The Tithonian chrono-biostratigraphy of the Neuquén Basin and related Andean areas: A review and update

Abstract

The main objective of this study is to provide a review of the Tithonian succession of the Neuquén Basin and related Andean areas with an update from recent results on biostratigraphy and radio-isotopic geochronology. The studied successions include continental clastics and volcaniclastics of the Tordillo Formation and economically-important hydrocarbon source rocks such as the widespread black shales of the Vaca Muerta Formation, which has been ranked in recent studies as one of the most important recoverable shale oil and gas resources at global level. Significant recent data include the discovery of hyaline calpionellids associated with global nannofossil markers which are relevant to investigations of the definition of the Tithonian/Berriasian boundary. In addition, new high precision radio-isotopic data provide robust evidence to modify the absolute ages presently assigned to the base and top of the Tithonian Stage by the International Commission on Stratigraphy.