Open AccessA geophysical study of the Rhinegraben — II. Gravity anomalies and geothermal implications
Author(s) -
Kahle HansGert,
Werner Dietrich
Publication year - 1980
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1980.tb02596.x
Subject(s) - bouguer anomaly , gravity anomaly , geology , geothermal gradient , geophysics , amplitude , anomaly (physics) , seismology , discontinuity (linguistics) , density contrast , mantle (geology) , wavelength , physics , paleontology , oil field , mathematical analysis , mathematics , optoelectronics , condensed matter physics , quantum mechanics , astronomy
Summary In this paper the relief of the Mohorovičić ( M‐ ) discontinuity as well as the crustal structure under the Rhinegraben and its surroundings are analysed in terms of density anomalies deduced from seismic information. The corresponding gravity effects are evaluated and compared with the observed Bouguer anomalies. A pronounced discrepancy of about 100 mgal (1 mgal= 10 −5 ms −2 ) is obtained. An attempt is made to study the sources of this missing high‐amplitude, long‐wavelength gravity high. It is shown that the Mesozoic sediment cover and the Tertiary sedimentary fill of the Rhinegraben proper do not produce sufficiently large gravity effects to solve the problem. Instead, it is suggested that a deep‐seated thermal anomaly exists underneath the Rhinegraben (see also Werner & Kahle 1980). The gravitational effects of this thermal anomaly are discussed and evaluated. It is shown that the thermally induced negative gravity effects are approximately of the same amplitude and wavelength as the positive gravity anomaly associated with the crustal and upper mantle structure.