Lower Paleozoic structure in the headwaters of Río Jachal, San Juan Province
Structures cropping out in the Jachal Valley from the Cuesta del Viento dam to the locality of Los Tuneles are described and analyzed. These structures affect the Ordovician Yerba Loca and Los Sombreros Formations and the Paleogene-Neogene Vallecito and Rodeo Formations. The oldest units form the he...
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todo:paper_00044822_v66_n1-2_p80_SellesMartinez2023-10-03T13:58:42Z Lower Paleozoic structure in the headwaters of Río Jachal, San Juan Province Sellés-Martínez, J. Azcurra, D. Andes Jáchal river Palaeozoic Precordillera Structure conglomerate deformation headwater Ordovician outcrop Paleozoic rhythmite structural geology Argentina Ecuador Galapagos Islands Isabela [Galapagos Islands] Jachal River Precordillera San Juan [Argentina] Sierra Negra Croton ovalifolius Structures cropping out in the Jachal Valley from the Cuesta del Viento dam to the locality of Los Tuneles are described and analyzed. These structures affect the Ordovician Yerba Loca and Los Sombreros Formations and the Paleogene-Neogene Vallecito and Rodeo Formations. The oldest units form the heights, Sierra Negra de Rodeo and Sierra de los Túneles, which are limited in their eastern flanks by the La Tranca and Los Blanquitos overthrusts, and by the angular unconformity underlying Rodeo Formation in their western ones. The regional folds show asymmetrical shapes and a wavelength comparable to the width of the Sierras, but minor structures ranging from meters to tens of meters are very common in their eastern limbs. Regional folds axis trend varies from Az 315 to Az 360 and the vergence of pre-carboniferous and andean structures point to the east, what makes very difficult to use orientation as a criterion to discriminate the differentiated deformational episodes. The comparison of sedimentological and structural features in the Rodeo area with those at the San Juan River evidences strong similarities but also important differences. Among the first ones, it can be mentioned the lithological and structural resemblance of the Ordovician units, which show NS trending axis in the eastern outcrops and point N-NW in the western ones. Main differences are the absence -in the Rodeo area- of the metapelites of the Silurian Calingasta Formation. and that of the conglomerates and rhythmites of the Devonian (?) El Planchón Formation. present in the San Juan River section. Fil:Sellés-Martínez, J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Azcurra, D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00044822_v66_n1-2_p80_SellesMartinez |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Andes Jáchal river Palaeozoic Precordillera Structure conglomerate deformation headwater Ordovician outcrop Paleozoic rhythmite structural geology Argentina Ecuador Galapagos Islands Isabela [Galapagos Islands] Jachal River Precordillera San Juan [Argentina] Sierra Negra Croton ovalifolius |
| spellingShingle |
Andes Jáchal river Palaeozoic Precordillera Structure conglomerate deformation headwater Ordovician outcrop Paleozoic rhythmite structural geology Argentina Ecuador Galapagos Islands Isabela [Galapagos Islands] Jachal River Precordillera San Juan [Argentina] Sierra Negra Croton ovalifolius Sellés-Martínez, J. Azcurra, D. Lower Paleozoic structure in the headwaters of Río Jachal, San Juan Province |
| topic_facet |
Andes Jáchal river Palaeozoic Precordillera Structure conglomerate deformation headwater Ordovician outcrop Paleozoic rhythmite structural geology Argentina Ecuador Galapagos Islands Isabela [Galapagos Islands] Jachal River Precordillera San Juan [Argentina] Sierra Negra Croton ovalifolius |
| description |
Structures cropping out in the Jachal Valley from the Cuesta del Viento dam to the locality of Los Tuneles are described and analyzed. These structures affect the Ordovician Yerba Loca and Los Sombreros Formations and the Paleogene-Neogene Vallecito and Rodeo Formations. The oldest units form the heights, Sierra Negra de Rodeo and Sierra de los Túneles, which are limited in their eastern flanks by the La Tranca and Los Blanquitos overthrusts, and by the angular unconformity underlying Rodeo Formation in their western ones. The regional folds show asymmetrical shapes and a wavelength comparable to the width of the Sierras, but minor structures ranging from meters to tens of meters are very common in their eastern limbs. Regional folds axis trend varies from Az 315 to Az 360 and the vergence of pre-carboniferous and andean structures point to the east, what makes very difficult to use orientation as a criterion to discriminate the differentiated deformational episodes. The comparison of sedimentological and structural features in the Rodeo area with those at the San Juan River evidences strong similarities but also important differences. Among the first ones, it can be mentioned the lithological and structural resemblance of the Ordovician units, which show NS trending axis in the eastern outcrops and point N-NW in the western ones. Main differences are the absence -in the Rodeo area- of the metapelites of the Silurian Calingasta Formation. and that of the conglomerates and rhythmites of the Devonian (?) El Planchón Formation. present in the San Juan River section. |
| format |
JOUR |
| author |
Sellés-Martínez, J. Azcurra, D. |
| author_facet |
Sellés-Martínez, J. Azcurra, D. |
| author_sort |
Sellés-Martínez, J. |
| title |
Lower Paleozoic structure in the headwaters of Río Jachal, San Juan Province |
| title_short |
Lower Paleozoic structure in the headwaters of Río Jachal, San Juan Province |
| title_full |
Lower Paleozoic structure in the headwaters of Río Jachal, San Juan Province |
| title_fullStr |
Lower Paleozoic structure in the headwaters of Río Jachal, San Juan Province |
| title_full_unstemmed |
Lower Paleozoic structure in the headwaters of Río Jachal, San Juan Province |
| title_sort |
lower paleozoic structure in the headwaters of río jachal, san juan province |
| url |
http://hdl.handle.net/20.500.12110/paper_00044822_v66_n1-2_p80_SellesMartinez |
| work_keys_str_mv |
AT sellesmartinezj lowerpaleozoicstructureintheheadwatersofriojachalsanjuanprovince AT azcurrad lowerpaleozoicstructureintheheadwatersofriojachalsanjuanprovince |
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