ISSN:0028-8306    

DOI:10.1080/00288306.1970.10428201

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The regional structure of the south-west Pacific is attributed to the spreading and segmentation by sub-crustal convection currents of a Paleozoic—Mesozoic geosynclinal belt marginal to the Australian craton, with migration of the separated sialic fragments northward and eastward into the Pacific Basin. The source of the convection currents presumably lay beneath the mid-ocean rises (Indian-Antarctic and Pacific-Antarctic Ridges) south of Australia and New Zealand.

ISSN:0028-8306    

DOI:10.1080/00288306.1970.10428202

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The transition in tectonic style from that of the Kertnadec island arc to that of continental crust in New Zealand has been ascribed, in global tectonic schemes, to the reduction of “shortening” rate as the pole of rotation between the Australian and Pacific crustal blocks is approached. However, the recognition of a west-facing island arc south of New Zealand and of widespread Quaternary crustal shortening within the New Zealand continental crust leads to the conclusion that the differing tectonic styles reflect instead the variation in mechanical response of oceanic and continental crust. The Alpine Fault is not considered to be a trench-trench transform because it parallels and co-exists with island arc features. Displacement of the early Tertiary Vening Meinesz fracture zone by the Alpine Fault indicates 70 km of late Tertiary-Quaternary horizontal motion along this fault. It is possible that the rest of the 500 km displacement along the South Island trace occurred during the late Mesozoic when the fault was a trench-trench transform between oppositely facing arcs in Northland and the Campbell Plateau.

ISSN:0028-8306    

DOI:10.1080/00288306.1970.10428203

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The activity and morphology of Fonualei, a dacitic volcanic island of the north Tonga group, are discussed.

ISSN:0028-8306    

DOI:10.1080/00288306.1970.10428204

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

A general survey of the sound-velocity structure of the South Pacific Ocean is presented. The type of variation of sound velocity with depth encountered depends on the area: antarctic, subantarctic, subtropical, and tropical velocity-depth profiles are defined. A major feature of the last three types of profile is the presence of aSOFARvelocity minimum between depths of 900 and 1,500 m. The actual depth of this minimum, together with other characteristics of the velocity structure, is affected by the South Pacific gyral and other anticyclonic eddies which are present in the Australasian area.

ISSN:0028-8306    

DOI:10.1080/00288306.1970.10428205

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The area west and south-west of Rakiraki, Fiji, is composed of basaltic and andesitic flows, fragmental and pillow lavas intruded by andesitic plugs, a gabbro pluton, and andesitic dikes. The area was a major volcanic centre in Pliocene-Pleistocene times. The stratigraphy and petrology are discussed.

ISSN:0028-8306    

DOI:10.1080/00288306.1970.10428206

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

In the north of New Caledonia glaucophane is found in a great variety of layered rocks ranging from metamorphosed shale with undeformed Cretaceous fossils high in the succession, to very coarsely crystalline gneisses of complex mesocopic structure, presumed to be deep in the succession. Lawsonite occurs in the finer-grained rocks of comparatively undeformed aspect. The metamorphism is probably Oligocene.

ISSN:0028-8306    

DOI:10.1080/00288306.1970.10428207

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Gravity and magnetic measurements from two profiles across the Derwent-Hunter Guyot in the Tasman Sea indicate that the volcanic core of the guyot is probably capped by vesicular volcanic rocks, and that the flanks are covered with a layer of sediments up to 2 – 5 km thick.

ISSN:0028-8306    

DOI:10.1080/00288306.1970.10428208

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The distribution of earthquakes and gravity anomalies in New Zealand are compared. Shocks classified as 12 km or less are more widespread than those classified as 33 km, but all crustal shocks are symmetrically disposed about the axis of the negative isostatic gravity anomalies. A minimum of seismicity occurs between the base of the crust and about 80 km depth which conflicts with the author's previous suggestion that low densities between these depths are associated with seismicity. The Benioff zone dips at 63° and high densities associated with this zone would be consistent with the positive gravity anomaly.

ISSN:0028-8306    

DOI:10.1080/00288306.1970.10428209

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The geology of New Caledonia, including lithology, stratigraphy, structure, and geomorphology, is summarised and compared with that of neighbouring islands in the Pacific, particularly New Zealand. Mineral deposits are not described.

ISSN:0028-8306    

DOI:10.1080/00288306.1970.10428210

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor