Petrology of the New Hebrides

Colley, H.; Warden, A. J.

doi:10.1130/0016-7606(1974)85<1635:potnh>2.0.co;2

Cited by 42 publications

(16 citation statements)

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“…Tectonic factors include tectonic erosion of the lower trench slope by subduction and rifting of the fore-arc region parallel to the trench (Karig, 1974). Whatever the cause, the phenomenon is clearly not restricted to the Mariana fore-arc region, because similar geometries are found in the New Hebrides arc (Esperitu Santo and Malekula: Colley and Warden, 1974), the Tonga arc (Eua: Ewart and Bryan, 1972), the Bonin arc (Tsuya, 1937), and other arc systems.…”

Section: Discussionmentioning

confidence: 99%

Petrology of Volcanic Rocks from the Fore-Arc Sites

Meijer¹,

Anthony²,

Reagan³

1982

Initial Reports of the Deep Sea Drilling Project, 60

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Late Eocene and Oligocene submarine lavas recovered along the Mariana arc-trench slope appear to represent an early stage of arc volcanism along the Palau-Kyushu-Mariana trend. At Site 458, 90 km west of the Mariana Trench, the oldest lavas recovered were two pyroxene andesites with chemical and mineralogic characteristics generally associated with the arc tholeiite series. These are overlain by an unusual series of pyroxene (bronzite) andesites with relatively high Mg, Ni, and Cr and very low Ti, Zr, Y, and REE contents. Lavas with similar characteristics from the Bonin Islands have been called boninites. Because the Site 458 samples show a wider range of textures than is commonly attributed to boninites, the term "boninite series" is suggested for the purpose of discussion. These lavas probably derived from wet partial melting of very depleted mantle materials overlying the Palau-Kyushu-Mariana subduction zone. In Hole 459B, 50 km west of the trench, all the lavas recovered have the general chemical characteristics of arc tholeiite series andesites. Petrographically, volcanic cobbles recovered in sedimentary deposits on the lower trench slope at Sites 460 and 461 (Holes 460, 460A, 461, and 461 A) 23 and 11 km, respectively, from the trench axis are similar to Hole 459B lavas. Chemical data for samples from these sites are compatible with this association.All the volcanic rocks recovered show evidence of secondary alteration. Secondary minerals include clays, carbonate, zeolite, cristobalite, quartz, tridymite, celadonite, chlorite/clay, Fe-hydroxides, and other minor phases. In spite of the alteration, primary phases including pyroxenes, Plagioclase, Fe-Ti-oxides, and glass remain unaltered in some samples. This type of alteration is similar to that observed in typical seafloor volcanic sections in the major ocean basins. No evidence of high P, low T metamorphic conditions has been uncovered.The proximity of arc-related volcanic rocks to the trench axis is difficult to explain in terms of current models of subduction complexes. Possible causes include magma generation at shallow depths along the Eocene-Oligocene subduction zone and tectonic erosion of the lower trench slope.

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Section: Discussionmentioning

confidence: 99%

Petrology of Volcanic Rocks from the Fore-Arc Sites

Meijer¹,

Anthony²,

Reagan³

1982

Initial Reports of the Deep Sea Drilling Project, 60

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“…The Central Chain of the Vanuatu island arc is predominantly composed of volcanic rocks with ages from Late Miocene -Early Pliocene up to the present (Coleman 1970;Colley & Warden 1974). We interpret the formation of the majority of volcanic islands of the Central Chain to be spatially and genetically connected with subduction V1.…”

Section: Geological Evidence Of Cyclic Character Of Subductionmentioning

confidence: 79%

“…This fracturing might play the role of feeding channels for the Late Eocene-Middle Miocene age volcanism of the Eastern Belt, and may also be responsible for the limited occurrence of ultrabasic rocks on Pentecost. The proposed mode of emplacement could influence the tholeiitic composition of volcanic rocks in the Eastern Belt, differing from the coeval calcalkaline suite of the Western Belt (Colley & Warden 1974). The fracturing could govern the basalt volcanism of the Eastern Belt from Late Miocene -Early Pliocene, that is, by the cessation of calcalkaline volcanic activity in the Vanuatu island arc.…”

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confidence: 97%

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Deep structure of the Vanuatu (New Hebrides) island arc: Intermediate depth collision of subducted lithospheric plates

Hanuš

Vaněk

1983

New Zealand Journal of Geology and Geophysics

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The distribution of earthquake foci in the Vanuatu region is interpreted as a result of the intermediate depth collision of 2 differently inclined lithospheric slabs produced by 2 consecutive subduction cycles of the same polarity. A correlation between the depth of penetration of the presently active subduction zone and the major physiographic units of the ocean floor implies a nonuniform rate of subduction along the New Hebrides trench due to the hampering effect of the main structural features of the subducting Australian plate. Two subduction cycles accompanied by fracturing in the basement of the archipelago can explain the formation of 3 belts of islands of the Vanuatu Archipelago. The well-investigated geology of the region allowed us to correlate the successive stages of the subduction process with the geological evolution of the Vanuatu island arc.

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“…All volcanic assemblages of Vanuatu and the eastern Solomon outliers, erupted both before and after polarity reversal that gave birth to the New Hebrides island arc from the precursor Vitiaz island arc, display geochemical and petrological signatures characteristic of arc volcanism (Colley and Warden, 1974;Dupuy et al, 1982). Andesitic rocks are dominant, but the full eruptive suite ranges petrologically from basalt to dacite.…”

Section: Geologic Contextmentioning

confidence: 99%

Petrography and geologic provenance of sand tempers in prehistoric potsherds from Fiji and Vanuatu, South Pacific

Dickinson

2001

Geoarchaeology

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Petrology of the New Hebrides

Cited by 42 publications

References 0 publications

Petrology of Volcanic Rocks from the Fore-Arc Sites

Petrology of Volcanic Rocks from the Fore-Arc Sites

Deep structure of the Vanuatu (New Hebrides) island arc: Intermediate depth collision of subducted lithospheric plates

Petrography and geologic provenance of sand tempers in prehistoric potsherds from Fiji and Vanuatu, South Pacific

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