The sandstone-hosted Beverley uranium Deposit, Lake Frome Basin, South Australia: Mineralogy, geochemistry, and a time-constrained model for its genesis

The sandstone-hosted Beverley uranium deposit is located in terrestrial sediments in the Lake Frome basin in the North Flinders Ranges, South Australia. The deposit is 13 km from the U-rich Mesoproterozoic basement of the Mount Painter inlier, which is being uplifted 100 to 200 m above the basin by neotectonic activity that probably initiated in the early Pliocene. The mineralization was deposited mainly in organic matter-poor Miocene lacustrine sands and partly in the underlying reductive strata comprising organic matter-rich clays and silts. The bulk of the mineralization consists of coffinite and/or uraninite nodules, growing around Co-rich pyrite with an S isotope composition (delta S-34 = 1.0 +/- 0.3 parts per thousand), suggestive of an early diagenetic lacustrine origin. In contrast, authigenic sulfides in the bulk of the sediments have a negative S isotope signature (delta S-34 ranges from -26.2 to -35.5 parts per thousand), indicative of an origin via bacterially mediated sulfate reduction. Minor amounts of Zn-bearing native copper and native lead also support the presence of specific, reducing microenvironments in the ore zone. Small amounts of carnotite are associated with the coffinite ore and also occur beneath a paleosoil horizon overlying the uranium deposit. Provenance studies suggest that the host Miocene sediments were derived from the reworking of Early Cretaceous glacial or glaciolacustrine sediments ultimately derived from Paleozoic terranes in eastern Australia. In contrast, the overlying Pliocene strata were in part derived from the Mesoproterozoic basement inlier. Mass-balance and geochemical data confirm that granites of the Mount Painter domain were the ultimate source of U and BEE at Beverley. U-Pb dating of coffinite and carnotite suggest that the U mineralization is Pliocene (6.7-3.4 Ma). The suitability of the Beverley deposit for efficient mining via in situ leaching, and hence its economic value, are determined by the nature of the hosting sand unit, which provides the permeability and low reactivity required for high fluid flow and low chemical consumption. These favorable sedimentologic and geometrical features result from a complex conjunction of factors, including deposition in lacustrine shore environment, reworking of angular sands of glacial origin, deep Pliocene weathering, and proximity to an active fault exposing extremely U rich rocks.

Denman-002 - A new CV3 chondrite from South Australia

Denman 002 is a new Australian carbonaceous chondrite. A single stone of 30 g was recovered in 1991 May near Fisher Station on the Trans Australian Railway, Nullarbor Plain, South Australia (30-degrees-36'S, 130-degrees-04'E). Texture, mineral and chemical composition indicate that it is a CV3 chondrite of oxidised subgroup with several similarities to Allende. It is composed of sharply defined chondrules, Ca-Al rich inclusions up to 3.5 mm across, olivine aggregates and fine-grained, nearly opaque matrix (40 vol%). Silicates are compositionally highly heterogeneous (olivine Fa: 0.2-45.6 mol%, PMD: 109.7). Denman 002 shows shock effects of stage S1 and weathering of category A

New Genetic and Linguistic Analyses Show Ancient Human Influence on Baobab Evolution and Distribution in Australia

This study investigates the role of human agency in the gene flow and geographical distribution of the Australian baobab, Adansonia gregorii. The genus Adansonia is a charismatic tree endemic to Africa, Madagascar, and northwest Australia that has long been valued by humans for its multiple uses. The distribution of genetic variation in baobabs in Africa has been partially attributed to human-mediated dispersal over millennia, but this relationship has never been investigated for the Australian species. We combined genetic and linguistic data to analyse geographic patterns of gene flow and movement of word-forms for A. gregorii in the Aboriginal languages of northwest Australia. Comprehensive assessment of genetic diversity showed weak geographic structure and high gene flow. Of potential dispersal vectors, humans were identified as most likely to have enabled gene flow across biogeographic barriers in northwest Australia. Genetic-linguistic analysis demonstrated congruence of gene flow patterns and directional movement of Aboriginal loanwords for A. gregorii. These findings, along with previous archaeobotanical evidence from the Late Pleistocene and Holocene, suggest that ancient humans significantly influenced the geographic distribution of Adansonia in northwest Australia.

Metal concentrations in soils around the copper smelter and surrounding industrial complex of Port Kembla, NSW, Australia

Anthropogenic emissions of metals from sources such as smelters are an international problem, but there is limited published information on emissions from Australian smelters. The objective of this study was to investigate the regional distribution of heavy metals in soils in the vicinity of the industrial complex of Port Kembla, NSW, Australia, which comprises a copper smelter, steelworks and associated industries. Soil samples (n=25) were collected at the depths of 0-5 and 5-20 cm, air dried and sieved to < 2 mm. Aqua regia extractable amounts of As, Cr, Cu, Ph and Zn were analysed by inductively coupled plasma mass spectrometry (lCP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES). Outliers were identified from background levels by statistical methods. Mean background levels at a depth of 0-5 cm were estimated at 3.2 mg/kg As, 12 mg/kg Cr, 49 mg/kg Cu, 20 mg/kg Ph and 42 mg/kg Zn. Outliers for elevated As and Cu values were mainly present within 4 km from the Port Kembla industrial complex, but high Ph at two sites and high Zn concentrations were found at six sites up to 23 km from Port Kembla. Chromium concentrations were not anomalous close to the industrial complex. There was no significant difference of metal concentrations at depths of 0-5 and 5-20 cm, except for Ph and Zn. Copper and As concentrations in the soils are probably related to the concentrations in the parent rock. From this investigation, the extent of the contamination emanating from the Port Kembla industrial complex is limited to 1-13 km, but most likely <4 km, depending on the element; the contamination at the greater distance may not originate from the industrial complex. (C) 2003 Elsevier B.V. All rights reserved.

La contrebasse : vaudeville en 1 acte / par M. Biéville...

Collection : La France dramatique au XIXe siècle

L'amour à l'aveuglette : vaudeville en 1 acte / par MM. Édouard Brisebarre et de Léris

Collection : La mosaïque ; n° 56