Deep-marine hyperpycnal channel-levee complexes in the Miocene of Tierra del Fuego, Argentina: Architectural elements and facies associations.

J. J. PONCE; E. B. OLIVERO; D. R. MARTINIONI

Ushuaia

Conferencia; AAPG Hedberg Research Conference: Sediment Transfer from Shelf to Deepwater - Revisiting the Delivery Mechanisms; 2008

American Association of Petroleum Geologists

SUMMARIZED CONTENT:   In the Miocene Cabo Viamonte beds, Austral Basin of Tierra del Fuego, deep-marine channel-levee complexes (CLC) were recognized at the toe of depositional slope breaks in sigmoid clinoforms. In contrast to published models of submarine fans, outcrop studies and inspection of seismic lines in Tierra del Fuego indicate that these CLC are not associated with canyons or other similar flow conduits. The channel deposits show complex internal geometries characterized by multiple, large-scale, lenticular cut-and-fill structures. Individual depositional units bear abundant fossil leaves and phytodetritus, and show recurrent lateral transition of current sedimentary structures that reflect fluctuations in flow velocity. These features suggest that the deposits of the CLC of the Cabo Viamonte beds accumulated from sustained and pulsating gravity flows generated by extraordinary fluvial discharges entering into the sea as hyperpycnal flows. The main objectives of this paper are to characterize the architectural elements, sedimentary facies, and facies associations of the hyperpycnal CLC systems from Tierra del Fuego and to discuss the sedimentary mechanisms involved in the generation of their complex fill.   -   (FULL TEXT: http://www.searchanddiscovery.net/abstracts/html/2008/hedberg_argentina/extended/ponce/ponce.htm)