Unravelling the oxygen isotope signal (δ18O) of rodent teeth from northeastern Iberia, and implications for past climate reconstructions
Introduction
The Iberian Peninsula is located at mid latitudes, with an area of 582,000 km2 and an average altitude of 660 m. This peninsula constitutes the southwestern extremity of the Eurasian continent, from which it is partially isolated by the Pyrenean Mountains. Today, Iberia experiences temperate climatic conditions, which nonetheless vary spatially due to the proximity of the Atlantic Ocean, the Mediterranean Sea and the Pyrenean Mountains. The specific orography of the Iberian Peninsula adds further complexity by structuring the climate and the landscape, with the Central Meseta located at high altitudes (660 m), surrounded by several ranges such as the Sierra Nevada and the Cantabrian Mountains. The Galician-Cantabrian and Pyrenean mountain systems shelter the rest of the peninsula from the Atlantic Ocean and the continental cold air masses coming from the northwest and the northeast, respectively. The combination of all these factors gives the Iberian Peninsula exceptional environmental conditions in relation to the rest of the Eurasian continent.
The Late Pleistocene glacial regime and subsequent glacial-interglacial fluctuations had an impact both on flora and fauna, including human populations throughout western Europe and the Iberian Peninsula (Uriarte, 2003; Arrizabalaga, 2004). In southern Europe, Marine Isotope Stage 3 (MIS 3; ca. 60-30 ka) was characterized by climate dynamics that alternated between warming and cooling periods of sea-surface temperatures, which on the continent generated phases of forest development and expansion of semi-arid areas, respectively (Fletcher et al., 2010; Harrison and Sanchez Goñi, 2010). However, pollen and small-mammal studies have shown that these alternations are not easily resolved in regional and local contexts, suggesting Iberia never underwent a complete loss of woodland, even during stadials or Heinrich events (Fletcher et al., 2010; López-García et al., 2014). Small-vertebrate assemblages, which reflect local environments, reveal cooler and wetter conditions for MIS 3. It has been observed that the coexistence of cold- and temperate-adapted species varies with the stadial and interstadial fluctuations, although woodland-dwelling species are always frequent (Fernández-García et al., 2016; López-García et al., 2014). The Iberian Peninsula served as a macro-refugium for many floral and faunal species during stadial periods, sheltering them from harsher climatic episodes until more favourable environmental conditions allowed their geographic radiation (Hewitt, 2000; Sommer and Nadachowski, 2006).
To obtain a more complete view of past changes in climate and biodiversity, it is necessary to expand the continental palaeoenvironmental record, which is underrepresented compared to marine and ice-core records. Geochemical approaches based on stable oxygen isotope compositions (δ18O) represent a promising tool for obtaining high-resolution environmental records from regional and local contexts. Isotope compositions measured from mammalian bone and tooth fossils permit the quantification of climatic parameters, due to the interdependence of climatic variables such as air temperatures, the oxygen isotope composition of meteoric waters (δ18Omw) and the oxygen isotope composition of body tissues (Dansgaard, 1964; Kolodny et al., 1983; Longinelli, 1984; Longinelli and Nuti, 1973; Luz et al., 1984; Rozanski et al., 1993). These isotopic data can be combined with palaeoecological data inferred from vertebrate assemblages in order to obtain a coherent and refined picture of continental palaeoenvironments (e.g. Freudenthal et al., 2014; Royer et al., 2013b, 2014). Advances in chemical techniques and analytical methodologies now offer an opportunity to perform geochemical analyses on small-mammal teeth, which are particularly relevant in documenting high-resolution climatic changes at a regional or a local scale (e.g. Barham et al., 2017; Freudenthal et al., 2014; García-Alix, 2015; Grimes et al., 2003; Héran et al., 2010; Jeffrey et al., 2015; Leichliter et al., 2017; Lindars et al., 2001; Navarro et al., 2004).
Unfortunately, interpreting the oxygen isotope composition of small-mammal skeletal apatite is not straightforward, and several questions concerning its application to the fossil record have recently been raised (Barham et al., 2017; Jeffrey et al., 2015; Peneycad et al., 2019; Royer et al., 2014, 2013a, 2013b). The question of prey-predator interactions is considered to be of paramount importance in deciphering the isotopic signal recorded in accumulated fossil rodent remains, especially for regions with a specific climatic mode such as the Iberian Peninsula. The main purpose of this work is thus to develop an isotopic framework for environmental and climatic reconstructions for the Iberian Peninsula, based on the oxygen isotope composition of phosphate (δ18Op) from present-day rodent teeth recovered from pellets. A first step aims to assess the specific role of the climatic context of the Iberian Peninsula, whilst a second one seeks to achieve a better understanding of δ18O from small-mammal teeth, focusing on the origin of the remains and their period of production. A refinement of the interpretation of the δ18Op of fossil rodent tooth phosphate in terms of palaeotemperature reconstructions is finally applied to Cova dels Xaragalls assemblage. This Iberian Late Pleistocene sedimentary sequence, rich in small-vertebrate remains, thus offers the opportunity to reconstruct climate parameters in a continental environment contemporaneous with MIS 3.
Section snippets
Cova dels Xaragalls (Tarragona, Spain)
Cova dels Xaragalls is located in Poblet Forest in the municipality of Vimbodí-Poblet (Tarragona), on the left margin of the Castellfollit Creek in the head of the Francolí River basin at 590 m a.s.l. (Fig. 1A). It is a fossiliferous cave of phreatic origin hosted within Mesozoic limestones and Paleozoic schist. The site can be separated into two main areas: a Holocene sequence is developed at the entrance, and at the interior termination of the cave system, in the “Sala Gran” gallery, there is
Modern samples from northeastern Iberia
Fourteen lower incisors from present-day rodents were collected from pellets to analyse their oxygen isotope composition (δ18O). These pellets were collected from five different sites located in northeastern Iberia (Fig. 1, Fig. 2; Table 1): Serinyà (Girona), Moià (Barcelona), Prades (Tarragona), Balaguer (Lleida) and El Catllar (Tarragona). The sites are distributed within the same latitudinal range (from 41°N to 42°N) but at different altitudes ranging from 188 m a.s.l. at Serinyà to 1000 m
Results and discussion
The reconstruction of past air temperatures from the oxygen isotope composition of rodent teeth is a two-step procedure: 1) the measured δ18Op values of the fossil rodent teeth allow the estimation of the δ18O values of local meteoric water (δ18Omw) and, 2) the calculated δ18Omw values can be used to estimate past air temperatures. Since pioneering works in the 1980's (Longinelli, 1984; Luz et al., 1984; Luz and Kolodny, 1985), many studies have explored the complex relationship between the
Conclusions
Oxygen isotope compositions were measured in rodent teeth accumulated in modern owl pellets from five different sites located in northeastern Iberia and complemented with previously published δ18O results from rodent teeth from the Iberian Peninsula. The peculiar orography and climatic mode of the Iberian Peninsula are emphasized by this study, which documents low δ18Op values and a large annual range of δ18Omw in comparison to southern France. On the basis of recent δ18Omw values extracted
Acknowledgements
The authors are grateful to Aitor Burguet Coca, Joan Burguet Ardiaca, Marta Puig Domènech, David Funosas, Marius Domingo de Pedro and Josep Maria Vergés for providing pellet samples. We also thank the team from the Laboratoire de Géologie of Lyon for allowing us to perform the isotope analysis, especially to Romain Amiot and Magali Seris. We also thank Christiane Denys, Emmanuelle Stoetzel and Hugues-Alexandre Blain for their help and advice during the preparation of the manuscript. We are also
References (96)
- et al.
Digesting the data - effects of predator ingestion on the oxygen isotopic signature of micro-mammal teeth
Quat. Sci. Rev.
(2017) - et al.
Pleistocene seasonal temperature variations recorded in the δ18O of Bison priscus teeth
Earth Planet. Sci. Lett.
(2009) - et al.
Long-term climate record inferred from early-middle Pleistocene amphibian and squamate reptile assemblages at the Gran Dolina Cave, Atapuerca, Spain
J. Hum. Evol.
(2009) - et al.
Refining upon the climatic background of the early Pleistocene hominid settlement in western Europe: Barranco León and Fuente Nueva-3 (Guadix-Baza basin, SE Spain)
Quat. Sci. Rev.
(2016) - et al.
Oxygen isotope systematics of biologically mediated reactions of phosphate: I. Microbial degradation of organophosphorus compounds
Geochim. Cosmochim. Acta
(1997) - et al.
Stable isotope time-series in mammalian teeth: in situ δ18O from the innermost enamel layer
Geochim. Cosmochim. Acta
(2014) - et al.
Oxygen isotopes in living mammal's bone phosphate: further results
Chem. Geol.
(1990) - et al.
Palaeoecological implications of rodents as proxies for the Late Pleistocene–Holocene environmental and climatic changes in northeastern Iberia
Comptes Rendus Palevol
(2016) - et al.
Millennial-scale variability during the last glacial in vegetation records from Europe
Quat. Sci. Rev.
(2010) - et al.
Review of paleo-humidity parameters in fossil rodents (Mammalia): isotopic vs. tooth morphology approach
Palaeogeogr. Palaeoclimatol. Palaeoecol.
(2014)
The correlation between 18O/16O ratios of meteoric water and surface temperature: its use in investigating terrestrial climate change over geologic time
Earth Planet. Sci. Lett.
A multiproxy approach for the reconstruction of ancient continental environments. The case of the Mio–Pliocene deposits of the Granada Basin (southern Iberian Peninsula)
Glob. Planet. Change
Triple oxygen isotope analysis of bioapatite as tracer for diagenetic alteration of bones and teeth
Palaeogeogr. Palaeoclimatol. Palaeoecol.
Is small beautiful? A review of the advantages and limitations of using small mammal teeth and the direct laser fluorination analysis technique in the isotope reconstruction of past continental climate change
Palaeogeogr. Palaeoclimatol. Palaeoecol.
Palaeogene palaeoclimate reconstruction using oxygen isotopes from land and freshwater organisms: the use of multiple palaeoproxies
Geochim. Cosmochim. Acta
Global patterns of vegetation response to millennial-scale variability and rapid climate change during the last glacial period
Quat. Sci. Rev.
Isotopic evidence for Last Glacial climatic impacts on Neanderthal gazelle hunting territories at Amud Cave, Israel
J. Hum. Evol.
Cenozoic long-term terrestrial climatic evolution in Germany tracked by δ18O of rodent tooth phosphate
Palaeogeogr. Palaeoclimatol. Palaeoecol.
Bioclimatic analysis of rodent palaeofaunas reveals severe climatic changes in Southwestern Europe during the Plio-Pleistocene
Palaeogeogr. Palaeoclimatol. Palaeoecol.
Influences on the stable oxygen and carbon isotopes in gerbillid rodent teeth in semi-arid and arid environments: implications for past climate and environmental reconstruction
Earth Planet. Sci. Lett.
Oxygen isotope variations in phosphate of biogenic apatites, I. Fish bone apatite rechecking the rules of the game
Earth Planet. Sci. Lett.
Thermal excursions in the ocean at the Cretaceous-Tertiary boundary (northern Morocco): δ18O record of phosphatic fish debris
Palaeogeogr. Palaeoclimatol. Palaeoecol.
Oxygen isotope exchange between dissolved phosphate and water at temperatures ≤135°C: inorganic versus biological fractionations
Geochim. Cosmochim. Acta
Aspects of the chemistry of modern and fossil biological apatites
J. Archaeol. Sci.
Stable carbon isotope ecology of small mammals from the Sterkfontein Valley: implications for habitat reconstruction
Palaeogeogr. Palaeoclimatol. Palaeoecol.
Phosphate δ18O determination of modern rodent teeth by direct laser fluorination: an appraisal of methodology and potential application to palaeoclimate reconstruction
Geochim. Cosmochim. Acta
Oxygen isotopes in mammal bone phosphate: a new tool for paleohydrological and paleoclimatological research?
Geochim. Cosmochim. Acta
Oxygen isotope measurements of phosphate from fish teeth and bones
Earth Planet. Sci. Lett.
Environmental and climatic context of neanderthal occupation in southwestern Europe during MIS3 inferred from the small-vertebrate assemblages
Quat. Int.
Oxygen isotope variations in phosphate of biogenic apatites, IV. Mammal teeth and bones
Earth Planet. Sci. Lett.
Fractionation of oxygen isotopes between mammalian
Geochim. Cosmochim. Acta
Oxygen isotope compositions of phosphate from arvicoline teeth and Quaternary climatic changes, Gigny, French Jura
Quat. Res.
Tooth enamel mineralization in ungulates: implications for recovering a primary isotopic time-series
Geochim. Cosmochim. Acta
Variability in the oxygen isotope compositions of modern rodent tooth carbonate: implications for palaeoclimate reconstructions
Palaeogeogr. Palaeoclimatol. Palaeoecol.
Turnover of oxygen and hydrogen isotopes in the body water, CO2, hair, and enamel of a small mammal
Geochim. Cosmochim. Acta
Quantification and propagation of errors when converting vertebrate biomineral oxygen isotope data to temperature for palaeoclimate reconstruction
Palaeogeogr. Palaeoclimatol. Palaeoecol.
What does the oxygen isotope composition of rodent teeth record?
Earth Planet. Sci. Lett.
Late Pleistocene (MIS 3-4) climate inferred from micromammal communities and δ18O of rodents from Les Pradelles, France
Quat. Res.
Summer air temperature, reconstructions from the last glacial stage based on rodents from the site Taillis-des-Coteaux (Vienne), Western France
Quat. Res.
The oxygen isotopic composition of seawater during the Last Glacial Maximum
Quat. Sci. Rev.
Reassessment of recommendations for processing mammal phosphate δ18O data for paleotemperature reconstruction
Palaeogeogr. Palaeoclimatol. Palaeoecol.
Wood mouse population dynamics: interplay among seed abundance seasonality, shrub cover and wild boar interference
Mamm. Biol.
A 200 year mid-European air temperature record preserved in lake sediments: an extension of the δ18Op-air temperature relation into the past
Geochim. Cosmochim. Acta
Experimentally-controlled carbon and oxygen isotope exchange between bioapatites and water under inorganic and microbially-mediated conditions
Geochim. Cosmochim. Acta
Owls, Caves and Fossils. Predation, Preservation and Accumulation of Small Mammal Bones in Caves, with an Analysis of the Pleistocene Cave Faunas from Westbury-sub-Mendip, Somerset, UK
Paleoclimatología y cronología del Würm reciente: un intento de síntesis
Zephyrus
The Online Isotopes in Precipitation Calculator, Version 3.1 (4/2017)
New insight from old bones: stable isotope analysis of fossil mammals
J. Mammal.
Cited by (5)
Redefining the MIS 3 climatic scenario for Neanderthals in northeastern Iberia: A multi-method approach
2023, Quaternary Science ReviewsEnvironment and climate during the Neanderthal-AMH presence in the Garraf Massif mountain range (northeastern Iberia) from the late Middle Pleistocene to Late Pleistocene inferred from small-vertebrate assemblages
2022, Quaternary Science ReviewsCitation Excerpt :On the other hand, the H5 to H3 events are characterized, according to Sánchez-Goñi et al. (2000), by a pattern divided into three phases: 1) the first comprising relatively high percentages of Euro-Siberian trees, such as deciduous Quercus and Ericaceae shrubs, as well as the end of a temperate and humid terrestrial phase; 2) a middle phase with an optimal development of steppe vegetation, thus reflecting synchronous terrestrial and oceanic cooling; 3) a ceiling associated with an increase in the proportions of Euro-Siberian trees and Ericaceae, reflecting a new temperate and humid period at average terrestrial latitudes and North Atlantic Ocean latitudes. In the southern Mediterranean region, the sites with small-vertebrate studies associated with the H5 event are Abric Romaní layer E (López-García and Cuenca-Bescós, 2010; Burjachs et al., 2012; Fernández-García et al., 2020), Xaragalls cave layer C4 (López-García et al., 2012c; Fernández-García et al., 2019), Fumane cave units A7 to A6 (López-García et al., 2015b), and Grotta del Broion Q3-1-P (Sala, 1980; Colamussi, 2002; Berto and Rubinato, 2013). The H4 event has been recognized in Fumane cave units A3 to A1 (López-García et al., 2015b) and Grotta del Broion layers I4-1 to H6-3 (Sala, 1980; Colamussi, 2002; Berto and Rubinato, 2013).
Combined palaeoecological methods using small-mammal assemblages to decipher environmental context of a long-term Neanderthal settlement in northeastern Iberia
2020, Quaternary Science ReviewsCitation Excerpt :In case of predation, the δ18Op should reflect the δ18Omw at the time and space each rodent was captured (Fernández-García et al., 2019; Peneycad et al., 2019; Royer et al., 2013a, 2013b). This work follows the three-step strategy proposed for δ18Op from rodent tooth accumulated in Iberia (Fernández-García et al., 2019) for estimating mean annual temperatures (MAT): calculation of δ18Omw from δ18Op throughout the linear oxygen isotope fractionation equation determined by Royer et al. (2013a) [δ18Op = 1.21 (±0.20) x δ18Omw + 24.76 (±2.70)];
The end of Late Glacial in north-eastern Iberia: the small mammal assemblage from Cudó cave (Mont-Ral, Tarragona)
2023, Earth and Environmental Science Transactions of the Royal Society of EdinburghNew insights in Neanderthal palaeoecology using stable oxygen isotopes preserved in small mammals as palaeoclimatic tracers in Teixoneres Cave (Moià, northeastern Iberia)
2022, Archaeological and Anthropological Sciences