Intermontane eolian sand sheet development, Upper Tulum Valley, central-western Argentina

Autor(es)

Fuhr Dal' Bo, Patrick Francisco ^[1] ; Basilici, Giorgio ^[2]

Afiliação do(s) autor(es)

^[1] Univ Fed Rio de Janeiro, Inst Geociencias, Dept Geol, Lab Geol Sedimentar, Rio De Janeiro, RJ - Brazil

^[2] Univ Estadual Campinas UNICAMP, Inst Geociencias, Dept Geol & Recursos Nat, Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: BRAZILIAN JOURNAL OF GEOLOGY; v. 45, n. 1, p. 97-115, AUG 2015.
• Citações Web of Science: 2

Resumo

The intermontane Upper Tulum eolian sand sheet covers an area of ca. 125 km(2) at north of the San Juan Province, central-western Argentina. The sand sheet is currently an aggrading system where vegetation cover, surface cementation and periodic flooding withhold the development of dunes with slipfaces. The sand sheet surface is divided into three parts according to the distribution of sedimentary features, which reflects the variation in sediment budget, water table level and periodic flooding. The central sand sheet part is the main area of eolian deposition and is largely stabilized by vegetation. The sedimentary succession is 4 m thick and records the vertical interbedding of eolian and subaqueous deposits, which have been deposited for at least 3.6 ky with sedimentation rates of 86.1 cm/ky. The construction of the sand sheet is associated with deflation of the sand-graded debris sourced by San Juan alluvial fan, which is available mainly in drier fall-winter months where water table is lower and wind speeds are periodically above the threshold velocity for sand transport. The accumulation of sedimentary bodies occurs in a stabilized eolian system where vegetation cover, thin mud veneers and surface cementation are the main agents in promoting accumulation. The preservation of the sand sheet accumulations is enabled by the progressive creation of the accommodation space in a tectonically active basin and the continuous burial of geological bodies favored by high rates of sedimentation. (AU)

• Processo FAPESP: 07/00140-6 - Relações entre depósitos e paleossolos de ambiente semi-árido: um exemplo antigo (Bacia de Bauru, estados de GO, MG e MS) e um análogo atual (Vale do rio Bermejo, W de Argentina)
• Beneficiário: Giorgio Basilici
• Modalidade de apoio: Auxílio à Pesquisa - Regular