Earth and Planetary Science Letters 395 (2014) 294–295

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Earth and Planetary Science Letters

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Reply to comment on “Magnitude and profile of organic carbonisotope records from the Paleocene–Eocene Thermal Maximum:Evidence from northern Spain” by Manners et al.[Earth Planet. Sci. Lett. 376 (2013) 220–230]

Hayley R. Manners a,b,∗, Stephen T. Grimes a, Paul A. Sutton a, Laura Domingo c,d,e,f,Melanie J. Leng g,h, Richard J. Twitchett a, Malcolm B. Hart a, Tom Dunkley Jones i,Richard D. Pancost j, Robert Duller k, Nieves Lopez-Martinez 1

a School of Geography, Earth & Environmental Sciences, Plymouth University, Drake Circus, Plymouth, Devon, PL4 8AA, UKb School of Ocean and Earth Sciences, University of Southampton, National Oceanography Centre, Waterfront campus, Southampton, SO14 3ZH, UKc Departamento de Paleontología, Universidad Complutense de Madrid, 28040, Madrid, Spaind Departamento de Estratigrafía, Universidad Complutense de Madrid, 28040, Madrid, Spaine Departamento de Ingeniería Geológica, Universidad Politécnica de Madrid, 28003, Madrid, Spainf Earth and Planetary Sciences Department, University of California, Santa Cruz, CA 95064, USAg Department of Geology, University of Leicester, Leicester, LE1 7RH, UKh NERC Isotope Geosciences Laboratory, British Geological Survey, Nottingham NG12 5GG, UKi School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UKj Organic Geochemistry Unit, The Cabot Institute, School of Chemistry, University of Bristol, Bristol, BS8 1TS, UKk Department of Earth, Ocean & Ecological Sciences, School of Environmental Sciences, University of Liverpool, Liverpool, L69 3BX, UK

a r t i c l e i n f o

Article history:Received 14 March 2014Received in revised form 24 March 2014Accepted 25 March 2014Editor: G. Henderson

We thank the authors for their comment and welcome the op-portunity to clarify our interpretations in view of the concernsraised.

First, Pujalte and Schmitz dismiss our dataset from Tendrui byclaiming that there is no Claret Conglomerate (CC) at this location.The Tendrui section of Domingo et al. (2009) and Manners et al.(2013) can be located using the coordinates recorded in Mannerset al. (2013; N 042◦ 10′07.2′′ , E 000◦ 51′25.3′′). When samplingat this location the CC was indeed exposed, as presented in thelogs of Domingo et al. (2009) and Manners et al. (2013). It maybe possible that the Tendrui section without the CC, referred toby Pujalte and Schmitz (2014), is exposed at a different location

DOI of original article: http://dx.doi.org/10.1016/j.epsl.2013.06.016.DOI of comment: http://dx.doi.org/10.1016/j.epsl.2014.03.054.

* Corresponding author at: School of Geography, Earth & Environmental Sciences,Plymouth University, Drake Circus, Plymouth, Devon, PL4 8AA, UK. Tel.: +44 (0)1752584987; fax: +44 (0)1752 584776.

E-mail address: h.r.manners@soton.ac.uk (H.R. Manners).1 Deceased.

http://dx.doi.org/10.1016/j.epsl.2014.03.0560012-821X/Crown Copyright © 2014 Published by Elsevier B.V. All rights reserved.

in the vicinity of Tendrui. Unfortunately their locality cannot beidentified as its precise location was not provided by Schmitz andPujalte (2007) or Pujalte et al. (2014).

Second, Pujalte and Schmitz (2014) claim that vegetation coversthe critical interval below the CC at the Claret road section (Fig. 1of their comment), making the sampling through this “covered” in-terval, as presented in Manners et al. (2013), impossible. There isvegetation in this area, but when sampled in March 2010, this wasnot so dense as to preclude trenching back into in-situ material(Fig. 1). This is how our samples were taken, with the express aimof providing a more complete record of the carbon isotope excur-sion (CIE) onset below the CC.

Third, in Fig. 1 of Pujalte and Schmitz (2014) they imply thatour Claret log is incorrect in the placement of the base of the CC.Domingo et al. (2009; Fig. 2) identify the base of the CC at the firstappearance of any gravel-sized material (as illustrated in Fig. 1,point 1). However, Domingo et al. (2009) also acknowledged thepresence of interbedded conglomerates, pebbly sands and sandymudstones, which is clearly illustrated toward the base of theirlog (Fig. 1, point 2). Therefore, there is no difference between our

H.R. Manners et al. / Earth and Planetary Science Letters 395 (2014) 294–295 295

Fig. 1. Part of the Claret road sections as logged by A) Manners et al. (2013) and B)Pujalte and Schmitz comment on Manners et al. (2013). The thick dotted black linesindicate the base and the top of the CC, including 1) the base of the CC as indicatedby a red line in Fig. 2 of Domingo et al. (2009) and 2) interbedded conglomerates,pebbly sands and sandy mudstones below the CC in its strictest sense. Comparingthe log of Manners et al. (2013) (A) to the log of Pujalte and Schmitz (2014) (B), itis important to note that the CC thickness is almost identical for both logs and thatthe CIE onset is recorded five samples below the CC (ca. 2.5 m below the CC).

stratigraphy and that of Pujalte and Schmitz (2014). Fig. 1 of thisreply clearly shows that the total thickness of the Claret Conglom-erate as measured by Manners et al. (2013) and Pujalte et al.(2014) are in fact similar (ca. 10 m). The dataset of Domingo etal. (2009) and Manners et al. (2013), therefore, support the on-set of the CIE below the CC, as the six lower samples that Pujalteand Schmitz (2014) refer to are indeed below the correctly definedbase of the CC.

With respect to the relationship between the CC and the on-set of the CIE, Schmitz and Pujalte (2007) appear to be arguing –on the basis of relatively low-resolution soil carbonate nodule iso-tope stratigraphies – for the synchronous, and near-geologicallyinstantaneous, deposition of a basin-wide fan conglomerate bodyin response to the onset of the PETM. In Manners et al. (2013),we argue for a more subtle and complex pattern of leads and lagsbetween the onset of the CIE and the progradation and deposi-tion of fan conglomerates, based on higher resolution bulk organiccarbon stratigraphies from four terrestrial PETM sections: Claret,Tendrui, Esplugafreda and Campo. In all of these locations the CIEis seen to commence stratigraphically below the CC or its down-system equivalent. The magnitude of this temporal lag betweenCIE onset and the onset of CC deposition also appears to increasedown-system (Manners et al., 2013, Figs. 5 and 6).

Finally, with respect to the marine sections, Pujalte and Schmitz(2014) suggest that our interpretation that “the greenish limestoneand the Siliciclastic Unit (SU ) may in fact be diachronous events” is

wrong. Our δ13CTOC data from Ermua suggest a different strati-graphic position for the CIE onset to that of the carbonate dataof Schmitz et al. (2001), which is fully discussed in Manners etal. (2013). Whilst we do not dispute the published lithological orbiostratigraphic data referred to by Pujalte and Schmitz (2014) inour paper (Manners et al., 2013), we would like to clarify our rea-soning in response to their concerns.

Although care was taken not to sample turbidite horizons atthe Ermua section, we agree with Pujalte and Schmitz (2014) thatreworking processes introduced by turbidites at the base of the Er-mua section may affect the δ13CTOC data interpretation. However,Schmitz et al. (2001, p. 312) suggest that “the turbidites may repre-sent reworked calcite from older periods with other oceanic δ13C signa-tures. For example, the turbidites in the basal SU show relatively positiveδ13C values, but this most likely reflects carbonate that was formed dur-ing pre-IETM times and transported to Ermua by mass flows during theIETM event”. If this is indeed the case, then the organic δ13C valuesrecorded by Manners et al. (2013) should also have been affectedby this reworking and therefore be more positive, not progres-sively more negative, during this interval if organic matter andcarbonates behave in the same way. Furthermore, whilst we agreewith Pujalte and Schmitz (2014) that “the greenish limestone and theSU are widespread in the Basque Basin, always occurring at the samestratigraphic position”, we would like to point out that basin-wideoccurrence of similar facies is not in, and of, itself an argumentagainst diachronous deposition.

Further work is clearly needed to elucidate the nature of theCIE at the Ermua section, but the fact remains that the recordedδ13CTOC profile suggests that the CIE onset occurs stratigraphicallylower than that recorded by carbonates, a phenomenon which isrecorded at most sections in the region (Manners et al., 2013).Therefore, we stand by our original conclusion that the sedimen-tary response to climate change at the time of Paleocene–EoceneThermal Maximum in northern Spain is diachronous.

References

Domingo, L., López-Martínez, N., Leng, M.J., Grimes, S.T., 2009. The Paleocene–Eocene Thermal Maximum record in the organic matter of the Claret and Ten-druy continental sections (South-central Pyrénées, Lleida, Spain). Earth Planet.Sci. Lett. 281, 226–237.

Manners, H.R., Grimes, S.T., Sutton, P.A., Domingo, L., Leng, M.J., Twitchett, R.T., Hart,M.B., Dunkley Jones, T., Pancost, R.D., Duller, R., Lopez-Martinez, N., 2013. Mag-nitude and profile of organic carbon isotope records from the Paleocene–EoceneThermal Maximum: evidence from northern Spain. Earth Planet. Sci. Lett. 377,220–230.

Pujalte, V., Schmitz, B., 2014. Comment on the discussion paper “Magnitude andprofile of organic carbon isotope records from the Paleocene–Eocene Ther-mal Maximum: evidence from northern Spain” by Manners et al. [EarthPlanet. Sci. Lett. 376 (2013) 220–230]. Earth Planet. Sci. Lett. 395, 291–293.http://dx.doi.org/10.1016/j.epsl.2014.03.054, in this volume.

Pujalte, V., Schmitz, B., Baceta, J.I., 2014. Sea-level changes across the Paleocene–Eocene interval in the Spanish Pyrenees, and their possible relationship withNorth Atlantic magmatism. Palaeogeogr. Palaeoclimatol. Palaeoecol. 393, 45–60.http://dx.doi.org/10.1016/j.palaeo.2013.10.016.

Schmitz, B., Pujalte, V., 2007. Abrupt increase in seasonal extreme precipitation atthe Palaeocene–Eocene boundary. Geology 35, 215–218.

Schmitz, B., Pujalte, V., Núñez-Betelu, K., 2001. Climate and sea-level perturbationsduring the Incipient Eocene Thermal Maximum: evidence from siliciclastic unitsin the Basque Basin (Ermua, Zumaia and Trabakua Pass), northern Spain. Palaeo-geogr. Palaeoclimatol. Palaeoecol. 165, 299–320.