New constraints on the source, composition, and post-emplacement modification of kimberlites from in situ C–O–Sr-isotope analyses of carbonates from the Benfontein sills (South Africa)

2020 ◽  
Vol 175 (4) ◽  
Author(s):  
Montgarri Castillo-Oliver ◽  
Andrea Giuliani ◽  
William L. Griffin ◽  
Suzanne Y. O’Reilly ◽  
Russell N. Drysdale ◽  
...  
Keyword(s):  
South Africa ◽  
Sr Isotope ◽  
Isotope Analyses

scholarly journals In situ Sr Isotope Compositions of Plagioclase from a Complete Stratigraphic Profile of the Bushveld Complex, South Africa: Evidence for Extensive Magma Mixing and Percolation

2017 ◽  
Vol 58 (11) ◽  
pp. 2285-2308 ◽  
Author(s):  
Bartosz T Karykowski ◽  
Sheng-Hong Yang ◽  
Wolfgang D Maier ◽  
Yann Lahaye ◽  
C Johan Lissenberg ◽  
...  
Keyword(s):  
South Africa ◽  
Bushveld Complex ◽  
Magma Mixing ◽  
Sr Isotope

scholarly journals In situ Sr isotope analyses by LA-MC-ICP-MS of igneous apatite and plagioclase from magmatic rocks at the CPGeo-USP

2016 ◽  
Vol 46 (suppl 1) ◽  
pp. 227-243
Author(s):  
Patricio Montecinos Munoz ◽  
Adriana Alves ◽  
Rogério Guitarrari Azzone ◽  
Pablo Cordenons ◽  
Sandra Morano ◽  
...  
Keyword(s):  
Magma Mixing ◽  
Successful Implementation ◽  
Geochemical Processes ◽  
Sr Isotope ◽  
Magmatic Rocks ◽  
Icp Ms ◽  
Isotope Analyses ◽  
Better Than

ABSTRACT: This contribution describes the successful implementation of in situ Sr isotope analyses by LA-MC-ICP-MS at the CPGeo-USP. The choice for an analytical configuration using measurements of half-masses allows the accurate assessment of lanthanide interferences, permitting the determination of Sr isotopes in important REE-rich accessory phases, such as apatite. Likewise, the on-peak-zero method effectively corrects the background contribution (both from Kr and residual Sr contributions from previous ablations) to the signals of the unknown samples. The analytical campaigns resulted in an accuracy, in respect to reference TIMS values, better than 57 ppm (~ ±0.000057 2σ SD) for a modern coral and the Batjberg clinopyroxene which impart significant quality to our data. Similarly, the majority of the stable Sr isotope ratios are close to the accepted values, which also confirms the effectiveness of the method. The achieved accuracy allows the identification and investigation of spatially-controlled isotopic heterogeneities on the micrometric scale in several Sr-rich minerals (apatite, carbonates, plagioclase, and clinopyroxene) with important implications to the understanding of relevant geochemical processes, particularly AFC, source geochemical heterogeneities and magma-mixing.

scholarly journals In Situ Fe and S isotope analyses in pyrite from the 3.2 Ga Mendon Formation (Barberton Greenstone Belt, South Africa): Evidence for early microbial iron reduction

Geobiology ◽  
2020 ◽  
Vol 18 (3) ◽  
pp. 306-325 ◽  
Author(s):  
Johanna Marin‐Carbonne ◽  
Vincent Busigny ◽  
Jennyfer Miot ◽  
Claire Rollion‐Bard ◽  
Elodie Muller ◽  
...  
Keyword(s):  
South Africa ◽  
Greenstone Belt ◽  
Iron Reduction ◽  
Barberton Greenstone Belt ◽  
Microbial Iron Reduction ◽  
Isotope Analyses ◽  
S Isotope

A geometallurgical characterization study of the Crystalkop Reef at the Great Noligwa Mine, Klerksdorp Goldfield, South Africa

2017 ◽  
Vol 120 (3) ◽  
pp. 303-322
Author(s):  
D. Pienaar ◽  
B.M. Guy ◽  
C. Pienaar ◽  
K.S. Viljoen
Keyword(s):  
South Africa ◽  
Treatment Plant ◽  
Processing Parameters ◽  
Processing Plant ◽  
Small Contribution ◽  
Gold Cyanide ◽  
Three Samples ◽  
Characterization Study ◽  
Different Sources

Abstract Mineralogical and textural variability of ores from different sources commonly leads to processing inefficiencies, particularly when a processing plant is designed to treat ore from a single source (i.e. ore of a relatively uniform composition). The bulk of the Witwatersrand ore in the Klerksdorp goldfield, processed at the AngloGold Ashanti Great Noligwa treatment plant, is derived from the Vaal Reef (>90%), with a comparatively small contribution obtained from the Crystalkop Reef (or C-Reef). Despite the uneven contribution, it is of critical importance to ensure that the processing parameters are optimized for the treatment of both the Vaal and C-Reefs. This paper serves to document the results of a geometallurgical study of the C-Reef at the Great Noligwa gold mine in the Klerksdorp goldfield of South Africa, with the primary aim of assessing the suitability of the processing parameters that are in use at the Great Noligwa plant. The paper also draws comparisons between the C-Reef and the Vaal Reef A-facies (Vaal Reef) and attempts to explain minor differences in the recovery of gold and uranium from these two sources. Three samples of the C-Reef were collected in-situ from the underground operations at Great Noligwa mine for mineralogical analyses and metallurgical tests. Laboratory-scale leach tests for gold (cyanide) and uranium (sulphuric acid) were carried out using dissolution conditions similar to that in use at the Great Noligwa plant, followed by further diagnostic leaching in the case of gold. The gold in the ore was found to be readily leachable with recoveries ranging from 95% to 97% (as opposed to 89% to 93% for the Vaal Reef). Additional recoveries were achieved in the presence of excess cyanide (96% to 98%). The recovery of uranium varied between 72% and 76% (as opposed to 30% to 64% for the Vaal Reef), which is substantially higher than predicted, given the amount of brannerite in the ore, which is generally regarded as refractory. Thus, the higher uranium recoveries from the C-Reef imply that a proportion of the uranium was recovered by the partial dissolution of brannerite. As the Vaal Reef contain high amounts of chlorite (3% to 8%), which is an important acid consumer, it is considered likely that this could have reduced the effectiveness of the H2SO4 leach in the case of the ore of the Vaal Reef. Since the gold and uranium recoveries from the C-Reef were higher than the recoveries from the Vaal Reef, the results demonstrate that the processing parameters used for treatment of the Vaal Reef are equally suited to the treatment of the C-Reef. Moreover, small processing modifications, such as increased milling and leach retention times, may well increase the recovery of gold (particularly when e.g. coarse gold, or unexposed gold, is present).

Rapid decomposition of geological samples by ammonium bifluoride (NH 4 HF 2 ) for combined Hf‐Nd‐Sr isotope analyses

2021 ◽  
Author(s):  
Gábor Újvári ◽  
Urs Klötzli ◽  
Monika Horschinegg ◽  
Wencke Wegner ◽  
Dorothee Hippler ◽  
...  
Keyword(s):  
Geological Samples ◽  
Sr Isotope ◽  
Rapid Decomposition ◽  
Ammonium Bifluoride ◽  
Isotope Analyses

Accuracy of laser-ablation (LA)-MC-ICPMS Sr isotope analysis of (bio)apatite – a problem reassessed

2016 ◽  
Vol 31 (1) ◽  
pp. 259-269 ◽  
Author(s):  
Wolfgang Müller ◽  
Robert Anczkiewicz
Keyword(s):  
Laser Ablation ◽  
Isotope Analysis ◽  
Sr Isotope ◽  
Plasma Laser ◽  
Interference Correction

Accurate in situ Sr isotope analysis of (bio)apatite via ‘robust-plasma’ laser-ablation MC-ICPMS with negligible 40Ca31P16O and reliable 87Rb interference correction.

scholarly journals Bottom temperature and in situ development of chokka squid eggs (Loligo vulgaris reynaudii) on mid-shelf spawning grounds, South Africa

2009 ◽  
Vol 66 (9) ◽  
pp. 1967-1971 ◽  
Author(s):  
Anè Oosthuizen ◽  
Mike J. Roberts
Keyword(s):  
South Africa ◽  
Bottom Temperature ◽  
Egg Development ◽  
Spawning Grounds ◽  
Loligo Vulgaris ◽  
Laboratory Results ◽  
Temperature Environment ◽  
Development Data ◽  
Shelf Temperature

Abstract Oosthuizen, A., and Roberts, M. J. 2009. Bottom temperature and in situ development of chokka squid eggs (Loligo vulgaris reynaudii) on mid-shelf spawning grounds, South Africa. – ICES Journal of Marine Science, 66: 1967–1971. The aim of the study was to test the development success of squid eggs on the mid-shelf (60–150 m deep) spawning grounds in relation to previous laboratory results, and to describe the mid-shelf temperature environment and how it could affect egg development. A series of in situ egg incubation experiments was conducted on the mid-shelf (∼119 m deep) spawning grounds using cages, temperature sensors, and acoustic releases for retrieval. Newly spawned eggs were collected by scuba, and continuous temperature data were collected at two points between the known inshore spawning grounds and the mid-shelf areas. Temperature variations followed a seasonal warming and cooling cycle, with superimposed peaks and troughs. Egg development data indicated that warm temperature peaks (10–13°C) are sufficient for normal development of eggs on the mid-shelf. Egg development time on the mid-shelf was 2–3 times longer (50–60 vs. 20–30 d) than inshore. The scarcity of abnormalities (0.45%) disputes previous laboratory results that suggested that ∼50% of eggs would suffer abnormalities in the colder mid-shelf temperature environment.

Review of High-Precision Sr Isotope Analyses of Low-Sr Geological Samples

2015 ◽  
Vol 26 (5) ◽  
pp. 763-774 ◽  
Author(s):  
Jie Lin ◽  
Yongsheng Liu ◽  
Haihong Chen ◽  
Lian Zhou ◽  
Zhaochu Hu ◽  
...  
Keyword(s):  
High Precision ◽  
Geological Samples ◽  
Sr Isotope ◽  
Isotope Analyses
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