Temperature logging in mineral exploration

Mwenifumbo, C J

doi:10.1016/0926-9851(93)90038-z

Cited by 14 publications

(6 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Sphalerite has a thermal conductivity of ~30 W/m.°C, which is three to ten times higher than many other metallic sulfides (Mwenifumbo 1991), though not as high as pyrite at ~40 W/m.°C (Khesin & Epplebaum 1994). Sphalerite has a slight paramagnetic susceptibility (Bleil & Petersen 1982).…”

Section: Physical Properties Of Important Zinc Mineralsmentioning

confidence: 99%

Geophysical properties of zinc‐bearing deposits

Bishop

Emerson²

1999

Australian Journal of Earth Sciences

View full text Add to dashboard Cite

At present, most, if not all zinc is being produced from the mineral sphalerite. With the exception of its piezoelectricity and in some cases its density, sphalerite has no salient physical properties to routinely allow its direct detection by geophysical methods. Although the mineral usually occurs with other sulfides, which do respond to various geophysical techniques, detection of zinc-bearing deposits is often difficult. In this paper, physical property measurements from numerous, mainly Australian, deposits are presented, together with examples from various geophysical surveys. The results are used to suggest the most effective geophysical technique for the direct detection of the different types of zinc-bearing deposits. Induced polarisation is probably the most effective technique for unmetamorphosed sediment-hosted deposits and for carbonate-hosted deposits, whereas electromagnetics is usually the most appropriate method to use for volcanic-hosted deposits and for sediment-hosted deposits that have been strongly metamorphosed. Magnetics is the best technique for skarn and 'Cobar-style' deposits. However, it must be emphasised that usually more than one geophysical technique is required before a prospect can be considered to have been thoroughly explored.

show abstract

Section: Physical Properties Of Important Zinc Mineralsmentioning

confidence: 99%

Geophysical properties of zinc‐bearing deposits

Bishop

Emerson²

1999

Australian Journal of Earth Sciences

View full text Add to dashboard Cite

show abstract

“…Figure 1d also demonstrates the way in which surface heat flow can be overestimated if it is measured above the inclined sides of mineralised bodies that contain highly conductive minerals [e.g. Mwenifumbo, 1993].…”

Section: Heat Conduction-2dmentioning

confidence: 99%

Heat flow and deep temperatures in the Southeast Basin of France: Implications for local rheological contrasts

Guillou-Frottier

Lucazeau

Garibaldi

et al. 2010

Bulletin De La Société Géologique De France

View full text Add to dashboard Cite

Triassic salt at 5-10 km depth may drive some of the recent tectonic features in southeastern France. We estimate the likely temperature range of the salt using two different approaches. The first of these, based on the extrapolation of deep temperatures obtained in oil exploration wells, predicts temperatures at a depth of 8 km to be in the range of 230-300 o C. However, this prediction could be biased by a lack of deep measurements and problems related to lateral heat transfer caused by thermal conductivity contrasts. The second approach can overcome these problems by modelling the actual heat transfer for appropriate basin geometry, including temperature-dependent thermal properties, and a mantle heat flow of 35 mW.m -2 . This latter value enables us to reproduce available temperature measurements and surface heat flow data. Here we evaluate the stationary temperature field along two sections constrained by seismic profiles, one at a local scale across the Vistrenque graben and the other at a more regional scale across the Southeast Basin. Our findings suggest that the temperatures in the deepest parts of the evaporitic layer (11 km depth) can reach up to 398 o C, but can be as low as 150 o C on the edge of the basin at the top of the salty layer. This temperature difference leads to important changes in salt viscosity. Results indicate that at a depth of 8 km, lateral viscosity contrasts within the evaporitic layer may reach 40. Such rheological contrasts might favour and amplify local subsidence, as seems to have been the case near the two Palaeogene half-grabens of Vistrenque and Valence, where deep hot zones are identified. Flux de chaleur et températures profondes dans le bassin du Sud-Est de la France : conséquences sur les contrastes rhéologiques locauxMots-clés. -Flux de chaleur, Cartes de températures, Modèles thermiques, Viscosité du sel.Résumé. -Le sel triasique à 5-10 km de profondeur peut guider la tectonique récente dans le Sud-Est de la France. Nous estimons ici, par le biais de deux approches différentes, le domaine des températures les plus probables dans cette couche salifère. La première approche est basée sur l'extrapolation de températures profondes mesurées en forages pé-troliers, et prédit des valeurs entre 230 et 300 o C à 8 km de profondeur. Cependant, ces estimations peuvent être biaisées par le faible nombre de températures profondes et par des problèmes reliés aux transferts latéraux de la chaleur, causés par des contrastes de conductivité thermique. La deuxième approche qui permet de contourner ces problèmes consiste à modéliser les transferts de chaleur dans un bassin dont la géométrie est connue, où les propriétés thermiques dépendent de la température, et où le flux de chaleur en provenance du manteau vaut 35 mW.m -2 . Cette valeur permet de reproduire les données de températures profondes et de flux de chaleur. Le champ de température est calculé le long de deux coupes contraintes par des profils sismiques, l'une à l'échelle du graben de Vistrenque et l'autre à une plus grande ...

show abstract

“…For example, subvertical mineralized bodies can be rich in highly conducting minerals (e.g., volcanic massive sulfides deposits, Mwenifumbo, 1993), which may result in large surface heat flow variations, whereas differences in subsurface temperatures may be negligible. These subtle effects are illustrated in Figure 1.4, where two scenarios of heat refraction effects are illustrated.…”

Section: Fourier' Law and Crustal Geothermsmentioning

confidence: 99%