Vertical gradient of the Bouguer gravity anomaly map of North America
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# Vertical gradient of the Bouguer gravity anomaly map of North America

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Written in English

## Book details:

Edition Notes

11

The Physical Object ID Numbers Contributions Pilkington, M. Pagination 1 sheet scale 1:10 000 000 Number of Pages 10 Open Library OL22040241M

The horizontal gradients of the Bouguer gravity anomaly (the positions of changes in the gravity anomaly values) are shown as grey shading with darker shading corresponding to larger changes. This gravity data set was compiled by the Decade of North American Geology project and consists of survey results gridded at ~6 km spacings. A detailed gravity survey comprising approximately 11 gravity stations has been carried out in a 33 km 2 region of the southern Canadian shield between the Sudbury and Kirkland Lake mining camps in east-central Ontario. The purpose of the survey was to shed some light on the economic mineral potential of the less well-explored parts of this very important mining district of Canada. The $$\partial^2 g / \partial x^2$$ and $$\partial^2 g / \partial y^2$$ terms can be obtained directly from a Bouguer anomaly map, so the $$\partial^2 g / \partial z^2$$ term can be derived. This last term describes how fast the “vertical rate of change in gravity” is changing. However the success of this process depends upon adequate data spacing. B5: Interpretation of gravity data B Bouguer anomaly maps Once the Free Air and Bouguer corrections have been made, the Bouguer anomaly should contain information about the subsurface density alone. The effect of latitude and elevation should have been removed. A map of the Bouguer anomaly gives a good impression of subsurface density.