| Registro completo |
| Provedor de dados: |
Anais da ABC (AABC)
|
| País: |
Brazil
|
| Título: |
Cordão Formation: loess deposits in the southern coastal plain of the state of Rio Grande do Sul, Brazil
|
| Autores: |
LOPES,RENATO P.
DILLENBURG,SERGIO R.
SCHULTZ,CESAR L.
|
| Data: |
2016-12-01
|
| Ano: |
2016
|
| Palavras-chave: |
Chuy Creek
Coastal plain
Last glacial stage
Loess
Pleistocene
|
| Resumo: |
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 pale-colored (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.
|
| Tipo: |
Info:eu-repo/semantics/article
|
| Idioma: |
Inglês
|
| Identificador: |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652016000602143
|
| Editor: |
Academia Brasileira de Ciências
|
| Relação: |
10.1590/0001-3765201620150738
|
| Formato: |
text/html
|
| Fonte: |
Anais da Academia Brasileira de Ciências v.88 n.4 2016
|
| Direitos: |
info:eu-repo/semantics/openAccess
|
