19dc5546-eaa2-4ea4-a588-f564da720c85 urn:uuid eng UTF-8 nonGeographicDataset nonGeographicDataset 2025-10-16T20:12:28 creation ISO 19115 2016 Gravity and Granites: Technical notes on mapping relationship between known granites and gravity 19dc5546-eaa2-4ea4-a588-f564da720c85 Gravity anomalies over granite bodies are often negative polarity and rounded polygons. These characteristics were used to trial a method to map possible locations of subsurface granite bodies. Two approaches were used to outline the geometry of rounded gravity anomalies: a) Contouring of the residual Bouguer gravity field after removal of a regional field computed by filtering of the gravity field. b) Detection of edges defined by maximum horizontal gradient of the residual Bouguer gravity field. The resulting polygons are coloured according to whether granite outcrop, or encounter in wells, falls within the gravity polygon, is near such outcrop, or not proximal to outcrop. The processing was done using software developed by the author in the Perl programming language and stored in the Energy Division software repository. The processing was organised to run in batch mode on any system on which Perl is installed, MS-Windows, Unix, Linux or NCI systems. The input and output data files are ERMapper ASCII vector format and exported to ArcGIS shape files. The visualisation tool was ER-Mapper. {"type": "Polygon", "coordinates": [[[112.0, -45.0], [155.0, -45.0], [155.0, -8.0], [112.0, -8.0], [112.0, -45.0]]]} 112.0 155.0 -45.0 -8.0 AU Earth Sciences GA Publication Published_External Record Download the Record (docx) documentDigital DOCX Download the Record (pdf) documentDigital Download the Record (pdf) PDF Unnamed resource documentDigital HTML