Mineral Deposits Studies Group Research Articles

Abstracts from the 2017–2018 Mineral Deposits Studies Group meeting

Abstracts from the 2017–2018 Mineral Deposits Studies Group meeting

Targeting VHMS mineralisation at Erayinia in the Archaean Yilgarn Craton, Western Australia: geochemical and hyperspectral halos

Mineral Deposits Studies Group Winter Meeting, University of Bristol, United Kingdom, 19-21 December 2016

Age and geochemistry of the Charlestown Group, Ireland: implications for the Grampian orogeny, its mineral potential and the Ordovician timescale

Mineral Deposits Studies Group Winter Meeting, University of Bristol, United Kingdom, 19-21 December 2016

Abstracts

s from the 38th Annual Winter Meeting of the Geological Society's Mineral Deposits Studies Group held on 18–19th December 2014 at the University of Southampton, UK. The meeting was organised by Dr Robert Knight from the University of Southampton.

Mineral Deposits Studies Group annual meeting, Leicester, January 2003: abstracts

Mineral Deposits Studies Group annual meeting, Leicester, January 2003: abstracts

Mineral Deposits Studies Group annual meeting, Southampton, January 2002: abstracts

Mineral Deposits Studies Group annual meeting, Southampton, January 2002: abstracts

Mineral Deposits Studies Group annual meeting, 1987

Report of a meeting of the Mineral Deposits Studies Group held on 14—15 December 1987, at the University of Newcastle upon Tyne. The meeting included a thematic session on the use of stable isotopes in ore genetic studies. In order to take advantage of the location, the annual meeting started with an excursion to visit sites of dolerite-associated mineralization within the North Pennine orefield, led by B. Young of the British Geological Survey. Thirty participants braved the seasonal weather for a most instructive day, and were joined later by a further seventy participants for the subsequent indoor activities of the conference. Details of the thematic session on Stable Isotopes in Ore Genetic Studies have already been given as part of the thematic set of papers published elsewhere in this issue. Other contributions covered a variety of topics. P. R. Ineson (University of Sheffield) reminded the audience of the importance of industrial minerals in his paper on sands which stressed the construction industry's need for good quality, salt-free, sand. Returning to base metals, D. A. C. Manning & E. 1. C. Rae (University of Newcastle upon Tyne) reported the results of experiments to determine the behaviour of Pb-rich feldspars during dissolution, which demonstrate that clastic feldspars within sediments are a significant potential source for Pb. The role of diagenetic processes in ore formation was examined further by M. C. Akhurst (University of Newcastle upon Tyne), who was able to place episodes of mineralization into the diagenetic sequence at Tynagh, and

Stable isotopes in ore genetic studies

A thematic session on the use of stable isotopes in the study of mineral deposits was held as part of the annual meeting of the Mineral Deposits Studies Group in Newcastle upon Tyne on 14th December 1987. Five of the papers presented at the meeting are published here, together with abstracts for six other contributions. The thematic session consisted of 15 papers, with invited contributions from D. T. Rickard and S. M. F. Sheppard. In order of presentation, S. H. Bottrell (University of Leeds) discussed the results of a stable isotope study of the Dolgellau black shale hosted gold mineralization, and demonstrated that the ore fluids were probably derived from an external igneous source, with considerable modification of isotope ratios by interaction with the host rock. P. Eakin (Queen's University of Belfast) then examined evidence for 13 C isotopic fractionation as a consequence of radioactivity within uraniferous hydrocarbons, comparing data for samples from the North Wales orefield with others from Scandinavia and South Africa. This study showed that fractionation effects in excess of 10% may be caused by this process, requiring caution when interpreting C isotope data for organic matter from uraniferous mineral deposits. The following two contributions introduced two recently developed techniques to those within the audience who were not specialist isotope geochemists. S. P. Kelley (with A. J. Boyce, A. E. Fallick, P. J. Hamilton and R. M. McIntyre; SURRC, East Kilbride) described the use of laser microprobe extraction techniques which allow small samples to be studied without the

Mineral Deposits Studies Group annual meeting, 1986

Report of a meeting of the Mineral Deposits Studies Group held on 15–16 December 1986, at the University of Southampton. The meeting included a thematic session on fluid inclusions which is reported elsewhere in this volume. Six presentations encompassed epithermal or volcanic-hosted precious-metal deposits and mineralized breccias. The Tambo deposit, near El Indio in Chile, was described by Bernard as a typical hot spring system with bedded sulphates, sulphate sinters, explosion breccias and native sulphur o sulphur overlying hydrothermal breccias and veins. Gold occurred as relatively coarse grains in the silicified wallrocks and also finely dispersed throughout barite. Mixing of ascending auriferous fluids with near-surface acid-sulphate waters was postulated to explain the mineral paragenesis. A similar mixing model was presented by Redwood to account for the disseminated and vein-type Au–Ag–Cu–Pb–Zn mineralization of the Altiplano in Bolivia. The mineralization was associated with silicic flow-dome complexes, and high-K calc-alkaline and shoshonitic magmatism; oxygen and hydrogen isotope data indicated an important magmatic input to the hydrothermal system. A silver-dominated vein-type mineralization comprising silver sulphosalts, native silver, argentite, minor sulphides, calcite, and baryte at Caracoles, northern Chile, was described by Fontbote, Schmidt & Flint, who emphasized the localization of high-grade ore at the intrusive contact between a porphyritic granite and bituminous siltstones and limestones. The role of decompressive shock and hydraulic decrepitation in the generation of hydrothermal breccias and lodes was reviewed by Halls & Allman-Ward. Mineralized hydromagmatic breccias of Hercynian age were identified as the source of the gold

Fluid inclusion studies

A thematic session on fluid inclusions was held on 15–16 December 1986, at the University of Southampton as part of the annual meeting of the Mineral Deposits Studies Group and was supported by the Applied Mineralogy Group of the Mineralogical Society. Four of the papers are published in this volume (referees: D. H. M. Alderton, A. V. Bromley, R. P. Foster, A. P. Gize, R. A. Ixer, N. J. Jackson, D. A. C. Manning and J. J. Wilkinson), and abstracts are presented for five other contributions. Providing as always an annual forum for the reporting and discussion of mineral deposits research, the 1986 meeting focused in part on fluid inclusion studies in metallogenesis. Opening the meeting, keynote speaker Roedder (Roedder and Howard) referred to a recent study of the Taolin Zn–Pb–fluorite deposit (People's Republic of China) in which homogenization temperatures of 120–200°C and salinity determinations of 0–14 wt% NaCl equiv. were more indicative of low-temperature epithermal mineralization than a Mississippi Valley-type deposit. Some of the data, particularly the homogenization data, differed significantly from the results of an earlier study and were used to emphasize the problems that can be encountered in fluid-inclusion studies. Particular reference was made to the stretching or decrepitation of earlier, lower-Th inclusions by later hotter fluids.later hotter fluids. In the more typical MW-type environment of the Illinois Fluorite District, petroleum-rich and aqueous inclusions were the subject of investigation by Gize and Richardson who observed that the petroleum phase was a strongly

Genesis of, and exploration for, industrial and ore minerals

Report of the 11th AGM of the Mineral Deposits Studies Group held in the Department of Applied Geology, University of Strathclyde, Scotland, 19–21 December 1985. The meeting titled 'Genesis of, and exploration for, industrial and ore minerals' was attended by 92 participants (from academia and industry) and included a field trip, 38 papers and several poster sessions. On the first day M. J. Russell and A. J. Hall led a field trip to Tyndrum where dumps, veins and wall rocks were examined in drizzle. A keynote address on Black Smokers and a video taken by submersible were given by John Edmond. He described hydrothermal activity on intermediate and fast spreading ridges in the Eastern Pacific. The fluids are of sea-water origin, acid (pH about 3) and with temperatures around 350 °C. Chloride is the only anion and H 2 S concentrations reach 300 ppm whereas Cu and Zn are usually between 1 and 5 ppm. While the metalliferous sediments are analogues to ophiolite-type massive sulphide ore bodies no active example has been found that remotely compares to them in size. Most of the ore-forming metals are lost as 'black smoke' and the ore localization mechanism is a puzzle. Hydrothermal fluids from the Gulf of California are alkaline, contain major ammonium and are depleted in ore metals possibly suggesting that a sediment-hosted massive sulphide deposit is forming at depths. Precipitation may be caused by reaction of the ore fluids with biogenic carbonate tests and with ammonia produced by the thermocatalytic breakdown of

Low-temperature mineralization

Report of the Mineral Deposits Studies Group Sixth Annual General Meeting held at St. Peter’s College, University of Aston in Birmingham, 17–19 September 1980. The Conference, ably organized by Dr R. A. Ixer with the co-operation of the University and the Department of Geological Sciences, to whom the Mineral Deposits Studies Group extend their thanks, was subdivided into 3 sections. The first day was devoted to a number of papers which covered varied aspects. Isotopic studies on the mineralization of the Ophir Valley, Colorado (Jackson), and the Ba-Zn deposit at Aberfeldy (Willan) were presented together with 2 papers on U mineralization in Namibia (Marlow and Clemmy). Ineson and Walters indicated the problems of correlating horizons and interpreting the attendant alteration associated with the igneous rocks in the South Pennine Orefield, while Alabaster & Pearce described the geological setting of the sulphide deposits in the Oman ophiolite complex. For this type of meeting, an unusual but interesting contribution by Broadbent et al. reviewed European Pb-Zn production and indicated recent research into new recovery processes for Pb, Zn and Cu as well as improving hydrometallurgical techniques. Well over 100 people attended the second day, and were no doubt attracted by a number of papers related to Permo-Triassic mineralization. A review of the Permo-Triassic rocks and related mineralization was given by Clarke who, in proposing new genetic models, caused some disquiet amongst the audience. On a more localized scale, isotopic evidence indicating possible inter-relationships was presented by Harwood & Coleman, while Turner &

Problems of mineralization associated with acid magmatism

The fifth annual conference and AGM of the Mineral Deposits Studies Group was held at the Uniuersity of Exeter on 13–15 December 1979 in conjunction with geologists working on the IGCP project 'Mineralization associated with acid magmatism' (MAWAM). It at- tracted about 100 participants from 20 counties.The meeting was organized by M . Stone, A. M . Euans and P. Garrard. In the context of magmatic evolution, Smith & Miller traced the path of Sn in the peraluminous Halifax pluton, Nova Scotia, showing that it concentrated initially in the silicate melt and eventually partitioned into aqueous hydrothermal fluid. Also in Nova Scotia, Chatterjee noted that the principal Sn mineralization was associated with para-intrusive granitoids and that cassiterite in albitized granites differed from that in greisenized granites. In Nigeria, Bowden & Kinnaird established that the economic elements concentrated in residual peralkaline fluids. Higher temperature fluids caused Nb mineralization and albitization, whereas lower temperature fluids (400–250°C) were associated with Sn-Zn mineralization and potassic alteration. Several papers concentrated almost entirely on hydrothermal fluids. Taylor & Fryer showed that the changing characteristics of the fluids could be monitored through the behaviour of the rare earth elements. They used an ion exchange and fluorescence technique that could produce 300–500 analyses per month. Haapala & Kinnunen classified the nature of fluids from data on inclusions. Norman & Trangcotchasan used a technique which yielded information on the pressure as well as the temperature of fluid inclusions and showed that salinity and CO 2 -content varied during the mineralizing period.

Dating mineralization

Report of the Mineral Deposits Studies Group Meeting held at Burlington House, 15 May 1979. The meeting was organized by Dr P. R. Ineson. The varied applications, advantages and disadvantages of Rb-Sr, K-Ar, U-Pb and Pb-Pb analytical dating techniques were outlined by the speakers. Beckinsale admitted that in the study of the tin granites of SE Asia, the Rb-Sr technique had not been directly applied to the elucidation of the mineralization. In describing the varied environmental, mineralogical and geochemical characteristics of the ‘I’ and ‘S’ types of granites, he noted that the mineralization was either of the finely disseminated type in greisenized hosts or pegmatite vein occurrences. The SE Asian granites had been involved in basinal structures which had undergone a number of re-heating phases. K-Ar isotopic geochronology on the granites had given excessively young ages. It was advanced, therefore, that Rb-Sr techniques were more applicable to dating the intrusion of the granites, while K-Ar techniques may elucidate re-setting events due to subsequent hydrothermal activity. Wilson reported various techniques which had been applied in order to date the uranium mineralization in northern Sweden. After outlining the general geological history of the Arjeplog–Arvidsjaur–Sorsele uranium province, he indicated that it was characterized by strong sodium metasomatism, development of skarn deposits and the presence of uranium and urano-titanites in both epigenetic and stratabound occurrences. U-Pb analyses on pure uraninite concentrates and whole-rock Pb-Pb dates had been used. The latter produced the most meaningful results, which were equated with the peak of

Teaching mineral deposit geology

T here has been a gradual trend during the last two decades towards the inclusion of more applied geology teaching in geology courses at British universities and polytechnics. This period has also seen the establishment of a number of applied geology degrees at both undergraduate and graduate levels. Clearly there is a new awareness in academic circles that all degree courses should contain a significant element of vocational training and the response of industry to the new applied courses indicates that they are filling a real need. It was therefore apposite that the Mineral Deposits Studies Group, in conjunction with the Earth Science Education Group, should organize a conference at which both industrial and academic geologists could take stock of the current situation in the teaching of mineral deposit geology. As an aid in this assessment, Taylor had circulated 50 departments with a questionnaire. This was kept simple to encourage replies, which had been received from 28 departments. It is impossible to tell whether or not these were mainly from those who had something positive to report, and therefore there may be a degree of bias in the returns. The substance of the replies is summarized in the abstract and indicates that there is still very little or no teaching of mineral deposit geology in some departments. One of the interesting and valuable trends which emerges from this inquiry is the increasing inclusion of time spent on industrial mineral deposits in undergraduate courses. This was reflected by Dixon and by Steed

Ore forming processes

THE MINERAL DEPOSITS STUDIES GROUP held its third residential conference at Sheffield University from 10 to 14 December 1977. Following two days' field excursions examining mineralization in northern Derbyshire twenty papers were presented by Group members. All but two were dominantly concerned with ore genesis and the majority of these dealt with deposits in the British Isles, four of them with Irish mineralization. A. M. Boast presented textural and isotopic evidence showing that much of the material, particularly the sulphur, of the Tynagh deposit was of synsedimentary origin. The weight of evidence for this and similar Irish ores undoubtedly suggests a very early time of deposition and M. J. Russell favoured a synsedimentary origin for all the larger Irish base metal deposits in the Lower Carboniferous. He discussed a mechanism whereby circulating sea water could have leached the metals from buried Lower Palaeozoic rocks. J. P. N. Badham put forward a fresh interpretation of the stratigraphy of the mineralized zones at Avoca and suggested that the stockwork feeder zone, a further possible orebody, has yet to be found. P. McArdle's work on Donegal base metal mineralization also suggests a revision of exploration philosophy in that he demonstrated that deposits in the Dalradian were originally of stratiform type. Rock alteration processes in two very different environments and their relationship to mineralization were discussed by five workers. D. H. M. Alderton presented an excellent documentation of wall rock alteration assemblages developed in the Cornish granites. He made considerable use of isotopic and

Current research on fluid inclusions and on mineral deposits

T he principal theme of this three-and-a-half-day conference (13–17 December 1976) at Durham University was the value of fluid inclusion studies in investigations into the origin of mineral deposits and rocks. Other sessions covered opaque mineralogy, studies on natural and synthetic sulphide systems and various other aspects of ore geology. For this conference the Mineral Deposits Studies Group joined forces with the Applied Mineralogy Group of the Mineralogical Society. There was also official participation by representatives from the Groupe Inclusions of the Société Française de Minéralogie et de Cristallographie and from C.N.R.S. centres at Paris and Nancy. Fluid inclusion papers were mainly concerned with studies of economic mineral deposits. It was stressed (Deicha) that they can now yield valuable data on the genesis of minerals formed over the full range of temperatures from magmatic (Althaus) to sedimentary (Sabouraud et al .). Four papers were concerned with fluid inclusions in fluorite. In one, P. J. Rogers showed that fluids in Derbyshire fluorites have similar salinities to those from the northern Pennine orefields, but a lower K/Na ratio. In another, F. W. Smith demonstrated how homogenization temperatures could be used to reconstruct the distribution of isothermal surfaces in veins so as to outline flow paths and calculate cooling gradients. There have been far too few intensive investigations of this sort on single veins. Such studies combined with Conolly diagrams could become important exploration tools and it is to be hoped that other workers will follow this lead. In work on other vein deposits