[Corals reef of the Upper Oligocene-Lower Miocene, of Turrialba, Costa Rica].
The outcrops at Jesús Maria (Turrialba, Cartago Province, Costa Rica) present limestone sequences 12 to 30 m thick (packstones: biolithites, biomicrites; and wackstones: biosparites, biomicrosparites), sandstones and conglomerates of Upper Oligocene-Lower Miocene age, correlated to the Punta Pelada Formation. The limestones are characterized by patch reefs with an irregular distribution and a reduced lateral extension (50 m), composed of corals (40%), calcareous algae and foraminiferans (30%), mollusks (20%), and in minor amounts fragments of barnacles, decapods, echinoderms and bryozoans. They consisted of low diversity communities possibly due to diverse geographical, geological and tectonic factors: a narrow continental shelf, very shallow and isolated environments, sea level fluctuations, and exposure to clastic sedimentation associated with intermitent volcanic activity. Equity was also low, with corals making up 40% of all macrofossils, and one species, Antiguastrea cellulosa, as predominant (80% of the corals present). These bioconstructions were developed in an open circulation lagoon environment with transitions, in several occasions, to shallower environments represented by elastic sediments.
Aguila
T
T
Escuela Centroamericana de Geología, Universidad de Costa Rica, 214-2060, San José, Costa Rica. aaguilar@cariari.ucr.ac.cr
Cortés
J
J
D000818:Animals; D037421:Anthozoa; D044822:Biodiversity; D002119:Calcium Carbonate; D003364:Costa Rica; D019015:Geologic Sediments; D012623:Seawater
D002119:Calcium Carbonate