543 research outputs found
Dialogues with the dead : an osteological analysis of the palaeodemography and life history of the 18th and 19th century northern frontier in South Africa
Bibliography: leaves 170-187.Osteological, dental, and molecular analyses were conducted on remains from seven historical archaeological sites within South Africa. The emphasis was on the collection of lifestyle data for the purpose of adding to the unwritten history of indigenous South African peoples and to give voice to a once forgotten group of peoples. The demographic distribution reveals three different community dynamics: the Griqua sample are a pastoralist group incorporating some agricultural activities, the Colesberg individuals are an indigenous group resembling a migrant workers population living on the margins of society, and the Wolmaransstad demographics are suggestive of a Zabantu labouring community. All individuals are relatively healthy with low rates of dental disease and trauma and share similar growth patterns to living populations. However all of these individuals display high frequencies of porotic hyperostosis and cribra orbitalia, skeletal manifestations of iron deficiency anaemia. Many theories about the occurrence of anaemia are discussed and the hypothesis that, in these individuals, it is related to infection by the smallpox virus is investigated through the analysis of ancient DNA
Mikrofluorimetrische Untersuchungen zur Charakterisierung der glucoseinduzierten langsamen Oszillationen der intrazellulären freien Calciumkonzentration in Pankreasinseln der Maus
[no abstract
Seep deposits from northern Istria, Croatia: a first glimpse into the Eocene seep fauna of the Tethys region
Carbon isotope excursions during the late Miocene recorded by lipids of marine Thaumarchaeota, Piedmont Basin, Mediterranean Sea
Late Jurassic–Early Cretaceous hydrocarbon seep boulders from Novaya Zemlya and their faunas
The paper describes Late Jurassic–Early Cretaceous seep carbonate boulders from the Russian Arctic island of Novaya Zemlya, collected in 1875 by A.E. Nordenskiöld during his expedition to Siberia. The carbonates are significantly depleted in heavy carbon isotopes (δ13C values as low as ca. − 40‰) and show textures typical for carbonates formed under the influence of hydrocarbons, such as fibrous carbonate cements and corrosion cavities. The rocks contain index fossils of Late Oxfordian–Early Kimmeridgian, Late Tithonian (Jurassic) and latest Berriasian–Early Valanginian (Cretaceous) age. The fossil fauna is species rich and dominated by molluscs, with subordinate brachiopods, echinoderms, foraminifera, serpulids and ostracods. Most of the species, including two chemosymbiotic bivalve species, likely belong to the ‘background’ fauna. Only a species of a hokkaidoconchid gastropod, and a possible abyssochrysoid gastropod, can be interpreted as restricted to the seep environment. Other seep faunas with similar taxonomic structure are suggestive of rather shallow water settings, but in case of Novaya Zemlya seep faunas such structure might result also from high northern latitude
The response of water column and sedimentary environments to the advent of the Messinian salinity crisis: insights from an onshore deepwater section (Govone, NW Italy)
Polyphasic carbonate precipitation in the shallow subsurface: insights from microbially-formed carbonate beds in Upper Miocene sediments of the Tertiary Piedmont Basin (NW Italy).
Methane seepage in a Cretaceous greenhouse world recorded by an unusual carbonate deposit from the Tarfaya Basin, Morocco
During the Cretaceous major episodes of oceanic anoxic conditions triggered large scale deposition of marine black shales rich in organic carbon. Several oceanic anoxic events (OAEs) have been documented including the Cenomanian to Turonian OAE 2, which is among the best studied examples to date. This study reports on a large limestone body that occurs within a black shale succession exposed in a coastal section of the Tarfaya Basin, Morocco. The black shales were deposited in the aftermath of OAE 2 in a shallow continental sea. To decipher the mode and causes of carbonate formation in black shales, a combination of element geochemistry, palaeontology, thin section petrography, carbon and oxygen stable isotope geochemistry and lipid biomarkers are used. The ¹³C-depleted biphytanic diacids reveal that the carbonate deposit resulted, at least in part, from microbially-mediated anaerobic oxidation of methane in the shallow subseafloor at a hydrocarbon seep. The lowest obtained δ¹³Ccarbonate values of −23.5‰ are not low enough to exclude other carbon sources than methane apart from admixed marine carbonate, indicating a potential contribution from in situ remineralization of organic matter contained in the black shales. Nannofossil and trace metal inventories of the black shales and the macrofaunal assemblage of the carbonate body reveal that environmental conditions became less reducing during the deposition of the background shales that enclose the carbonate body, but the palaeoenvironment was overall mostly characterized by high productivity and episodically euxinic bottom waters. This study reconstructs the evolution of a hydrocarbon seep that was situated within a shallow continental sea in the aftermath of OAE 2, and sheds light on how these environmental factors influenced carbonate formation and the ecology at the seep site
An archeal biomarker record of paleoenvironmental change across the onset of the Messinian salinity crisis in the absence of evaporites
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