Having had the Web as our infrastructure for geological information transmission and retrieval, we are confronted with three major problems, which are platform heterogeneity, structure heterogeneity, and particularly semantic heterogeneity. An approach of geological data integration and sharing on the semantic level is proposed here. Ontology views are built through extracting common concepts in heterogeneous data, and based on that, semantic mappings between data sources are created. The solutions to key technologies are also sorted out, including ontology building, semantic mapping and query processing. [ABSTRACT FROM PUBLISHER]