000			01838nab a2200205 4500
005			20260520000312.0
008			260224s2011 xxu
100	1		_aKietzmann, Diego A. _951839
100	1		_aMartín-Chivelet, Javier _951840
100	1		_aPalma, Ricardo M. _93314
245	0	0	_aEvidence 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
260			_csep. 2011
270			_a05/10/2011 ; 05/10/2011
300			_a16 p. ; 1459-1474
520			_aTranscripción del resumen del autor. 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.
581			_a9
773	0		_tAAPG Bulletin _g95
942			_cARTICULO
999			_c186055 _d186055