CIG   05423
CENTRO DE INVESTIGACIONES GEOLOGICAS
Unidad Ejecutora - UE
artículos
Título:
The Upper Jurassic (Kimmeridgian) fluvial/aeolian systems of southern Neuquén Basin, Argentina
Autor/es:
VEIGA, G.D.; SPALLETTI, L.A.
Revista:
GONDWANA RESEARCH
Editorial:
Elsevier
Referencias:
Año: 2007 vol. 11 p. 286 - 302
ISSN:
1342-937X
Resumen:
Abstract: The Kimmeridgian Quebrada del Sapo Formation in the southernmost Neuquén Basin in Argentina represents a succession up to 40 m-thick of coarse- to fine-grained fluvial deposits overlain by aeolian deposits. These fluvial/aeolian deposits represent a significant palaegeographic change in the basin and are related to a major, tectonically enhanced, relative sea-level fall. The fluvial section is dominated by braided-channel deposits, fine-grained ephemeral and sheetflood deposits. Aeolian facies are dominated by dune deposits, with minor sandsheet and wet interdune units. Changes in the nature of both fluvial and aeolian accumulation within the studied area suggest a regional variability of accommodation/sediment supply conditions. The regional changes of the aeolian succession in the study area may likely reflect different relative positions within a major erg. In the upwind margin of the erg, a relatively shallow water table promoted waterlain accumulation in interdune areas, whereas in the central parts of the erg, dry accumulation took place above the regional water-table level. The vertical transition observed in the Quebrada del Sapo Fm from fluvial to aeolian deposits may be the result of a local climatic change to drier conditions related to the development of a climatic barrier due to the vertical growth of a magmatic arc to the west. Alternatively, the vertical transition could be related to a general water table lowering associated with the compartmentalisation of the basin during a period of low relative sea-level. Argentina represents a succession up to 40 m-thick of coarse- to fine-grained fluvial deposits overlain by aeolian deposits. These fluvial/aeolian deposits represent a significant palaegeographic change in the basin and are related to a major, tectonically enhanced, relative sea-level fall. The fluvial section is dominated by braided-channel deposits, fine-grained ephemeral and sheetflood deposits. Aeolian facies are dominated by dune deposits, with minor sandsheet and wet interdune units. Changes in the nature of both fluvial and aeolian accumulation within the studied area suggest a regional variability of accommodation/sediment supply conditions. The regional changes of the aeolian succession in the study area may likely reflect different relative positions within a major erg. In the upwind margin of the erg, a relatively shallow water table promoted waterlain accumulation in interdune areas, whereas in the central parts of the erg, dry accumulation took place above the regional water-table level. The vertical transition observed in the Quebrada del Sapo Fm from fluvial to aeolian deposits may be the result of a local climatic change to drier conditions related to the development of a climatic barrier due to the vertical growth of a magmatic arc to the west. Alternatively, the vertical transition could be related to a general water table lowering associated with the compartmentalisation of the basin during a period of low relative sea-level. Argentina represents a succession up to 40 m-thick of coarse- to fine-grained fluvial deposits overlain by aeolian deposits. These fluvial/aeolian deposits represent a significant palaegeographic change in the basin and are related to a major, tectonically enhanced, relative sea-level fall. The fluvial section is dominated by braided-channel deposits, fine-grained ephemeral and sheetflood deposits. Aeolian facies are dominated by dune deposits, with minor sandsheet and wet interdune units. Changes in the nature of both fluvial and aeolian accumulation within the studied area suggest a regional variability of accommodation/sediment supply conditions. The regional changes of the aeolian succession in the study area may likely reflect different relative positions within a major erg. In the upwind margin of the erg, a relatively shallow water table promoted waterlain accumulation in interdune areas, whereas in the central parts of the erg, dry accumulation took place above the regional water-table level. The vertical transition observed in the Quebrada del Sapo Fm from fluvial to aeolian deposits may be the result of a local climatic change to drier conditions related to the development of a climatic barrier due to the vertical growth of a magmatic arc to the west. Alternatively, the vertical transition could be related to a general water table lowering associated with the compartmentalisation of the basin during a period of low relative sea-level. én Basin in Argentina represents a succession up to 40 m-thick of coarse- to fine-grained fluvial deposits overlain by aeolian deposits. These fluvial/aeolian deposits represent a significant palaegeographic change in the basin and are related to a major, tectonically enhanced, relative sea-level fall. The fluvial section is dominated by braided-channel deposits, fine-grained ephemeral and sheetflood deposits. Aeolian facies are dominated by dune deposits, with minor sandsheet and wet interdune units. Changes in the nature of both fluvial and aeolian accumulation within the studied area suggest a regional variability of accommodation/sediment supply conditions. The regional changes of the aeolian succession in the study area may likely reflect different relative positions within a major erg. In the upwind margin of the erg, a relatively shallow water table promoted waterlain accumulation in interdune areas, whereas in the central parts of the erg, dry accumulation took place above the regional water-table level. The vertical transition observed in the Quebrada del Sapo Fm from fluvial to aeolian deposits may be the result of a local climatic change to drier conditions related to the development of a climatic barrier due to the vertical growth of a magmatic arc to the west. Alternatively, the vertical transition could be related to a general water table lowering associated with the compartmentalisation of the basin during a period of low relative sea-level.