‘X-ray plunge projection’— understanding structural geology from grade data / ‘Рентгеновская проекция погружения" - понимание структурной геологии на основе данных об уровне содержаний

This paper introduces a new down-plunge projection method that allows geologists to rapidly determine the first-order structural geometries of mineral deposits. The method assumes that the mineralised bodies under analysis resulted when hydrothermal fluids flowed through highly permeable zones that were formed from deformation. Therefore, the grade patterns should mimic the significant structures that controlled the fluid flow. Once these structural geometries are determined, the patterns can be used to simplify, speed up, and substantially increase the accuracy of the geological modelling processes of both explicit and implicit methods of modelling.
Down-plunge projection, or down-structure method, is a way to examine structures on a geological map by orientating the map so as to look down into, and along, the direction of the plunging structural features, such as folds and fault intersections. This method of deriving true sectional geological structural geometries from an oblique viewing angle has been known to geologists for more than 100 years. However, this practical technique has not been extensively used in the field of economic geology, even though the application is very broad and relevant to the interpretation of grade distribution in mineral deposits. This century-old graphical methodology is reintroduced in this paper by combiningit with a computer rendering technique called Maximum Intensity Projection (MIP). MIP is a 2D projection method that displays the highest value point of a point cloud along a line-of-sight orthogonal to the computer screen. This allows the geologist to ‘see through’ a dense 3D grade point cloud on a computer monitor and aids structural interpretation of the details of the high-grade core that is surrounded by lowgrade values. Because the rendering method appears to allow the skeletal core of a grade dataset to be visualised through a low-grade surrounding, it is informally termed the ‘X-ray’ method of grade data visualisation <...>