GEO-HISTÓRIA DA BACIA DE CAMPOS, BRASIL: DO ALBIANO AO MAASTRICHTIANO

The Cretaceous foraminifera fauna of nearly 50 wells drilled in the Campos Basin has been searched for paleoecological purposes. The paleogeographical development of the area has been reconstructed by means of maps concerning each of the stratigraphical intervals recognized. Marine sedimentation in the area began in the Early to Middle Albian with the deposition of carbonates in hypersaline, shallow neritic environrnent. Later, during the Late Albian/Early Turonian, the regional bathymetric conditions became some what deeper (deep neritic/upper bathyal), thus allowing the system to attain normal salinity. During the same period the basin was submitted to an anoxic event of worldwide extent. ln the Middle to Late Turonian, the ecological and geographical conditions were thoroughly modified by the settlement of bathyal environments over wide areas of the basin. Since then, during the whole Late Cretaceous, sediments were deposited under greater depths, though the water masses remained well oxygenated and allowed a textulariid benthic fauna thrive in the area.