摘要:

Deposits of Lower Eocene low-grade swelling bentonite of marine origin are widespread in North Canterbury.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10431099

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Differentiation of these formulae with respect tozyields the higher vertical derivatives directly from the observed anomalies. The methods include allowance for local variations in the density of observation points, and are designed to prepare data for the drawing of contour maps on a uniform basis by mechanical means; of the two methods that of the exponential filter exhibits much greater numerical stability in handling irregularly distributed observations.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10431100

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Contouring gravity anomalies by digital plotter given values at points on a square grid is achieved by two-way polynomial interpolation so that the interpolated values fit exactly at the grid points. Contours are drawn for one grid square at a time using the 2n× 2narray of grid values surrounding the square. The method of polynomial interpolation is designed to ensure continuity in the gradients of the contours across the boundaries of each square.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10431101

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Bouguer and residual gravity anomaly maps of the Lower Awatere District are presented. The gravity measurements support the concept that dip-slip faulting during the upper Tertiary was followed by transcurrent faulting in the Quaternary. A structural contour map of the top of the Torlesse Group basement derived from the residual gravity anomalies shows that the upper Tertiary rocks in the Lower Awatere Valley lie in a shallow basin centred about 3 miles east of Seddon. Positive residual anomalies over Torlesse Group greywackes are interpreted as resulting from basic igneous intrusions at depths less than 2 miles.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10431102

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The present and suggested stage and substage divisions of the Wanganui Series are discussed and stratigraphic sections in Wanganui, Hawke' Bay, southern Waira-rapa, and North Canterbury are reviewed to determine the ranges of molluscs formerly used to define stages and substages. It is concluded that the Opoitian, Waipipian, Mangapanian, Nukumaruan, and Castlecliffian are recognisable stages, and the Okehuan and Putikian are recognisable substages of the Castlecliffian Stage.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10431103

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Rare fossils including the gastropodPeruvispiraaff.imbricataWaterhouse and the bivalveAtomodesmaaff.marwickiWaterhouse indicate a late Lower Permian age for the middle part of the Greenhills Group.Plerophyllumaff.timorenseGerth occurs in a lower horizon of the Greenhills Group. Bands of marble containing shell prisms, rare radiolarians, and other microfossils occur in the upper part of the section.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10431104

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The heat flow at 23 sites in the North Island of New Zealand was deduced from the geothermal gradients measured in drillholes and the thermal conductivities of the rocks penetrated. The flow is below normal to the south-east and above normal to the north-west of the active volcanic belt. Within and near this belt, zero geothermal gradients were measured, although the combined heat flow from the hydrothermal fields is known to be equivalent to a mean heat flow 20 times the normal value for the whole belt. The hydrothermal fields are regarded as narrow upflow zones in convectively circulated meteoric water systems. The zero geothermal gradients suggest that a large part of the whole volcanic belt and some areas immediately west of it provide the intake for these convective systems.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10431105

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

A modern accelerated erosion phase, post-dating the beginning of European-style farming in New Zealand, is associated with a depletion in the vegetation cover of Centre Creek catchment (Broken River area, South Island), and has caused substantial modification of streambed forms. An increase in the supply of debris to stream beds resulting from concentrated gullying, mass movement processes, and snow avalanche activity has caused (a) changes in the shape of the longitudinal profiles, (bl the formation of alluvial, valley bottom terraces, and (c) general widening and aggradation of the stream bed in the lower reaches. Some of the streambed processes operating in Centre Creek are briefly described.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10431106

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

A marine deposit has been discovered at 30 m above sea level near Cape Barne. A faunal analysis indicates that it was probably deposited in 180 m (100 fm) of water, and a C-14 determination indicates that it is approximately 35,000 yr old. This age places the time of deposition in one of the mid-Wiirm interstadials of Europe. It is concluded that this deposit has been elevated to its present position through isostatic rebound following the removal of an ice sheet which extended to at least 300 m above the present sea level.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10431107

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

New Zealand Permian stages are discussed. Two horizons are recognised below the lowest formally named stage, and the Braxtonian Stage is subdivided into the Barrettian and Flettian substages. Recent advances in the Permian geology of Siberia, and work by the writer on huge collections from the Canadian Arctic, reveal that the pattern of stages proposed for New Zealand also holds true for the Arctic realm. A visit to Tasmania confirmed that the stages can also be recognised there, including a very high Permian fauna in the upper Ferntree beds, equivalent to the New Zealand Waiitian Stage. The persistence over much of the world of brachiopod and bivalve horizons suggests that more stress should be given to these groups in attempting world correlations for the Permian, and therefore correlations for New Zealand stages are adjusted accordingly, bringing the stages into harmony with some fusuline and ammonoid evidence, but conflicting with the views of some workers on fusulinids and ammonoids. Most of the divergence in opinion concerns the relative position of the Kazanian and theCyclolobusammonoid zone. The Kazanian is here considered to be relatively low in the New Zealand Permian, and to be followed by three stages, not two as considered by Chao (1965), or one as considered by most ammonoid workers.Cyclolobusis also considered to come low in the upper Permian, and to be followed by two world-wide stages, instead of lying at the top of the Permian. The paleogeographic significance of New Zealand's similarity to Arctic realms is noted, with the suggestion that support is thereby added for continental displacement.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10431108

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor