Environmental magnetism in fluvial and loessic Holocene sediments and paleosols from the Chacopampean plain (Argentina)

The magnetic signals of fluvial and loessic sediments and paleosol sequences developed in the Chacopampean plain (Buenos Aires province, Argentina) are described and interpreted. To provide an analysis of the rock magnetism, sedimentological studies were performed, which led to a stratigraphic frame...

Descripción completa

Guardado en:
Detalles Bibliográficos
Autores principales: Orgeira, María Julia, Walther, Ana Maria, Tofalo, Ofelia Rita de las Mercedes, Vasquez, Carlos Alberto
Publicado: 2003
Materias:
Environmental magnetism
Late cenozoic
Paleoclimate
Paleosol
Holocene
loess
paleoclimate
paleomagnetism
paleosol
pedogenesis
stratigraphy
Argentina
Buenos Aires Province
Chacopampean Plain
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v16_n4_p259_Orgeira
http://hdl.handle.net/20.500.12110/paper_08959811_v16_n4_p259_Orgeira
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_08959811_v16_n4_p259_Orgeira
record_format dspace
spelling paper:paper_08959811_v16_n4_p259_Orgeira2023-06-08T15:48:13Z Environmental magnetism in fluvial and loessic Holocene sediments and paleosols from the Chacopampean plain (Argentina) Orgeira, María Julia Walther, Ana Maria Tofalo, Ofelia Rita de las Mercedes Vasquez, Carlos Alberto Environmental magnetism Late cenozoic Paleoclimate Paleosol Holocene loess paleoclimate paleomagnetism paleosol pedogenesis stratigraphy Argentina Buenos Aires Province Chacopampean Plain The magnetic signals of fluvial and loessic sediments and paleosol sequences developed in the Chacopampean plain (Buenos Aires province, Argentina) are described and interpreted. To provide an analysis of the rock magnetism, sedimentological studies were performed, which led to a stratigraphic framework of so-called 'post-Pampean' sediments deposited in different paleoenvironments.The Luján formation, composed of fine sand and pelitic sediments, is fluvial and includes floodplain facies, whereas the La Postrera Formations is eolian but particularly loessic. Variations in the magnetic signals observed in paleosols in the units were ascribed to pedogenic processes that occurred at different stages of soil development. An extensive process of dissolution of detrital ferrimagnetic minerals was recognized. In one paleosol, dissolution was accompanied by the appearance of a superparamagnetic (SP) fraction, which may indicate that the loss is connected to subsequent formation of ferrimagnetic minerals in the same paleosol. Both processes did not act simultaneously. The abundant rainfall and absence of CO3Ca in the parent material could be necessary conditions for a defensible scenario for SP genesis. In the loessic sediments (Tapalqué locality), dissolution could be associated with the genesis of a high coercive fraction. The presence of high coercivity minerals may indicate a climate with a distinctly dry season, though their lack does not necessarily imply the absence of a dry season. © 2003 Elsevier Ltd. All rights reserved. Fil:Orgeira, M.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Walther, A.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Tófalo, R.O. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Vásquez, C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2003 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v16_n4_p259_Orgeira http://hdl.handle.net/20.500.12110/paper_08959811_v16_n4_p259_Orgeira
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Environmental magnetism
Late cenozoic
Paleoclimate
Paleosol
Holocene
loess
paleoclimate
paleomagnetism
paleosol
pedogenesis
stratigraphy
Argentina
Buenos Aires Province
Chacopampean Plain
spellingShingle Environmental magnetism
Late cenozoic
Paleoclimate
Paleosol
Holocene
loess
paleoclimate
paleomagnetism
paleosol
pedogenesis
stratigraphy
Argentina
Buenos Aires Province
Chacopampean Plain
Orgeira, María Julia
Walther, Ana Maria
Tofalo, Ofelia Rita de las Mercedes
Vasquez, Carlos Alberto
Environmental magnetism in fluvial and loessic Holocene sediments and paleosols from the Chacopampean plain (Argentina)
topic_facet Environmental magnetism
Late cenozoic
Paleoclimate
Paleosol
Holocene
loess
paleoclimate
paleomagnetism
paleosol
pedogenesis
stratigraphy
Argentina
Buenos Aires Province
Chacopampean Plain
description The magnetic signals of fluvial and loessic sediments and paleosol sequences developed in the Chacopampean plain (Buenos Aires province, Argentina) are described and interpreted. To provide an analysis of the rock magnetism, sedimentological studies were performed, which led to a stratigraphic framework of so-called 'post-Pampean' sediments deposited in different paleoenvironments.The Luján formation, composed of fine sand and pelitic sediments, is fluvial and includes floodplain facies, whereas the La Postrera Formations is eolian but particularly loessic. Variations in the magnetic signals observed in paleosols in the units were ascribed to pedogenic processes that occurred at different stages of soil development. An extensive process of dissolution of detrital ferrimagnetic minerals was recognized. In one paleosol, dissolution was accompanied by the appearance of a superparamagnetic (SP) fraction, which may indicate that the loss is connected to subsequent formation of ferrimagnetic minerals in the same paleosol. Both processes did not act simultaneously. The abundant rainfall and absence of CO3Ca in the parent material could be necessary conditions for a defensible scenario for SP genesis. In the loessic sediments (Tapalqué locality), dissolution could be associated with the genesis of a high coercive fraction. The presence of high coercivity minerals may indicate a climate with a distinctly dry season, though their lack does not necessarily imply the absence of a dry season. © 2003 Elsevier Ltd. All rights reserved.
author Orgeira, María Julia
Walther, Ana Maria
Tofalo, Ofelia Rita de las Mercedes
Vasquez, Carlos Alberto
author_facet Orgeira, María Julia
Walther, Ana Maria
Tofalo, Ofelia Rita de las Mercedes
Vasquez, Carlos Alberto
author_sort Orgeira, María Julia
title Environmental magnetism in fluvial and loessic Holocene sediments and paleosols from the Chacopampean plain (Argentina)
title_short Environmental magnetism in fluvial and loessic Holocene sediments and paleosols from the Chacopampean plain (Argentina)
title_full Environmental magnetism in fluvial and loessic Holocene sediments and paleosols from the Chacopampean plain (Argentina)
title_fullStr Environmental magnetism in fluvial and loessic Holocene sediments and paleosols from the Chacopampean plain (Argentina)
title_full_unstemmed Environmental magnetism in fluvial and loessic Holocene sediments and paleosols from the Chacopampean plain (Argentina)
title_sort environmental magnetism in fluvial and loessic holocene sediments and paleosols from the chacopampean plain (argentina)
publishDate 2003
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v16_n4_p259_Orgeira
http://hdl.handle.net/20.500.12110/paper_08959811_v16_n4_p259_Orgeira
work_keys_str_mv AT orgeiramariajulia environmentalmagnetisminfluvialandloessicholocenesedimentsandpaleosolsfromthechacopampeanplainargentina
AT waltheranamaria environmentalmagnetisminfluvialandloessicholocenesedimentsandpaleosolsfromthechacopampeanplainargentina
AT tofaloofeliaritadelasmercedes environmentalmagnetisminfluvialandloessicholocenesedimentsandpaleosolsfromthechacopampeanplainargentina
AT vasquezcarlosalberto environmentalmagnetisminfluvialandloessicholocenesedimentsandpaleosolsfromthechacopampeanplainargentina
_version_ 1768541659076755456

Ejemplares similares