(Table) Bacterial counts and Fe, Mn and SO4 content in sediments and pore waters of two cores from Lake Baikal

Sediments at the bottom of Lake Baikal are mostly oxidized at their surface, and the oxidized sedimentary deposits are enriched in Fe and Mn hydroxides. The thickness of the oxidized zone of the pelagic sediments averages at 5 cm and locally reaches 10-15, occasionally exceeding 20 cm. Both the thickness of the oxidized layer and the degree of its enrichment in iron and manganese hydroxides are controlled by the depth to which oxygen can penetrate into the sedimentary deposits, which is, in turn, closely related to the sedimentation conditions in the lake (which broadly vary). The sedimentation rate far off the shores of Lake Baikal ranges from <0.02 mm/year to 1.5 mm/year, and the content of organic matter buried in the sediments varies from 0.1 to >4%. The variability of the sedimentation process makes Lake Baikal very convenient to study its diagenetic processes related to redox reactions in sediments, first of all, processes responsible for the redistribution of Fe and Mn compounds. Although the diagenetic enrichment of Fe and Ni in bottom sediments is known to be of biogenic character, very scarce information is available so far on the microorganisms involved in the redistribution of these elements in sediments in Lake Baikal, which lately led us to explore this issue in detail. Our research was centered on the role played by the microbial community in the diagenetic transformations of Fe and Mn with reference to sedimentation conditions in Lake Baikal.

Stable carbon, nitrogen and sulphur isotope analysis of permafrost preserved human hair from rescue excavations (2009, 2010) at the precontact site of Nunalleq, Alaska

Acknowledgments This work was funded by an Arts and Humanities Research Council (AH/K006029/1) grant awarded to Rick Knecht, Kate Britton and Charlotta Hillerdal (Aberdeen); an AHRC-LabEx award (AH/N504543/1) to KB, RK, Keith Dobney (Liverpool) and Isabelle Sidéra (Nanterre); the Carnegie Trust to the Universities of Scotland (travel grant to KB); and the Max Planck Institute for Evolutionary Anthropology. The onsite collection of samples was carried out by staff and students from the University of Aberdeen, volunteer excavators and the residents of Quinhagak. We had logistical and planning support for fieldwork by the Qanirtuuq Incorporated, Quinhagak, Alaska, and the people of Quinhagak, who we also thank for sampling permissions. Special thanks to Warren Jones and Qanirtuuq Incorporated (especially Michael Smith and Lynn Church), and to all Nunalleq project team members, in Aberdeen and at other institutions, particularly Charlotta Hillerdal and Edouard Masson-Maclean (Aberdeen) for comments on earlier versions of this manuscript, and also to Véronique Forbes, Ana Jorge, Carly Ameen and Ciara Mannion (Aberdeen) for their inputs. Thanks also to Michelle Alexander (York). Finally, thank you to Ian Scharlotta (Alberta) for inviting us to contribute to this special issue, to the Editor, and to three anonymous reviewers, whose suggestions and recommended changes to an earlier version of this manuscript greatly improved the paper.

Composition of melt inclusions and age of zircons of plagiogneisses from the Kola Superdeep Borehole

A comprehensive study of melt inclusions and SHRIMP dating of zircons from trondhjemite gneisses of the sequence VIII from the Kola Superdeep Borehole has revealed presence of old primary magmatic crystals with age up to 2887+/-15 Ma. This is not consistent with the previous view, according to which the oldest zircons from the Archean Complex in SG-3 are products of granulite metamorphism. Primary magmatic zircons of early generation (from 2887 to 2842 Ma) formed in deep-seated magma chambers during partial crystallization of CO2-saturated trondhjemite estimates on duration of generation of tonalite-trondhjemite-granite melts through partial melting of mafic rocks.