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Abstract: Rodríguez-Ramírez and Yáñez-Camacho (2008), Rodríguez-Vidal et al. (2009) and Rodríguez-Ramírez et al. (2009) have kept an ongoing discussion about the validity of radiocarbon ages in reconstructing Holocene palaeogeographical models in the Gulf of Cadiz. The discussion considered the validity and correctness of the ΔR value to be used in the area to calibrate radiocarbon ages of marine samples. These papers suggest that the ΔR value proposed by Lario (1996) and Dabrio et al. (1999, 2000) is erroneous, and consequently, that all the evolutionary models based on radiocarbon ages from marine samples that have been proposed in this area since 1996 must be revised. However, the papers commented here use erroneously the R, regional R and ΔR values. After reviewing the published data, it is apparent that the most reliable values of ΔR in the Gulf of Cadiz for middle-late Holocene samples range between ΔR =35±85yr and ΔR =95±15yr. This means that the values used in Lario (1996) and Dabrio et al. (1999, 2000) fall in this range, and also that the calibrated ages used by several authors adopting these values are fully reliable. Calibrations using ΔR values inside this range do not yield significant differences in terms of geological age owing to the magnitude of errors resulting from the methods employed. [ABSTRACT FROM AUTHOR]

Abstract: It is paradoxical that work in question (Rodríguez-Ramírez and Yánez-Camacho, 2008) has started a debate in the scientific community about the values of the reservoir effect used in the 14C dates in the Gulf of Cádiz, since in their Comments Rodríguez-Vidal et al. (2009), Monges Soares (2010-this issue) and Lario et al. (2010-this issue), have not taken into account that these values are in reference to earlier studies (Morales et al., 2008). The new figures suggested by Rodríguez-Vidal et al. (2009) and Monges Soares (2010-this issue) for this part of the Gulf of Cadiz (Soares, 2008) had not been reported when the earlier papers were accepted and published. The values for the reservoir effect applied on the South Atlantic coast of the Iberian Peninsula need to be continually adjusted, due to the new contributions that have been made in recent years as a result of developments of the research being undertaken in this field. Without doubt, in the future, as further progress is made, the values will be even more finely tuned and the present ones will become obsolete, as our understanding of marine and estuarine dynamics in this sector over the last few thousand years is a topic which remains open to new interpretations. The new figures for the reservoir effect are an important contribution in determining more accurately the chronology of events in the Holocene, and they make it necessary to revise the previous studies on marine Holocene formations in the Gulf of Cadiz with 14C dates, owing to the errors that have occurred in this respect. For this reason the Comment should not be aimed at one paper alone, and instead this matter should be reviewed at a regional level. Those of us who are not specialists in the topic welcome these clarifications, which can help shed additional light on the chronological problems. [ABSTRACT FROM AUTHOR]