Evolution of a simple Island arc: The Lau-Tonga Ridge

G. H. Packham

doi:10.1071/EG978133

ISSN: 0812-3985
E-ISSN: 1834-7533

Evolution of a simple Island arc: The Lau-Tonga Ridge
Authors G. H. Packham^a
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^a Department of Geology & Geophysics, University of Sydney, , Sydney, , NSW, 2006
Publisher: Australian Society of Exploration Geophysicists
Source: Exploration Geophysics, Volume 9, Issue 3, Sep 1978, p. 133 - 140
DOI: https://doi.org/10.1071/EG978133
- Published online: 01 Sep 1978

Abstract

The Pacific Plate is being consumed under the Lau-Tonga Ridge down a subduction zone dipping at 45°. The trench inner wall has ultramafic rocks exposed, possibly within the accretionary wedge or prism. The fore-arc basin has a pre-Late Eocene basement overlain by 3-5 km of Late Eocene to Recent sediments. Plio-Pleistocene volcanics occur at the rear of the present fore-arc zone. The Lau basin was formed by rifting apart of the former Lau-Tonga Ridge between the fore-arc and the volcanic arc in the Early Pliocene, the Lau Ridge (the old volcanic arc) is capped by a line of volcanic piles certainly as old as Miocene but probably extending back to the Late Eocene. The size of the accumulated pile increases towards the north. The western flank of the Lau Ridge was built by a volcanic accumulation of over 3 km thickness on oceanic crust of the South Fiji Basin formed during the Ofigocene, This sea floor postdates the inception of arc volcanism. In the discussion it is suggested that (a) the region has had high heat flow since the volcanism started and most of the magma has come from the mantle wedge overlying the downgoing slab, (b) the volcanism was initiated in the Tonga region over a steeply dipping Benioff Zone, (c) the locus of volcanism moved rearwards during the Late Eocene as the dip of the Benioff Zone became gentler, (d) the crust of the region reached its present thickness by (i) addition of sediment to the Tonga Ridge after the first volcanic phase and volcanic activity on the Lau Ridge and (ii) intrusions into the deeper crust, (e) the crustal thickening by both processes increased to the north as subduction rates increased away from the Pacific-India plate poles of relative rotation.

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References

BARAZANGI, M., (SACKS, B., DUBOIS, J., and PASCAL, G., 1974. Seismic wave attenuation in the upper mantle beneath the southwest Pacific. Tectonophysics 24: 1-12
BURNS, R.E., ANDREWS, J.E., etal., 1973. Initial reports of the Deep Sea Drilling Project, 21. US Government Printing Office, Washington, DC.
COLEMAN, P.J., and PACKHAM, G.H., 1976. The Melanesian borderlands and India-Pacific Plates Boundary. Earth-Science Rev. 12: 197-233
EWART, A., and BRYAN, W.G., 1972. Petrography and geochemistry of the igneous rocks from ‘Eua, Tonga Islands. Geol. Soc. Am. Bull. 83: 3281-3298
EWART, A., and BRYAN, W.G., 1973. The Western Pacific: Island Arc, Marginal Seas, Geochemistry. Univ. W. Aust. Press, Perth, 503-522
FALVEY, O.A., 1978. Analysis of palaeomagnetic data from the New Hebrides. This issue.
FISHER, R.L., 1974. Pacific type continental margins. In C.A. Burk and C.L. Drake (Eds), The Geology of Continental Margins, Springer-Verlag, New York, 25-41
FISHER, R.L., and ENGEL, C.G., 1969. Ultramafic and basaltic rocks dredged from the nearshore flank of the Tonga Trench. Bull. Geol. Soc. Am. Bull. 80: 1373-1378
Gl LL, J.B., 1970. Geochemistry of Viti Levu, Fiji, and its evolution as an island arc. Contr. Mineral. Petrol. 27: 179-203
gill, J.B., 1976. Composition and age of Lau Basin and Ridge volcanic rocks: implications for evolution of an interarc basin and remnant arc. Geol. Soc. Am. Bull. 87: 1384-1395
GILL, J.B., and McDOUGALL, I., 1973. Biostratigraphic and geological significance of Miocene-Pliocene volcanism in Fiji. Nature 241: 176-180
green, D., and cullen, D.J., 1973. The tectonic evolution of the Fiji region. In P.J. Coleman (Ed.), The Western Pacific: Island Arcs, Marginal Seas, Geochemistry. Univ. W. Aust. Press, Perth, 127-145
HAYES, D.E., and EWING, M., 1971. The Louisville Ridge - A possible extension of the Eltanin fracture zone. Antarctic Res. Ser. 15, Biology of the Antarctic seas IV. J.L. Reid (Ed.), Am. Geophys. Union, 223-228
HAYES, D.E., HOUTZ, R., TALWANI, M., WATTS, A.B., WEISSEL, J., and AITKEN, T., 1975. Preliminary report of volume 23. USNS Eltanin, Cruises 33-38, March 1968-May 1969. Lamont-Doherty Survey of the World Ocean. M. Talwani (Ed.). 214 pp
HAWKINS, J.W., 1974. Geology of the Lau Basin, a marginal sea behind the Tonga Arc. In C.A. Burkand C.L. Drake (Eds), The Geology of Continental Margins, Springer-Verlag, New York, 505-520
HAWKINS, J.V., 1976. Petrology and geochemistry of basaltic rocks of the Lau Basin. Earth Planet. Sci. Lett. 28: 283-297
HOFFMEISTER, J.E., 1932. Geology of ‘Eua, Tonga. Bern. P. Bishop Mus. Honolulu, Bull. 96: 93 pp
ISACKS, B., OLIVER, J., and SYKES, L., 1968. Seismology and the new global tectonics. J. geophys. Res. 73: 5855-5900
JAMES, A. and FALVEY, D.A., 1978. Analysis of palaeomagnetic data from Viti Levu, Fiji. This issue
KARIG, D.E., and SHARMAN, G.F., 1975. Subduction and Accretion in Trenches. Geol, Soc. Am. Bull. 86: 377-389
KATZ, H.R., 1974. Margins of the southwest Pacific. In C.A. Burk and C.L. Drake (Eds), The Geology of Continental Margins, Springer-Verlag, New York, 549-564
KROENKE, L.W., and TONGILAVA, S.L., 1975. A Structural interpretation of two reflection profiles across the Tonga Arc. S. Pacif. Mar. Geol. Notes, Suva, 1: 9-15
LABRECQUE, J.L., KENT, D.V., and CANDE, S.C., 1977. Revised magnetic polarity time scale for Late Cretaceous and Cenozoic time. Geology 5: 330-335
LAPOUILLE, A., 1978. Southern New Hebrides Basin and western South Fiji Basin as a single marginal basin. This issue
MITCHELL A.H.G., and READING, H.G., 1971. Evolution of island arcs. J. Geol’. 79: 253-284
MITRONOVAS, W., ISACKS, B., and SEEBER, L., 1969. Earthquake locations and seismic wave propagation in the upper 250 km of the Tonga Arc. Bull, seismol. Soc. Am. 59: 1115-1137
PACKHAM, G.H., and terrill, a., 1975. Submarine Geology of the South Fiji Basin. In Andrews, J.E., Packham, G.H., et al., Initial Reports of the Deep Sea Drilling Project, 30, Washington, US Govt. Printing Office
ringwood, A.E., 1974. The petrological evolution of island arc systems, j. geol. Soc. Lond. 130: 183-204
RODDA, P., 1967. Outline of the geology of Viti Levu. NZ J. Geol. Geophys. 10: 1260-1273
RODDA, P., SNELLING, N.T., and REX, D.C., 1967. Radiometric age data on rocks from Viti Levu, Fiji. NZ J. Geol. Geophys. 10: 1248-1259
SHOR, G.G., KIRK, H.K., and MENARD, H.W., 1971. Crustal structure of the Melanesian Area. J. geophys. Res. 76: 2562-2586
STEARNS, H.T., 1971. Geologic setting of an Eocene fossil deposit on ‘Eua Island, Tonga. Geol. Soc. Am. Bull. 82: 2541-2552
TONGILAVA, S.L., and KROENKE, L.W., 1975. Oil prospecting in Tonga 1968-1974. S. Pacif. Mar. Geol. Notes, Suva 1: 1-8
WATTS, A.B., WEISSEL, J.K., and DAVEY, F.J., 1977. Tectonic evolution of the South Fiji marginal basin. In Talwani, M., and Pitman III, W.C. (Eds.), Island Arcs, Deepsea Trenches and Back-arc Basins. Am. Geophys. Un., Ewing Series, 1: 419-427
WEISSEL, J.K., WATTS, A.B., 1975. Tectonic complexities in the South Fiji marginal basin. Earth Planet. Sci. Lett. 28: 121-126

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Evolution of a simple Island arc: The Lau-Tonga Ridge

Abstract

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