Reworked calcretes: their significance in the reconstruction of alluvial sequences (Permian and Triassic, Minorca, Balearic Islands, Spain)

The Permian and Triassic of Minorca (Balearic Islands) consists of a 670-m-thick, red, alluvial succession that includes in situ calcrete profiles and reworked calcrete material. In the Permian succession, the calcretes vary from laminar forms developed on the Carboniferous basement to weakly develo...

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Detalles Bibliográficos
Autores: Gómez Gras, D., Alonso Zarza, Ana María
Tipo de recurso: artículo
Fecha de publicación:2003
País:España
Institución:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/59027
Acceso en línea:https://hdl.handle.net/20.500.14352/59027
Access Level:acceso abierto
Palabra clave:552.5(460.32)
Balearic Islands
Calcretes
Reworked calcrete deposits
Fluvial systems
Floodplain
Permian
Triassic
Petrología
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spelling Reworked calcretes: their significance in the reconstruction of alluvial sequences (Permian and Triassic, Minorca, Balearic Islands, Spain)Gómez Gras, D.Alonso Zarza, Ana María552.5(460.32)Balearic IslandsCalcretesReworked calcrete depositsFluvial systemsFloodplainPermianTriassicPetrologíaThe Permian and Triassic of Minorca (Balearic Islands) consists of a 670-m-thick, red, alluvial succession that includes in situ calcrete profiles and reworked calcrete material. In the Permian succession, the calcretes vary from laminar forms developed on the Carboniferous basement to weakly developed nodular calcretes in fluvial sediments. The palaeosols in the Triassic are mostly dolomitic, and the profiles reach up to Stage III of soil development (Spec. Pap.-Geol. Surv. Am. 203, (1995) 1). The clasts, formed through reworking of the palaeosol profiles, are about 0.5–10 cm across and include mosaics of calcite/dolomite crystals, brecciated clasts, rhizolith fragments, and aggregates of clay and/or silt. These clasts appear in three different types of deposits. Type 1 corresponds to lenticular bodies that fill small scour surfaces, and consists only of intraformational conglomerates. These deposits are interpreted as ephemeral channels and sheet-floods that represent the interfluvial drainage systems that captured only the precipitation falling on the alluvial plain. Type 2 includes sand dune 3-D bodies with flat bottoms and convex tops. These bodies are about 20 cm high and 2 m wide, and were formed by floodwaters that flowed down the levees of the major streams. Type 3 channel deposits contain reworked calcretes and extrabasinal clasts, which overlie erosive surfaces and are found in layers within cross-bedded sandstones and conglomerates. These are interpreted as channel-floor lag deposits of major channels that entered from distant uplands and drained the alluvial plain. Variations in the aggradation rates of the floodplain resulted in five different infill stages. In the lowstand to early transgressive interval, as in stages I (P1) and IV (B1), the fluvial deposits filled palaeovalleys; calcretes and reworked calcrete deposits were of difficult formation (apart from terraces) and preservation. Accommodation space was at its greatest in the transgressive, stages II (P2) and V (B2). This caused the greatest aggradation of the floodplains, which are formed of thick sequences of fine-grained sediments, isolated meandering channels, weakly developed calcretes (compound) and reworked calcrete deposits, mostly of types 1 and 2. The density of channels notably increased in stage III (P3), highstand interval, because of the reduction of accommodation space, this could favour the formation of composite or even cumulative palaeosols, but of difficult preservation. Reworked calcrete deposits are mostly of type 3, but types 1 and 2 are also recognised. The reworked calcrete deposits are an important part of the Permian and Triassic fluvial sediments and their occurrence and characteristics are important in order to interpret the infill of terrestrial basins and the construction of floodplains.ElsevierUniversidad Complutense de Madrid20032003-01-0120032003-01-01journal articlehttp://purl.org/coar/resource_type/c_6501info:eu-repo/semantics/articleapplication/pdfhttps://hdl.handle.net/20.500.14352/59027reponame:Docta Complutenseinstname:Universidad Complutense de Madrid (UCM)Inglésengopen accesshttp://purl.org/coar/access_right/c_abf2info:eu-repo/semantics/openAccessoai:docta.ucm.es:20.500.14352/590272026-06-02T12:44:21Z
dc.title.none.fl_str_mv Reworked calcretes: their significance in the reconstruction of alluvial sequences (Permian and Triassic, Minorca, Balearic Islands, Spain)
title Reworked calcretes: their significance in the reconstruction of alluvial sequences (Permian and Triassic, Minorca, Balearic Islands, Spain)
spellingShingle Reworked calcretes: their significance in the reconstruction of alluvial sequences (Permian and Triassic, Minorca, Balearic Islands, Spain)
Gómez Gras, D.
552.5(460.32)
Balearic Islands
Calcretes
Reworked calcrete deposits
Fluvial systems
Floodplain
Permian
Triassic
Petrología
title_short Reworked calcretes: their significance in the reconstruction of alluvial sequences (Permian and Triassic, Minorca, Balearic Islands, Spain)
title_full Reworked calcretes: their significance in the reconstruction of alluvial sequences (Permian and Triassic, Minorca, Balearic Islands, Spain)
title_fullStr Reworked calcretes: their significance in the reconstruction of alluvial sequences (Permian and Triassic, Minorca, Balearic Islands, Spain)
title_full_unstemmed Reworked calcretes: their significance in the reconstruction of alluvial sequences (Permian and Triassic, Minorca, Balearic Islands, Spain)
title_sort Reworked calcretes: their significance in the reconstruction of alluvial sequences (Permian and Triassic, Minorca, Balearic Islands, Spain)
dc.creator.none.fl_str_mv Gómez Gras, D.
Alonso Zarza, Ana María
author Gómez Gras, D.
author_facet Gómez Gras, D.
Alonso Zarza, Ana María
author_role author
author2 Alonso Zarza, Ana María
author2_role author
dc.contributor.none.fl_str_mv Universidad Complutense de Madrid
dc.subject.none.fl_str_mv 552.5(460.32)
Balearic Islands
Calcretes
Reworked calcrete deposits
Fluvial systems
Floodplain
Permian
Triassic
Petrología
topic 552.5(460.32)
Balearic Islands
Calcretes
Reworked calcrete deposits
Fluvial systems
Floodplain
Permian
Triassic
Petrología
description The Permian and Triassic of Minorca (Balearic Islands) consists of a 670-m-thick, red, alluvial succession that includes in situ calcrete profiles and reworked calcrete material. In the Permian succession, the calcretes vary from laminar forms developed on the Carboniferous basement to weakly developed nodular calcretes in fluvial sediments. The palaeosols in the Triassic are mostly dolomitic, and the profiles reach up to Stage III of soil development (Spec. Pap.-Geol. Surv. Am. 203, (1995) 1). The clasts, formed through reworking of the palaeosol profiles, are about 0.5–10 cm across and include mosaics of calcite/dolomite crystals, brecciated clasts, rhizolith fragments, and aggregates of clay and/or silt. These clasts appear in three different types of deposits. Type 1 corresponds to lenticular bodies that fill small scour surfaces, and consists only of intraformational conglomerates. These deposits are interpreted as ephemeral channels and sheet-floods that represent the interfluvial drainage systems that captured only the precipitation falling on the alluvial plain. Type 2 includes sand dune 3-D bodies with flat bottoms and convex tops. These bodies are about 20 cm high and 2 m wide, and were formed by floodwaters that flowed down the levees of the major streams. Type 3 channel deposits contain reworked calcretes and extrabasinal clasts, which overlie erosive surfaces and are found in layers within cross-bedded sandstones and conglomerates. These are interpreted as channel-floor lag deposits of major channels that entered from distant uplands and drained the alluvial plain. Variations in the aggradation rates of the floodplain resulted in five different infill stages. In the lowstand to early transgressive interval, as in stages I (P1) and IV (B1), the fluvial deposits filled palaeovalleys; calcretes and reworked calcrete deposits were of difficult formation (apart from terraces) and preservation. Accommodation space was at its greatest in the transgressive, stages II (P2) and V (B2). This caused the greatest aggradation of the floodplains, which are formed of thick sequences of fine-grained sediments, isolated meandering channels, weakly developed calcretes (compound) and reworked calcrete deposits, mostly of types 1 and 2. The density of channels notably increased in stage III (P3), highstand interval, because of the reduction of accommodation space, this could favour the formation of composite or even cumulative palaeosols, but of difficult preservation. Reworked calcrete deposits are mostly of type 3, but types 1 and 2 are also recognised. The reworked calcrete deposits are an important part of the Permian and Triassic fluvial sediments and their occurrence and characteristics are important in order to interpret the infill of terrestrial basins and the construction of floodplains.
publishDate 2003
dc.date.none.fl_str_mv 2003
2003-01-01
2003
2003-01-01
dc.type.none.fl_str_mv journal article
http://purl.org/coar/resource_type/c_6501
dc.type.openaire.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv https://hdl.handle.net/20.500.14352/59027
url https://hdl.handle.net/20.500.14352/59027
dc.language.none.fl_str_mv Inglés
eng
language_invalid_str_mv Inglés
language eng
dc.rights.none.fl_str_mv open access
http://purl.org/coar/access_right/c_abf2
dc.rights.openaire.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv open access
http://purl.org/coar/access_right/c_abf2
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
dc.source.none.fl_str_mv reponame:Docta Complutense
instname:Universidad Complutense de Madrid (UCM)
instname_str Universidad Complutense de Madrid (UCM)
reponame_str Docta Complutense
collection Docta Complutense
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,301603

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