Fluvial-derived Turbidites in the Los Molles Formation (Jurassic of the Neuquén Basin): Initation, Transport, and Deposition

PAIM, PAULO; LAVINA, ERNESTO; FACCINI, URBIRATAN ; DA SILVEIRA, ARIANE; LEANZA, HÉCTOR; D'AVILA, ROBERTO

AAPG Studies in Geology

AAPG

Año: 2011 p. 95 - 116

0271-8510

This chapter is about an almost uninterrupted exposure of the Jurassic Los Molles Formation in theArroyo La Jardinera region in the southernNeuquen Basin (western Argentina). It is based on the analysis of high-esolution satellite images linked with extensive field data. Its main goal is to present a conceptual model for the studied turbidite systemcapable of explaining how sand and gravel were brought onto and removed from the shelf margin and how these coarse-grained sediments were transported along and deposited on the slope and basin plain. The facies tract ascribed to this turbidite system represents high- frequency lowstand system tracts. From proximal to distal, it includes the record of fluvial channels incised into mid- to outer-shelf deposits, turbidite channels scoured on slope strata, turbidite lobes resting on slope rise facies, and poorly developed turbidite lobe fringes enclosed within basin plain strata. These gravity flow strata were assigned to short-lived (surges) moderately efficient turbidity currents derived from the almost continuous failure of delta-front deposits (sand and gravel) during ordinary fluvial floods.