Negative gravity anomalies over acid “Intrusions” and their relation to the structure of the earth's crust
By: Bott, M.H.P
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Material type: 
ArticleDescription: 257-267pp.Subject(s): Gravity anomalies | Intrusions and their relation - Structure of the earth | Earth crust | Gravity survey
In:
Geological magazine : Vol. 90 Iss. 1-6 Year. 1953Summary: Abstract
The results of gravity surveys over various exposed and buried acid intrusions are summarized. Some sample density determinations are discussed. It is found that the acid intrusions considered are almost invariably associated with negative Bouguer anomalies, which are certainly often caused by direct density contrast between the less dense acid intrusive, and the denser country rock. This has two immediate implications. (1) Large negative Bouguer anomalies over “granites” may suggest magmatic origin. (2) These gravity anomalies, supported by seismological and seismic evidence, and the petrological distribution of igneous rocks, lead to the postulation of a denser “metasedimentary” layer overlying the “granitic” layer. The bearing of this on the mechanism of intrusion is briefly discussed.
| Item type | Current location | Collection | Call number | Status | Date due | Barcode |
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Article
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Library and Information Centre Periodical Section | Bound Journal Collection | Not for loan | 002541_43 | ||
Serials/Scientific Journal
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Library and Information Centre Periodical Section | Bound Journal Collection | 550 GEO (Browse shelf) | Available | 002541 |
Abstract
The results of gravity surveys over various exposed and buried acid intrusions are summarized. Some sample density determinations are discussed. It is found that the acid intrusions considered are almost invariably associated with negative Bouguer anomalies, which are certainly often caused by direct density contrast between the less dense acid intrusive, and the denser country rock. This has two immediate implications. (1) Large negative Bouguer anomalies over “granites” may suggest magmatic origin. (2) These gravity anomalies, supported by seismological and seismic evidence, and the petrological distribution of igneous rocks, lead to the postulation of a denser “metasedimentary” layer overlying the “granitic” layer. The bearing of this on the mechanism of intrusion is briefly discussed.
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