Structural, tectonic and glaciological controls on the evolution of fjord landscapes
The fjord landscape of South America, stretching ~ 1500 km between Golfo Corcovado (~ 43°S) and Tierra del Fuego (~ 56°S), is the largest continuous fjord landscape on Earth. This paper presents the results of new structural geological and geomorphological mapping of this landscape using optical sat...
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todo:paper_0169555X_v105_n3-4_p291_Glasser2023-10-03T15:07:12Z Structural, tectonic and glaciological controls on the evolution of fjord landscapes Glasser, N.F. Ghiglione, M.C. Fjords Glacial geomorphology Patagonia South America Structural geology Tectonics Cretaceous digital elevation model fjord geological structure geomorphology glaciology ice sheet landscape evolution lineament satellite imagery strike-slip fault Patagonia South America The fjord landscape of South America, stretching ~ 1500 km between Golfo Corcovado (~ 43°S) and Tierra del Fuego (~ 56°S), is the largest continuous fjord landscape on Earth. This paper presents the results of new structural geological and geomorphological mapping of this landscape using optical satellite images and digital elevation models. First-order geological structures are represented by strike-slip faults forming lineaments up to hundreds of kilometres long. The strike-slip faulting has been active since Late Cretaceous times and is responsible for the presence of a conspicuous structural cleavage visible as lineaments up to ~ 10 km long. A detailed analysis of these second-order lineaments from digital image data was carried out in three sectors. In Sector 1, located northwest of the North Patagonian Icefield, there are three distinct mean orientations, characterized by a main nearly orogen-parallel orientation (az. ~ 145°) and two orogen-oblique secondary orientations (az. ~ 20° and az. ~ 65°). In Sector 2, located west of the South Patagonian Icefield, there are also three separate mean orientations, with most of the lineaments concentrated between azimuths 0° and 80° (mean at ~ 36°); and two other orogen-oblique means at azimuth ~ 122° and ~ 163°. In Sector 3, around the Cordillera Darwin, there is a single main orogen-parallel mean at ~ 100-115°. In all three sectors, mapped fjord orientations bear a striking similarity to the structural data, with fjords orientated preferentially in the same direction as structural lineaments. We infer that successive glaciations followed the same ice-discharge routes, widening and deepening pre-existing geological structures at the expense of the surrounding terrain to create the fjord landscape. This study has broader implications for ice sheet reconstructions and landscape evolution beneath ice sheets because we demonstrate that the primary control on fjord development in glaciated areas is geological and not glaciological. © 2008 Elsevier B.V. All rights reserved. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_0169555X_v105_n3-4_p291_Glasser |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Fjords Glacial geomorphology Patagonia South America Structural geology Tectonics Cretaceous digital elevation model fjord geological structure geomorphology glaciology ice sheet landscape evolution lineament satellite imagery strike-slip fault Patagonia South America |
| spellingShingle |
Fjords Glacial geomorphology Patagonia South America Structural geology Tectonics Cretaceous digital elevation model fjord geological structure geomorphology glaciology ice sheet landscape evolution lineament satellite imagery strike-slip fault Patagonia South America Glasser, N.F. Ghiglione, M.C. Structural, tectonic and glaciological controls on the evolution of fjord landscapes |
| topic_facet |
Fjords Glacial geomorphology Patagonia South America Structural geology Tectonics Cretaceous digital elevation model fjord geological structure geomorphology glaciology ice sheet landscape evolution lineament satellite imagery strike-slip fault Patagonia South America |
| description |
The fjord landscape of South America, stretching ~ 1500 km between Golfo Corcovado (~ 43°S) and Tierra del Fuego (~ 56°S), is the largest continuous fjord landscape on Earth. This paper presents the results of new structural geological and geomorphological mapping of this landscape using optical satellite images and digital elevation models. First-order geological structures are represented by strike-slip faults forming lineaments up to hundreds of kilometres long. The strike-slip faulting has been active since Late Cretaceous times and is responsible for the presence of a conspicuous structural cleavage visible as lineaments up to ~ 10 km long. A detailed analysis of these second-order lineaments from digital image data was carried out in three sectors. In Sector 1, located northwest of the North Patagonian Icefield, there are three distinct mean orientations, characterized by a main nearly orogen-parallel orientation (az. ~ 145°) and two orogen-oblique secondary orientations (az. ~ 20° and az. ~ 65°). In Sector 2, located west of the South Patagonian Icefield, there are also three separate mean orientations, with most of the lineaments concentrated between azimuths 0° and 80° (mean at ~ 36°); and two other orogen-oblique means at azimuth ~ 122° and ~ 163°. In Sector 3, around the Cordillera Darwin, there is a single main orogen-parallel mean at ~ 100-115°. In all three sectors, mapped fjord orientations bear a striking similarity to the structural data, with fjords orientated preferentially in the same direction as structural lineaments. We infer that successive glaciations followed the same ice-discharge routes, widening and deepening pre-existing geological structures at the expense of the surrounding terrain to create the fjord landscape. This study has broader implications for ice sheet reconstructions and landscape evolution beneath ice sheets because we demonstrate that the primary control on fjord development in glaciated areas is geological and not glaciological. © 2008 Elsevier B.V. All rights reserved. |
| format |
JOUR |
| author |
Glasser, N.F. Ghiglione, M.C. |
| author_facet |
Glasser, N.F. Ghiglione, M.C. |
| author_sort |
Glasser, N.F. |
| title |
Structural, tectonic and glaciological controls on the evolution of fjord landscapes |
| title_short |
Structural, tectonic and glaciological controls on the evolution of fjord landscapes |
| title_full |
Structural, tectonic and glaciological controls on the evolution of fjord landscapes |
| title_fullStr |
Structural, tectonic and glaciological controls on the evolution of fjord landscapes |
| title_full_unstemmed |
Structural, tectonic and glaciological controls on the evolution of fjord landscapes |
| title_sort |
structural, tectonic and glaciological controls on the evolution of fjord landscapes |
| url |
http://hdl.handle.net/20.500.12110/paper_0169555X_v105_n3-4_p291_Glasser |
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AT glassernf structuraltectonicandglaciologicalcontrolsontheevolutionoffjordlandscapes AT ghiglionemc structuraltectonicandglaciologicalcontrolsontheevolutionoffjordlandscapes |
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