Cordão Formation: loess deposits in the southern coastal plain of the state of Rio Grande do Sul, Brazil
dc.contributor.author | Lopes, Renato Pereira | pt_BR |
dc.contributor.author | Dillenburg, Sergio Rebello | pt_BR |
dc.contributor.author | Schultz, Cesar Leandro | pt_BR |
dc.date.accessioned | 2017-12-12T02:23:44Z | pt_BR |
dc.date.issued | 2016 | pt_BR |
dc.identifier.issn | 0001-3765 | pt_BR |
dc.identifier.uri | http://hdl.handle.net/10183/171124 | pt_BR |
dc.description.abstract | Loess consists of silt-dominated sediments that cover ~10% of the Earth’s surface. In southern South America it occurs in Argentina, Bolivia, Paraguay and Uruguay, and its presence in southern Brazil was never studied in detail. Here is proposed a new lithostratigraphic unit, Cordão Formation, consisting of loess deposits in the southern Brazilian coastal plain. It consists of fine-very fine silt with subordinate sand and clay, found mostly in lowland areas between Pleistocene coastal barriers. These sediments are palecolored (10YR hue) and forms ~1,5-2,0 meter-thick stable vertical walls. The clay minerals include illite, smectite, interstratified illite/smectite and kaolinite, the coarser fraction is mostly quartz and plagioclase. Caliche and iron-manganese nodules are also present. The only fossils found so far are rodent teeth and a tooth of a camelid (Hemiauchenia paradoxa). Luminescence ages indicate that this loess was deposited in the latest Pleistocene, between ~30 and 10 kyrs ago, and its upper portion was modified by erosion and accumulation of clay and organic matter in the Holocene. The estimated accumulation rate was ~630 g/ m2/year. The probable source of this loess is the Pampean Aeolian System of Argentina and it would have been deposited by the increased aeolian processes of the last glacial. | en |
dc.format.mimetype | application/pdf | |
dc.language.iso | eng | pt_BR |
dc.relation.ispartof | Anais da Academia Brasileira de Ciências. Vol. 88, n.4 (Out./ Dez. 2016), p.2143-2166 | pt_BR |
dc.rights | Open Access | en |
dc.subject | Chuy Creek | en |
dc.subject | Planície costeira | pt_BR |
dc.subject | Pleistoceno | pt_BR |
dc.subject | Coastal plain | en |
dc.subject | Unidade lito-estratigrafica | pt_BR |
dc.subject | Last glacial stage | en |
dc.subject | Loess | en |
dc.subject | Rio Grande do Sul | pt_BR |
dc.subject | Pleistocene | en |
dc.title | Cordão Formation: loess deposits in the southern coastal plain of the state of Rio Grande do Sul, Brazil | pt_BR |
dc.type | Artigo de periódico | pt_BR |
dc.identifier.nrb | 001049215 | pt_BR |
dc.type.origin | Nacional | pt_BR |
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