Evidence of cyclic climatic changes recorded in clay mineral assemblages from a continental Paleocene-Eocene sequence, northwestern Argentina
The continental Paleocene-Eocene sequence investigated in this study belongs to the Salta Group, deposited in an intracontinental rift, the Salta Basin (NW Argentina), that evolved from the lower Cretaceous to the middle Paleogene, and is subdivided into the Pirgua, the Balbuena and the Santa Barbar...
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2018
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00370738_v368_n_p44_DoCampo http://hdl.handle.net/20.500.12110/paper_00370738_v368_n_p44_DoCampo |
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paper:paper_00370738_v368_n_p44_DoCampo2023-06-08T15:02:15Z Evidence of cyclic climatic changes recorded in clay mineral assemblages from a continental Paleocene-Eocene sequence, northwestern Argentina Clay minerals Continental basins Kaolinite Paleoclimate reconstruction Paleosols Clay minerals Scanning electron microscopy Soils Weathering X ray diffraction Chemical weathering Clay mineral assemblages Continental basins Cyclic climatic changes Northern Hemispheres Paleoclimate reconstruction Paleosols Southern Hemisphere Kaolinite clay mineral climate variation kaolinite mineralogy Paleocene-Eocene boundary paleoclimate paleosol reconstruction scanning electron microscopy X-ray diffraction Argentina The continental Paleocene-Eocene sequence investigated in this study belongs to the Salta Group, deposited in an intracontinental rift, the Salta Basin (NW Argentina), that evolved from the lower Cretaceous to the middle Paleogene, and is subdivided into the Pirgua, the Balbuena and the Santa Barbara Subgroups. The Maíz Gordo Formation (200 m thick) is the middle unit of the Santa Bárbara Subgroup, deposited during late post-rift sedimentation. We studied the mineralogy of fine-grained horizons of this formation by X-ray diffraction and Scanning Electron Microscopy (SEM) in order to examine the connection between vertical changes in clay mineralogy in alluvial sediments and paleosols, and global paleoclimatic changes registered during the Paleogene. Paleosols vary from calcic vertisols in the lowermost levels, to inseptisols and gleysols in intermediate positions, to gleyed oxisols in the upper section, indicating increased chemical weathering through time. Clay mineral relative abundances vary with a general increase in kaolinite content from bottom to top. However, at one site there are significant variations in kaolinite/muscovite (Kln/Ms) that define five cycles of kaolinite abundance and Kln/Ms. that indicate cyclic patterns of paleoprecipitation and paleotemperature. These are interpreted as several short-lived hyperthermals during the Paleocene-early Eocene in the Southern Hemisphere, which correlate with well-established episodes of warmth documented from the Northern Hemisphere. © 2018 Elsevier B.V. 2018 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00370738_v368_n_p44_DoCampo http://hdl.handle.net/20.500.12110/paper_00370738_v368_n_p44_DoCampo |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Clay minerals Continental basins Kaolinite Paleoclimate reconstruction Paleosols Clay minerals Scanning electron microscopy Soils Weathering X ray diffraction Chemical weathering Clay mineral assemblages Continental basins Cyclic climatic changes Northern Hemispheres Paleoclimate reconstruction Paleosols Southern Hemisphere Kaolinite clay mineral climate variation kaolinite mineralogy Paleocene-Eocene boundary paleoclimate paleosol reconstruction scanning electron microscopy X-ray diffraction Argentina |
| spellingShingle |
Clay minerals Continental basins Kaolinite Paleoclimate reconstruction Paleosols Clay minerals Scanning electron microscopy Soils Weathering X ray diffraction Chemical weathering Clay mineral assemblages Continental basins Cyclic climatic changes Northern Hemispheres Paleoclimate reconstruction Paleosols Southern Hemisphere Kaolinite clay mineral climate variation kaolinite mineralogy Paleocene-Eocene boundary paleoclimate paleosol reconstruction scanning electron microscopy X-ray diffraction Argentina Evidence of cyclic climatic changes recorded in clay mineral assemblages from a continental Paleocene-Eocene sequence, northwestern Argentina |
| topic_facet |
Clay minerals Continental basins Kaolinite Paleoclimate reconstruction Paleosols Clay minerals Scanning electron microscopy Soils Weathering X ray diffraction Chemical weathering Clay mineral assemblages Continental basins Cyclic climatic changes Northern Hemispheres Paleoclimate reconstruction Paleosols Southern Hemisphere Kaolinite clay mineral climate variation kaolinite mineralogy Paleocene-Eocene boundary paleoclimate paleosol reconstruction scanning electron microscopy X-ray diffraction Argentina |
| description |
The continental Paleocene-Eocene sequence investigated in this study belongs to the Salta Group, deposited in an intracontinental rift, the Salta Basin (NW Argentina), that evolved from the lower Cretaceous to the middle Paleogene, and is subdivided into the Pirgua, the Balbuena and the Santa Barbara Subgroups. The Maíz Gordo Formation (200 m thick) is the middle unit of the Santa Bárbara Subgroup, deposited during late post-rift sedimentation. We studied the mineralogy of fine-grained horizons of this formation by X-ray diffraction and Scanning Electron Microscopy (SEM) in order to examine the connection between vertical changes in clay mineralogy in alluvial sediments and paleosols, and global paleoclimatic changes registered during the Paleogene. Paleosols vary from calcic vertisols in the lowermost levels, to inseptisols and gleysols in intermediate positions, to gleyed oxisols in the upper section, indicating increased chemical weathering through time. Clay mineral relative abundances vary with a general increase in kaolinite content from bottom to top. However, at one site there are significant variations in kaolinite/muscovite (Kln/Ms) that define five cycles of kaolinite abundance and Kln/Ms. that indicate cyclic patterns of paleoprecipitation and paleotemperature. These are interpreted as several short-lived hyperthermals during the Paleocene-early Eocene in the Southern Hemisphere, which correlate with well-established episodes of warmth documented from the Northern Hemisphere. © 2018 Elsevier B.V. |
| title |
Evidence of cyclic climatic changes recorded in clay mineral assemblages from a continental Paleocene-Eocene sequence, northwestern Argentina |
| title_short |
Evidence of cyclic climatic changes recorded in clay mineral assemblages from a continental Paleocene-Eocene sequence, northwestern Argentina |
| title_full |
Evidence of cyclic climatic changes recorded in clay mineral assemblages from a continental Paleocene-Eocene sequence, northwestern Argentina |
| title_fullStr |
Evidence of cyclic climatic changes recorded in clay mineral assemblages from a continental Paleocene-Eocene sequence, northwestern Argentina |
| title_full_unstemmed |
Evidence of cyclic climatic changes recorded in clay mineral assemblages from a continental Paleocene-Eocene sequence, northwestern Argentina |
| title_sort |
evidence of cyclic climatic changes recorded in clay mineral assemblages from a continental paleocene-eocene sequence, northwestern argentina |
| publishDate |
2018 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00370738_v368_n_p44_DoCampo http://hdl.handle.net/20.500.12110/paper_00370738_v368_n_p44_DoCampo |
| _version_ |
1768546245567053824 |