Structure and development of the Andean system between 36° and 39°S
One of the main morphological changes along the Southern Central Andes occurs from 36° to 39°S. The northern portion is characterized by prominent basement structures and a thick-skinned orogenic front with relief of over 2000. m with a deep level of exhumation where more than 4. km of section has b...
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todo:paper_02643707_v73_n_p34_RojasVera2023-10-03T15:12:45Z Structure and development of the Andean system between 36° and 39°S Rojas Vera, E.A. Folguera, A. Zamora Valcarce, G. Bottesi, G. Ramos, V.A. Extensional reactivation Fold and thrust belt Neogene contraction Southern Central Andes exhumation extensional tectonics fold and thrust belt geomorphology Neogene orogeny structural geology tectonic evolution Andes One of the main morphological changes along the Southern Central Andes occurs from 36° to 39°S. The northern portion is characterized by prominent basement structures and a thick-skinned orogenic front with relief of over 2000. m with a deep level of exhumation where more than 4. km of section has been eroded. Contrastingly, the southern part is formed by mildly inverted basement structures restricted mainly to the hinterland zone, which reaches only 1500-1700. m relief. We quantify the variable contributions of two main contractional stages through the construction of three regionally balanced sections across the Andes, constrained by field and geophysical data. Extensional re-activation described for this segment in late Oligocene-early Miocene and Pliocene to Quaternary times, after the two main contractional episodes, suggests only 3. km of stretching that represents 30-10% of the original longitude. We, therefore, conclude that while initial Late Cretaceous to Eocene compression was similar along strike (~10-7. km), it is the contrasting degrees of Neogene shortening (~16-6. km) that have played the largest role in the along strike differences in structure and morphology along this portion of the southern Andes. Variable Neogene arc expansion could be responsible for the contrasting contractional deformation: In the north, late Miocene arc-related rocks cover most of the retroarc zone (>200. km with respect to the late Miocene arc front in the south), presumably driven by a shallow subduction episode in the area, whereas to the south they remain restricted to the continental drainage divide. Other factors involving architecture of previous rift structures, are proposed as additional mechanisms that accommodated variable shortening magnitudes through inversion. © 2013 Elsevier Ltd. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_02643707_v73_n_p34_RojasVera |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Extensional reactivation Fold and thrust belt Neogene contraction Southern Central Andes exhumation extensional tectonics fold and thrust belt geomorphology Neogene orogeny structural geology tectonic evolution Andes |
| spellingShingle |
Extensional reactivation Fold and thrust belt Neogene contraction Southern Central Andes exhumation extensional tectonics fold and thrust belt geomorphology Neogene orogeny structural geology tectonic evolution Andes Rojas Vera, E.A. Folguera, A. Zamora Valcarce, G. Bottesi, G. Ramos, V.A. Structure and development of the Andean system between 36° and 39°S |
| topic_facet |
Extensional reactivation Fold and thrust belt Neogene contraction Southern Central Andes exhumation extensional tectonics fold and thrust belt geomorphology Neogene orogeny structural geology tectonic evolution Andes |
| description |
One of the main morphological changes along the Southern Central Andes occurs from 36° to 39°S. The northern portion is characterized by prominent basement structures and a thick-skinned orogenic front with relief of over 2000. m with a deep level of exhumation where more than 4. km of section has been eroded. Contrastingly, the southern part is formed by mildly inverted basement structures restricted mainly to the hinterland zone, which reaches only 1500-1700. m relief. We quantify the variable contributions of two main contractional stages through the construction of three regionally balanced sections across the Andes, constrained by field and geophysical data. Extensional re-activation described for this segment in late Oligocene-early Miocene and Pliocene to Quaternary times, after the two main contractional episodes, suggests only 3. km of stretching that represents 30-10% of the original longitude. We, therefore, conclude that while initial Late Cretaceous to Eocene compression was similar along strike (~10-7. km), it is the contrasting degrees of Neogene shortening (~16-6. km) that have played the largest role in the along strike differences in structure and morphology along this portion of the southern Andes. Variable Neogene arc expansion could be responsible for the contrasting contractional deformation: In the north, late Miocene arc-related rocks cover most of the retroarc zone (>200. km with respect to the late Miocene arc front in the south), presumably driven by a shallow subduction episode in the area, whereas to the south they remain restricted to the continental drainage divide. Other factors involving architecture of previous rift structures, are proposed as additional mechanisms that accommodated variable shortening magnitudes through inversion. © 2013 Elsevier Ltd. |
| format |
JOUR |
| author |
Rojas Vera, E.A. Folguera, A. Zamora Valcarce, G. Bottesi, G. Ramos, V.A. |
| author_facet |
Rojas Vera, E.A. Folguera, A. Zamora Valcarce, G. Bottesi, G. Ramos, V.A. |
| author_sort |
Rojas Vera, E.A. |
| title |
Structure and development of the Andean system between 36° and 39°S |
| title_short |
Structure and development of the Andean system between 36° and 39°S |
| title_full |
Structure and development of the Andean system between 36° and 39°S |
| title_fullStr |
Structure and development of the Andean system between 36° and 39°S |
| title_full_unstemmed |
Structure and development of the Andean system between 36° and 39°S |
| title_sort |
structure and development of the andean system between 36° and 39°s |
| url |
http://hdl.handle.net/20.500.12110/paper_02643707_v73_n_p34_RojasVera |
| work_keys_str_mv |
AT rojasveraea structureanddevelopmentoftheandeansystembetween36and39s AT folgueraa structureanddevelopmentoftheandeansystembetween36and39s AT zamoravalcarceg structureanddevelopmentoftheandeansystembetween36and39s AT bottesig structureanddevelopmentoftheandeansystembetween36and39s AT ramosva structureanddevelopmentoftheandeansystembetween36and39s |
| _version_ |
1782028003468902400 |