摘要:

A detailed account is given of plant microfossils recovered from shales and siltstones that represent three of the four Triassic formations developed in the vicinity of Poatina, north‐central Tasmania. The microfloral assemblages comprise 44 species of spores and pollen grains, of which nine species are described as new. The diagnosis ofLundbladisporaBalme is emended. Comparison with existing records of Australian and overseas Triassic microfloras indicates that at least the greater part of the Triassic is represented in the Poatina sequence, which has itself been regarded as the most complete development of the System in Tasmania. This work serves to emphasize the unique and potential value of palynology in the resolution of difficulties of correlation within the Tasmanian Triassic.

ISSN:0016-7614    

DOI:10.1080/00167616508728592

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor

摘要:

The occurrence of water in natural opaline silicas has been studied by differential thermal analysis, thermogravimetric analysis, infra‐red analysis and nuclear magnetic resonance. The results show that in the “crystalline” opals studied, some 90 per cent or more of the total water is physically adsorbed whereas in “amorphous” opals, at least 20 per cent but perhaps much more of the total water is held as hydroxyl groups chemically bonded to the silica surface. The rate of water loss on heating is also different, being chiefly controlled by the pore structure in “crystalline” opals but to a significant extent by the surface structure in “amorphous”.

ISSN:0016-7614    

DOI:10.1080/00167616508728593

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor

ISSN:0016-7614    

DOI:10.1080/00167616508728594

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor

摘要:

Goniomyasp. ind., andGoniomyasp. ind. aff.G. kasanensis(Geinitz), described by Diener (1903) from the Permian of the Central Himalayas, are shown to belong toUndulomya. Goniomya uhligiHoldhaus, 1913, thought by Holdhaus to be of Jurassic age, is also regarded as anUndulomyaand con‐specific with or closely related to the above species.Cosmomya egregariaHoldhaus, 1913, the type species ofCosmomyaHoldhaus, 1913, which comes from the same locality asUndulomya uhligi,is regarded as congeneric withPalaeocosmomyaFletcher, 1946.Palaeocosmomyatherefore, becomes a synonym ofCosmomya,but is retained at the subgeneric level. The evidence now available indicates thatUndulomya uhligiandCosmomya egregariaare of Late Permian age.

ISSN:0016-7614    

DOI:10.1080/00167616508728595

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor

摘要:

Christmas Island consists of an interbedded sequence of volcanic and carbonate rocks, mainly of Eocene and Miocene age. The volcanic rocks are successively more basic, varying from andesite to limburgite. The carbonate rocks are limestones and dolomites and are mainly of the reef‐wall and lagoonal facies. The phosphate deposits consist of three main mineral groups: apatite, barrandite and crandallite‐millisite. They are essentially superficial. Apatite occurs on irregular karrenfelder of carbonate rock and as secondary replacement deposits. Barrandite has formed by the supergene replacement of volcanic rocks. Crandallite and millisite occur in the lateritic profiles derived from apatite and barrandite and the weathering, in the presence of phosphate, of the carbonate and volcanic rocks.

ISSN:0016-7614    

DOI:10.1080/00167616508728596

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor

ISSN:0016-7614    

DOI:10.1080/00167616508728597

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor

摘要:

Potassium‐argon and rubidium‐strontium isotopic age measurements show that emplacement of granitic rocks in Tasmania occurred during the Late Devonian and Early Carboniferous and in pre‐Devonian times, possibly in the Cambrian. In addition, a Precambrian granite, dated at about 750 m.y., has been recognized on the west coast of King Island.

ISSN:0016-7614    

DOI:10.1080/00167616508728598

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor

摘要:

Detrital minerals in Recent sediments from the Sahul Shelf show a well‐defined distribution pattern which can be related to nearby river estuaries. Two major contrasting heavy mineral provinces are evident, characterized in turn by an unstable and a stable suite of minerals. A zone of relatively high feldspar content coincides with the unstable heavy mineral province. The source of the detrital grains is considered to be the dissected lateritic hinterland, and the depth of dissection in any area may determine whether stable or unstable minerals are supplied to the ocean.

ISSN:0016-7614    

DOI:10.1080/00167616508728599

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor

ISSN:0016-7614    

DOI:10.1080/00167616508728600

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor

ISSN:0016-7614    

DOI:10.1080/00167616508728601

出版商:Taylor & Francis Group    

年代:1965

数据来源: Taylor