Outcrop 5. NW Margin of the Paine ‘C’ Channel Complex, Silla Syncline

Abstract Outcrop accessibility: easy Outcrop Coordinates: 51.1199°S; 72.9701°W Refer to outcrop 5 on location map The northwestern portion of the Paine C channel complex (Fig. 5.1A) is easily accessible from the Torres del Paine park highway. Exposures of the Paine C continue throughout the axis of the Silla Syncline from the park highway south to Laguna Negra (Fig. 5.1B). Stratigraphically, the Paine C lies directly above a regionally correlated mass transport complex informally named the Laguna Negra Debris Flow (Fig. 5.1C). The channels within the complex show overall paleoflow toward the southeast and south (Figs. iii.5 and 5.1C). The greatest preserved thickness of channel deposits trends southeast from section 11 to section 21 at the southeastern edge of the syncline (Fig. 5.1B). Given the orientation of the channel complex with respect to paleoflow, the limbs of the Silla Syncline expose a somewhat oblique cross-sectional view of the Paine C channel complex (Fig. 5.1C). Measured sections along the west limb of the syncline demonstrate that the Paine C thickens progressively to the south by the addition of sediment at the top of the section. A minimum of six stacked channel margins are present between the park highway and Lago Sarmiento Chico (Fig. 5.1C). Channel margins are identified by erosional surfaces which may or may not be mudstone draped and against which sandstones, conglomerates and interbedded sandstone and mudstone units onlap. The approximate locations of