Search results for "NDI"
showing 10 items of 20275 documents
A sea surface temperature reconstruction for the southern Indian Ocean trade wind belt from corals in Rodrigues Island (19°S, 63°E)
2016
Abstract. The western Indian Ocean has been warming rapidly over recent decades, causing a greater number of extreme climatic events. It is therefore of paramount importance to improve our understanding of links between Indian Ocean sea surface temperature (SST) variability, climate change and sustainability of tropical coral reef ecosystems. Here we present monthly resolved coral Sr ∕ Ca records from two different locations from Rodrigues Island (63° E, 19° S) in the south-central Indian Ocean trade wind belt. We reconstruct SST based on a linear relationship with the Sr ∕ Ca proxy with records starting from 1781 and 1945, respectively. We assess relationships between the observed long-ter…
Climate variability and lake ecosystem responses in western Scandinavia (Norway) during the last Millennium
2017
This paper provides a high-resolution temperature reconstruction for the last Millennium from Lake Atnsjøen, SE Norway (61°52′31″N, 10°10′37″E). The sedimentary record reveals strong influence of the large-scale global climate patterns on the local climate in southern part of Eastern Norway. We reconstructed mean July air temperature using Chironomidae-based transfer function and fossil Chironomidae assemblages. The reconstruction was supported by a selection of climate-sensitive geochemical and paleoecological sedimentary proxies of terrestrial and aquatic origin, including Cladocera, pollen and macrofossils. Presented results revealed that summer temperatures were 1–2 °C warmer than the m…
Rethinking the perishable: Identifying organic remains in metal objects at the Iron Age site of La Bastida de les Alcusses (Moixent, Spain)
2019
Abstract The use of certain perishable materials for handicraft, such as wood, has been underestimated in archaeological investigation due to their poor preservation. Its study through indirect evidence (other non-perishable materials, ethnographic sources) is partial, and does not account for the real importance of wood in domestic, craft and ritual contexts in past societies. In this review we reclaim the use of wood as a co-constitutive material of objects by focusing on Iron Age tools, weapons and carpentry elements from a case-study in the Western Mediterranean. We also suggest the adoption of protocols for sampling and analysing the remains of wood adhered to metal objects, which may …
Evidence for “Celtic migrations”? Strontium isotope analysis at the early La Tène (LT B) cemeteries of Nebringen (Germany) and Monte Bibele (Italy)
2013
Abstract Strontium isotope analysis on human remains from the Iron Age (4th/3rd century BC) cemeteries of Nebringen, Germany and Monte Bibele, Italy were carried out to investigate the role of residential changes during the period of the historic “Celtic migrations”. From an archaeological perspective, the location of the cemeteries in the Celtic core (Nebringen) and expansion area (Monte Bibele), and the distinctive development of their material culture, suggest that the buried populations had differing mobility rates. On the contrary, the strontium results indicate that only few individuals were mobile or non-local. There is, however, a difference in variation of strontium isotope ratios …
Earliest evidence of Neolithic collective burials from Eastern Iberia: Radiocarbon dating at the archaeolgoical site of Les Llometes (Alicante, Spain)
2016
AbstractIn the Valencia region of Spain, the dominant use of natural caves for collective burials during the Late Neolithic and Chalcolithic periods has been documented. Collective burials are central to the hypothesis about social relationships in Copper Age societies from Iberia, and key to interpreting kinship-based societies. Les Llometes (Alcoi, Alicante) is one of the biggest collective burial sites existing in eastern Iberia. This article presents the direct14C dates on 25 skeletal remains at the site. The results indicate that the site was used as a burial place from the end of the 5th millennium cal BC until the end of the 4th millennium cal BC, and is a first milestone for future …
Causes and consequences of past and projected Scandinavian summer temperatures, 500-2100 AD
2011
Tree rings dominate millennium-long temperature reconstructions and many records originate from Scandinavia, an area for which the relative roles of external forcing and internal variation on climatic changes are, however, not yet fully understood. Here we compile 1,179 series of maximum latewood density measurements from 25 conifer sites in northern Scandinavia, establish a suite of 36 subset chronologies, and analyse their climate signal. A new reconstruction for the 1483–2006 period correlates at 0.80 with June–August temperatures back to 1860. Summer cooling during the early 17th century and peak warming in the 1930s translate into a decadal amplitude of 2.9°C, which agrees with existin…
A low seasonality scenario in the Mediterranean Sea during the Calabrian (Early Pleistocene) inferred from fossil Arctica islandica shells
2017
Understanding past seasonal temperature variability in the ocean is essential to evaluate the effects of future climate change on marine ecosystems. Here, we estimate seasonal water temperature amplitudes from stable oxygen isotope (δ18Oshell) values of fossil shells of Arctica islandica (assuming δ18Owater= + 0.9 ± 0.1â° V-SMOW). Specimens were collected from three Pleistocene successions (Emilian and Sicilian substages of the Calabrian) in Central and Southern Italy (i.e., Rome, Lecce and Sicily). Biostratigraphic analyses from Rome Quarry deposits indicate an age between 1.6 and 1.2 Ma, whereas Sicily and Lecce successions are slightly more recent (between 1.1 and 0.62 Ma). Prior to …
New research on the development of high-resolution palaeoenvironmental proxies from geochemical properties of biogenic carbonates
2017
Abstract Geochemical signatures from biogenic carbonates are being increasingly employed as palaeoenvironmental proxies. In turn, many of these proxy archives including mollusc shells, corals, and otoliths have periodic growth structures, which allow the reconstruction of chronologically constrained records of palaeoenvironmental variability at unparalleled high temporal resolution. Studying the growth and chemistry of these periodic growth structures is known as sclerochronology. Biogenic hard parts accumulate in geological or archaeological deposits, and can be directly dated using radiometric and racemisation methods. They therefore offer the opportunity for high-resolution palaeoenviron…
Using growth and geochemical composition of Clathromorphum compactum to track multiscale North Atlantic hydro-climate variability
2020
International audience; Records of ocean/atmosphere dynamics over the past centuries are essential to understand processes driving climate variability. This is particularly true for the Northwest Atlantic which is a key region with an essential role in global climate regulation. Over the past two decades, coralline red algae have been increasingly used as environmental and climatic archives for the marine realm and hold the potential to extend long-term instrumental measurements. Here, we investigate the possibility to extract climate and environmental information from annual growth patterns and geochemical composition of the coralline red algae, Clathromorphum compactum, from Saint-Pierre …
Problems in the identity of "Crioceras" barremense Kilian, 1895 (Ancyloceratida, Late Barremian), and their proposed resolution
2010
17 pages; The study of "Crioceras" barremense KILIAN was undertaken as a part of the revision of the Hemihoplitidae. This species was considered "classic" and has been used as the index of an Upper Barremian subzone; this usage raises a number of problems. The type specimen from Tyrol was a fragment described and illustrated by UHLIG as Crioceras sp. ind. aff. roemeri. This specimen could not be retrieved, and a topotype could not be collected. Our study revealed that there is both a biostratigraphic hiatus and important differences between conceptions of this species: (1) that ascribed UHLIG's type specimen (Upper Barremian, Tyrol), (2) KILIAN's concept of the specimen he found and named "…