Linking orogenic deformation, exhumation, and basin evolution in the Patagonian Andes and Magallanes Basin, southernmost South America
Abstract/Contents
- Abstract
- Convergent orogenic belts evolve through the interactions among topographic growth by crustal thickening and magmatic arc emplacement, lithospheric deformation, and mass redistribution by surface processes. While feedbacks among these processes are becoming well-understood for orogenic systems within cratonal or continental lithosphere, mountain belts that evolve in predecessor backarc and rift settings appear to exhibit fundamental differences in structural style and basin physiography. This dissertation investigates the thermotectonic evolution of the Patagonian Andes and Magallanes retroforeland basin of southernmost South America and demonstrates that inherited tectonic history can profoundly affect the style of subsequent crustal deformation, spatio-temporal distribution of rock unroofing, and many aspects of foreland basin character. Geologic mapping across the Patagonian fold-thrust belt and subsurface foreland basin stratigraphy documents ~32-40 km (19-23%) of retroarc crustal shortening and inversion of rift-related structures. This work identifies an important shift from thin-skinned thrusting across the Late Cretaceous thrust belt to early Miocene deep-seated thrusting and uplift of the Cretaceous foreland depocenter. Apatite and zircon (U-Th)/He results from across the sub-Andean orogen show that the locus of deep crustal exhumation has migrated eastward from the batholith since ca. 30 Ma. Deep exhumation has been focused on the retroarc (leeward) side of the Patagonian Andes since ca. 22-18 Ma, coeval with structural uplift and unroofing of the fine-grained siliciclastic strata in the sub-Andean thrust sheets. Detrital thermochronology and thermal modeling results indicate that (1) sedimentary burial of the Paleocene basin-fill was much deeper than previously thought, and (2) sediment recycling of Mesozoic basement zircons in Upper Cretaceous foredeep deposits was an important sediment source for the Oligocene-Miocene depocenter. Finally, elasto-plastic modeling of lithospheric deflection in the Upper Cretaceous Magallanes Basin suggests that plastic yielding during plate bending appears to be an important mechanism of lithospheric deformation in successor foreland basins. These findings have important implications for interpreting tectonic histories from basin stratigraphy and dispersal patterns compared to foreland basins that develop on cratonal lithosphere.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2011 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Fosdick, Julie Catherine |
|---|---|
| Associated with | Stanford University, Department of Geological and Environmental Sciences. |
| Primary advisor | Graham, S. A. (Stephan Alan), 1950- |
| Thesis advisor | Graham, S. A. (Stephan Alan), 1950- |
| Thesis advisor | Dumitru, Trevor (Trevor Alan) |
| Thesis advisor | Grove, Marty, 1958- |
| Thesis advisor | Hilley, George E |
| Advisor | Dumitru, Trevor (Trevor Alan) |
| Advisor | Grove, Marty, 1958- |
| Advisor | Hilley, George E |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Julie Catherine Fosdick. |
|---|---|
| Note | Submitted to the Department of Geological and Environmental Sciences. |
| Thesis | Ph. D. Stanford University 2011 |
| Location | electronic resource |
Access conditions
- Copyright
- © 2011 by Julie Catherine Fosdick
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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