IDEAN   23403
INSTITUTO DE ESTUDIOS ANDINOS "DON PABLO GROEBER"
Unidad Ejecutora - UE
artículos
Título:
Evidence of precessional and eccentricity orbital cycles in a Tithonian source rock: The mid-outer carbonate ramp of the Vaca Muerta Formation, northern Neuquén Basin, Argentina.
Autor/es:
KIETZMANN, D. MARTÍN-CHIVELETTJJ PALMAMA, R. JOSÉ LÓPEZ-GÓMEZZ JJ LESCANONO, M. Y CONCHEYRO, A
Revista:
AAPG BULLETIN
Editorial:
AMER ASSOC PETROLEUM GEOLOGIST
Referencias:
Lugar: Tulsa; Año: 2010
ISSN:
0149-1423
Resumen:
Basin to mid-ramp cyclic facies of the Tithonian Vaca Muerta  Formation are exposed in the Loncoche creek section of the Neuquén Basin, Mendoza province, Argentina. This unit is Formation are exposed in the Loncoche creek section of the Neuquén Basin, Mendoza province, Argentina. This unit is characterized by a decimeter-scale rhythmic alternation of marls and/or shales and limestones and extends from the lower Tithonian to upper Berriasian. Cyclostratigraphic studies based on a detailed facies analysis allowed the identification of cyclic patterns with frequencies within the Milankovitch band. According to biostratigraphic data, the dominant cycle in the studied section has a period of 20 k.y., which correlates with  the Earth’s axis precession element. Spectral analysis based  on series of compacted and decompacted cycle thickness identified a subordinate frequency of about 90 to 120 k.y., which we interpret as the modulation of the precessional cycle caused by the Earth’s orbital eccentricity. The strength of the precession signal, together with the absence of a well defined cyclicity attributable to the obliquity orbital cycle (i.e., ∼40 k.y.), is in agreement with previous data from the Northern Hemisphere. characterized by a decimeter-scale rhythmic alternation of marls and/or shales and limestones and extends from the lower Tithonian to upper Berriasian. Cyclostratigraphic studies based on a detailed facies analysis allowed the identification of cyclic patterns with frequencies within the Milankovitch band. According to biostratigraphic data, the dominant cycle in the studied section has a period of 20 k.y., which correlates with  the Earth’s axis precession element. Spectral analysis based  on series of compacted and decompacted cycle thickness identified a subordinate frequency of about 90 to 120 k.y., which we interpret as the modulation of the precessional cycle caused by the Earth’s orbital eccentricity. The strength of the precession signal, together with the absence of a well defined cyclicity attributable to the obliquity orbital cycle (i.e., ∼40 k.y.), is in agreement with previous data from the Northern Hemisphere.