ANÁLISIS SECUENCIAL DE ALTA FRECUENCIA EN EL LÍMITE CRETÁCICO-PALEÓGENO DEL GRUPO SALTA, SUBCUENCA DE METÁN, NOROESTE ARGENTINO. ESTADO ACTUAL Y PERSPECTIVAS FUTURAS

LEANDRO C. GALLO; G. TERRA; G.RAJA GABAGLIA; ALEJANDRA DALENZ FARJAT; R. LYKAWKA; JUAN I. HERNANDEZ; RENATA N. TOMEZZOLI; E. BORGES RODRIGUEZ; E. BENTO FREIRE; ROBERTO M. HERNÁNDEZ

Ciencias de la Tierra y Recursos Naturales del NOA Relatorio del XX Congreso Geológico Argentino

Asociación geológica Argentina

Lugar: CABA; Año: 2017; p. 1046 - 1079

High-resolution sequence stratigraphy within the Cretaceous-Tertiary boundary in Salta Group, Metan Sub-basin, NorthwesternArgentina. Up-to-date and Future Perspectives. The Salta Group (Lower Cretaceous to Eocene) is essentiallycomposed of clastic sedimentary rocks with carbonates and evaporites, which were deposited in diff erent sedimentaryenvironments: alluvial fans, rivers and braided fl oodplains, ephemeral sandy-braided rivers, eolian, mudfl ats, salt mud fl ats and lacustrine environments with occasional marine infl uence. The thickness of these depositsis greater than 3,500 m measured in the main sub-basins. The Salta Group is genetically related to a continental riftbasin, located to the east of the Southamerican-Pacifi c plate boundary. This rift basin development is synchronicwith the Occidental Gondwana break-up.Four second-order sequences have been defi ned related to changes in the accommodation/sedimentation balance,and separated by unconformity surfaces: Pirgua, Balbuena, Santa Barbara and Lumbrera sequences. Eachsequence has been internally divided into minor-scale third-order sequences with their corresponding divisionsestablishing the sequence stratigraphic framework of the basin. Each of the four sequences mentioned is characterizedby a distinctive paleogeography that controls the facies association and system tracks arrangement.The high-resolution-sequence-stratigraphy analysis linked to orbital cycles within the clastic and carbonate rocksof the Balbuena Sequence (Cretaceous-Tertiary) has been performed. Its stratigraphic similarities to the stromatolitedeposits present in the Pre-Sal section in southeastern Brasil offshore basins, has encouraged the analysis ofsequence-stratigraphy controls within the Balbuena interval. This analysis implied the use of multiple techniquesrelated to precise absolute dating (SHRIMP, CA-IDTIMS in zircons), gamma ray profiles (K, U, Th), laser-scanningand GPR (Ground Penetrating Radar) applied to outcrops, petrographic and palynological analysis.Keywords: high-resolution sequence stratigraphy, Balbuena.