These files contain gravity anomaly grids for New Zealand region between 25°S to 60°S and 160°E to 170°W. The grids were initially developed for quasigeoid modelling over New Zealand, but have been adapted to be used for more general geophysical research including investigating crustal structure, faults, sedimentary basin and volcanic bodies. Interpretation of the grids can help identify areas where higher resolution gravity data might be of interest for local geological investigations and mineral exploration.
All data used to make the grids were corrected for the gravitational effect of the GRS80 reference ellipsoid and tied to the I.G.S.N.71 gravity datum. The gravity anomaly data from all sources were combined using the method of least squares collocation with a three dimensional logarithmic covariance function. An error grid is provided that gives the estimated residual gravity noise determined during the least squares collocation process. A full description of the data sources, analysis and gridding process are in McCubbine JC, Stagpoole V, Caratori Tontini F, Amos M, Smith E, Winefield R, (2017). Gravity Anomaly Grids for the New Zealand Region. New Zealand Journal of Geology and Geophysics. http://dx.doi.org/10.1080/00288306.2017.1346692
Gravity grids are in Arc-ascii format