World Atlas of late Quaternary Foraminiferal Oxygen and Carbon Isotope Ratios

We present a global atlas of downcore foraminiferal oxygen and carbon isotope ratios available at https://doi.pangaea.de/10.1594/PANGAEA.936747 (Mulitza et al., 2021). The database contains 2,108 published and previously unpublished stable isotope downcore records with 362,067 stable isotope values of various planktonic and benthic species of foraminifera from 1,265 sediment cores. Age constraints are provided by 6,153 uncalibrated radiocarbon ages from 598 (47 %) of the cores. Each stable isotope and radiocarbon series is provided in a separate netCDF file containing fundamental meta data as attributes. The data set can be managed and explored with the free software tool PaleoDataView. The atlas will provide important data for paleoceanographic analyses and compilations, site surveys, or for teaching marine stratigraphy. The database can be updated with new records as they are generated, providing a live ongoing resource into the future.

A database of Holocene nearshore marine mollusc shell geochemistry from the Northeast Pacific

The shells of marine invertebrates can serve as high-resolution records of oceanographic and atmospheric change through time. In particular, oxygen and carbon isotope analyses of nearshore marine calcifiers that grow by accretion over their lifespans provide seasonal records of environmental and oceanographic conditions. Archaeological shell middens generated by Indigenous communities along the Northeast Pacific coast contain shells harvested over multiple seasons for millennia. These shell middens, as well as analyses of archival and modern shells, have the potential to provide multi-site, seasonal archives of nearshore conditions throughout the Holocene. A significant volume of oxygen and carbon isotope data from archaeological shells exists, yet is separately published in archaeological, geochemical, and paleoceanographic journals and has not been comprehensively analyzed to examine oceanographic change over time. Here, we compiled a database of previously published oxygen and carbon isotope data from archaeological, archival, and modern marine molluscs from the North American coast of the Northeast Pacific (32° N to 50° N). This database includes oxygen and carbon isotope data from over 550 modern, archaeological, and sub-fossil shells from 8880 years before present (BP) to the present, from which there are 4,845 total δ13C and 5,071 total δ18O measurements. Shell dating and sampling strategies vary among studies (1–118 samples per shell) and vary significantly by journal discipline. Data are from various bivalves and gastropod species, with Mytilus spp. being the most commonly analyzed taxon. This novel database can be used to investigate changes in nearshore sea surface conditions including warm-cool oscillations, heat waves, and upwelling intensity, and provides nearshore calcite δ13C and δ18O values that can be compared to the vast collections of offshore foraminifera calcite δ13C and δ18O data from marine sediment cores. By utilizing previously published geochemical data from midden and museum shells rather than sampling new specimens, future scientific research can reduce or omit the alteration or destruction of culturally valued specimens and sites. The data set is publicly available through PANGAEA at https://doi.org/10.1594/PANGAEA.932671 (Palmer et al., 2021).

Supplemental Material: Identification of seasonal varves in the lower Pliocene Bouse Formation, lower Colorado River Valley, and implications for Colorado Plateau uplift

<div>Oxygen and carbon isotope analyses of laminated Bouse marl. <br></div>

Supplemental Material: Identification of seasonal varves in the lower Pliocene Bouse Formation, lower Colorado River Valley, and implications for Colorado Plateau uplift

<div>Oxygen and carbon isotope analyses of laminated Bouse marl. <br></div>

Neotropical Ostracode Oxygen and Carbon Isotope Signatures - Implications for Calcification Conditions

Calcitic valves of non-marine ostracodes are important geochemical archives. Investigations of the relationship between the isotopic ranges of modern ostracode populations and their host water provide important information on local or regional conditions and influences. Here we present the first δ18Oostracode and δ13Costracode dataset of the freshwater ostracode species Cytheridella ilosvayi along with characterization of the precipitating water - chemical composition, δDwater, δ18Owater, δ13CDIC values - covering a large geographical range (Florida to Brazil). With this data we extended a newly developed approach based on the estimation of δ18O values of monthly equilibrium calcites as references for the interpretation of δ18Oostracode values.The expected apparent oxygen isotope fractionation between CaCO3 - and H2O is correlated with temperature with smaller values occurring at higher temperatures as valid at isotope equilibrium (δ18Ocalcite_eq). Additional to a species-specific offset, unusual high deviations of δ18Oostracode vs. δ18Owater values most likely reflect the time lag between valve calcification and sampling. Coincidence between δ18Oostracode and δ18Ocalcite_eq is restricted to few months indicating a seasonal calcification of Cytheridella. There is a characteristic pattern in its difference between mean δ18Oostracode and δ18Ocalcite_eq which implies that Cytheridella provides a synchronous life cycle in its geographical range with two calcification periods in spring (May, June) and autumn (October). This ubiquitous life cycle of Cytheridella in the entire study area is considered to be phylogenetically inherited. It might have originally been adapted to environmental conditions but has been conserved during the migration and radiation of the group over the Neotropical realm.

The Middle Paleolithic Occupations of Mutzig-Rain (Alsace, France)

The Paleolithic site of Mutzig, discovered by chance in 1992 (Sainty 1992), has been the focus of several excavations since 2009. Located in Alsace (Bas-Rhin, France), it is presently one of only a handful of sites reliably attributed to the Middle Paleolithic in this area, thus providing rare evidence for a zone still relatively unknown for Early Prehistoric remains. The excellent preservation of the remains and the long stratigraphic sequence, with 6 to 8 in situ archaeological levels, make Mutzig a potential reference site for environmental and behavioral analyses for the Middle Paleolithic of the region. At least four archaeological levels contain burnt elements, and one level features a hearth structure. Taken together, the archaeological material, which is abundant in each of the different layers, forms an assemblage of more than 3000 faunal remains and more than 1500 lithic artifacts. Analyses of this site provide valuable insights into the environment and Neandertal ways of life in Alsace. We provide here only general results, with more detailed descriptions of the lithic and faunal remains presented in Diemer (this volume) and Sévêque (this volume). The faunal remains recovered from the human occupations in Levels 5 and 7 reflect the same relatively cold steppe-like environmental context and include reindeer, woolly mammoth, steppe horse, steppe bison and woolly rhinoceros. Small vertebrates also indicate a cold climate, though not related to the Pleniglacial. Confirmed isotopic data, from oxygen and carbon isotope measurements of horse and mammoth teeth, indicate temperatures lower than those of today and an open environment. Levels 9 and 10, however, tend to reveal a more temperate climate. The available OSL and ESR/U-series dates place the Mutzig occupations within the Early Weichselian Glacial (MIS 5, ca. 90,000 BP), an attribution which biometric analyses and the large and small fauna record tend to corroborate (Koehler et al. 2016a).

CHARACTERISTICS OF STABLE ISOTOPES IN NATURAL WATERS OF THE VITIM RIVER BASIN

In this paper first data of the complex analysis of the hydrogen, oxygen and carbon isotope composition in waters and dissolved inorganic carbon (DIC) of the largest East Siberia river Vitim and some of its inflows are presented. The δD and δO values for waters under investigation indicating meteoric origin of waters and varies from -173,0 to -149,1 ‰ for hydrogen and from -23,3 to -20,2 ‰ for oxygen. Concentration of the DIC in waters depends on the type of landscape while δС values varies from -17,1 to -9,0 ‰ and pointed out the participation of soil diffusion and vegetative CO in formation of hydrocarbonate-ion.

Coeval primary and diagenetic carbonates in lacustrine sediments challenge palaeoclimate interpretations

Lakes are sensitive to climate change and their sediments play a pivotal role as environmental recorders. The oxygen and carbon isotope composition (δ18O and δ13C) of carbonates from alkaline lakes is featured in numerous studies attempting a quantitative reconstruction of rainfall, temperature and precipitation-evaporation changes. An often-overlooked challenge consists in the mineralogically mixed nature of carbonates themselves. We document a large variability of carbonate components and their respective distinct δ18O and δ13C values from sediments of Lake Van (Turkey) covering the last 150 kyr. The carbonate inventory consists of primary (1) inorganic calcite and aragonite precipitating in the surface-water, (2) biogenic calcite ostracod valves; and post-depositional phases: (3) dolomite forming in the sediment, and previously overlooked, (4) aragonite encrustations formed rapidly around decaying organic matter. We find a systematic relation between the lithology and the dominant deep-water carbonate phase formed recurrently under specific hydrological conditions. The presence of the different carbonates is never mutually exclusive, and the isotopic composition of each phase forms a distinctive cluster characteristic for the depth and timing of their formation. Our findings stretch the envelope of mechanisms forming lacustrine carbonates and highlight the urge to identify and separate carbonate components prior to geochemical analyses.