S.M. Hubbard, A. Fildani, 2009. "Outcrop 14. Tres Pasos Formation Slope Complex, Sierra Dorotea Outcrop Belt", Stratigraphic Evolution of Deep-Water Architecture: Examples of controls and depositional styles from the Magallanes Basin, southern Chile, Andrea Fildani, Stephen M. Hubbard, Brian W. Romans, J.A. Covault, W.H. Crane, A. Bernhardt, Z.R. Jobe, D.A. Armitage, J.C. Fosdick, M.R. Shultz, J. Clark, D.R. Lowe, S.A. Graham
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Outcrop accessibility: easy to moderate Outcrop Coordinates: 51.3696°S, 72.4210°W Refer to outcrop 14 on location map
A thick sandstone package (~350 m) characterizes the Tres Pasos Formation outcrop between Laguna Figueroa and Arroyo Picana along the Puerto Natales-Cerro Castillo highway (Fig. 14.1). Overlying this sandstone package is a succession of mudstone-dominated strata on the order of 1000 m thick. Sierra Dorotea is capped by deltaic deposits of the Dorotea Formation. In the satellite image presented in Figure 14.1, the northern part of Sierra Dorotea, Cerro Sol and Cerro Cazador are featured. The interpreted stratigraphic architecture consists of large-scale slope surfaces (Chingue, Figueroa, and Puma) building southward (the image is oriented along depositional dip). Sandstones of the Tres Pasos Formation at Laguna Figueroa are interpreted as base-of-slope deposits. Conversely, the corresponding topset units are attributed to the shallow-marine Dorotea Formation. Individual slope surfaces are locally identified as resistant ridges in the satellite image (surface length ~30–35 km; surface stratigraphic relief ~1600 m; slope angle ~2.5–3 degrees). A schematic diagram of the architecture in the region is presented inFigure 14.3, incorporating the location of the El Chingue Bluff slope minibasin fill within the regional context (Outcrop 13).
Architectural elements along the lower part of slope surfaces include mud clast-filled bypass channels, channelized sheets and sandstone-filled channels, featured on the following pages.
Figures & Tables
Stratigraphic Evolution of Deep-Water Architecture: Examples of controls and depositional styles from the Magallanes Basin, southern Chile
This large format (11 × 17 inch) all color outcrop atlas and field guide was produced for the SEPM Research Conference held in Chile in February, 2009. It contains a wealth of information on the world class deep water outcrops of the Cretaceous of the Magallanes Basin in the Ultima Esperanza District, Chilean Patagonia. This book covers the significant outcrops in the region the Punta Barrosa Formation, CerroToro Fm., and the Tres Pasos Fm.