The Late Carboniferous Glacial to Postglacial Transition: Facies and Sequence Stratigraphy, Western Paganzo Basin, Argentina

Namurian-early Westphalian glacial-postglacial deposits have been documented in the Paganzo Basin, Argentina, but integrated sequence stratigraphic and sedimentological analyses of the glacial-postglacial transition are rare. In the Cuesta de Huaco section the glacial-postglacial transition encompas...

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Autor principal: Pazos, P.J.
Formato: JOUR
Materias:
Carboniferous
Glaciation
Gondwana
Ichnology
Sequence stratigraphy
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_1342937X_v5_n2_p467_Pazos
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_1342937X_v5_n2_p467_Pazos2023-10-03T16:09:39Z The Late Carboniferous Glacial to Postglacial Transition: Facies and Sequence Stratigraphy, Western Paganzo Basin, Argentina Pazos, P.J. Carboniferous Glaciation Gondwana Ichnology Sequence stratigraphy Namurian-early Westphalian glacial-postglacial deposits have been documented in the Paganzo Basin, Argentina, but integrated sequence stratigraphic and sedimentological analyses of the glacial-postglacial transition are rare. In the Cuesta de Huaco section the glacial-postglacial transition encompasses the lower sequence of the existing schemes. Glacioeustatic changes in sea-level controlled the architecture and vertical arrangement of fades. The basal sequence boundary is coeval with the onset of glaciation when sea level fell, contemporaneous with glacial erosion and bypass of sediment. The upper sequence boundary is a high-frequency sequence boundary. The basal deposits are interpreted as an early transgressive systems tract (ETST) initiated during glacial retreat. The interval fines upward, contains current reworked diamictites, conglomerates and sandstones deposited in a subglacial to proglacial environment (Facies I-II) and ice-rafted glaciomarine rhythmites (Facies III). Postglacial brackish-marine black shales (Facies IV) represent the late transgressive systems tract (LTST). Micritic-limestone beds were deposited during a period of sediment starvation coeval with the maximum marine inundation in the basin (MFZ). It marks a turnaround in the stacking pattern that became coarsening and thickening upward during the overlying highstand systems tract (HST). It consists of fine-grained turbidites (Facies V) and classical turbidites with wave reworked beds at the top (Facies VI) deposited in a shallow deltaic systems. Intervening postglacial brackish deposits contain an ichnofauna dominated by trackways of arthropods and minor grazing traces, preserved in bedding planes, that resemble nonmarine ichnocoenoses and differ from the archetypal brackish ichnofaunas, even when palynological data support the saline-depleted environment. Fil:Pazos, P.J. 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_1342937X_v5_n2_p467_Pazos
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Carboniferous
Glaciation
Gondwana
Ichnology
Sequence stratigraphy
spellingShingle Carboniferous
Glaciation
Gondwana
Ichnology
Sequence stratigraphy
Pazos, P.J.
The Late Carboniferous Glacial to Postglacial Transition: Facies and Sequence Stratigraphy, Western Paganzo Basin, Argentina
topic_facet Carboniferous
Glaciation
Gondwana
Ichnology
Sequence stratigraphy
description Namurian-early Westphalian glacial-postglacial deposits have been documented in the Paganzo Basin, Argentina, but integrated sequence stratigraphic and sedimentological analyses of the glacial-postglacial transition are rare. In the Cuesta de Huaco section the glacial-postglacial transition encompasses the lower sequence of the existing schemes. Glacioeustatic changes in sea-level controlled the architecture and vertical arrangement of fades. The basal sequence boundary is coeval with the onset of glaciation when sea level fell, contemporaneous with glacial erosion and bypass of sediment. The upper sequence boundary is a high-frequency sequence boundary. The basal deposits are interpreted as an early transgressive systems tract (ETST) initiated during glacial retreat. The interval fines upward, contains current reworked diamictites, conglomerates and sandstones deposited in a subglacial to proglacial environment (Facies I-II) and ice-rafted glaciomarine rhythmites (Facies III). Postglacial brackish-marine black shales (Facies IV) represent the late transgressive systems tract (LTST). Micritic-limestone beds were deposited during a period of sediment starvation coeval with the maximum marine inundation in the basin (MFZ). It marks a turnaround in the stacking pattern that became coarsening and thickening upward during the overlying highstand systems tract (HST). It consists of fine-grained turbidites (Facies V) and classical turbidites with wave reworked beds at the top (Facies VI) deposited in a shallow deltaic systems. Intervening postglacial brackish deposits contain an ichnofauna dominated by trackways of arthropods and minor grazing traces, preserved in bedding planes, that resemble nonmarine ichnocoenoses and differ from the archetypal brackish ichnofaunas, even when palynological data support the saline-depleted environment.
format JOUR
author Pazos, P.J.
author_facet Pazos, P.J.
author_sort Pazos, P.J.
title The Late Carboniferous Glacial to Postglacial Transition: Facies and Sequence Stratigraphy, Western Paganzo Basin, Argentina
title_short The Late Carboniferous Glacial to Postglacial Transition: Facies and Sequence Stratigraphy, Western Paganzo Basin, Argentina
title_full The Late Carboniferous Glacial to Postglacial Transition: Facies and Sequence Stratigraphy, Western Paganzo Basin, Argentina
title_fullStr The Late Carboniferous Glacial to Postglacial Transition: Facies and Sequence Stratigraphy, Western Paganzo Basin, Argentina
title_full_unstemmed The Late Carboniferous Glacial to Postglacial Transition: Facies and Sequence Stratigraphy, Western Paganzo Basin, Argentina
title_sort late carboniferous glacial to postglacial transition: facies and sequence stratigraphy, western paganzo basin, argentina
url http://hdl.handle.net/20.500.12110/paper_1342937X_v5_n2_p467_Pazos
work_keys_str_mv AT pazospj thelatecarboniferousglacialtopostglacialtransitionfaciesandsequencestratigraphywesternpaganzobasinargentina
AT pazospj latecarboniferousglacialtopostglacialtransitionfaciesandsequencestratigraphywesternpaganzobasinargentina
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