Depositional models of lacustrine evaporites in the SE margin of the Ebro Basin (Paleogene, NE Spain)
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| Format: | Artículo científico |
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Universitat de Barcelona
2007
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| _version_ | 1876480857505529856 |
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| author | L. Rosell |
| author_facet | L. Rosell |
| contents | Depositional models of lacustrine evaporites in the SE margin of the Ebro Basin (Paleogene, NE Spain) L. Rosell M. Inglès F. Ortí E. Playà Ciencias de la Tierra Gypsum Eocene Oligocene Evaporites Saline lake models An important evaporitic sedimentation occurred during the Paleogene (Eocene to lower Oligocene) in the Barberàsector of the southeastern margin of the Tertiary Ebro Basin. This sedimentation took place in shallowlacustrine 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 semiaridclimate; and 4) the development of large alluvial fans along the basin margin, which also conditioned the locationof the saline lakes. The evaporites are currently composed of secondary gypsum in surface and anhydrite atdepth. There are, however, vestiges of the local presence of sodium sulphates. The evaporite units, with individualthicknesses ranging between 50 and 100 m, are intercalated within various lithostratigraphic formationsand exhibit a paleogeographical pattern. The units located closer to the basin margin are characterized by a massivegypsum 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 earlydiagenetic, lacustrine product. Cyclicity in these proximal units indicates the progressive development of lowsalinity,lacustrine bodies on red mud flats. At the top of some cycles, exposure episodes commonly resulted indissolution, erosion, and the formation of edaphic features. In contrast, the units located in a more distal positionwith regard to the basin margin are formed by an alternation of banded-nodular gypsum and laminated gypsumlayers in association with grey lutites and few clastic intercalations. These distal units formed in salinelakes with a higher ionic concentration. Exposure episodes in these lakes resulted in the formation of synsedimentaryanhydrite and sabkha cycles. In some of these units, however, outer rims characterized by a lithofaciesassociation similar to that of the proximal units occur (nodular gypsum, massive gypsum and chert nodules). 2007 artículo científico 1695-6133 https://www.redalyc.org/articulo.oa?id=50550102 en http://www.redalyc.org/revista.oa?id=505 Geologica Acta: an international earth science journal application/pdf Universitat de Barcelona Geologica Acta: an international earth science journal (España) Num.1 Vol.5 |
| format | Artículo científico |
| id | redalyc_50550102 |
| institution | Redalyc |
| language | en |
| publishDate | 2007 |
| publisher | Universitat de Barcelona |
| spellingShingle | Depositional models of lacustrine evaporites in the SE margin of the Ebro Basin (Paleogene, NE Spain) L. Rosell Ciencias de la Tierra Gypsum Eocene Oligocene Evaporites Saline lake models Depositional models of lacustrine evaporites in the SE margin of the Ebro Basin (Paleogene, NE Spain) L. Rosell M. Inglès F. Ortí E. Playà Ciencias de la Tierra Gypsum Eocene Oligocene Evaporites Saline lake models An important evaporitic sedimentation occurred during the Paleogene (Eocene to lower Oligocene) in the Barberàsector of the southeastern margin of the Tertiary Ebro Basin. This sedimentation took place in shallowlacustrine 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 semiaridclimate; and 4) the development of large alluvial fans along the basin margin, which also conditioned the locationof the saline lakes. The evaporites are currently composed of secondary gypsum in surface and anhydrite atdepth. There are, however, vestiges of the local presence of sodium sulphates. The evaporite units, with individualthicknesses ranging between 50 and 100 m, are intercalated within various lithostratigraphic formationsand exhibit a paleogeographical pattern. The units located closer to the basin margin are characterized by a massivegypsum 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 earlydiagenetic, lacustrine product. Cyclicity in these proximal units indicates the progressive development of lowsalinity,lacustrine bodies on red mud flats. At the top of some cycles, exposure episodes commonly resulted indissolution, erosion, and the formation of edaphic features. In contrast, the units located in a more distal positionwith regard to the basin margin are formed by an alternation of banded-nodular gypsum and laminated gypsumlayers in association with grey lutites and few clastic intercalations. These distal units formed in salinelakes with a higher ionic concentration. Exposure episodes in these lakes resulted in the formation of synsedimentaryanhydrite and sabkha cycles. In some of these units, however, outer rims characterized by a lithofaciesassociation similar to that of the proximal units occur (nodular gypsum, massive gypsum and chert nodules). 2007 artículo científico 1695-6133 https://www.redalyc.org/articulo.oa?id=50550102 en http://www.redalyc.org/revista.oa?id=505 Geologica Acta: an international earth science journal application/pdf Universitat de Barcelona Geologica Acta: an international earth science journal (España) Num.1 Vol.5 |
| title | Depositional models of lacustrine evaporites in the SE margin of the Ebro Basin (Paleogene, NE Spain) |
| topic | Ciencias de la Tierra Gypsum Eocene Oligocene Evaporites Saline lake models |
| url | https://www.redalyc.org/articulo.oa?id=50550102 |