British Geological Survey

About: British Geological Survey is a government organization based out in Nottingham, United Kingdom. It is known for research contribution in the topics: Groundwater & Aquifer. The organization has 2561 authors who have published 7326 publications receiving 241944 citations.

The Global Stratotype Sections and Points for the bases of the Selandian (Middle Paleocene) and Thanetian (Upper Paleocene) stages at Zumaia, Spain

Abstract: The global stratotype sections and points for the bases of the Selandian (Middle Paleocene) and Thanetian (Upper Paleocene) stages have been defined in the coastal cliff along the Itzurun Beach at the town of Zumaia in the Basque Country, northern Spain. In the hemipelagic section exposed at Zumaia the base of the Selandian Stage has been placed at the base of the Itzurun Formation, ca. 49 m above the Cretaceous/ Paleogene boundary. At the base of the Selandian, marls replace the succession of Danian red limestone and limestone-marl couplets. The best marine, global correlation criterion for the basal Selandian is the second radiation of the important calcareous nannofossil group, the fasciculiths. Species such as Fasciculithus ulii, F. billii, F. janii, F. involutus, F. pileatus and F. Tympaniformis have their first appearance in the interval from a few decimetres below up to 1.1 m above the base of the Selandian. The marker species for nannofossil Zone NP5, F. tympaniformis , first occurs 1.1 m above the base. Excellent cyclostratigraphy and magnetostratigraphy in the section creates further correlation potential, with the base of the Selandian occuring 30 precession cycles (630 kyr) above the top of magnetochron C27n. Profound changes in sedimentology related to a major sea-level fall characterize the Danian-Selandian transition in sections along the margins of the North Atlantic. The base of the Thanetian Stage is placed in the same section ca. 78 m above the Cretaceous/Paleogene boundary. It is defined at a level 2.8 m or eight precession cycles above the base of the core of the distinct clay-rich interval associated with the Mid-Paleocene Biotic Event, and it corresponds to the base of magnetochron C26n in the section. The base of the Thanetian is not associated with any significant change in marine micro-fauna or flora. The calcareous nannofossil Zone NP6, marked by the first occurrence of Heliolithus kleinpelli starts ca. 6.5 m below the base of the Thanetian. The definitions of the global stratotype points for the bases of the Selandian and Thanetian stages are in good agreements with the definitions in the historical stratotype sections in Denmark and England, respectively.

Isotope domain mapping of 87Sr/86Sr biosphere variation on the Isle of Skye, Scotland

Abstract: The potential of 87 Sr/ 86 Sr isotope composition for tracking and determining the origin of material, whether it is humans, animals, water or wine can be fully realized only if high-quality reference datasets are available against which to compare the unknowns. This is currently not the case. Despite the rapid increase in 87 Sr/ 86 Sr-based provenance studies of biosphere materials there are no well-documented maps available. Most researchers resort to generating reference maps from a variety of geological datasets plus the analysis of sparse ’environmental9 samples. A major reason for this lack of reference material is the investment needed to undertake systematic sampling and analysis over large areas. A further problem is associated with the choice of proxy material, as organisms differ in their habitat and exploitation of resources. In this paper various approaches to isotope biosphere sampling are considered, some of the problems are assessed, the precision required for the study of human populations is discussed, and a first attempt is made to condense all of the available information into an ’isotope package9 map. The work is based on a study undertaken on the Isle of Skye, in the Inner Hebrides, and reduces the complexity of geological and isotope data into five main 87 Sr/ 86 Sr packages: Package 1 (northern area) = 0.705–0.7092; Package 2 (NE coast) = 0.7082–0.7102; Package 3 (granitic rocks) = 0.716–0.720; Package 4 (metamorphic rocks) = 0.7092–0.7188; Package 5 (seawater) = 0.7092 ± 0.005% (2σ). The approach of trying to constrain the isotope composition of certain areas and/or lithologies offers the possibility of extrapolating to other similar areas without having to sample at the original density.

Characterizing the availability of metals in contaminated soils. I. The solid phase: sequential extraction and isotopic dilution

Abstract: The two approaches most commonly applied to characterizing the chemical form and ‘reactivity’ of metals in the soil solid phase are sequential extraction procedures (SEPs) and isotopic dilution (ID). The development and limitations of both approaches are described and their application to contaminated soils discussed. It may be argued that ID offers a better means of discriminating between ‘reactive’ and ‘inert’ forms of metal. However, the literature on SEPs is considerably larger, providing greater scope for comparative analysis of new data. Although ID methods are subject to operational constraints, the procedural dependency of SEPs is probably much greater. Thus greater effort has been expended to standardize and verify methodologies for SEPs. However, despite achieving a level of ‘political ratification’ at the procedural level, the use of SEPs within risk assessments for planning or development purposes is currently almost absent. The future for ID methods in this context may lie in site-specific risk assessments that include improved methods for the prediction of metal solubility and bioavailability.