A Global Database for the Compilation and Assessment of Holocene Sedimentary Paleomagnetic Records

Global geomagnetic field reconstructions for the Holocene can provide powerful information about the geodynamo process and can constrain geomagnetic shielding, important for our understanding of the interaction between the geomagnetic field and cosmogenic nuclide production. Coherent structure is evident in these reconstructions and this has significant implications for controls on the geodynamo. However, the resolution and reliability of current models require improvements and are limited by: 1) the restricted global coverage of sites, especially in the southern hemisphere; 2) the low precision of some magnetic data and independent dates; 3) an incomplete assessment of data quality. Improving these aspects for sedimentary records is particularly important as loosely constrained sedimentary data have a large influence on model output from spherical harmonic reconstructions of the Holocene geomagnetic field (e.g., CALS7k.2, CALS3k.3, CALS10k.1b and SED3k.1). In addition, the current SECRV00 database lacks data from the most recent studies and a number of older studies. We present our current effort to assess data quality through the design of a new database for global sedimentary data covering the last 10 ka; implemented as part of the successful GEOMAGIA50 database, already constructed for paleomagnetic data from archaeological and volcanic materials. Our aim is two-fold: 1) to transparently catalogue all available sedimentary data for the Holocene, so the broader scientific community can access a range of information related to specific cores; 2) to design a database with the functionally to select paleomagnetic data based upon parameters that reflect the fidelity of the data. To make accurate assessments of data quality it is necessary to determine paleomagnetic, rock magnetic, mineralogical and chronological parameters that may influence the fidelity of the record. We show these selected parameters and how they are implemented in the database design. All available data are catalogued based on these parameters. Measurements on the same specimen are tied to their age and/or depth, so it is possible to select data that satisfy specific quality criteria only. The new database also allows retrieval of both core and stacked data, permitting assessment of individual sections of core data, consistency between core records and their relative influence on the stacked record. Compiling a broad range of queryable parameters for both core and stacked records will allow a complete assessment of the fidelity of directional, relative paleointensity and chronological data. High quality data can then be selected to optimize subsequent global modeling of the Holocene geomagnetic field and the influence of choosing specific data selection parameters on the output of these models can be assessed.