IGEBA   23946
INSTITUTO DE GEOCIENCIAS BASICAS, APLICADAS Y AMBIENTALES DE BUENOS AIRES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
New microfossil data for Tithonian?Valanginian interval of Puerta Curaco section, Neuquén basin (Argentina)
Autor/es:
DIEGO ALEJANDRO KIETZMANN; MARIA PAULA IGLESIA LLANOS; DARIA K. IVANOVA1; MELISA KOHAN MARTÍNEZ
Lugar:
Bratislava
Reunión:
Conferencia; 14 Jurassica international conference; 2019
Institución organizadora:
Earth Science Institute
Resumen:
The Early Tithonian-Early Valanginian of the Neuquén Basin, Argentina, is mainly represented by distal marine facies known as Vaca Muerta Formation. This unit has received worldwide attention during the last decade, since the Vaca Muerta Formation is considered as a world-class unconventional oil and gas play, as well as its abundant fossil content and temporal continuity along several hundred meters of section that comprise the Jurassic - Cretaceous boundary. Although considerable work has been done regarding paleontological, sedimentological and stratigraphical aspects, so far there is there is still no full agreement in the biostratigraphic correlations between the Andes and the Tethys. The Puerta Curaco section is a well-exposed stratigraphically continuous basinal section of the Tithonian-Valanginian, located 30 km eastern of the Chos Malal town in the northern part of the Neuquén Embayment. It is located within the thin-skinned Chos Malal fold-and-thrust-belt, which forms part of the Cordillera Principal in the Andes. The Vaca Muerta Formation is formed by a 407 m thick marlstone/limestone rhythmic succession and comprises the Early Tithonian?Early Valanginian Virgatosphinctes andesensis to Neocomites wichmanni Andean ammonite Zones (Kietzmann et al. 2016). The Vaca Muerta Formation in Puerta Curaco area has been interpreted as a shallowing upward carbonate ramp system, characterized by basinal to outer ramp deposits, where 5 composite depositional sequences and 15 high-ordered depositional sequences has been recognized and correlated along several stratigraphic section in the Neuquén basin (Kietzmann et al. 2016). In the section all the Andean ammonite zones were identified and a detailed magnetostratigraphy is being developed, as well as obtaining absolute ages (Kohan Martinez et al. in preparation).Detailed micropaleontological studies of Vaca Muerta Formation (Early Tithonian - Early Valanginian) in the southern Mendoza Neuquén Basin (Puerta Curaco section) demonstrate similarity to the micropaleontological content of outcrops already examined by the same basin: Arroyo Loncoche, Río Seco del Altar and Tres Esquinas sections (Ivanova & Kietzmann, 2017; Kietzmann, 2017). They are all characterized by a relatively rich micropaleontological assemblage of calcareous dinoflagellate cysts, as well as levels with poor preserved calpionellids/calpionellids and benthic foraminifera. In the Early Tithonian ? Early Valanginian interval the dinocysts zones previously proposed for the Tethyan realm and confirmed in the Vaca Muerta Formation (Arroyo Loncoche, Río Seco del Altar and Tres Esquinas sections) were also established in the outcrop of Puarta Curaco: Carpistomiosphaera tithonica, Parastomiosphaera malmica, Colomisphaera tenuis, Colomisphaera fortis, Stomiosphaerina proxima, Stomiosphaera wanneri, Colomisphaera conferta and Carpistomiosphaera valanginiana. The distribution of calpionellid species allows recognizing three of the calpionellid standard zones: Chitinoidella, Crasicollaria and Calpionella Zones.