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Calcareous algae and microbial structures from the Capitan Reef

Calcareous algae are abundant constituents in the Permian rocks of the famous Capitan Reef. Purpose of the present paper is to present and describe calcareous algae and microbial structures from the uppermost Guadalupian Tansill Formation of the Reef complex, Guadeloupe Mountains, New Mexico. Besides algae, the investigated samples contain abundant foraminifera, gastropods, crinoids, Tubiphytes, and lumps. The algae assemblage is dominated by dasycladaleans. Mizziais dominating in samples AM 332, AM 333 and AM 338. Most specimens belong to Mizzia velebitana(including the synonyme morphotype Eogoniolina johnsoni). Two other different species (a larger and a smaller ones) have been also observed. The sample AM 329 is dominated by a Gyroporella species which seems to belong to a new taxon. At least one different Gyroporella species is associated. The gymnocodiacean algae are represented by Permocalculus fragments mostly belonging to Permocalculus plumosus. Solenoporacean red algae are also present as large clasts. Filamentous cyanobacteria consist of hemispherical or elongated small bodies. Microbial activity generated also these “porostromate” structures. The “porostromate” nodules seem to be made by a fenestral- microbial mat trapping peloids and reworked bioclasts (e.g. Gyroporella fragments). It is probably that the microbial activity also contributedto the formation of a stalactitic fibrous cement occurring in some thin sections of the sample AM 329. Finally, the microproblematicum Tubiphytes obscurusis another constituent of the Permian limestones from Capitan Reef, with possible algal- cyanobacterial-microbial affinity.

Permian; algae; microbialites; New Mexico

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