Date of Award


Document Type


Degree Name

Bachelor of Science (BS)




A Lower Permian phylloid algal bioherm, developed in the middle of the Laborcita Formation near Tularosa, New Mexico, is comprised of blue green algal bound phylloid algal wackestones and packstones. It contains a restricted fauna of erect, interlocking phylloid algae encrusted by wavy, digitate, and botryoidal masses of blue green algae and other minor epibionts. Primary void space developed in the bioherm as shelter cavities beneath phylloid algal thalli. Fan arrays of slightly radial fibrous cement, which appear as dark patches in the core rocks, developed in the submarine environment on masses of blue green algae and on phylloid plates and grew into the shelter cavities. They exhibit three stages of inversion and recrystallization which progressively obscure the original fibrous fabric. The intimate association between robust phylloid algae and encrusting blue green algae, penecontemporaneous marine cementation and infiltration of micrite and layered pelletal micrite between algal thalli controlled mound development.

After deposition of the mound, subaerial diagenesis created an extensive network of interconnected solution voids which transect primary structures. Subsequently, the bioherm was saturated by fresh water below the water table where the solution voids were lined by a clear, equant to slightly bladed, isopachous cement. A second solution initiated neomorphism of micrite and allochems to microspar and precipitated a clear, coarsely crystalline, calcite mosaic in remaining void space.