Hostname: page-component-cd9895bd7-gxg78 Total loading time: 0 Render date: 2024-12-27T22:54:53.108Z Has data issue: false hasContentIssue false
  • English
  • Français

Early Miocene extrusives and shallow intrusives from Small Nggela, Solomon Islands

Published online by Cambridge University Press:  01 May 2009

I. R. Plimer  and
G. Neef
I. R. Plimer
Affiliation:
University of New South Wales, W. S. & L. B. Robinson University College, P.O. Box 334, Broken Hill, N.S.W. 2880, Australia
G. Neef
Affiliation:
University of New South Wales, W. S. & L. B. Robinson University College, P.O. Box 334, Broken Hill, N.S.W. 2880, Australia
Get access Rights & Permissions [Opens in a new window]

Summary

Chemically similar altered gabbro, tholeiitic basalt, basaltic andesite and calc-alkaline rhyolite of Early Miocene age is present on Small Nggela, Solomon Islands. Large vesicles are invariably lacking from the autochthonous basaltic pillow lava which has narrow chilled margins, but clasts of allochthonous basalt present in coeval Early Miocene sediment are commonly vesicular. This suggests that the autochthonous lava was deposited in deep water (> 2.5 km) whereas the allochthonous lava was formed upslope in shallow water. A progressive increase in the tholeiite in Zr, Ti, K2O/(K2O+Na2O), Rb/Sr and K2O/Rb from N to S confirms that an Early Miocene southward-descending subduction zone, postulated by some authors, was present. Its recognition implies that the subduction zone did not migrate far during the Early Miocene.

Type
Articles
Information
Geological Magazine , Volume 117 , Issue 6 , November 1980 , pp. 565 - 578
Copyright
Copyright © Cambridge University Press 1980

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

ABEM. 1967. Report on an Airborne Geophysical Survey in the British Solomon Islands, 1965&1966. Stockholm: Aktiebolag Elektrisk Malmletning (two volumes).Google Scholar
Allum, J. A. E. 1967. Regional Photogeological Interpretation of the British Solomon Islands. United Nations special development program. Aerial geophysics survey project report. Honiara, B.S.I.P. Government Printer.Google Scholar
Berggren, W. A. & van Couvering, J. A. 1974. The Late Neogene: biostratigraphy, geochronology and paleoclimatology of the last 15 million years in marine and continental sequences. Palaeogeogr., Palaeoclimatol., Palaoeocol. 16 1–216.Google Scholar
Coleman, P. J. 1966. The Solomon Islands as an island arc. Nature, Lond. 211 1249–51.CrossRefGoogle Scholar
Coleman, P. J. 1976. A re-evaluation of the Solomon Islands as an arc system in Marine Geological Investigations in the Southwest Pacific and Adjacent Areas (ed. Glasby, G. P. & Katz, H. R.). Comm. Co-ord. Joint Props. Miner. Resour. Sth Pacif. Offshore areas (COOP/SOPAC), UN Econ. Social Commiss. Asia & Pacific. Tech. Bull. 2 134–40.Google Scholar
Coleman, P. J. & Packham, G. H. 1976. The Melanesian borderlands and India-Pacific plates boundary. Earth Science Reviews 12 197–233.CrossRefGoogle Scholar
Guppy, H. B. 1887. The Solomon Islands: their Geology, General Features and Suitability for Colonisation. London: Swann Sonnenschein, Lowrey and Co.Google Scholar
Hackman, B. D. 1973. The Solomon Islands fractured arc. In The Western Pacific: Island arcs, Marginal seas, Geochemistry (ed. Coleman, P. J.), pp. 179–91. Perth: University of Western Australia Press.Google Scholar
Halunen, J. A. & von Herzen, R. P. 1973. Heat flow in the western equatorial Pacific Ocean. J. Geophys. Res. 78 387–99.CrossRefGoogle Scholar
Hughes, C. W. & Turner, C. C. 1977. Upraised Pacific Ocean floor, southern Malaita, Solomon Islands. Bull. geol. Soc. Am. 88 412–424.2.0.CO;2>CrossRefGoogle Scholar
Jakes, P. & White, A. J. R. 1970. K/Rb ratios of rocks from island arcs. Geochem. Cosmochim. Acta 34 849–56.CrossRefGoogle Scholar
Jakes, P. & White, A. J. R. 1972. Major and trace element abundances in volcanic rocks of orogenic areas. Bull. geol. Soc. Am. 83 29–40.CrossRefGoogle Scholar
Karig, D. E. & Mammerickx, J. 1972. Tectonic framework of the New Hebrides Island arc. Marine Geol. 12 187–205.CrossRefGoogle Scholar
Karig, D. E. & Sharman, G. F. III 1975. Subduction and accretion in trenches. Bull. geol. Soc. Am. 86 377–89.2.0.CO;2>CrossRefGoogle Scholar
Kuno, H. 1966. Lateral variation of basaltic magma type across continental margins and island arcs. Bull. Volcanol. 29 195–222.CrossRefGoogle Scholar
Moore, J. G. 1965. Petrology of deep sea basalt near Hawaii. Am. Jour. Sci. 263 40–52.CrossRefGoogle Scholar
Neef, G. 1978. A convergent subduction model for the Solomon Islands. Aust. Soc. Explor. Geophys. Bull. 9, 99–103.CrossRefGoogle Scholar
Neef, G. 1979. Cenozoic stratigraphy of Small Nggela Island, Solomon Islands — early Miocene deposition in a fore arc basin followed by Pliocene patch reef deposition. N.Z. J. Geol. Geophysics 72 53–70.CrossRefGoogle Scholar
Neef, G. & McDougall, I. 1976. Potassium-argon ages on rocks from Small Nggela Island, British Solomon Islands. Pacific Geology II, 81–5.Google Scholar
Neef, G. & Plimer, I. R. 1979. Ophiolite complexes on Small Nggela Island, Solomon Islands. Bull. geol. Soc. Amer. 90 136–8.2.0.CO;2>CrossRefGoogle Scholar
Norrish, K. & Chappell, B. W. 1967. X-ray fluorescence spectrography. In Physical Methods of Determinative Mineralogy (ed. Zussman, J.), pp. 161–214. London: Academic Press.Google Scholar
Pearce, J. A. & Cann, J. R. 1973. Tectonic setting of basic volcanic rocks determined using trace element analyses. Earth Planet. Sci. Lett. 19 290–300.CrossRefGoogle Scholar
Ramsay, W. R. H. 1979. Crustal strain phenomena in the Solomon Islands, constraints from field evidence, and relationship to the India-Pacific Plate boundary. Abstr. 49th ANZAAS Congress, Auckland.Google Scholar
Reed, S. J. B. & Ware, N. G. 1975. Quantitative electron microprobe analysis of silicates using energy dispersive X-ray spectrometry. J. Petrology 16 499–519.CrossRefGoogle Scholar
Stanton, R. L. & Bell, J. D. 1969. Volcanic and associated rocks of the New Georgia Group, British Solomon Islands Protectorate. Overseas Geol. Miner. Resour. 10 113–45.Google Scholar
Stoiber, R. E. & Carr, M. J. 1971. Lithospheric plates, Benoiff zones and volcanoes. Bull. geol. Soc. Am. 82 515–22.Google Scholar
Taylor, G. R. 1974. Volcanogenic mineralisation in the islands of the Florida Group. Trans. Inst. Min. Metall. Section B 83, B120–B130.Google Scholar
Thompson, R. B. 1958. The geology of the Florida Group. Memoir Geol. Surv. Brit. Solomon Is. 2 97–101.Google Scholar
van Deventer, J. & Postuma, J. A. 1973. Early Cenomanian to Pliocene deep marine sediments from North Malaita, Solomon Islands. J. geol. Soc. Aust. 120 145–50.CrossRefGoogle Scholar
Walcott, R. I. 1978. Geodetic strains and large earthquakes in the axial tectonic belt of North Island, New Zealand. J. Geophys. Res. 83 4419–29.CrossRefGoogle Scholar
Warden, A. J., Mitchell, A. H. G., Espirat, J. J. & Quantin, R. 1967. The geology of the Central Islands. New Hebrides Condominium, Geol. Surv. Rep. 5.Google Scholar