Structure of the Patagonian Andes: Regional Balanced Cross Section at 50° S, Argentina

Stratigraphic evolution of a submarine channel–lobe complex system in a narrow fairway within the Magallanes foreland basin, Cerro Toro Formation, southern Chile

“…However, the precise timing of the formation of these boundary structures is ambiguous. Additionally, the Silla Syncline lies within a basinwide deformational domain characterized by gentle folding and smalloffset faulting (Wilson, 1983), which is generally regarded to reflect Oligocene-Miocene deformation (Ramos, 1989;Kraemer, 1998;Ramos et al, 2004). Crane and Lowe (2008) inferred that the Silla Syncline formed as a slope or piggyback basin between the western edge of the Andean fold-and-thrust belt and fault-related structural high on the seafloor to the east.…”

Neogene uplift of central eastern Patagonia: Dynamic response to active spreading ridge subduction?

“…Between 47°30′S and 49°S, this shortening resulted in the formation of a complex fold‐and‐thrust belt in which the Tertiary molasse sequence (marine and continental) is involved [ Ramos , 1989]. Shortening varies between 45 and 22 km from the north (47°40′S) to the south (49°S) of the fold‐and‐thrust belt [ Ramos , 1989] and is at least of 35 km during the late Miocene in the fold belt at 50°S [ Kraemer , 1998]. The segment of the Patagonian Andes located north of the present‐day triple junction is characterized by a weaker Oligo‐Miocene shortening, resulting in restricted areas of foreland sedimentation that only accumulated about 100 m of synorogenic deposits [ Ramos and Kay , 1992].…”

Have the southernmost Andes been curved since Late Cretaceous time? An analog test for the Patagonian Orocline

“…These processes resulted in the consolidation of the crystalline domain by latest Cretaceous time, before the formation of the thin-skinned fold-andthrust belt in the early Tertiary (Klepeis and Austin, 1997;Kraemer, 2003). Whereas shortening across the thin-skinned fold-and-thrust belt occurred principally from the middle Eocene to early Oligocene in Tierra del Fuego (Klepeis and Austin, 1997;Ghiglione and Ramos, 2005), deformation and uplift occurred mainly during Miocene time in the Patagonian Andes, although deformation there began during the Eocene (Ramos, 1989;Kraemer, 1998). Furthermore, contractional deformation of the Fuegian Andes stopped during the Oligocene and changed in character to a wrench deformation regime produced by the spread of the transform plate boundary between the South America and Scotia plates named the MagallanesFagnano fault zone (Klepeis and Austin, 1997;Figs.…”

“…1 and 2). The approximate total shortening in the Patagonian external domain is 35 km (~30%) at the northern end of the studied bend (Kraemer, 1998;Fig. 2).…”