科研之友
微信
新浪微博
Facebook
分享链接
摘要
Late Jurassic-Early Cretaceous nannoconid assemblages are reported from 11 sections in the Neuquen Basin. Six species and 11 subspecies of Nannoconus Kamptner are studied systematically. Among them, Nannoconus kamptneri minor Bralower, Nannoconus kamptneri kamptneri Bronnimann, Nannoconus bucheri Bronnimann, Nannoconus circularis Deres and Acheriteguy and Nannoconus ligius Applegate and Bergen are highlighted as markers for the studied interval. Nannoconus elongatus minutus Van Niel, Nannoconus quadriangulus apertus Deflandre y Deflandre-Rigaud, Nannoconus truitti frequens Deres and Acheriteguy, Nannoconus truitti rectangularis Deres and Acheriteguy, Nannoconus truitti truitti Bronnimann are described for the first time in the Neuquen Basin. Nannoconus steinmannii minor Deres and Acheriteguy is reported for the first time in the Southern Hemisphere. The biostratigraphic analysis suggests an ampliation of the stratigraphic ranges of Nannoconus elongatus minutus, Nannoconus quadriangulus quadriangulus Deflandre and Deflandre-Rigaud, Nannoconus quadricanalis Bown and Concheyro, Nannoconus truitti frequens and Nannoconus truitti rectangularis. Changes in the composition and diversity of the recorded nannoconid assemblages suggest variations in the paleobiogeographic and paleoecological conditions that may be helpful in the characterization of the sedimentary environments represented in the Vaca Muerta and Agrio Formations.
- 出版日期2014
