Controls on Along-Strike Variations in Stratigraphy and Provenance of a Successor Foreland Basin System, Jurassic-Cretaceous Evolution of the Southern Patagonian Andes and the Magallanes-Austral Basin

• Main Author: Malkowski, Matthew A
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2016
• Subjects: Geology; Plate Tectonics; Sedimentary Geology; Andes Mountains; Patagonia (region)
• ISBN: 9798662546868

Sedimentary basins that develop adjacent to convergent plate margins are intrinsically linked to an array of tectonic processes, including those associated with subduction dynamics, crustal shortening, exhumation and topographic uplift, and lithospheric flexure. In turn, each of these processes help to govern the timing and nature in which sediment is transported from mountain belts to ocean basins. Thus, the stratigraphic fill of sedimentary basins is often the best available record for understanding the integrated evolution of convergent plate margins over geologic time scales. However, deciphering that record can be challenging in basin systems with complex histories that include multiple tectonic regimes, tectonic overprinting, and/or incomplete preservation of stratigraphy. This dissertation examines the influences that tectonic inheritance and predecessor basin history can have on the evolution of successor foreland basin systems. While previous workers have demonstrated the temporal influence of tectonic inheritance, this work assesses the spatial relationships by considering along-strike (orogen-parallel) variations in the timing of tectonic events (rifting, collision, basin initiation), stratigraphy and distribution of facies, and source area exhumation and sediment routing. The following four chapters explore the Jurassic-Cretaceous tectonic evolution of southern Patagonia, which consists of a two-part history that begins with the development of a predecessor backarc rift basin (the Rocas Verdes Basin) and is followed by a successor retroarc foreland basin system (the Magallanes-Austral Basin). Chapter 1 investigates the geochronology of rifting in the predecessor Rocas Verdes Basin from the northern (Austral) basin sector to assess the basin-scale, along-strike variability in relative timing and duration of Jurassic-Early Cretaceous rifting. Chapter 2 examines the distribution of deep-water facies and the relative timing of deposition that represents the transition to, and development of, foreland basin sedimentation in the Magallanes-Austral Basin. Chapter 3 explores the role of longitudinal vs. transverse sediment supply during the early evolution of the Magallanes-Austral foreland basin system. Finally, chapter 4 examines along-strike variations in the provenance, timing of deposition, and distribution of facies within a deep-water canyon channel system represented by the Upper Cretaceous (Turonian-Santonian) Cerro Toro Formation.