|
|
|
|
| |
|
| |
|
|
Wesselingh, F.P.; Ranzi, A.; Räsänen, M.E.. |
Thirteen species of fossil molluscs are reported from the Solimões Formation of western Brazilian Amazonia. Based on mammalian chronology of the Solimões Formation and radiometric ages reported from coeval deposits in adjacent Peru, the age of the fauna is established as Late Miocene. The fauna includes five prosobranch gastropod species, seven pearly freshwater mussel species and one sphaeriid bivalve species. The supposed presence of Pachydon (Corbulidae: Bivalvia) in these deposits is rejected; Pachydon acreanum, whose status has long been uncertain, is transferred to the unionoid genus Callonaia. The Solimões mollusc fauna is entirely composed of obligate freshwater taxa, resembling species-poor modern Amazonian fluvial faunas. The presence of the... |
Tipo: Article / Letter to the editor |
Palavras-chave: Mollusca; Western Amazonia; Miocene; Solimões Formation.; 38.22; 42.73. |
Ano: 2006 |
URL: http://www.repository.naturalis.nl/record/209736 |
| |
|
|
Wesselingh, F.P.; Kaandorp, R.J.G.; Vonhof, H.B.; Räsänen, M.E.; Renema, W.; Gingras, M.. |
The Miocene Pebas Formation from the section Santa Rosa de Pichana (Loreto, Peru) was investigated using a combination of analyses of sedimentary facies, molluscan communities and taphonomy, and stable isotopes of both entire shells and growth bands in bivalves. Three sequences, comprising a succession of transgressive, maximum flooding and regressive/prograding intervals, are documented. Molluscs are most common in the transgressive/highstand intervals and are almost absent in regressive/prograding intervals. The fauna is dominated by endemic Pebasian species, such as Pachydon and Dyris spp. The nature of the deposits as well as the availability of oxygen varied in a predictable way within each of the sequences and determined the nature of the... |
Tipo: Article / Letter to the editor |
Palavras-chave: Miocene; Amazonia; Palaeoecology; Sedimentology; Stable isotopes; 38.22; 42.73. |
Ano: 2006 |
URL: http://www.repository.naturalis.nl/record/209732 |
| |
|
|
|