Diamictites in the Agua Colorada Formation (northwestern Argentina): New evidence of Carboniferous glaciation in South America

The Agua Colorada Formation crops out in the Famatina System (northwestern Argentina) and is composed of sandstones, conglomerates, mudstones, some coal seams, and diamictites. The diamictites are not abundant in the formation, but they form thick beds in the lower member. The diamictites are divide...

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Autores principales:	Limarino, C., Gutierrez, P.
Formato:	JOUR
Materias:	Agua Colorado Formation Carboniferous diamictite Famatina System glaciation tillite Argentina
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_08959811_v3_n1_p9_Limarino
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	todo:paper_08959811_v3_n1_p9_Limarino
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spelling	todo:paper_08959811_v3_n1_p9_Limarino2023-10-03T15:43:06Z Diamictites in the Agua Colorada Formation (northwestern Argentina): New evidence of Carboniferous glaciation in South America Limarino, C. Gutierrez, P. Agua Colorado Formation Carboniferous diamictite Famatina System glaciation tillite Argentina The Agua Colorada Formation crops out in the Famatina System (northwestern Argentina) and is composed of sandstones, conglomerates, mudstones, some coal seams, and diamictites. The diamictites are not abundant in the formation, but they form thick beds in the lower member. The diamictites are divided into two major genetic types; the first is interpreted as resedimented lacustrine diamictites and therefore is not considered a tillite. The massive diamictites included in the second type are considered true tillites. The principal features that suggest a glacial origin are: 1) very poor sorting; 2) small grain size (clay to very fine sand) of the matrix; 3) massive bedding; 4) existence of faceted and striated clasts; and 5) very close relationship with lacustrine sequences containing dropstones. According to Eyles' methodology, several lithofacies have been recognized in the diamictites of the Las Gredas locality: Dmm, Dcm, Dcs, and Dcg. Dmm (matrix-supported massive diamictites) and Dcm (clast-supported massive) are the most frequent and very probably represent tillitic deposits. The Dcs (clast-supported stratified) and Dcg (clast-supported graded) lithofacies are interpreted as originated by slides and gravity flows. The finding of a rich palynological assemblage obtained in lacustrine deposits (closely associated with the diamictites) allows the dating of the glacial event as early Late Carboniferous. This age is based on the presence of diagnostic cosmopolitan taxa together with monosaccate pollen grains. © 1990. Fil:Gutierrez, P. 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_08959811_v3_n1_p9_Limarino
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Agua Colorado Formation Carboniferous diamictite Famatina System glaciation tillite Argentina
spellingShingle	Agua Colorado Formation Carboniferous diamictite Famatina System glaciation tillite Argentina Limarino, C. Gutierrez, P. Diamictites in the Agua Colorada Formation (northwestern Argentina): New evidence of Carboniferous glaciation in South America
topic_facet	Agua Colorado Formation Carboniferous diamictite Famatina System glaciation tillite Argentina
description	The Agua Colorada Formation crops out in the Famatina System (northwestern Argentina) and is composed of sandstones, conglomerates, mudstones, some coal seams, and diamictites. The diamictites are not abundant in the formation, but they form thick beds in the lower member. The diamictites are divided into two major genetic types; the first is interpreted as resedimented lacustrine diamictites and therefore is not considered a tillite. The massive diamictites included in the second type are considered true tillites. The principal features that suggest a glacial origin are: 1) very poor sorting; 2) small grain size (clay to very fine sand) of the matrix; 3) massive bedding; 4) existence of faceted and striated clasts; and 5) very close relationship with lacustrine sequences containing dropstones. According to Eyles' methodology, several lithofacies have been recognized in the diamictites of the Las Gredas locality: Dmm, Dcm, Dcs, and Dcg. Dmm (matrix-supported massive diamictites) and Dcm (clast-supported massive) are the most frequent and very probably represent tillitic deposits. The Dcs (clast-supported stratified) and Dcg (clast-supported graded) lithofacies are interpreted as originated by slides and gravity flows. The finding of a rich palynological assemblage obtained in lacustrine deposits (closely associated with the diamictites) allows the dating of the glacial event as early Late Carboniferous. This age is based on the presence of diagnostic cosmopolitan taxa together with monosaccate pollen grains. © 1990.
format	JOUR
author	Limarino, C. Gutierrez, P.
author_facet	Limarino, C. Gutierrez, P.
author_sort	Limarino, C.
title	Diamictites in the Agua Colorada Formation (northwestern Argentina): New evidence of Carboniferous glaciation in South America
title_short	Diamictites in the Agua Colorada Formation (northwestern Argentina): New evidence of Carboniferous glaciation in South America
title_full	Diamictites in the Agua Colorada Formation (northwestern Argentina): New evidence of Carboniferous glaciation in South America
title_fullStr	Diamictites in the Agua Colorada Formation (northwestern Argentina): New evidence of Carboniferous glaciation in South America
title_full_unstemmed	Diamictites in the Agua Colorada Formation (northwestern Argentina): New evidence of Carboniferous glaciation in South America
title_sort	diamictites in the agua colorada formation (northwestern argentina): new evidence of carboniferous glaciation in south america
url	http://hdl.handle.net/20.500.12110/paper_08959811_v3_n1_p9_Limarino
work_keys_str_mv	AT limarinoc diamictitesintheaguacoloradaformationnorthwesternargentinanewevidenceofcarboniferousglaciationinsouthamerica AT gutierrezp diamictitesintheaguacoloradaformationnorthwesternargentinanewevidenceofcarboniferousglaciationinsouthamerica
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Diamictites in the Agua Colorada Formation (northwestern Argentina): New evidence of Carboniferous glaciation in South America

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