Hostname: page-component-78c5997874-j824f Total loading time: 0 Render date: 2024-11-10T11:05:05.381Z Has data issue: false hasContentIssue false
  • English
  • Français

Geochemistry and Rb-Sr geochronology of Mesozoic granites from Hong Kong

Published online by Cambridge University Press:  03 November 2011

R. J. Sewell ,
D. P. F. Darbyshire ,
R. L. Langford  and
P. J. Strange
R. J. Sewell
Affiliation:
R. J. Sewell, Hong Kong Geological Survey, Geotechnical Engineering Office, 11/F Civil Engineering Building, 101 Princess Margaret Road, Homantin, Kowloon, Hong Kong
D. P. F. Darbyshire
Affiliation:
D. P. F. Darbyshire, NERC Isotope Geosciences Laboratory, Keyworth, Nottingham NG12 5GG., U.K
R. L. Langford
Affiliation:
R. L. Langford, Hong Kong Geological Survey, Geotechnical Engineering Office, 11/F Civil Engineering Building, 101 Princess Margaret Road, Homantin, Kowloon, Hong Kong
P. J. Strange
Affiliation:
P. J. Strange, British Geological Survey, Keyworth, Nottingham NG12 5GG, U.K
Get access Rights & Permissions [Opens in a new window]

Abstract

The granites of Hong Kong comprise a variety of assemblages dominated by chemically evolved compositions. They are divided into two suites based on petrographic, geochemical, and age criteria. The oldest and most primitive intrusive units are deformed biotite-hornblende granodiorites and monzogranites of the Lamma Suite. These rocks are characterised by high CaO (1·4-2·7%), and low Nb and Y contents. The Lion Rock Suite (LRS) is dominated by relatively undeformed monzogranite with subordinate quartz syenite and comprises three subgroups. Granites of subgroup I are separated into coarse- and fine- to medium-grained lithologies. The fine- to medium-grained granites are predominantly fluorite-bearing with silica contents ranging from 75·5-78%. They are characterised by high total REE, Ga, F, Rb, Nb, and Y contents and yield a Rb-Sr whole-rock isochron age of 155 ± 6 Ma with an initial 87Sr/86Sr ratio of 0·7101 ± 0·0060 (MSWD = 4·6). Granites of subgroup II comprise a diverse range of compositions (SiO2 = 63–77%) and are characterised by highly variable trace element abundances. Coarse-grained granites yield an age of 148 ± 9 Ma with an initial 87Sr/86Sr ratio of 0·7060 ± 0·0006 (MSWD = 0·1). Granites of subgroup III are moderately to highly evolved (SiO2 = 72·5-77·9%) and the silica-rich compositions are marked by enrichment in Y, Nb, Rb and depletion in Ba and Sr. Rb-Sr whole-rock isochron ages for individual plutons vary from 138 ± 1 to 136 ± 1 and corresponding initial 87Sr/86Sr ratios are 0·7080 ± 0·0002 (MSWD = 1·2) and 0·7092 ± 0·0006 (MSWD = 0·4). Granites of the Lamma Suite and coarse-grained granites of LRS subgroup I are interpreted as synorogenic I-types, whereas those of LRS subgroups II and III are interpreted as late-orogenic to postorogenic, fractionated I-types. Fineto medium-grained granites of LRS subgroup I have distinctive A-type affinities and together with their association with quartz syenite indicate a transition from compressional to tensional tectonics.

Keywords

Age datingA-typefluoritefractionatedgranodioriteisotopesI-typepetrologyS Chinasyenitetectonic setting
Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 83 , Issue 1-2: Second Hutton Symposium: The Origin of Granites and Related Rocks , 1992 , pp. 269 - 280
Copyright
Copyright © Royal Society of Edinburgh 1992

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

Addison, R. 1986. Geology of Sha Tin, 1:20000 Sheet 7. HONG KONG GEOL SURV MEM 1.Google Scholar
Allen, P. M. & Stephens, E. A. 1971. Report on the geological survey of Hong Kong. Hong Kong: Government PressGoogle Scholar
Brooks, C.Hart, S. R. & Wendt, I. 1972. Realistic use of two error regression treatment as applied to rubidium-strontium data. REV GEOPHYS SPACE PHYS 10, 551–57.CrossRefGoogle Scholar
Chappell, B. W. & White, A. J. R. 1974. Two contrasting granite types. PAC GEOL 8, 173–4.Google Scholar
Cobbing, E. J., Mallick, D. I. J., Pitfield, P. E. J. & Teoh, L. H. 1986. The granites of the Southeast Asian Tin Belt. J GEOL SOC LONDON 143, 537–50.CrossRefGoogle Scholar
Eby, G. N. 1990. The A-type granitoids: A review of their occurrence and chemical characteristics and speculations on their petrogenesis. In Woolley, A. R. & Ross, M. (eds) Alkaline igneous rocks and carbonatites. LITHOS 26, 115–34.CrossRefGoogle Scholar
Harris, N. B. W., Marzouki, F. M. H. & Ali, S. 1986. The label Sayid Complex, Arabian Shield: geochemical constraints on the origin of peralkaline and related granites. 1 GEOL SOC LONDON 143, 287–95.CrossRefGoogle Scholar
Huan, W.Shi, Z. & Yan, J. 1982. Meso-Cenozoic tectonic evolution of eastern China and adjacent area and movement of the Pacific plate. (Abstr.) SCI GEOL SINICA 2, 190.Google Scholar
Huang, C. C. 1978. An outline of the tectonic characteristics of China. ECLOGAE GEOL HELVETIAE 71, 611–35.Google Scholar
Jahn, B. M., Chen, P. Y. & Yen, T. P. 1976. Rb-Sr ages of granitic rocks in southeastern China and their tectonic significance. BULL GEOL SOC AM 86, 763–76.2.0.CO;2>CrossRefGoogle Scholar
Langford, R. L., Lai, K. W., Arthurton, R. S. & Shaw, R. 1989. Geology of the Western New Territories, 1:20 000 sheets 2, 5 and 6. HONG KONG GEOL SURV MEM 3.Google Scholar
Loiselle, M. C. & Wones, D. R. 1979. Characteristics and origin of anorogenic granites. GEOL SOC AM, ABSTR PROG 11, 468.Google Scholar
Miller, C. F. & Mittlefehldt, D. W. 1982. Depletion of light rare-earth elements in felsic magmas. GEOLOGY 10, 129–33.2.0.CO;2>CrossRefGoogle Scholar
Pankhurst, R. J. & O'Nions, R. K. 1973. Determination of Rb/Sr and 87Sr/86Sr ratios of some standard rocks and evaluation of X-ray spectrometry in Rb-Sr geochemistry. CHEM GEOL 12, 127–36.CrossRefGoogle Scholar
Pearce, J. A., Harris, N. B. W. & Tindle, A. G. 1984. Trace element discrimination diagrams for the tectonic interpretation of granitic rocks. J PETROL 25, 956–83.CrossRefGoogle Scholar
Pitfield, P. E. J., Teoh, L. H. & Cobbing, E. J. 1990. Textural variation and tin mineralization in granites from the Main Range Province of the Southeast Asian Tin Belt. GEOL J 25, 419–29.CrossRefGoogle Scholar
Sawka, W. N., Chappell, B. W. & Norrish, K. 1984. Light rare-earth-element zoning in sphene and allanite during granitoid fractionation. GEOLOGY 12, 131–34.2.0.CO;2>CrossRefGoogle Scholar
Sawka, W. N., Heizler, M. T., Kistler, R. W. & Chappell, B. W. 1990. Geochemistry of highly fractionated I- and S-type granites from the tin-tungsten province of western Tasmania. GEOL SOC AM SPEC PAP 246, 161–79.Google Scholar
Steiger, R. H. & Jager, E. 1977. Subcommission on geochronology; convention on the use of decay constants in geo- and cosmo-chronology. EARTH PLANET SCI LETT 36, 359–62.CrossRefGoogle Scholar
Strange, P. J. & Shaw, R. 1986. Geology of Hong Kong Island and Kowloon, 1:20000 sheets 11 and 15. HONG KONG GEOL SURV MEM 2.Google Scholar
Strange, P. J., Shaw, R. & Addison, R. 1990. Geology of Sai Kung and Clear Water Bay, 1:20 000 sheets 8, 12 and 16. HONG KONG GEOL SURV MEM 4.Google Scholar
Strange, P. J., Langford, R. L. & Sewell, R. J. 1991. Classification and nomenclature for Hong Kong granitoids. In Chappell, B. W. (ed.) Second Hutton Symposium on Granites and Related Rocks, Canberra 1991. BUR MIN RES, GEOL GEOPHYS REC 1991/25.Google Scholar
Walsh, J. N., Buckley, F. & Barker, J. 1981. The simultaneous determination of rare-earth elements in rocks using inductively coupled plasma source spectrometry. CHEM GEOL 33, 141–53.CrossRefGoogle Scholar
Whalen, J. B. 1983. The Ackley City Batholith, southeastern Newfoundland: evidence for crystal versus liquid-state fractionation. GEOCHIM COSMOCHIM ACTA 47, 1443–57.CrossRefGoogle Scholar
Whalen, J. B., Currie, K. L. & Chappell, B. W. 1987. A-type granites: geochemical characteristics, discrimination and petrogenesis. CONTRIB MINERAL PETROL 95, 407–19.CrossRefGoogle Scholar
Yang, Z.Cheng, Y. & Wang, , 1986. The geology of China, Oxford Monographs on Geology and Geophysics 3. Oxford: Clarendon Press.Google Scholar
York, D. 1969. Least squares fitting of a straight line with correlated errors. EARTH PLANET SCI LETT 5, 320–24.CrossRefGoogle Scholar