As stated in one of the contributions to this volume, the Neuquen Basin-covering more than 160,000 km2 between c. 32° and 42° S and 68° and 71° W, and containing a Meso-zoic-Cenozoic sedimentary succession at least 7 km thick-is perhaps one of the most thoroughly prospected areas in Argentina. Its geological study goes back to the 19th Century, and shows an exponential increase throughout the 20th, when it became the main source of Argentine oil and gas production.