Publication Date:
2011-09-01
Description:
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 characterized by a decimeter-scale rhythmic alternation of marls, shales and limestones and extends from the lower Tithonian to the 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 a 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. Diego A. Kietzmann graduated in geological sciences from the University of Buenos Aires, where he has been an assistant teacher since 2005. He is completing his Ph.D., studying the Jurassic–Cretaceous boundary of the Neuquén Basin. He has authored different articles on sedimentology, stratigraphy, paleontology, and taphonomy. Javier Martín-Chivelet received his Ph.D. in geology from the Universidad Complutense de Madrid, Spain, in 1992, and did his postdoctoral fellowship at the University of California at Riverside. He is currently a professor at Universidad Complutense de Madrid, and his research focuses on carbonate rocks as high-resolution indicators of past changes in climate and environment. Ricardo M. Palma holds a B.S. degree and a Ph.D. in geological sciences from the Tucumán National University, Argentina. Since 1987, he has worked at the University of Buenos Aires. Since 1998, he has been a professor in stratigraphy and carbonate rocks, being a specialist in carbonate rocks, sedimentology, and stratigraphy. He has published articles in national and international specialized journals. He works as an independent researcher with the Consejo Nacional de Investigaciones Científicas y Técnicas. José López-Gómez studied and received his Ph.D in geology from the Universidad Complutense de Madrid in 1985. He was at Montreal University and Imperial College, London (United Kingdom) with a postdoctoral grant. He is currently doing his main research in carbonate and siliciclastic Permian–Triassic and Jurassic rocks. Marina Lescano graduated with a degree in biological sciences from the San Juan Bosco University, Argentina. She is finishing her doctorate at the University of Buenos Aires, trying to characterize the Late Jurassic–Early Cretaceous calcareous nannofossils of the Neuquén Basin. She has published preliminary results on the biostratigraphy and taxonomy of these microfossils. Andrea Concheyro received her Ph.D. in geological sciences and became a lecturer in paleontology at the University of Buenos Aires. She is a researcher of the Consejo Nacional de Investigaciones Científicas y Técnicas and the Argentinean Antarctic Institute. Her investigations are concentrated in Mesozoic and Cenozoic calcareous nannofossils, biostratigraphy, and paleobiogeography of Patagonia and Antarctica.
Print ISSN:
0149-1423
Electronic ISSN:
1943-2674
Topics:
Geosciences
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