Hostname: page-component-848d4c4894-m9kch Total loading time: 0 Render date: 2024-05-02T23:11:16.126Z Has data issue: false hasContentIssue false
  • English
  • Français

Unusual, oil-bearing inclusions in fluorite from Baluchistan, Pakistan

Published online by Cambridge University Press:  05 July 2018

A. H. Rankin ,
B. L. Hodge  and
M. Moser
A. H. Rankin
Affiliation:
Department of Geology, Imperial College of Science, Technology and Medicine, London SW7 2BP
B. L. Hodge
Affiliation:
B. L. Hodge and Partners, London SW20 0NF
M. Moser
Affiliation:
Departments of Geology, Imperial and University Colleges, London
Get access Rights & Permissions [Opens in a new window]

Abstract

Phenomenally large (up to 2 mm) oil-bearing and associated brine inclusions in fluorite from carbonate-hosted, epigenetic, fluorite-calcite-(baryte) deposits of the Koh-e-Maran area are investigated using a combination of microthermometry, UV-microscopy and FTIR microspectroscopy. The liquid hydrocarbon phase in primary ‘oil’ inclusions is brown in colour and is dominated by saturated, low molecular weight, aliphatic hydrocarbons.

Two types of mixed aqueous and ‘oil’ inclusions occur. Aqueous/oil types represent co-eval trapping of immiscible drops of oil and brine during primary growth. In oil/aqueous inclusions the oil appears to ‘wet’ the aqueous phase resulting in an odd ‘dish-shaped’ meniscus. The oil or liquid hydrocarbon part of the inclusion is primary but the aqueous part is thought to represent a secondary infill. The fluid inclusion evidence suggests that fluorite precipitated from a dilute (3.5 wt.% NaCl) brine at temperatures around 110–140°C in the presence of an immiscible liquid hydrocarbon phase dominated by saturated, light hydrocarbons. This ‘oil’ was present as an emulsion in the aqueous fluid and the phenomenal size of the inclusions is thought to reflect the large droplet size in the emulsion. Infiltration of a more saline, calcium-enriched brine into pre-existing oil inclusions resulted in complex oil-water inclusions showing a reversal in the nature and shape of the oil-water interface due to the presence of unspecifed surfactants in the brine which affected the wetting characteristics of the oil.

The homogenization temperatures and the presence of liquid petroleum inclusions are characteristic of Mississippi Valley-type (MVT) and manto-type fluorite deposits in many other parts of the world.

Keywords

fluoriteoil-bearing inclusionsbrine inclusionsBaluchistanPakistan
Type
Near-surface and surficial environments
Information
Mineralogical Magazine , Volume 54 , Issue 375 , June 1990 , pp. 335 - 342
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1990

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Aines, R. and Rossman, G. (1984) J. Geophys. Res. 89, B6, pp. 4059-71.CrossRefGoogle Scholar
Archer, J. S. and Wall, C. G. (1986) Petroleum Engineering; Principles and Practice. Graham & Trotman (London), 362 pages.Google Scholar
Barres, O., Burneau, A., Dubessey, J. and Pagel, M. (1987) Appl. Spectroscopy, 41, 1000-8.CrossRefGoogle Scholar
Burruss, R. C. (1981) In Short Course on Fluid Inclusions; Applications to Petrology (Hollister, L. S. and Crawford, M. L., eds.). Min. Assoc., Canada, No. 6, 138-56.Google Scholar
Colthup, N. B., Daly, L. H. and Wiberley, S. E. (1975) Introduction to Infrared and Raman Spectroscopy. 2nd Edition, Academic Press, New York, 523 pages.Google Scholar
Guilhaumou, N., Touray, J. C. and Bouhlel, S. (1988) Bull. Mineral. 111, 421-6.Google Scholar
Guilhaumou, N., Szydlowski, N. and Pradier, B. (1990) Mineral. Mag. 54, this issue.Google Scholar
Hall, D. L., Sterner, S. M. and Bodnar, R. J. (1988) Econ. Geol. 83, 197-202.CrossRefGoogle Scholar
Hitchon, B. (1974) In Natural Gases in Marine Sediments (Kaplan, I. R., ed.) 195–225, Plenum Press N.Y. CrossRefGoogle Scholar
Kesler, S. E. (1977) Econ. Geol. 72, 204-18.CrossRefGoogle Scholar
McLimans, R. K. (1987) Appl. Geochem. 2, 585–604.CrossRefGoogle Scholar
Rankin, A. H. (1990) In 75 years of progress in oilfield science and technology (Ala, M. et al., eds.), Baljema Publishers, Rotterdam. In press.Google Scholar
Roedder, E. (1972) US Geol. Surv. Bull. 440-JJ.Google Scholar
Roedder, E. (1976) In Handbook of Stratabound and Stratiform Ore Deposits (Wolfe, K. H., ed.). Elsevier, Amsterdam, 4 (2), 67–110.Google Scholar
Roedder, E. (1984) Review in Mineralogy, 12, Min. Soc. Amer., 644 pages.Google Scholar
Shcheglov, A. D. (1969) Mem. Geol. Surv. Pakistan, 7, 12 pages.Google Scholar
Sillitoe, R. H. (1978) J. Geol. Soc. London, 135, 37-87.CrossRefGoogle Scholar
Sumner, C. G. (1954) Clayton's. The Theory of Emulsions, 5th Edition (J. A. Churchill Ltd, London), 669 pages.Google Scholar
Sverjensky, D. A. (1986) Ann. Rev. Earth Planet. Sci. 14, 17-99.CrossRefGoogle Scholar