Stable isotope paleoclimatology

POSTER: Multiproxy record of environmental and climatic variations during the Eemian from the Northern France calcareous tufa of Caours: combining petrography, malacology and geochemistry.

by Julie Dabkowski

Co-authored with Nicole Limondin-Lozouet, Pierre Antoine, Julian Andrews, Christine Chaussé, Pierre Carbonel, Jean-Luc Locht and Alina Marca-Bell.
Presented at the INQUA Congress 2011 (Bern), in session 69 "Reconstructing environmental impacts of climate changes from MIS 5 to present, based on terrestrial and lacustrine archives".

The site of Caours exhibits a calcareous tufa deposit of >10 000 m2 and up to 3.5 m thick, overlying lower terrace... more The site of Caours exhibits a calcareous tufa deposit of >10 000 m2 and up to 3.5 m thick, overlying lower terrace fluvial deposits of a Somme River (Northern France) tributary. The whole calcareous tufa sequence is attributed to the Eemian Interglacial (MIS 5e) according to its location within the Somme River terraces system, palaeontological data, and U/Th TIMS dating (average of 124 ± 4 ky BP). Since 2005, archaeological excavations of a Middle Palaeolithic site at the base of the tufa formation have provided long stratigraphic profiles (up to 20m long), supporting multidisciplinary studies. Palaeoenvironmental data from a petrographic study and molluscs were compared to geochemical proxies recording temperature (δ18O) and humidity (δ13C and trace elements Mg and Sr).
In thin section the main Cyanobacteria taxa precipiting tufa were identified as the fossil genus Broutinella and Ponsinella. Broutinella built massive “cauliflower” tufas. This subaqueous facies is associated with aquatic molluscs and ostracods. Ponsinella produces the “mille-feuilles” facies with thin laminations testifying of diffuse flow periods. This facies is associated to malacofauna dominated by land snails.
The cauliflower facies is dominant in the lower part of the sequence, where more pluvial conditions are suggested by δ13C data. This wettest part is also the warmest according to δ18O, and corresponds to the expansion of woodland molluscs. Moreover, the maxima of temperature and humidity (from δ18O and δ13C) are correlated with the Climatic Optimum (highest number of forest species diversity and mollusc shells). In the upper part, the mille-feuilles facies becomes better developed as spring flow waned, based on the δ13C data. Dry conditions are also indicated by mollusc fauna which record a landscape of mainly open areas and some forest remnants.
Clear environmental modifications caused by climatic changes are thus reconstructed from the tufa at Caours especially around the Interglacial Optimum.

Stable isotope composition of Late Pleistocene-Holocene Eobania vermiculata (Müller, 1774) (Pulmonata, Stylommatophora) shells from the Central Mediterranean basin: Data from Grotta d’Oriente (Favignana, Sicily)

by Andre Carlo Colonese

Reconstructing the paleoenvironment of East Central Europe in the Late Pleistocene using the oxygen and carbon isotopic signal of tooth in large mammal remains

by János Kovács

Kovács et al. published in 'Quaternary International'

Stable carbon and oxygen isotope values (δ13C, δ18O) of structural carbonate were determined in the bioapatite... more Stable carbon and oxygen isotope values (δ13C, δ18O) of structural carbonate were determined in the bioapatite component of fossil teeth from the Czech Republic, Slovakia and Hungary. Oxygen isotope compositions of enamel and dentin samples provide new quantitative records of the Late Pleistocene climate in East Central Europe (ECE). These δ18O data were combined with records of oxygen isotope values of recent and paleogroundwaters to study the spatial patterns and temporal variations in the oxygen isotope composition of precipitation and the thermal climate over ECE. The new isotopic data suggest that surface air temperatures in the study region between 33 and 12 ka were 2–9°C colder than present. Specimens of woolly mammoth, rhino and horse from the Late Pleistocene were primarily C3 grazers.

Reconstruction of late Pleistocene climate in the Valsequillo Basin (Central Mexico) through isotopic analysis of terrestrial and freshwater snails

by Rhiannon Stevens

Upper Cretaceous inter-hemispheric correlation between the Southern Tethys and the Boreal: chemo-and biostratigraphy and paleoclimatic reconstructions from a new section in the Tethys Himalaya, S-Tibet

by Ines Wendler

Wendler, I., Willems, H., Gäfe, K.-U., Ding, L., Luo, H., 2011. Newsletters on Stratigraphy, 44 (2), 137-171.

A new, 430 m long and mostly continuous Upper Cretaceous section from southern hemisphere low paleolatitudes in the... more A new, 430 m long and mostly continuous Upper Cretaceous section from southern hemisphere low paleolatitudes in the Tethys Himalaya (Guru, Tibet) is presented. The lithology, microfacies and fossil contents of the Guru section indicate a continuous shallowing trend from open oceanic conditions at the slope during the Turonian to shallow marine inner shelf environments in the Maastrichtian, interrupted by short periods of stagnation or slight deepening. Strong variations in sedimentation rates and contents of carbonate, quartz, organic carbon and sulfur appear to reflect a combination of regional and global processes. On regional scale, the patterns of varying clastic sediment supply seem to be related to the fast northward drift of the Indian plate from the temperate climate belt in the Turonian and Coniacian, crossing the arid zone during the Santonian and early Campanian, and passing into the tropical humid belt in the late Campanian. On global scale, similar sedimentary changes as in Guru with a transition from clay-rich Turonian sediments to Coniacian carbonates are found in other regions of the world, suggesting an additional influence of global oceanic and climatic factors. Intervals of omission, erosion and reworking in upper Coniacian and lower Campanian sediments of the Guru section appear to coincide with global sea-level lowstands.
Well preserved planktic foraminifera occur over most of the Guru section and provide good biostratigraphic control for correlation of stable carbon and oxygen isotopes with data from the reference section for the boreal white chalk in northern Germany at Lägerdorf-Kronsmoor and with the English Chalk reference section, showing detailed correlation of bulk sediment carbon isotopes and comparable trends in oxygen isotopes. The Campanian and Maastrichtian carbon isotope fluctuations can be related to cyclic variations in carbonate content at Lägerdorf-Kronsmoor which are thought to be driven by long eccentricity. This indicates orbital forcing of both carbonate accumulation and carbon isotope signature, most likely mediated by global sealevel changes. The possibility of detailed d13C correlation from boreal sections of the northern hemisphere to a low-latitude section of the southern hemisphere allows for global correlation with an accuracy not achieved by biostratigraphic methods so far. It further enables linking of microfossil and macrofossil biozones, facilitating precise comparison of shallow and deep water sections, which is essential for the improvement of our understanding of timing, causes and effects of climatic and oceanographic processes.

Enregistrement des variations climatiques au cours des interglaciaires d'après l'étude des isotopes stables de la calcite de tufs pléistocène du nord de la France : exemple des séquences de Caours (SIM 5e; Somme) et La-Celle-sur-Seine (MIS 11 ; Seine-et-Marne)

by Julie Dabkowski

Co-authored with N. Limondin-Lozouet, P. Antoine, A. Marca-Bell and J. Andrews.
Published in Quaternaire, 22 (4), 2011

RECORD OF CLIMATIC CHANGES DURING INTERGLACIALS FROM STABLE ISOTOPES IN NORTHERN FRANCE PLEISTOCENE TUFA CALCITE:... more RECORD OF CLIMATIC CHANGES DURING INTERGLACIALS FROM STABLE ISOTOPES IN NORTHERN FRANCE PLEISTOCENE TUFA CALCITE: EXAMPLES OF CAOURS (MIS 5e; SOMME) AND LA CELLE (MIS 11; SEINE ET MARNE).
Tufas are mainly composed of calcite (CaCO3) which makes them suitable for geochemical investigation, especially oxygen and carbon stable isotopes (δ18O and δ13C). These isotopic parameters have already been shown to record temperature and humidity variations in the Holocene tufas, proving their suitability as climatic proxies. This study focuses on two French Pleistocene sites, Caours and La Celle. Results are compared to palaeoenvironmental, especially malacological, data. This comparison shows that δ18O and δ13C in tufas are important proxies of palaeoclimatic variation during Pleistocene interglacials, just as they are during the Holocene.


La composition minéralogique des tufs calcaires, essentiellement constitués de CaCO3, permet l’utilisation d’indicateurs climatiques géochimiques et en particulier l’étude des isotopes stables de l’oxygène et du carbone (δ18O et δ13C). Ces derniers sont déjà bien connus dans les tufs holocènes comme marqueurs des variations de température et d’humidité. L’analyse des isotopes stables a été réalisée ici sur les séquences de tuf pléistocènes de Caours (SIM 5e, Somme) et de La Celle (SIM 11, Seine et Marne). Les résultats de cette étude géochimique ont été comparés aux données paléoenvironnementales, notamment malacologiques. Ces premières analyses montrent que, comme dans le cas des tufs holocènes, les variations des isotopes stables du carbone et de l’oxygène dans les tufs pléistocènes constituent des indicateurs fiables des variations climatiques au cours des interglaciaires pléistocènes.

Nitrogen isotope analyses of reindeer (Rangifer tarandus), 45,000 BP to 9,000 BP: Palaeoenvironmental reconstructions

by Rhiannon Stevens

Paleodiets and paleoenvironments of late Miocene gazelles from North China: evidence from stable carbon isotopes

by Jussi Eronen

Strengthened East Asian summer monsoons during a period of high-latitude warmth? Isotopic evidence from Mio-Pliocene fossil mammals and soil carbonates from …

by Jussi Eronen

The East Asian monsoons have fluctuated in concert with high-latitude warmth during the past several hundred thousand... more The East Asian monsoons have fluctuated in concert with high-latitude warmth during the past several hundred thousand years, with humid summer monsoon-dominant climates characterizing warm intervals, including interglacials and interstadials, and arid winter monsoon-dominant climates characterizing cool intervals, including glacials and stadials. Of the states comprising the mid-Pleistocene to recent climatic regime, interglacials are most similar in terms of high latitude ice volumes and temperatures to those extant during the late Miocene and early Pliocene. Thus, an important question is whether Mio-Pliocene climates in northern China were analogous to a hypothetical ‘prolonged interglacial state,’ with increased summer monsoon precipitation and expansion of forest and steppe environments at the expense of desert environments. We utilize new and previously published carbon isotopic data from fossil teeth and soil carbonates to place constraints on paleovegetation distributions and to help infer the behavior of the monsoon system between ∼ 7 and 4 Ma. We find that plants using the C4 photosynthetic pathway—which today are largely grasses found in regions with warm season precipitation—were present in northern China by late Miocene time, demonstrating that the C4 expansion in China was not significantly delayed compared to the global C4 event. During the late Miocene–early Pliocene interval, soil carbonate and tooth enamel δ13C data indicate: 1) that nearly pure C3-plant ecosystems existed in the southern Chinese Loess Plateau (CLP), and therefore ecosystems there were dominated by woody dicot, herbaceous dicot, or cool-season grass vegetation (or a combination of these), and 2) that the CLP was characterized by a pattern of northward-increasing C4 vegetation and aridity. Utilizing a broadened conceptual model for interpreting δ13C data, and citing independent faunal, floral, and lithostratgraphic data, we
suggest that these patterns reflect northward expansion of forest and steppe ecosystems and relatively humid monsoon climates during the late Miocene and early Pliocene. An important implication of this interpretation is that the forcing mechanism illuminated by the temporal correlation during the Pleistocene between warm high latitudes and strong East Asian summer monsoons is a robust feature of the Eurasian tectonic–climatic system that predates the Plio-Pleistocene climatic reorganization.

Seasonal photosynthetic gas exchange and water-use efficiency in a constitutive CAM plant, the giant saguaro cactus (Carnegiea gigantea)

by Nathan English

A 26-year stable isotope record of humidity and El Niño-enhanced precipitation in the spines of saguaro cactus, Carnegiea gigantea

by Nathan English

Published in Palaeogeography, Palaeoclimatology, Palaeoecology

Molybdenum isotope signatures in continental margin marine sediments

by Chris Siebert

PGE, Re-Os and Molybdenum isotope systematicsin Archean and early Proterozoic sedimentary systems as proxies for redox conditions of the early Earth

by Chris Siebert

Molybdenum isotope records as a potential new proxy for paleoceanography

by Chris Siebert

Radiocarbon and stable isotope investigations at the Central Rhineland sites of Gönnersdorf and Andernach-Martinsberg, Germany

by Rhiannon Stevens

Mid-Miocene paleoproductivity in the Atlantic Ocean and implications for the global carbon cycle

by Darren Gröcke

Paleoceanography, 24, PA1209, doi:10.1029/2008PA001605

A prominent, middle Miocene (17.5–13.5 Ma) carbon isotope excursion ubiquitously recorded in carbonate sediments has... more A prominent, middle Miocene (17.5–13.5 Ma) carbon isotope excursion ubiquitously recorded in carbonate sediments has been attributed to enhanced marine productivity and sequestration of 13C depleted organic carbon in marine sediments or enhanced carbon burial in peat/lignite deposits on land. Here we test the hypothesis that the marine δ13C record reflects a change in productivity with proxy records from three Atlantic Ocean sites (Deep Sea Drilling Program Site 608 and Ocean Drilling Program Sites 925 and 1265). Our multiproxy approach is based on benthic foraminiferal accumulation rates, elemental ratios (Ba/Al and P/Al), the δ13C of bulk sedimentary organic matter, and dissolution indices. We compare these proxies to benthic foraminiferal δ13C values measured on the same samples. Our results indicate that marine paleoproductivity in the Atlantic Ocean is not related to the benthic foraminiferal δ13C excursion. A numerical box model confirms that marine productivity cannot account for the δ13C maximum. The model shows that sequestration of 1.5 x 10^18 mol C in the terrestrial realm over a period of 3 Ma leads to a 0.9% δ13C increase in the deep ocean, which is near the observed records. Therefore, an increase in continental organic carbon sequestration is the most plausible way to enrich the ocean’s carbon pool with 13C, which is consistent with coeval lignite deposits worldwide. The δ13C values of bulk sedimentary organic matter parallel the δ13C of dissolved inorganic carbon as reflected by benthic foraminiferal δ13C values suggesting no significant change in atmospheric pCO2 levels over the investigated period.

Atypical diagenetic effects on strontium-isotope composition of Early Jurassic belemnites, Queen Charlotte Islands, British Columbia, Canada

by Darren Gröcke

In this study, strontium-, carbon- and oxygen-isotope data are reported from Early Jurassic belemnites from Yakoun... more In this study, strontium-, carbon- and oxygen-isotope data are reported from Early Jurassic belemnites from Yakoun River, Queen Charlotte Islands (QCI), British Columbia. Assuming that the established ammonite correlations between Canada and Europe are accurate, the seawater 87Sr/86Sr curve between Europe and QCI should be similar. However, the Rarenodia planulata and Phymatoceras crassicosta ammonite biozones from Yakoun River record 87Sr/86Sr values that are lower than expected. This shift is interpreted to be a result of diagenetic alteration by later hydrothermal fluid (87Sr-depleted). In general, the diagenetic samples have more negative δ13Cbel and δ18Obel values, and higher Mn concentrations, but show no difference in Fe concentration. A δ13Cbel curve from diagenetically screened samples exhibits only slightly depleted values with respect to a similar curve generated from Europe. A similar curve for δ18Obel shows a striking similarity with that generated from Europe. This study illustrates that diagenetic effects on Sr-isotope composition can lower values from the expected seawater 87Sr/86Sr curve, thus potentially producing erroneous correlations between ammonite biostratigraphic schemes. Traditional screening methods for diagenesis, such as cathodoluminescence and trace-element abundances, were inadequate for evaluating diagenesis in the Yakoun River sections. Other such studies must also consider alternative and (or) a combination of methods in evaluating geochemical data from belemnites.

Marine osmium isotope record across the Triassic-Jurassic boundary from a Pacific pelagic site

by Darren Gröcke

Geology,38, 1095–1098, doi:10.1130/G31223.1

The Triassic-Jurassic (T-J) boundary ca. 200 Ma represents one of the major mass extinction events of the Phanerozoic;... more The Triassic-Jurassic (T-J) boundary ca. 200 Ma represents one of the major mass extinction events of the Phanerozoic; however, the cause of this event remains controversial because of a paucity of geological evidence. In this study we present an isotopic record of osmium extracted from a bedded chert succession across the T-J boundary in the Kurusu section of Japan, deposited within a Paleo- Pacific (Panthalassa) deep basin. The data show a gradual decrease in seawater 187Os/188Os values during the Rhaetian, followed by a sharp increase in the latest Rhaetian, and a subsequent stable phase across the T-J boundary. The decreasing trend of 187Os/188Os values during the Rhaetian indicates a gradual increase in the relative supply rate of unradiogenic Os from the mantle associated with emplacement of the Central Atlantic Magmatic Province. The subsequent shift toward radiogenic values reflects an increased supply of radiogenic Os due to enhanced continental weathering. This interval marks more nega- tive isotopic values of organic carbon, the onset of radiolarian faunal turnover, and conodont extinctions, indicating that the rapid increase in continental weathering rate was closely linked to the perturbation of the carbon cycle and the T-J biotic crisis.

Sea level controls sedimentation and environments in coastal caves and sinkholes

by Darren Gröcke

Marine Geology, 286, 35–50, doi:10.1016/j.margeo.2011.05.004

Quaternary climate and sea-level research in coastal karst basins (caves, cenotes, sinkholes, blueholes, etc.)... more Quaternary climate and sea-level research in coastal karst basins (caves, cenotes, sinkholes, blueholes, etc.) generally focuses on analyzing isotopes in speleothems, or associating cave elevations prior sea-level highstands. The sediments in coastal karst basins represent an overlooked source of climate and sea-level information in the coastal zone, but to accurately interpret these sediments first requires an understanding of the forcing mechanisms that emplace them. In this study, we hypothesize that coastal karst basins transition through vadose, littoral, anchialine, and finally into submarine environments during sea-level rise because groundwater and sea level oscillate in near synchrony in the coastal zone, causing each environment to deposit a unique sedimentary facies. To test this hypothesis, the stratigraphy in twelve sediment cores from a Bermudian underwater cave (Green Bay Cave) was investigated and temporally constrained with twenty radiocarbon dates. The results indicate that we recovered the first succession spanning the entire Holocene from an underwater cave (~13 ka to present). The sediments were characterized with X-radiography, fossil remains, bulk organic matter, organic geochemistry (δ13Corg, C:N), and grain size analysis. Four distinct facies represent the four depositional environments: (i) vadose facies (> 7.7 ka, calcite rafts lithofacies), (ii) littoral facies (7.7 to 7.3 ka: calcite rafts and mud lithofacies), (iii) anchialine facies (7.3 to 1.6 ka: slackwater and diamict lithofacies), and (iv) submarine facies (< 1.6 ka: carbonate mud and shell hash lithofacies). The onset and duration of these sedimentary depositional environments are closely linked to Holocene sea-level rise in Bermuda, indicating that sea level controls environmental development in coastal karst basins. Finally, we present a conceptual model for interpreting the sediments and environments in coastal karst basins as a result of sea-level change.

Nitrogen isotope evidence for water mass denitrification during the early Toarcian (Jurassic) oceanic anoxic event

by Darren Gröcke

Bulk sedimentary nitrogen isotope (d15Ntot) data have been generated from Lower Jurassic black, carbon-rich shales in... more Bulk sedimentary nitrogen isotope (d15Ntot) data have been generated from Lower Jurassic black, carbon-rich shales in the British Isles and northern Italy deposited during the early Toarcian oceanic anoxic event. A pronounced positive d15Ntot excursion through the exaratum Subzone of the falciferum Zone (defined by characteristic ammonites in the British Isles) broadly correlates with a relative maximum in weight percent total organic carbon and, in some sections, with a negative d13Corg excursion. Upwelling of a deoxygenated water mass that had undergone partial denitrification is the likely explanation for relative enrichment of d15Ntot, and parallels may be drawn with Quaternary sediments of the Arabian Sea, Gulf of California, and northwest Mexican margin. The development of Early Toarcian suboxic water masses and consequent partial denitrification is attributed to increases in organic productivity. Approximately coincident phenomena include the following: a relative climatic optimum, realignment of major oceanic current systems, and a possible release of methane gas hydrates from continental margin sediments early in the history of the oceanic anoxic event.