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# Data integration and standardization: Topical databases PetDB, SedDB, VentDB, Geochron, and NAVDAT  Topical synthesis databases provide integrated geochemical data for a specific topic of interest. Integration of geochemical data means that measurements, standards, and preparation are documented in a standard way, and delivered to the user in a single table from up to hundreds of original publications. Tabulation of such data by hand may take years, but synthesis databases have the benefit of years of operation. Examples of specific topics include ocean floor geochemistry [PetDB](http://www.earthchem.org/petdb), geochemistry of sediments [SedDB](http://www.earthchem.org/seddb), hydrothermal vent systems [VentDB](http://www.earthchem.org/ventdb), xenoliths (Deep Lithosphere Data Set - now part of [PetDB](http://www.earthchem.org/petdb)), Ar-Ar geochronology ([Geochron](http://www.geochron.org)), and North American volcanic rocks (NAVDAT) ([NAVDAT](http://www.navdat.org))  (Table 1).   Integrated data are used in compilations to examine larger scale geochemical trends. Examples of such compilations that have used PetDB include “Origin of a 'Southern Hemisphere' geochemical signature in the Arctic upper mantle” \citep{Goldstein_2008}, and "Composition of the depleted mantle" \citep{Salters_2004}.