摘要:

A new formation—Colville Formation—is proposed for newly discovered outcrops of Tertiary sedimentary rocks near Cape Colville, Coromandel Peninsula. Along with a small area previously mapped as Torehina Formation (Te Kuiti Group), the rocks are correlated with Waitemata Group of the Auckland region on the basis of fauna, lithologies, and conformity with overlying andesitic deposits of Beesons Island Volcanics. The correlation provides a link between the andesitic eruptions of West Auckland and the early volcanism of the Coromandel Peninsula.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10420286

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10420287

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Microfloras have been extracted from the Aztec Siltstone and Lashly Formation of the Beacon Valley area, Antarctica. On the basis of comparison with Australian occurrences a Frasnian age is suggested for the Aztec Siltstone assemblage and a probable Ladinian age is indicated for the Lashly Formation microfloras.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10420288

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Implications of Allan's redefinition (1933) of the Awamoan Stage are assessed using stratigraphic trends in the lineages ofHaeuslerella pukeuriensisParr andGlobigerinoides trilobus trilobus(Reuss) observed in the section at “Old Rifle Butts”, Oamaru.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10420289

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Potassium-argon dates determined on hornblendes from amphibolites in the regionally metamorphosed gneisses and schists of the Nimrod Group at the head of the Nimrod Glacier range in age from 500 to 1,050 m.y. The younger dates agree with previously determined K—Ar ages on micas and probably indicate reheating of the metamorphic terrane during emplacement of the Granite Harbour Intrusives in the Ordovician. Precambrian ages clustered between 1,000 and 1,050 m.y. probably date the end of the regional metamorphism that is termed Nimrod Orogeny and is the earliest event known to have affected the Transantarctic Mountains. An event at about the same time has been recognised on the continental margin of east Antarctica between 90° E and 130° E and in western Queen Maud Land. Elsewhere it has been overprinted with loss of radiogenic argon and strontium by later events, especially the 450–520 m.y. Ross Orogeny.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10420290

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The Waipapa Group of Permian-Jurassic age comprises a geosynclinal succession of lithic and feldspathic greywackes and argillites; cherts; and spilitic lavas. Low-grade metamorphism of these rocks has resulted in the development of a mineral assemblage characteristic of the prehnite-pumpellyite metagreywacke facies of Coombs (1960). The major detrital components of the greywackes are feldspar, quartz, lithic fragments, and a matrix. The composition of the greywackes is directly related to their grain size which in turn varies with bed thickness. The largely reconstituted matrix is considered of primary origin in massive, coarse-grained greywackes, but is in part secondary in most medium- and fine-grained rocks. The present study suggests that the conditions most conducive to the formation of a secondary matrix in metagreywackes are the presence of abundant labile detrital particles of fine sand-size, poor sorting, and low resistance of the rocks to shearing stresses. The sedimentary rocks represent a mixture of granitic and acid to intermediate volcanic detritus with a small contribution from a metamorphic source.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10420291

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Andesite volcanoes of the North Island of New Zealand are divided on the basis of their potash contents into two groups; a low potash group which includes the Northland, Coromandel, and Taupo Volcanic Zone andesites, and a high potash group which contains the volcanoes of western Taranaki. There are no significant differences among the chemistries of the low potash andesites from the different regions, leading to the proposition that they have a similar origin. It is suggested that an andesite “source zone” developed in the upper mantle beneath the old arcuate structure during Miocene time and has propagated eastwards across the North Island. The high potash andesites appear to be associated with events beneath the old arcuate structure rather than with the active margin of the east coast of the North Island. The chemistries of the New Zealand andesites are compared with analyses from other active regions and the invariance of the soda content is contrasted with the large potash variation.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10420292

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

The generaNotorotalia, Cribrorotalia, Discorotalia, andParrellinaare reviewed and their internal structure described. All are considered valid genera belonging within the subfamily Notorotaliinae. The North Pacific genusPolystomellinais considered to be a trochoidalElphidium, andPorosorotalia, from the Miocene of Kamchatka, is distinct fromCribrorotalia. The Notorotal iinae are not directly descended fromRotaliabut are possibly an offshoot from a form resemblingProtelphidiumorElphidiellawhich may have given rise toCribrorotaliafrom which the other genera of the Notorotaliinae appear to have descended.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10420293

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Four Waitotaran bathyal molluscan faunas are listed, from localities at Palliser Bay and south-east of Martinborough. Additions to the list of species from the Lake Ferry coral thicket are made.Scaphander flemingiMarwick,Parvamussiumaff.maoriumDell,Retusa oruaensis(Webster),Euthrenopsis venustaPowell,Friginatica amphiala(Watson), andPoroleda lanceolata(Hutton) are recorded from the beds, andTropbon murdochiMarwick is recorded and placed inTerefundus. New species ofLimopsis, Conominolia, andMioawateriaare described, and the status ofPelicaria mangaopariaVella is discussed.Austrofusus incertusKing is placed inBenthindsiaIredale, andMioawateriais classed as a full genus of the Daphnellinae.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10420294

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor

摘要:

Expressions are given for the gravitational potential and its first and second derivatives for a right circular cylinder. The formulae, involving infinite series of Legendre polynomials, are appropriate for the calculation of the gravitational and magnetic effects using an electronic computer.

ISSN:0028-8306    

DOI:10.1080/00288306.1969.10420295

出版商:Taylor & Francis Group    

年代:1969

数据来源: Taylor