INVESTIGADORES
LOPEZ Luciano
artículos
Título:
Tectonostratigraphic analysis of the Late Triassic-Early Jurassic syn-rift sequence of the Neuquen Basin in the Sañico depocentre, Neuquen Province, Argentina.
Autor/es:
D´ELIA, LEANDRO; MURAVCHIK, MARTÍN; FRANZESE, JUAN; LÓPEZ, LUCIANO
Revista:
ANDEAN GEOLOGY
Editorial:
SERVICIO NACIONAL GEOLOGIA MINERVA
Referencias:
Lugar: Santiago de Chile; Año: 2011 vol. 39 p. 133 - 157
ISSN:
0718-7092
Resumen:
The initial syn-rift infill (Upper
Triassic-Lower Jurassic) of the Neuquén Basin involved a complex
stacking of lava, pyroclastic and sedimentary units, in which volcanic
rocks compose up to 72% of the infill. The high-quality outcrops of the
southern Sañicó depocentre, which was uplifted and exposed during the
Andean orogeny, were studied in order to determine the lithofacies
arrangements, the tectonostratigraphic framework and the main controls
over the syn-rift succession. The tectonostratigraphic study made it
possible to determine three sections characterized by the predominance
of effusive, pyroclastic or sedimentary deposits. These sections
indicate three different evolutionary stages of the volcanic rifting.
The onset of this rift stage was dominated by effusive rocks with minor
ignimbrite and alluvial volcaniclastic units, which indicates the
occurrence of composite volcanoes at the boundaries of the depocentre.
The mid-rift stage was characterized by the development of
fault-controlled, large ignimbrite deposits intebedded with
volcaniclastic alluvial deposits and lava units, which suggests a
volcano-tectonic depression related to asymmetrical and incremental
subsidence. The end of the volcanic rifting event was marked by a
decrease in the volume of the volcanic rocks and the occurrence of
low-relief effusive aggradational volcanic edifices and lava fields in
close relation with alluvial, deltaic and lacustrine units. The analysis
of the syn-rift sequence in the Sañicó depocentre showed the complex
relationships between tectonic and volcanic controls which occurred in
different magnitudes and times during the rifting evolution.