Sedimentary paleoenvironments of the Toro Negro Formation (Neogene), Andean broken foreland, northwest Argentina

The Toro Negro Formation (Neogene) records the sedimentation in the broken-foreland Vinchina Basin during the Andean Orogeny, in northwestern Argentina. This unit is composed of conglomerates, sandstones and mudstones together with some beds of breccias and tuffs deposited mainly in fluvial environm...

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Autores principales: Ciccioli, P.L., Marenssi, S.A.
Formato: JOUR
Materias:
Andes
Broken-foreland
Continental sedimentation
Neogene
NW argentina
alluvial deposit
alluvial plain
conglomerate
foreland basin
lacustrine environment
lithostratigraphy
Miocene
mudstone
paleoenvironment
sandstone
sedimentation
Argentina
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_07187092_v39_n3_p407_Ciccioli
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_07187092_v39_n3_p407_Ciccioli2023-10-03T15:36:39Z Sedimentary paleoenvironments of the Toro Negro Formation (Neogene), Andean broken foreland, northwest Argentina Ciccioli, P.L. Marenssi, S.A. Andes Broken-foreland Continental sedimentation Neogene NW argentina alluvial deposit alluvial plain conglomerate foreland basin lacustrine environment lithostratigraphy Miocene mudstone Neogene paleoenvironment sandstone sedimentation Argentina The Toro Negro Formation (Neogene) records the sedimentation in the broken-foreland Vinchina Basin during the Andean Orogeny, in northwestern Argentina. This unit is composed of conglomerates, sandstones and mudstones together with some beds of breccias and tuffs deposited mainly in fluvial environments. Eleven facies associations (FA) were identified in this unit, eight of them corresponding to the lower member and three to the upper member. FAI is composed of massive intraformational megabreccias and cross-bedded conglomerates deposited in braided fluvial systems that filled a deep fluvial paleovalley formed in the north of the studied region. FAII was only identified in marginal positions of the paleovalley and is composed of intraformational breccias and sandstones forming channel belts incised within alluvial plains deposits. FAIII comprises gravelly channel belts and sandy floodplains dominated by crevasse splays interpreted as deposited in semiarid anastomosing fluvial systems. FAIV shows coarsening-upward successions with thick muddy alluvial plain deposits including thin crevasse splays and gravelly single channels. Encapsulated channel complexes composed of coarse-grained sandstones and scarce conglomerates, form FAV. FAVI covers a low-relief erosive surface and is mainly composed of conglomerates and gravelly sandstones deposited in broad alluvial plains. This fluvial complex evolved to a lower-energy system (FAVII) characterized by an increase of muddy floodplain deposits and the existence of fine-grained sandstone lobes with gravelly lenses. FAVIII is dominated by mudstones deposited in a playa lake environment. In the upper member, FAIX corresponds to deep gravel-bed braided streams. FAX is composed of fine-grained deposits of a highly aggradational fluvial plain. Finally, FAXI mainly consists of breccias and conglomerates deposited in streamflow-dominated piedmonts. Three stages were recognized in the paleoenvironmental evolution of the Toro Negro Formation. Stage I (Early Miocene) corresponds to the generation and infill of the paleovalley, by fluvial systems coming from the west (FAI-V) in the northern-central part of the basin. Stage II (Medium to Late Miocene) consists of gravelly-sandy fluvial systems (FAVI-VII) prograding from the north-northwest towards the playa lake (FAVIII) developed in the south. Finally, Stage III (upper member, Late Miocene-Early Pliocene) corresponds to pulses of clastic-wedge progradation (FAIX-XI) from the west (Precordillera). Fil:Ciccioli, P.L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Marenssi, S.A. 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_07187092_v39_n3_p407_Ciccioli
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
Broken-foreland
Continental sedimentation
Neogene
NW argentina
alluvial deposit
alluvial plain
conglomerate
foreland basin
lacustrine environment
lithostratigraphy
Miocene
mudstone
Neogene
paleoenvironment
sandstone
sedimentation
Argentina
spellingShingle Andes
Broken-foreland
Continental sedimentation
Neogene
NW argentina
alluvial deposit
alluvial plain
conglomerate
foreland basin
lacustrine environment
lithostratigraphy
Miocene
mudstone
Neogene
paleoenvironment
sandstone
sedimentation
Argentina
Ciccioli, P.L.
Marenssi, S.A.
Sedimentary paleoenvironments of the Toro Negro Formation (Neogene), Andean broken foreland, northwest Argentina
topic_facet Andes
Broken-foreland
Continental sedimentation
Neogene
NW argentina
alluvial deposit
alluvial plain
conglomerate
foreland basin
lacustrine environment
lithostratigraphy
Miocene
mudstone
Neogene
paleoenvironment
sandstone
sedimentation
Argentina
description The Toro Negro Formation (Neogene) records the sedimentation in the broken-foreland Vinchina Basin during the Andean Orogeny, in northwestern Argentina. This unit is composed of conglomerates, sandstones and mudstones together with some beds of breccias and tuffs deposited mainly in fluvial environments. Eleven facies associations (FA) were identified in this unit, eight of them corresponding to the lower member and three to the upper member. FAI is composed of massive intraformational megabreccias and cross-bedded conglomerates deposited in braided fluvial systems that filled a deep fluvial paleovalley formed in the north of the studied region. FAII was only identified in marginal positions of the paleovalley and is composed of intraformational breccias and sandstones forming channel belts incised within alluvial plains deposits. FAIII comprises gravelly channel belts and sandy floodplains dominated by crevasse splays interpreted as deposited in semiarid anastomosing fluvial systems. FAIV shows coarsening-upward successions with thick muddy alluvial plain deposits including thin crevasse splays and gravelly single channels. Encapsulated channel complexes composed of coarse-grained sandstones and scarce conglomerates, form FAV. FAVI covers a low-relief erosive surface and is mainly composed of conglomerates and gravelly sandstones deposited in broad alluvial plains. This fluvial complex evolved to a lower-energy system (FAVII) characterized by an increase of muddy floodplain deposits and the existence of fine-grained sandstone lobes with gravelly lenses. FAVIII is dominated by mudstones deposited in a playa lake environment. In the upper member, FAIX corresponds to deep gravel-bed braided streams. FAX is composed of fine-grained deposits of a highly aggradational fluvial plain. Finally, FAXI mainly consists of breccias and conglomerates deposited in streamflow-dominated piedmonts. Three stages were recognized in the paleoenvironmental evolution of the Toro Negro Formation. Stage I (Early Miocene) corresponds to the generation and infill of the paleovalley, by fluvial systems coming from the west (FAI-V) in the northern-central part of the basin. Stage II (Medium to Late Miocene) consists of gravelly-sandy fluvial systems (FAVI-VII) prograding from the north-northwest towards the playa lake (FAVIII) developed in the south. Finally, Stage III (upper member, Late Miocene-Early Pliocene) corresponds to pulses of clastic-wedge progradation (FAIX-XI) from the west (Precordillera).
format JOUR
author Ciccioli, P.L.
Marenssi, S.A.
author_facet Ciccioli, P.L.
Marenssi, S.A.
author_sort Ciccioli, P.L.
title Sedimentary paleoenvironments of the Toro Negro Formation (Neogene), Andean broken foreland, northwest Argentina
title_short Sedimentary paleoenvironments of the Toro Negro Formation (Neogene), Andean broken foreland, northwest Argentina
title_full Sedimentary paleoenvironments of the Toro Negro Formation (Neogene), Andean broken foreland, northwest Argentina
title_fullStr Sedimentary paleoenvironments of the Toro Negro Formation (Neogene), Andean broken foreland, northwest Argentina
title_full_unstemmed Sedimentary paleoenvironments of the Toro Negro Formation (Neogene), Andean broken foreland, northwest Argentina
title_sort sedimentary paleoenvironments of the toro negro formation (neogene), andean broken foreland, northwest argentina
url http://hdl.handle.net/20.500.12110/paper_07187092_v39_n3_p407_Ciccioli
work_keys_str_mv AT cicciolipl sedimentarypaleoenvironmentsofthetoronegroformationneogeneandeanbrokenforelandnorthwestargentina
AT marenssisa sedimentarypaleoenvironmentsofthetoronegroformationneogeneandeanbrokenforelandnorthwestargentina
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