CIG   05423
CENTRO DE INVESTIGACIONES GEOLOGICAS
Unidad Ejecutora - UE
artículos
Título:
Comment on: ?Chemostratigraphic constraints on early Ediacaran carbonate ramp dynamics, Río de la Plata craton, Uruguay? by Aubet et al. Gondwana Research, Volume 22, Issues 3-4, November 2012, Pages 1073-1090
Autor/es:
GAUCHER, CLAUDIO; SIAL, ALCIDES; FREI, ROBERTO; SPRECHMANN, PETER; BOSSI, JORGE; POIRÉ, DANIEL G.; BLANCO, GONZALO; SÁNCHEZ BETTUCCI, LEDA
Revista:
GONDWANA RESEARCH
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2012
ISSN:
1342-937X
Resumen:
The Arroyo del Soldado Group of Uruguay is a key unit for unraveling several, still unsolved cardinal problems in Neoproterozoic research.Thus, we welcome in principle publications contributing to our knowledge of this and other units. Regarding Aubet et al.´s (2012) paper, we contest their age assumptions and chemostratigraphic inferences and thereby call into question the core message of the paper. Moreover, we also show below that it does not make proper acknowledgement of sources. The problems begin already in page 2, where we read: ?The group reaches almost 3000 m in thickness, and has been subdivided into four formations: the Yerbal, Polanco Limestones, Cerro Espuelitas and Barriga Negra formations (sensu Pecoits et al., 2008; Pecoits, 2010)?? The reader will understand from this statement that Pecoits et al. (2008) and Pecoits (2010) were the authors that first separated and mapped the mentioned formations of the Arroyo del Soldado Group. However, the Yerbal Formation was formally erected by Gaucher et al. (1998a) and Gaucher (2000), the Polanco Limestones Formation and the Cerro Espuelitas Formation were formally defined by Gaucher et al. (1996) and later described in more detail by Gaucher (2000), and the Barriga Negra Formation was erected by Midot(1984) and later included in the Arroyo del Soldado Group by Gaucher et al. (1998a) and Gaucher (2000). The same stratigraphic subdivision was adopted by Bossi et al. (1998) and Bossi and Ferrando (2001) for the geological map of Uruguay. The previous works have not been cited at all, neither at the referred passage nor elsewhere. Over half a dozen papers were just replaced by two self-citations. This amounts to claiming results from research conducted by others. In chapter 4.1 Aubet et al. describe limestone?dolostone alternations (rhythmites), hummocky cross-stratification, swaley crossstratified calcarenites and dolostone rip-up clasts, as if they were unknown before. They also state in page 4 that ?These deposits are interpreted to represent a storm-dominated inner ramp setting?, suggesting that this is a novel interpretation. They fail to mention that the same rocks, at the same sections (Recalde, Los Tapes and parastratotype of the Barriga Negra Formation) were already thoroughly described and classified as such one decade earlier by Gaucher (2000) and Gaucher et al. (2004). The same interpretation of a storm-dominated ramp can be found in Gaucher et al. (2004), a paper cited by Aubet et al. elsewhere but conspicuously absent in chapter 4.1, thus failing to acknowledge previous work done in the studied units. In page 15 the authors state: ?Water column stratification during the deposition of the lower part of the Arroyo del Soldado Group has been suggested based on the development of iron formation in the upper part of the Yerbal Formation (Pecoits et al., 2008; Pecoits, 2010)?? Again in this case, iron formation in the Yerbal Formation was first described and water column stratification proposed by Gaucher et al. (1998b, 2004) and Gaucher (2000), not by Pecoits and coworkers, as implied by Aubet et al. (2012). Finally, the map in Fig. 1B is derived from Fig. 3 of Mallmann et al. (2007), published in Gondwana Research, but no reference is provided. The figure is not derived from Bossi (2003).Aubet et al.´s (2012) paper, we contest their age assumptions and chemostratigraphic inferences and thereby call into question the core message of the paper. Moreover, we also show below that it does not make proper acknowledgement of sources. The problems begin already in page 2, where we read: ?The group reaches almost 3000 m in thickness, and has been subdivided into four formations: the Yerbal, Polanco Limestones, Cerro Espuelitas and Barriga Negra formations (sensu Pecoits et al., 2008; Pecoits, 2010)?? The reader will understand from this statement that Pecoits et al. (2008) and Pecoits (2010) were the authors that first separated and mapped the mentioned formations of the Arroyo del Soldado Group. However, the Yerbal Formation was formally erected by Gaucher et al. (1998a) and Gaucher (2000), the Polanco Limestones Formation and the Cerro Espuelitas Formation were formally defined by Gaucher et al. (1996) and later described in more detail by Gaucher (2000), and the Barriga Negra Formation was erected by Midot(1984) and later included in the Arroyo del Soldado Group by Gaucher et al. (1998a) and Gaucher (2000). The same stratigraphic subdivision was adopted by Bossi et al. (1998) and Bossi and Ferrando (2001) for the geological map of Uruguay. The previous works have not been cited at all, neither at the referred passage nor elsewhere. Over half a dozen papers were just replaced by two self-citations. This amounts to claiming results from research conducted by others. In chapter 4.1 Aubet et al. describe limestone?dolostone alternations (rhythmites), hummocky cross-stratification, swaley crossstratified calcarenites and dolostone rip-up clasts, as if they were unknown before. They also state in page 4 that ?These deposits are interpreted to represent a storm-dominated inner ramp setting?, suggesting that this is a novel interpretation. They fail to mention that the same rocks, at the same sections (Recalde, Los Tapes and parastratotype of the Barriga Negra Formation) were already thoroughly described and classified as such one decade earlier by Gaucher (2000) and Gaucher et al. (2004). The same interpretation of a storm-dominated ramp can be found in Gaucher et al. (2004), a paper cited by Aubet et al. elsewhere but conspicuously absent in chapter 4.1, thus failing to acknowledge previous work done in the studied units. In page 15 the authors state: ?Water column stratification during the deposition of the lower part of the Arroyo del Soldado Group has been suggested based on the development of iron formation in the upper part of the Yerbal Formation (Pecoits et al., 2008; Pecoits, 2010)?? Again in this case, iron formation in the Yerbal Formation was first described and water column stratification proposed by Gaucher et al. (1998b, 2004) and Gaucher (2000), not by Pecoits and coworkers, as implied by Aubet et al. (2012). Finally, the map in Fig. 1B is derived from Fig. 3 of Mallmann et al. (2007), published in Gondwana Research, but no reference is provided. The figure is not derived from Bossi (2003).