Grain size discrimination between sands of desert and coastal dunes from northwestern Mexico
A textural study of grain-size distribution parameters (mean graphic size Mz, sorting σ, skewnessSki, kurtosis KG) was carried out in the state of Sonora, in NW Mexico. The aim was to distinguish betweendesert and coastal dunes based on the textural parameters of the sands. Sixty two sand s...
| Autores: | , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2005 |
| País: | México |
| Institución: | Universidad Nacional Autónoma de México |
| Repositorio: | Redalyc-UNAM |
| OAI Identifier: | oai:redalyc.org:57222311 |
| Acceso en línea: | https://www.redalyc.org/articulo.oa?id=57222311 |
| Access Level: | acceso abierto |
| Palabra clave: | Ciencias de la Tierra Sonora Mexico desert dunes Altar Desert coastal dunes |
| Sumario: | A textural study of grain-size distribution parameters (mean graphic size Mz, sorting σ, skewnessSki, kurtosis KG) was carried out in the state of Sonora, in NW Mexico. The aim was to distinguish betweendesert and coastal dunes based on the textural parameters of the sands. Sixty two sand samples werecollected from the slip face and crest of linear and sand sheet dunes from the desert and coastal zone of theAltar Desert, Sonora. Textural parameters were determined by a Laser Particle Size Analyzer (Coulter).Among the four groups of dunes studied, El Pinacate desert dune sands are signifi cantly different fromthe rest of the dune groups in terms of grain size and skewness. This is due to the selectiveness of thenorthwesterly winds that concentrates fi ner sizes with longer wind transport from the source (ColoradoRiver delta sediments) to the El Pinacate dune fi elds. In contrast, the grain size distributions for the restof the dune fi elds are affected by their proximity to the sediment sources, tidal transport, long shore driftsand southwesterly and southeasterly winds. Coastal dune sands are coarser than the desert dune sands.This may be caused by the effect of the tidal currents and local winds of the Colorado River delta sedimentsthat locally carry coarser grains onto the beach and landwards. Bioclasts of the beach sand in PuertoPeñasco also exerts a control in the grain size distribution of the dune sand. The linear discriminantanalysis and ANOVA test are useful tools to discriminate between desert and coastal dune sands. Somesimilarities were detected for the grain size distributions between the Altar Desert sands (Mz=1.34φ 2.79φ; σ=0.35φ 1.60φ) and the Kalahari Desert sands (Mz=1.55φ 2.38φ; σ=0.51φ 1.52φ) thatare probably associated with the sediment source of the sands, dune morphology and wind patterns. |
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