The rate of change during this “geomagnetic spike” [defined as virtual axial dipole moment Variations of the Earth’s geomagnetic field during the Holocene are important for understanding centennial to millennial-scale processes of the Earth’s deep interior and have enormous potential implications for chronological correlations (e.g., comparisons between different sedimentary recording sequences, archaeomagnetic dating).Here, we present 21 robust archaeointensity data points from eastern China spanning the past ∼6 kyr.We can also provide magnetic material characterization for calibrating and modelling large-scale gradiometer 'geophys' surveys.[top] John Shaw & Mimi Hill, John Shaw phone: 0151 7943463John Shaw email: [email protected] Mimi Hill phone: 01517943460Mimi Hill email: M.It is straightforward to make the necessary measurements for a sample and to plot results within the domain state framework based on the boundaries defined by Day et al. We discuss 10 issues that limit Day diagram interpretation, including (1) magnetic mineralogy, (2) the associated magnetocrystalline anisotropy type, (3) mineral stoichiometry, (4) stress state, (5) surface oxidation, (6) magnetostatic interactions, (7) particle shape, (8) thermal relaxation, (9) magnetic particle mixtures, and (10) definitional/measurement issues.
Furthermore, in comparing the new data with previous archaeomagnetic studies from Timna, we can assert the existence of simultaneous copper production at the archaeological Sites 30, 30a and 34.Geo Quest works in conjunction with Museum of London Archaeology in carrying out site visits, context assessment and sampling, with subsequent laboratory processing and analysis in our laboratory on the Isle of Man.[top] Sarah Jones, Phone: 020 7410 2287Email: [email protected] The Geomatics team of Museum of London Archaeology collect samples for archaeomagnetic dating, which are processed and dated by Mark Noel, Geo Quest Associates.This gives further support to the claim of intense smelting in the central Timna Valley during the early Iron Age.Finally, this project demonstrates the potential of archaeomagnetic experiments to provide chronological insights, and their particular advantage in addressing pyrotechnology-related cases.