The camera and the interrogator How odd it is that anyone should not see that all observations must be for or against some view if it is to be of any service. Charles Darwin, 1870 Speak to exploration geologists and you will find two views about what a […]
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Vergences and fractals Field geologists have long known that the style and relationships of structures seen in a hand specimen, outcrop or drill core can mimic the style and relationships of much larger structures that formed during the same deformation but occur at the scale of a geological […]
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Using Stereonets Cheap, versatile, reliable, compact, robust, ultra lightweight and does not need any batteries: there should be a stereonet in every geologist’s field kit. A stereonet is a tool (a type of nomogram[see footnote 1]) that allows the attitude of planes and lines in three-dimensional space […]
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This post is about the different techniques used by explorationists to collect samples for assay from exposed bedrock – a process known generically as rock chip sampling. Explorationists seek to find new ore bodies. Ore bodies that reach or approach the surface are the easiest to find, […]
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In the grey light of a tropical dawn on 6th July 1968, fifty men assembled at the government wharf, Sohano, on the south coast of Bougainville Island. They were members of the Royal Papua Nugini Constabulary, and they were armed with long wooden pick-axe handles. An […]
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Exploration for a mineral deposit begins with generating prospects which can then be tested with a staged series of exploration programs that hopefully will lead to ore discovery and eventually a mine. Obviously not all prospects that are generated will make it through to a mine. In […]
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All metal deposits that have formed later than the rocks that host them (that is, epigenetic deposits) have got there by virtue of fluid transport along faults and their location, shape, size and attitude are largely determined by the strain states that existed within the fault […]
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The science of geology was born in the last few decades of the 18th and the first few decades of the 19th centuries. Its development was one of advancing ideas and knowledge, but the new knowledge above all was driven by the progressive improvement in geological method, and in […]
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Strike and dip is a convention for measuring the attitude of a planar structure, such as a bedding plane, fault, joint or vein, in terms of the angles which it makes with the geographic coordinates of the earth’s surface – north-south, east-west and up-down. You probably know […]
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Why make a geological map? Mapping epithermal gold veins along the coast of Sumbawa, Indonesia. It’s a hard life, but someone has to do it. A geological map is a graphical presentation of geological observations and interpretations on a horizontal plane[1]. A geological section is identical in […]
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