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Alegret, Ortiz & Kaminski (eds.), 2012. Ninth International Workshop on Agglutinated Foraminifera, Abstract Volume Reolid, M., Sebane, A., Rodríguez-Tovar, F.J. & Marok, A. 2012. Foraminiferal morphogroups as a tool to approach the Toarcian Anoxic Event in the Western Saharan Atlas (Algeria). Palaeogeography, Palaeoclimatology, Palaeoecology, 323–325, 87–99. Suan, G., Nikitenko, B.L., Rogov, M.A., Baudin, F., Spangenberg, J.E., Knyazev, V.G., Glinskikh, L.A., Goryacheva, A.A., Adatte, T., Riding, J.B., Föllmi, K.B., Pittet, B., Mattioli, E. and Lécuyer, C. 2011. Polar record of Early Jurassic massive carbon injection. Earth and Planetary Science Letters, 312, 102–113. Wignall, P.B., Newton, R.J. & Little, C.T.S. 2005. The timing of paleoenvironmental change and cause-and-effect relationships during the Early Jurassic mass extinction in Europe. American Journal of Science, 305, 1014–1032. 83
Alegret, Ortiz & Kaminski (eds.), 2012. Ninth International Workshop on Agglutinated Foraminifera, Abstract Volume Regional diversity of agglutinated foraminifera from western and eastern Venezuela (Neogene to Pliocene). A preliminary report Dennis SANCHEZ Petroleos de Venezuela Sociedad Anonima (PDVSA). Gerencia General de Exploracion y Estudios Integrados, Laboratorio Geologico El Chare. Avenida Igor Rodriguez, Edificio Principal Oficina 3 e-mail: sanchezdk@pdvsa.com The present study describes the Early Miocene to Pliocene diversity of agglutinated foraminifera from three different sections in Venezuela. These include: 1) Agua Salada Group, western Venezuela (Falcon Basin), 2) Carapita Formation Eastern Venezuela Basin (EVB) and 3) Offshore Venezuela (Tres Puntas, Cubagua and Cumana formations). The main objective of this study is to establis a precise correlation of these stratigraphic units using well-preserved agglutinated foraminifera from the AGS and Carapita outcrops and to compare them with porly preserved microfaunas from the exploration wells. Age determinations were possible using planktonic foraminifera interpolated or adapted from the Cenozoic tropical planktonic foraminiferal scheme of Wade et al. (2011). To determine the general depth distribution I have used classical publications such as Renz (1948), Phleger and Parker (1951), Bandy (1967), van Morkhoven et al. (1986), Whittaker (1988), Robertson (1988) and Kaminski and Gradstein (2005). Terminology and numerical bathymetric estimates were taken from van Morkhoven et al. (1986). Important studies have been made on the Agua Salada Group (ASG). H.H. Renz (1948) was the first to chart the Neogene diversity of agglutinated foraminifera from the Falcon Basin (ASG) and compare them with different localities from the Caribbean. The type section of the Agua Salada Group is located northwest of the town of Chichiriviche between the locality of El Pozon and The Menes of Acosta, Falcon State. In the EVB the Carapita Formation is ~ 4500 to 6000 m thick in outcrops, extending from northeastern Anzoátegui and North of Monagas States to the Gulf of Paria. This formation is both an important oil reservoir towards the east and the main seal rock for the Late Oligocene to the Early Miocene reservoir in the north of Monagas State. Important studies have been made on the Carapita Formation by Hedberg (1937), Franklin (1944) and a series of internal/unpublished foraminiferal reports by the National Oil Company of Venezuela (PDVSA) have been carried out by Fournier (1957), Jouval and Villain (1986), Saint Marc (1988), De Cabrera and De Macquhae (1990) and Sanchez (2006, 2010). In addition samples from 20-exploration wells located offshore Venezuela (Ensenada of Barcelona, West and East Blanquilla, and North of Paria) have been analyzed in this work. In the studied area the ASG spans the Late Oligocene to Late Miocene (zones O6 to M12) and the agglutinated foraminifera assemblages are characterized by: Ammobaculites cf. strathearnensis, Ammodiscus parianus, Glomospira charoides, Cyclammina cancellata, Haplophragmoides carinatum, H. coronatum, H. emaciatum, Textularia abreviata, T. leuzingeri, T. panamensis, T. pozonensis, Textulariella miocenica Trochammina pacifica, Valvulina flexilis, Vulvulina jacuarensis and V. pachyhellus. On the other hand, the Carapita Formation in the outcrop section spans Early to Middle Miocene (zones M3 to M6) and the agglutinated foraminifera assemblages are distinguished by: Dorothia brevis, Cyclammina cancellata, Haplophragmoides carinatum, Valvulina flexilis, Alveovalvulinela pozonensis, Glomospira charoides, Valvulina flexilis, Paratrochamminoides irregularis, Vulvulina jarvisi 84
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