, and articulated and disarticulated ostracodes
embedded in micrite. The close-ups for section B show numerous thin algal
laminae, some separated by thinner cream-colored clay layers. Similar
laminae were broken up and redeposited to form tiny algal fragments in
matrix. The circular object above the 9 cm mark on the ruler is a sponge
encrusted by calcareous algae. The porous nature of the sponge tissue is
visible in the most enlarged portion of section B. The thin section of the
same slab shows spicules within the sponge wall. Profuse algal growth
suggests deposition in well-lit, shallow water. Fragmentation of the algal
crusts and plates indicates energetic waves and current action.

View thin section

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