Search Results (7)

The environment of the Marseille basin in the Early Pleistocene was reconstructed through a multiproxy study of fluvial tufa deposits. Palaeomagnetic measurements revealed the Jaramillo subchron and dated the tufa to within the 0.8–1.5 Ma interval, probably between 0.9 and1.2 Ma. Sedimentological studies show varied depositional environments comprising natural dams formed by accumulations of plants promoting the development of upstream water bodies. The very negative δ¹³C values indicate that the Marseille tufa is not travertine sensu stricto but tufa deposited by local cold-water rivers. Palynological analyses indicate a semi-forested, diverse, mosaic vegetation landscape dominated by a Mediterranean pine and oak forest. Along the streams, the riparian forest was diverse and included Juglans, Castanea, Platanus and Vitis. The potential diet reconstructed from pollen was varied. The most surprising discovery was the presence of proto-cereals, which could potentially enrich the diet with carbohydrates. The identification of spores of coprophilous fungi seems to indicate the presence in situ of large herbivore herds. It is possible that, as in Anatolia, the disturbance of ecosystems by large herbivores was responsible for the genetic mutation of Poaceae and the appearance of proto-cereals. Climatic reconstructions indicate a slightly cooler and wetter climate than the present. Full article

Aotearoa/New Zealand was first settled by the Māori people some 800–1000 years ago. Archaeomagnetism provides one of the few means of dating early sites of Māori occupation, particularly when radiocarbon dating is not feasible. This involves dating the thermoremanent magnetization imparted to the heat-retaining stones used in traditional Māori earth ovens, hāngī or umu, at the time of their last cooling. The direction of this magnetization is correlated with the reference curve of the changes in the geomagnetic field direction in New Zealand over the past 1000 years, NZPSV1k.2023. Here, we describe the application of archaeomagnetic dating to indigenous hāngī sampled at two sites in the North Island of New Zealand. The first, in the present-day city of Napier on the east coast, has been studied in detail and is shown to have been occupied, possibly intermittently, over 400–600 years, while the second, in present-day Waikanae on the west coast, is tentatively dated to ca. 1760 AD, just decades before the first European arrival in New Zealand. Full article

A c. 31 m thick section straddling the fossil find of an Early Pliocene baleen whale (“Brunella”, hereafter), made in 2007 in the sedimentary fill of the Middle Ombrone Basin of Tuscany, is investigated for depositional age and environment combining palaeomagnetic, micropalaeontological (Foraminifera and calcareous nannofossils) and sedimentary facies analyses. Resting unconformably onto Late Miocene continental deposits, the Early Pliocene marine deposits include, from bottom to top, a coarse-grained wave-winnowing lag, the few metres-thick fossiliferous sandstone bedset from which Brunella was unearthed, and several metres of clays. The stratigraphic organisation of these deposits indicate deposition in a deepening upward inner shelf environment. Successful isolation of characteristic remanent magnetisation and calcareous nannofossil content indicate the investigated marine section was deposited during the interval of polarity Chron C3n.2n corresponding to the basal part of the Mediterranean nannofossil zone MNN13 (between Helicosphaera sellii Base common and the Amaurolithus primus Top) and allow estimating the depositional age of Brunella to c. 4.6 Ma. Sedimentary facies, benthic Foraminifera association and anisotropy of magnetic susceptibility characterising the deposits that embedded Brunella suggest deposition above the fair-weather base level. Full article

Road-deposited dust (RD) is a pervasive form of particulate pollution identified (typically via epidemiological or mathematical modelling) as hazardous to human health. Finer RD particle sizes, the most abundant (by number, not mass), may pose greater risk as they can access all major organs. Here, the first in vitro exposure of human lung epithelial (Calu-3) cells to 0–300 µg/mL of the ultrafine (<220 nm) fraction of road dust (UF-RDPs) from three contrasting cities (Lancaster and Birmingham, UK, and Mexico City, Mexico) resulted in differential oxidative, cytotoxic, and inflammatory responses. Except for Cd, Na, and Pb, analysed metals were most abundant in Mexico City UF-RDPs, which were most cytotoxic. Birmingham UF-RDPs provoked greatest ROS release (only at 300 µg/mL) and greatest increase in pro-inflammatory cytokine release. Lancaster UF-RDPs increased cell viability. All three UF-RDP samples stimulated ROS production and pro-inflammatory cytokine release. Mass-based PM limits seem inappropriate given the location-specific PM compositions and health impacts evidenced here. A combination of new, biologically relevant metrics and localised regulations appears critical to mitigating the global pandemic of health impacts of particulate air pollution and road-deposited dust. Full article

We present new palaeomagnetic and rock magnetic results with a stratigraphic interpretation of the late Early–Middle Pleistocene deposits exposed on the left bank of the River Danube at Dolynske, southern Ukraine. A thick succession of water-lain facies is succeeded by reddish-brown clayey soils, topped by a high-resolution loess–palaeosol sequence. These constitute one of the most complete recently discovered palaeoclimate archives in the Lower Danube Basin. The suggested stratigraphy is based on the position of the Matuyama–Brunhes boundary, rock magnetic, palaeopedological and sedimentological proxies, and it is confidently correlated with other loess records in the region (Roksolany and Kurortne), as well as with the marine isotope stratigraphy. The magnetic susceptibility records and palaeosol characteristics at Dolynske show an outstanding pattern that is transitional between eastern and south-eastern European loess records. Our data confirm that the well-developed S4 soil unit in Ukraine, and S5 units in Romania, Bulgaria and Serbia, correlate with the warm MIS 11. Furthermore, we suggest the correlation of rubified S6 palaeosols in Romania and Bulgaria and the V-S7–V-S8 double palaeosol in Serbia with S6 in Ukraine, a strong Mediterranean-type palaeosol which corresponds to MIS 15. Our new results do not support the hypothesis of a large magnetic lock-in depth like that previously interpreted for the Danube loess, and they prove that the Matuyama–Brunhes boundary is located within the palaeosol unit corresponding to MIS 19. The proposed stratigraphic correlation scheme may serve as a potential basis for further regional and global Pleistocene climatic reconstructions. Full article

Background and scope: The late Villafranchian large mammal age (~2.0–1.2 Ma) of the Early Pleistocene is a crucial interval of time for mammal/hominin migrations and faunal turnovers in western Eurasia. However, an accurate chronological framework for the Balkans and adjacent territories is still missing, preventing pan-European biogeographic correlations and schemes. In this article, we report the first detailed chronological scheme for the late Villafranchian of southeastern Europe through a comprehensive and multidisciplinary dating approach (biochronology, magnetostratigraphy, and cosmogenic radionuclides) of the recently discovered Lower Pleistocene vertebrate site Tsiotra Vryssi (TSR) in the Mygdonia Basin, Greece. Results: The minimum burial ages (1.88 ± 0.16 Ma, 2.10 ± 0.18 Ma, and 1.98 ± 0.18 Ma) provided by the method of cosmogenic radionuclides indicate that the normal magnetic polarity identified below the fossiliferous layer correlates to the Olduvai subchron (1.95–1.78 Ma; C2n). Therefore, an age younger than 1.78 Ma is indicated for the fossiliferous layer, which was deposited during reverse polarity chron C1r. These results are in agreement with the biochronological data, which further point to an upper age limit at ~1.5 Ma. Overall, an age between 1.78 and ~1.5 Ma (i.e., within the first part of the late Villafranchian) is proposed for the TSR fauna. Conclusions: Our results not only provide age constraints for the local mammal faunal succession, thus allowing for a better understanding of faunal changes within the same sedimentary basin, but also contribute to improving correlations on a broader scale, leading to more accurate biogeographic, palaeoecological, and taphonomic interpretations. Full article

A combination of mineralogical, rock-magnetic and palaeomagnetic methods were employed in an attempt to shed a new light on the tectonism and paleogeography of Central Western Svalbard. The focus is on six metadolerite sites from the metamorphic Proterozoic–Lower Palaeozoic complex of south-western Oscar II Land (Western Spitsbergen). The primary mineral compositions of the metadolerites were strongly remineralized during Caledonian (sensu lato) greenschist-facies metamorphism although some younger tectonothermal modification is also apparent from the rock-magnetic studies. Rock-magnetic experiments supported by thin-section mineral identification and separation of Fe-containing fractions indicate that the main ferromagnetic carriers of the Natural Remanent Magnetization are represented by low-coercivity pyrrhotite and magnetite/maghemite. The investigated metadolerites are characterized by complex pattern of magnetization. The low-temperature palaeomagnetic components which demagnetized up to 250 °C, are characterized by high inclinations (~70–80°) potentially representing Mesozoic–Cenozoic remagnetization. The most stable middle-high temperature directions which demagnetized from 250 °C, were obtained from only two of six sites. Two Virtual Geomagnetic Poles calculated from two of the middle-high temperature site means do not correlate with the Laurussia reference path for syn- to post-Caledonian time. Two possible explanations of observed inconsistency are discussed. These are a modification of the Oscar II Land Caledonian basement geometry by listric faulting and/or tectonic rotations related to Daudmannsdalen–Protectorbreen high-strain (shear) zone. The results presented here suggest that post-Caledonian tectonic modification of the palaeomagnetic directions may be more a widespread feature of Western Svalbard. Full article