A detailed rock density model of the Hong Kong territories

Abstract

We used the geological map and published rock density measurements to compile the digital rock density model for the Hong Kong territories. We then estimated the average density for the whole territory. According to our result, the rock density values in Hong Kong vary from 2101 to 2681 kg·m−3. These density values are typically smaller than the average density of 2670 kg·m−3, often adopted to represent the average density of the upper continental crust in physical geodesy and gravimetric geophysics applications. This finding reflects that the geological configuration in Hong Kong is mainly formed by light volcanic formations and lava flows with overlying sedimentary deposits at many locations, while the percentage of heavier metamorphic rocks is very low (less than 1%). This product will improve the accuracy of a detailed geoid model and orthometric heights.