Investigation of the potential of using seismic attenuation and velocity to identify massive sulphide ore deposits

Dewan, Asma (2014) Investigation of the potential of using seismic attenuation and velocity to identify massive sulphide ore deposits. Masters thesis, Memorial University of Newfoundland.

[English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (3MB)

Abstract

Massive sulphide ore deposits are one of the major sources of valuable minerals. Therefore, identifying massive sulphide ores from their associated host rocks is of great interest in mineral exploration. The seismic P-wave velocity and density of massive sulphides and associated host rocks has been studied significantly but there has been very little work on attenuation. This thesis reports on a comprehensive assessment of attenuation and loss factor along with velocity for the sulphide minerals (pyrite, chalcopyrite, sphalerite and pyrrhotite) and the felsic and mafic host rocks. The Spectral Ratio Technique is used to measure attenuation. The relationships among velocity, attenuation and loss factor along with their sensitivity with hydrostatic confining pressure (10-600 MPa) will be discussed. Seismic P-wave velocity for silicates and massive sulphides shows positive change with pressure. Except for low pyrite, Q shows modest pressure dependence for other rocks. The low pressure results for Q are not systematic and low pyrite shows anamolus behaivour for Q and loss factor at low pressure. The changes in loss factor in felsic and mafic silicates are not pronounced compared to that in massive sulphides, however the response of Q with pressure is much more complicated than loss factor. The applicability of the joint interpretation of these parameters (velocity, attenuation and loss factor) to identify massive sulphides is the key of this research. Moreover the response of these parameters in low (below 100 Mpa) and high (above 100 Mpa) pressure zones are observed separately to observe their pattern of change and gradient with pressure to establish a relationship with pressure.

Actions (login required)

View Item