Depositional models of lacustrine evaporites in the SE margin of the Ebro Basin (Paleogene, NE Spain)

An important evaporitic sedimentation occurred during the Paleogene (Eocene to lower Oligocene) in the Barberà sector of the southeastern margin of the Tertiary Ebro Basin. This sedimentation took place in shallow lacustrine environments and was controlled by a number of factors: 1) the tectonic str...

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Main Authors: F. Ortí, L. Rosell, M. Inglès, E. Playa
Format: Article
Language:English
Published: Universitat de Barcelona (UB), Geociències Barcelona (Geo3BCN), Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDAEA), Universitat Autònoma de Barcelona (UAB) 2007-01-01
Series:Geologica Acta
Subjects:
Online Access:https://revistes.ub.edu/index.php/GEOACTA/article/view/1891
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author F. Ortí
L. Rosell
M. Inglès
E. Playa
author_facet F. Ortí
L. Rosell
M. Inglès
E. Playa
author_sort F. Ortí
collection DOAJ
description An important evaporitic sedimentation occurred during the Paleogene (Eocene to lower Oligocene) in the Barberà sector of the southeastern margin of the Tertiary Ebro Basin. This sedimentation took place in shallow lacustrine environments and was controlled by a number of factors: 1) the tectonic structuration of the margin; 2) the high calcium sulphate content in the meteoric waters coming from the marginal reliefs; 3) the semiarid climate; and 4) the development of large alluvial fans along the basin margin, which also conditioned the location of the saline lakes. The evaporites are currently composed of secondary gypsum in surface and anhydrite at depth. There are, however, vestiges of the local presence of sodium sulphates. The evaporite units, with individual thicknesses ranging between 50 and 100 m, are intercalated within various lithostratigraphic formations and exhibit a paleogeographical pattern. The units located closer to the basin margin are characterized by a massive gypsum lithofacies (originally, bioturbated gypsum) bearing chert, and also by meganodular gypsum locally (originally, meganodules of anhydrite) in association with red lutites and clastic intercalations (gypsarenites, sandstones and conglomerates). Chert, which is only linked to the thickest gypsum layers, seems to be an early diagenetic, lacustrine product. Cyclicity in these proximal units indicates the progressive development of low-salinity, lacustrine bodies on red mud flats. At the top of some cycles, exposure episodes commonly resulted in dissolution, erosion, and the formation of edaphic features. In contrast, the units located in a more distal position with regard to the basin margin are formed by an alternation of banded-nodular gypsum and laminated gypsum layers in association with grey lutites and few clastic intercalations. These distal units formed in saline lakes with a higher ionic concentration. Exposure episodes in these lakes resulted in the formation of synsedimentary anhydrite and sabkha cycles. In some of these units, however, outer rims characterized by a lithofacies association similar to that of the proximal units occur (nodular gypsum, massive gypsum and chert nodules).
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spelling doaj.art-5ea9cc5dd05743aca32ff82464db508a2023-10-20T07:12:06ZengUniversitat de Barcelona (UB), Geociències Barcelona (Geo3BCN), Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDAEA), Universitat Autònoma de Barcelona (UAB)Geologica Acta1696-57282007-01-015110.1344/105.000000307Depositional models of lacustrine evaporites in the SE margin of the Ebro Basin (Paleogene, NE Spain)F. Ortí0L. Rosell1M. Inglès2E. Playa3Universitat de Barcelona.Universitat de Barcelona.Universitat de Barcelona.Universitat de Barcelona.An important evaporitic sedimentation occurred during the Paleogene (Eocene to lower Oligocene) in the Barberà sector of the southeastern margin of the Tertiary Ebro Basin. This sedimentation took place in shallow lacustrine environments and was controlled by a number of factors: 1) the tectonic structuration of the margin; 2) the high calcium sulphate content in the meteoric waters coming from the marginal reliefs; 3) the semiarid climate; and 4) the development of large alluvial fans along the basin margin, which also conditioned the location of the saline lakes. The evaporites are currently composed of secondary gypsum in surface and anhydrite at depth. There are, however, vestiges of the local presence of sodium sulphates. The evaporite units, with individual thicknesses ranging between 50 and 100 m, are intercalated within various lithostratigraphic formations and exhibit a paleogeographical pattern. The units located closer to the basin margin are characterized by a massive gypsum lithofacies (originally, bioturbated gypsum) bearing chert, and also by meganodular gypsum locally (originally, meganodules of anhydrite) in association with red lutites and clastic intercalations (gypsarenites, sandstones and conglomerates). Chert, which is only linked to the thickest gypsum layers, seems to be an early diagenetic, lacustrine product. Cyclicity in these proximal units indicates the progressive development of low-salinity, lacustrine bodies on red mud flats. At the top of some cycles, exposure episodes commonly resulted in dissolution, erosion, and the formation of edaphic features. In contrast, the units located in a more distal position with regard to the basin margin are formed by an alternation of banded-nodular gypsum and laminated gypsum layers in association with grey lutites and few clastic intercalations. These distal units formed in saline lakes with a higher ionic concentration. Exposure episodes in these lakes resulted in the formation of synsedimentary anhydrite and sabkha cycles. In some of these units, however, outer rims characterized by a lithofacies association similar to that of the proximal units occur (nodular gypsum, massive gypsum and chert nodules).https://revistes.ub.edu/index.php/GEOACTA/article/view/1891EvaporitesGypsumSaline lake modelsEoceneOligocene.
spellingShingle F. Ortí
L. Rosell
M. Inglès
E. Playa
Depositional models of lacustrine evaporites in the SE margin of the Ebro Basin (Paleogene, NE Spain)
Geologica Acta
Evaporites
Gypsum
Saline lake models
Eocene
Oligocene.
title Depositional models of lacustrine evaporites in the SE margin of the Ebro Basin (Paleogene, NE Spain)
title_full Depositional models of lacustrine evaporites in the SE margin of the Ebro Basin (Paleogene, NE Spain)
title_fullStr Depositional models of lacustrine evaporites in the SE margin of the Ebro Basin (Paleogene, NE Spain)
title_full_unstemmed Depositional models of lacustrine evaporites in the SE margin of the Ebro Basin (Paleogene, NE Spain)
title_short Depositional models of lacustrine evaporites in the SE margin of the Ebro Basin (Paleogene, NE Spain)
title_sort depositional models of lacustrine evaporites in the se margin of the ebro basin paleogene ne spain
topic Evaporites
Gypsum
Saline lake models
Eocene
Oligocene.
url https://revistes.ub.edu/index.php/GEOACTA/article/view/1891
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