Reply to comment by J.L. D¨ªaz-Hern¨¢ndez and R. Juli¨¤ on ¡°Quaternary landscape evolution and erosion rates for an intramontane Neogene basin (Guadix-Baza basin, SE Spain)¡±

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• 作者：Jos¨¦ Vicente P¨¦rez-Pe?a ; Jos¨¦ Miguel Aza?¨®n ; Antonio Azor ; Isabel Mar¨ªa S¨¢nchez-Almazo ; Paola Tuccimei ; Marta Della Seta ; Michele Soligo
• 关键词：U/Th dating ; Guadix-Baza basin ; Erosion rates
• 刊名：Geomorphology
• 出版年：2012
• 出版时间：15 October, 2012
• 年：2012
• 卷：171-172
• 期：Complete
• 页码：204-209
• 全文大小：853 K

文摘

We demonstrate that the age of 43 ka obtained for the topmost calcrete layer in the Guadix-Baza remains the only reliable numerical dating of the flat geomorphic surface that marks the end of the sedimentation in the basin. Consequently, the late Pleistocene to Holocene erosion rates derived from the incision of the present-day drainage network into the flat geomorphic surface remain valid. The calcrete radiometric ages reported by D¨ªaz-Hern¨¢ndez and Juli¨¤ (2012) in their comment are untenable due to the contamination with detrital ²³⁰Th (not corrected with the applied U/Th technique) and the possible mix of textural elements with different ages (older inherited grains and newly formed grains). D¨ªaz-Hern¨¢ndez and Juli¨¤ also quote U/Th ages for travertine terraces formed later than the calcrete layer. These ages lack internal consistency probably due to systematic contamination and/or weathering of the samples. The archaeological ages reported by D¨ªaz-Hern¨¢ndez and Juli¨¤ are subjected to great uncertainties, but independently of the age assumed as most realistic, they are completely compatible with the age of 43 ka that we obtained for the topmost calcrete layer in the Guadix-Baza basin.