摘要:

Well-sorted sandstone intrudes the Amuri Limestone at Hurunui River Mouth, North Canterbury. Some intrusions pierced the Limestone and extruded onto the seafloor between Lower Oligocene (?Whaingaroan) and uppermost Oligocene to Lower Miocene (?Waitakian to Otaian) time. The source bed for the diapiric complex is an Eocene sandstone which conformably underlies the Amuri Limestone in this area. Flow structures, commonly denned by concentrations of brecciated limestone fragments, are present in many intrusions. A sharp, planar, undeformed but gently tilted unconformity truncates the diapiric complex and is marked by a concentration of shallow subhorizontal burrows. A mixture of reworked phosphatised limestone clasts, locally derived from a post-Amuri disconformity, and unphosphatised limestone chips supplied by the sand diapir are present for several centimetres directly above the unconformity.

ISSN:0028-8306    

DOI:10.1080/00288306.1979.10424100

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Geological, geochemical, and mineralogical studies were carried out during a programme of base metal mineral exploration on a band of volcanic rocks intercalated within a flysch sequence of Cretaceous age (Mokoiwi Formation). The volcanics occur in the Tapuaeroa Valley—Te Kumi area, East Cape, New Zealand.

ISSN:0028-8306    

DOI:10.1080/00288306.1979.10424101

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Schist surrounding the scheelite-bearing Glenorchy Lode was analysed for Ni, Cu, Zn, As, Rb, Sr, Y, Zr, Nb, Sb, Cs, Ba, rare earth elements, W, Pb, Th, and U.

ISSN:0028-8306    

DOI:10.1080/00288306.1979.10424102

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

In the vicinity of the Broken Hills mine, flow-banded rhyolites are overlain by silicified rhyolite pyroclastics composed of fine to coarse pyroclastic-flow lapilli sheets and airfall ash and lapilli. Within the Broken Hills mine, epithermal subvolcanic gold-silver-selenium-arsenic mineralisation occurs in both fissure veins and in several breccia pipes. The grain size of the mineralisation is typically 50 μm or less. Some of the gold and silver is inferred to occur either as a solid solution with pyrite, or as submicroscopic inclusions of electrum within pyrite. Microprobe examination of the electrum shows that it is strongly zoned, with silver ranging from 25–64 weight percent, with the highest silver content observed on the outer margins of the electrum grains. Four previously undescribed gold-silver arsenic sulpho-selenides, and trechmannite (AgA5S2`), previously known only from Binnetal, Switzerland are described. Members of the acanthite-aguilarite-naumannite series are also present in association with the above minerals in the large breccia pipe and in the fissure veins in association with electrum. A depth of approximately 200 m is inferred for deposition within the veins, and for the breccia pipe, 60 m. The deposition of gold in the fissure veins and the breccia pipe involves the deposition of electrum in response to changes in the oxygen fugaciry, and boiling of the ascending hydrothermal solutions.

ISSN:0028-8306    

DOI:10.1080/00288306.1979.10424103

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Scallop Hill Formation was sampled at the northern end of Brown Peninsula, in the McMurdo Sound area, Antarctica. This paper describes the stratigraphy and age relationships, paleoecology, petrography, and genesis of the formation.

ISSN:0028-8306    

DOI:10.1080/00288306.1979.10424104

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Steam explosions ejecting country rock and lake-floor sediments from Rotomahana-Waimangu accompanied eruption of basaltic scoria from Tarawera Volcanic Complex during the early morning of 1886 June 10. The near-source Rotomahana ejecta displays wave-like internal bed forms typical of base surge eruption mechanisms. Deposition occurred from high velocity, steam-fluidised density currents, which carried ejecta laterally outwards from the base of a large vertical eruption column. The surges extended at least 6 km west of the source and passed over steep hills that rise to 350 m above the eruptive vents.

ISSN:0028-8306    

DOI:10.1080/00288306.1979.10424105

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

A large number of discrete planation levels, with a superimposed pattern of dominant levels, are identified in the Wellington City area of Port Nicholson. These dominant levels are related to marine terraces to the west of the harbour on the outer coast. Many of these planation surfaces, assumed to be marine terraces, are cut into Late Quaternary deposits which are found up to about 200 ft (61 m), but higher terraces are identified up to 582 ft (177 m) cut into basement greywacke. The pattern of dominant levels can be seen in a number of localities of Late Pleistocene age outside the area. There is a noticeable absence of levels between 61 m and 73 m. The data suggest a relatively stable Late Quaternary period between the earlier major folding along the Wellington Fault which formed the basin, and recent tectonic movements.

ISSN:0028-8306    

DOI:10.1080/00288306.1979.10424106

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The continental slope off the Canterbury Plains, New Zealand, is a progradational feature dissected by submarine canyons to the north and by submarine slides to the south.

ISSN:0028-8306    

DOI:10.1080/00288306.1979.10424107

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

A marine mid-Pleistocene invertebrate fauna is described from sediments 36–40 m below the sea floor at the site of the Maui-A development platform, Taranaki Bight.

ISSN:0028-8306    

DOI:10.1080/00288306.1979.10424108

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

ISSN:0028-8306    

DOI:10.1080/00288306.1979.10424109

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor