Magnetostratigraphy of the Upper Jurassic–Lower Cretaceous from Argentina: Implications for the J-K boundary in the Neuquén Basin
A systematic sedimentologic and paleomagnetic study was carried out in the Vaca Muerta Formation, cropping out in the northern Neuquén Basin, west-central Argentina. The studied section is c. 280 m-thick and represents a carbonate ramp system bearing ammonites that indicate Late Jurassic–Early Creta...
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2017
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01956671_v70_n_p189_IglesiaLlanos http://hdl.handle.net/20.500.12110/paper_01956671_v70_n_p189_IglesiaLlanos |
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paper:paper_01956671_v70_n_p189_IglesiaLlanos2023-06-08T15:20:21Z Magnetostratigraphy of the Upper Jurassic–Lower Cretaceous from Argentina: Implications for the J-K boundary in the Neuquén Basin Iglesia Llanos, Maria Paula Kietzmann, Diego Alejandro Palma, Ricardo Manuel Andean ammonite zones Jurassic-Cretaceous boundary Paleomagnetism Vaca Muerta Formation ammonite Andean orogeny biostratigraphy carbonate ramp hydrocarbon reservoir Jurassic-Cretaceous boundary magnetostratigraphy paleomagnetism sedimentology Argentina Neuquen Basin Ammonoidea A systematic sedimentologic and paleomagnetic study was carried out in the Vaca Muerta Formation, cropping out in the northern Neuquén Basin, west-central Argentina. The studied section is c. 280 m-thick and represents a carbonate ramp system bearing ammonites that indicate Late Jurassic–Early Cretaceous ages. The Vaca Muerta Formation is one of the most important unconventional hydrocarbon reservoirs in the world and its thorough study has become a relevant target in Argentina. The J-K boundary is comprised within this unit, and although it is well-dated through biostratigraphy (mainly ammonites), the position of particularly the boundary is yet a matter of hot debate. Therefore, the systematic paleomagnetic and cyclostratigraphic study in the Vaca Muerta Formation was considered relevant in order to obtain the first Upper Jurassic–Lower Cretaceous magnetostratigraphy of the southern hemisphere on the first place and to precise the position of the J-K boundary in the Neuquén Basin, on the other. Biostratigraphy is well studied in the area, so that paleomagnetic sampling horizons were reliably tied, particularly through ammonites. Almost 450 standard specimens have been processed for this study distributed along 56 paleomagnetic sampling horizons that were dated using ammonites. Paleomagnetic behaviours showed to be very stable, and their quality and primary origin have been proved through several paleomagnetic field tests The resultant magnetostratigraphic scale is made up of 11 reverse and 10 normal polarity zones, spanning the Andean Virgatosphinctes mendozanus (lower Tithonian) to Spiticeras damesi Zones (upper Berriasian). These polarity zones were correlated with those of the International Geomagnetic Polarity Time Scale 2012 and 2016 through the correlation between Andean and Tethyan ammonite zones. Cyclostratigraphy on the other hand, proved to be quite consistent with the magnetostratigraphy. Through the correlation of the resultant paleomagnetic and cyclostratigraphic data, it was possible to date the section with unprecedented precision, and therefore, to establish the position of the Jurassic-Cretaceous boundary. The paleomagnetic pole calculated from the primary magnetization is located at: Lon = 191.6°E, Lat = 76.2°S, A95 = 3.5°, indicating a c. 24° clockwise rotation for the studied section, which is consistent with structural data of the region. © 2016 Elsevier Ltd Fil:Iglesia Llanos, M.P. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Kietzmann, D.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Palma, R.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2017 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01956671_v70_n_p189_IglesiaLlanos http://hdl.handle.net/20.500.12110/paper_01956671_v70_n_p189_IglesiaLlanos |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Andean ammonite zones Jurassic-Cretaceous boundary Paleomagnetism Vaca Muerta Formation ammonite Andean orogeny biostratigraphy carbonate ramp hydrocarbon reservoir Jurassic-Cretaceous boundary magnetostratigraphy paleomagnetism sedimentology Argentina Neuquen Basin Ammonoidea |
| spellingShingle |
Andean ammonite zones Jurassic-Cretaceous boundary Paleomagnetism Vaca Muerta Formation ammonite Andean orogeny biostratigraphy carbonate ramp hydrocarbon reservoir Jurassic-Cretaceous boundary magnetostratigraphy paleomagnetism sedimentology Argentina Neuquen Basin Ammonoidea Iglesia Llanos, Maria Paula Kietzmann, Diego Alejandro Palma, Ricardo Manuel Magnetostratigraphy of the Upper Jurassic–Lower Cretaceous from Argentina: Implications for the J-K boundary in the Neuquén Basin |
| topic_facet |
Andean ammonite zones Jurassic-Cretaceous boundary Paleomagnetism Vaca Muerta Formation ammonite Andean orogeny biostratigraphy carbonate ramp hydrocarbon reservoir Jurassic-Cretaceous boundary magnetostratigraphy paleomagnetism sedimentology Argentina Neuquen Basin Ammonoidea |
| description |
A systematic sedimentologic and paleomagnetic study was carried out in the Vaca Muerta Formation, cropping out in the northern Neuquén Basin, west-central Argentina. The studied section is c. 280 m-thick and represents a carbonate ramp system bearing ammonites that indicate Late Jurassic–Early Cretaceous ages. The Vaca Muerta Formation is one of the most important unconventional hydrocarbon reservoirs in the world and its thorough study has become a relevant target in Argentina. The J-K boundary is comprised within this unit, and although it is well-dated through biostratigraphy (mainly ammonites), the position of particularly the boundary is yet a matter of hot debate. Therefore, the systematic paleomagnetic and cyclostratigraphic study in the Vaca Muerta Formation was considered relevant in order to obtain the first Upper Jurassic–Lower Cretaceous magnetostratigraphy of the southern hemisphere on the first place and to precise the position of the J-K boundary in the Neuquén Basin, on the other. Biostratigraphy is well studied in the area, so that paleomagnetic sampling horizons were reliably tied, particularly through ammonites. Almost 450 standard specimens have been processed for this study distributed along 56 paleomagnetic sampling horizons that were dated using ammonites. Paleomagnetic behaviours showed to be very stable, and their quality and primary origin have been proved through several paleomagnetic field tests The resultant magnetostratigraphic scale is made up of 11 reverse and 10 normal polarity zones, spanning the Andean Virgatosphinctes mendozanus (lower Tithonian) to Spiticeras damesi Zones (upper Berriasian). These polarity zones were correlated with those of the International Geomagnetic Polarity Time Scale 2012 and 2016 through the correlation between Andean and Tethyan ammonite zones. Cyclostratigraphy on the other hand, proved to be quite consistent with the magnetostratigraphy. Through the correlation of the resultant paleomagnetic and cyclostratigraphic data, it was possible to date the section with unprecedented precision, and therefore, to establish the position of the Jurassic-Cretaceous boundary. The paleomagnetic pole calculated from the primary magnetization is located at: Lon = 191.6°E, Lat = 76.2°S, A95 = 3.5°, indicating a c. 24° clockwise rotation for the studied section, which is consistent with structural data of the region. © 2016 Elsevier Ltd |
| author |
Iglesia Llanos, Maria Paula Kietzmann, Diego Alejandro Palma, Ricardo Manuel |
| author_facet |
Iglesia Llanos, Maria Paula Kietzmann, Diego Alejandro Palma, Ricardo Manuel |
| author_sort |
Iglesia Llanos, Maria Paula |
| title |
Magnetostratigraphy of the Upper Jurassic–Lower Cretaceous from Argentina: Implications for the J-K boundary in the Neuquén Basin |
| title_short |
Magnetostratigraphy of the Upper Jurassic–Lower Cretaceous from Argentina: Implications for the J-K boundary in the Neuquén Basin |
| title_full |
Magnetostratigraphy of the Upper Jurassic–Lower Cretaceous from Argentina: Implications for the J-K boundary in the Neuquén Basin |
| title_fullStr |
Magnetostratigraphy of the Upper Jurassic–Lower Cretaceous from Argentina: Implications for the J-K boundary in the Neuquén Basin |
| title_full_unstemmed |
Magnetostratigraphy of the Upper Jurassic–Lower Cretaceous from Argentina: Implications for the J-K boundary in the Neuquén Basin |
| title_sort |
magnetostratigraphy of the upper jurassic–lower cretaceous from argentina: implications for the j-k boundary in the neuquén basin |
| publishDate |
2017 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01956671_v70_n_p189_IglesiaLlanos http://hdl.handle.net/20.500.12110/paper_01956671_v70_n_p189_IglesiaLlanos |
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