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This blog will provide informal updates on the HiTech AlkCarb project, written by different researchers highlighting fieldwork, lab studies, conferences and Expert Council meetings. Keep track by following our Twitter account (@HiTech_AlkCarb) and sign up to our monthly newsletter.

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Fieldwork in the NW Scottish Highlands and Expert Council Three in Edinburgh

Participants (L to R) E. Deady, G. Gunn (both BGS) and H. Elliott (CSM) admiring fenite in the snow at Ledmore Marble Quarry.
All field trip participants at the UK’s only carbonatite on the shore of Loch Urigill.

The fantastic scenery of the Scottish Highlands is undoubtedly the best place to observe the large–scale geological processes that shaped Britain during and after the Caledonian Orogeny (Cambrian to Devonian). Eleven intrepid HiTech AlkCarb members and three expert councillors (Gus Gunn, BGS; Ian Parsons, University of Edinburgh; and Anatoly Zaitsev, St Petersburg State University), set out from Edinburgh in April to visit key localities for Scottish alkaline intrusive rocks.

Hosted by Kathryn Goodenough, Eimear Deady and Gus Gunn of the British Geological Survey, the aim of this fieldtrip was to investigate the possibility that the Loch Borralan Complex could be used as a plutonic analogue for volcanism observed during Expert Council One, in the Italian Apennines. Braving horizontal snow and high winds, the group visited a classic Moine Thrust locality at Knockan Crag. Walking up through the stratigraphy, Kathryn delivered a tectonic overview allowing everyone to orient themselves in the geological setting. Following a teashop stop and narrowly missing a ferocious hail storm, the team headed to Ledmore marble quarry, where pseudoleucite syenite and nepheline syenite bodies (the so-called ‘borolanite’) intruded dolostone. The resulting metasomatic reactions and breccia bodies were spectacular! Many samples and one broken rucksack later, the team went in search of (and eventually found) Alan Woolley’s fabled REE–enriched fenites within pseudoleucite syenites in a small waterfall described in his 1972 paper.

Well–rested and well–fed, the following day involved visiting the disused Allt a'Mhuilinn Quarry – the 'borolanite' type locality, before heading along a forestry track in search of 1980's excavations showing pyroxenite and nepheline syenite intruding quartzites. On the shores of Loch Urigill, the team visited the UK's only carbonatite, associated with the intrusion of the Loch Borralan pluton.

On route to the Loch Loyal Complex, the group engaged in some geo–tourism, visiting an Archaean layered mafic intrusion at Scourie More and the infamous Laxford Bridge road cutting. Arriving at Cnoc nan Cuilean on the shores of Loch Loyal, the team set to work finding the REE and Th enriched hydrothermal veins cutting syenites described by Hughes et al., 2013. Although the main exposure had collapsed into the waterfall, smaller veins and brilliant magma mingling textures were observed within the syenites and melasyenites.

Returning to Edinburgh, via the Edradour whiskey distillery, the fieldtrip gang were joined by consortium partners for a two–day Expert Council workshop at the Surgeons Hall. Experts in the fields of roof zone volatiles in carbonatites and alkaline rocks, in addition to sustainable mining were invited to present. Day one focused on roof zone volatiles, with overviews of current research being undertaken at two of our natural laboratories – Greenland, presented by postdoctoral researcher Will Hutchinson, and Kaiserstuhl, Germany delivered by postdoc Ben Walters. Our geophysical partner, Terratec Geoservices, delivered their latest update on the geophysical interpretation of surveys conducted at Kaiserstuhl during late 2016. The second day addressed the 'advancing sustainability' work package and saw several round table discussions. These pertained to the potential issues of mining carbonatites and alkaline complexes, and the information that can be provided by geologists to further sustainable development of potentially exploitable deposits.

Completing a fantastic week, a final bank holiday geologising day was spent at the well–exposed Elie Ness diatreme on the East Fife coastline. Here the remaining few sought the 'Elie Rubies', aka garnets within mantle xenoliths hosted in the diatreme fill.

Holly Elliott and Eimear Deady, May 2017

Airborne geophysical survey of the Kaiserstuhl complex and project presentation by  ”terratec

Talk of M. Tauchnitz (terratec) given at the DGG conference in Potsdam, Germany.
Interpreted model Resistivity section of Line_4 extracted from the 3D model.

The airborne magnetic and radiometric survey of the Kaiserstuhl Complex, one of the main natural labs for HiTech AlkCarb, has been completed by terratec geophysical services. 3600 line kilometres were flown and processing of the data is underway. Terratec would like to thank the team for the great work done and special thanks to Kai Naujokat from HTC Germany for flying this difficult survey.

In March 2017 Michael Tauchnitz (terratec) gave a talk with the title "Geophysical Investigation at the Central Carbonatite Complex Kaiserstuhl" at the German Geophysical Society (DGG) conference in Potsdam. The HiTech AlkCarb project, the test site of the central carbonatite complex in the Kaiserstuhl, the geophysical methods applied, and the preliminary results obtained were presented to the audience. The focus of the presentation was the joint data processing and 3D modelling/inversion of the high resolution near-surface and deep (approx. 300 m) Resistivity and Induced Polarization (IP) measurements. As a preliminary result, the interpreted model resistivity depth section of line_4 showing a good correlation to the known geology was shown and discussed.


Expert Council Two – Malawi – Fenite and Geophysics as Exploration Tools

View of the fenite breccia ring dyke from the central carbonatite at Tundulu.
Group photo of HiTech AlkCarb workshop attendees in gardens of Sunbird Kuchawe Hotel.
Monazite crystals (green) within dolomite carbonatite at Kangunkunde.
Small herd of elephants on the bank of the River Shire, Liwonde National Park.

The Chilwa Province, Malawi is famous for its early Cretaceous carbonatitic and alkaline volcanism in addition to excellent exposure of fenites (metasomatically altered rocks), providing a perfect destination for another HiTech AlkCarb Expert Council. Project partners from Mkango Resources Ltd, Alex Lemon and Will Dawes, teamed up with SoS RARE partner, Sam Broom–Fendley (Camborne School of Mines) to lead 50 expert geoscientists on fieldwork to six volcanic complexes. This was the largest geological research conference ever held in Malawi.

Lying at the southern end of the East African Rift, the Chilwa Alkaline Province displays a range of rocks including carbonatites, nepheline syenites and peralkaline granites in a Precambrian gneiss and granulite basement. The igneous complexes have been shallowly eroded, exposing intrusions and breccia above the magma chamber. Therefore the only way to understand deeper processes is to analyse surface exposures of intrusions and fenites or to use geophysical techniques.

After many attendees had journeyed over 48 hours, they showed their commitment listening to the first seminar session. Dr Alan Woolley, a world renowned carbonatite specialist, opened the talks introducing the geology of Malawi, followed by Sam Broom–Fendley acquainting us with Songwe Hill and Will Dawes (Mkango) providing an exploration company’s perspective on Malawi prospects.

The first site was Songwe Hill, the flagship deposit of Mkango Resources, visiting trenches which revealed an outcrop of synchysite–rich carbonatite named 'the tip of the iceberg' by the Mkango team. Fenite breccias and late stage REE rich carbonatite intrusions were also viewed on site followed by a rare opportunity to view Songwe halved drill core.

Although evenings were filled with seminar sessions, one day was spent at the hotel for talks regarding the workshop subject – geophysics and fenites. Pete Siegfried opened talks by discussing how geophysical techniques play a role in the search for and understanding of alkaline complexes. After lunch, the fenite session convened with talks from specialists such as Sven Dahlgren, who has conducted significant research on Fen, Norway – the fenite type site.

Our break from fieldwork was followed by a visit to Kangankunde. Upon arrival geologists reverted to kids, hammering boulders of monazite–bearing carbonatite to find shiny green monazite crystals. That afternoon, the team were privileged to visit the core shed of Mota–Engil and spent happy hours inspecting Tundulu breccias and intrusions. The phosphate mine at Tundulu was visited the next day, where an Optichem employee showed the group where apatite rich carbonatites were mined for fertilizer.

After the last field day, visiting Nkalonje's fenite breccias and carbonatite intrusions, the workshop attendees dressed up in their glad rags to attend the gala dinner. Starting off formally with speeches from Prof Frances Wall, Alex Lemon and the Honourable Bright Msaka SC (Minister for Natural Resources, Energy and Mining), the night ended with dancing along to Malawian music celebrity Lucius Banda.

Whilst the majority of the workshop delegation flew home on day 8, a small hard–core group of geologists remained on for a 10 day fenite sampling mission. After a much needed afternoon off hippo, elephant and crocodile spotting on the Shire River, the team re-visited and sampled each complex. Data produced from the 190 kg collected, will be fed into a HiTech AlkCarb geomodel of alkaline and carbonatite systems. Read a longer account of the trip.

Holly Elliott, November 2016


Greenland fieldwork July–August 2016

The University of St Andrews team in the field, including Adrian Finch (left), Nicola Horsburgh (middle) and Will Hutchison (right).
Roof zone of the Ilimaussaq intrusion. The contact between the layers of country rock (predominantly black units, dipping to the right of the image) and alkaline intrusion (light grey) is visible in the centre left.

In July and August 2016 members of the HiTech AlkCarb project team (from the University of St Andrews) visited the Gardar Province in South Greenland. The Gardar is an ancient rift zone that was volcanically and tectonically active between 1300 and 1100 million years ago. Although the province is no longer active, it is of major interest to geologists because the subsequent uplift and glacial erosion have cut deep into the rift and exposed the rocks and magma chambers that once lay well below the surface.

Magma that stalled at upper crustal levels in the Gardar rift evolved to very extreme compositions. This generated high concentrations of incompatible elements, including uranium, thorium, niobium and tantalum, in the tops of these magma chambers. As a result the Gardar Province hosts some of the world’s best mineralised magma bodies and our field work aimed to identify the roof zones of these alkaline complexes and understand more about the processes that concentrate the so–called 'rare–earth elements' (REE).

Our focus was the roof zones of the alkaline complexes Ilímaussaq and Motzfeldt. These complexes are only 50 km apart, host significant REE resources and yet their composition and magmatic evolution appears to be quite different. By comparing and contrasting these two unique complexes we wanted to understand whether or not the same underlying processes were taking place.

We were fortunate to have 5 weeks of glorious weather and this allowed spectacular views of the intrusions and detailed sampling surveys to be undertaken. We also had breathtaking views of the fjords, glaciers and mountain ranges of South Greenland. Intriguingly, despite the compositional differences between the Ilímaussaq and Motzfeldt complexes, we found that the magmatic processes taking place in the roof zones were very similar. In both cases we were able to identify sinuous alkaline dykes and sheets penetrating the country rock, and comparable chemical alteration textures were visible around the margins of each intrusion. We collected a range of geological samples and our next objective is to characterise rigorously their mineralogy and alteration using petrographic and microanalytical geochemical tools. We will develop a set of geochemical indicators for alkaline roof zones and use these new tools to evaluate other complexes in Europe (e.g., Kaiserstuhl, Germany) and understand whether or not these prospects might offer comparable REE resources to those in the Gardar.

HiTech AlkCarb – Expert Council One – Italy

June 15th saw the first expert council meeting of the HiTech AlkCarb team and associated expert council members. Attendees travelled from around the world to Italy to examine some examples of volcanic carbonatites and alkaline rocks, whilst being treated to Italian culture and food. The first expert council was convened to review the first five months work on the EU funded project and to focus on questions relating volcanic expressions of carbonatitic and alkaline rocks to the processes operating at depth.

Why Italy?

The group examining an outcrop at San Venanzo.

The Università degli Studi "G. d'Annunzio" Chieti–Pescara team are leading the research linking volcanic rocks to economic mineral–forming processes within the crust. The meeting aimed to bring the group together to see some examples of Italian carbonatites and alkaline rocks. We had two days in the field examining a phosphate–rich deposit that overlies a carbonatite, where a herd of cows seemed as interested in the rocks as we were. On day two of fieldwork we visited the volcanic complex at San Venanzo, and the diatremeic volcano at Polino. The fieldwork was complemented with plentiful, delicious Italian feasts and on the third day we arrived in Chieti ready for some serious discussions.

The village of Torrevecchia Teatina just outside the city of Chieti was the location for our presentation and discussion sessions. The morning session consisted of talks by team members on their research so far. The invited expert councilors (Marie Edmonds, Jock Harmer, Stefano Salvi, Tony Mariano Snr and Tony Marino Jnr) gave presentations on related aspects of the science or exploration as it currently stands. The afternoon was spent on 'sand–pit' discussions, which aimed to get us out of our comfort zones discussing a range of topics, with a range of different people from the group.

The fantastic trip was organized by Prof. Francesco Stoppa, Dr. Gianluigi Rosatelli and Dr. Andrea Tranquilli who brought together a mixture of geology, food and culture, leaving us all with very fond memories of Italy and stimulated to get back to the labs to continue our research.


The cows at Pianciano carbonatite and phosphate deposit. Photo courtesy of Alex Speiser.
Prof. Stoppa leads a discussion about the San Venanzo complex at a wall in the town which is built upon part of the pyroclastic material from one eruption.

Ground geophysics under way at Kaiserstuhl

Terratec have started the ground geophysical work at the Badberg location in the Kaiserstuhl, with two Electrical Resistivity Profiles looking down to approx.100 m. The data are very good quality, and promise well for the deeper investigations planned to start on the 25th of July. The terratec team was accompanied in the field by Björn Heincke from GEUS. As an outcome of this field work and the discussions we had, we will fine tune the future profiles and methodologies for ground geophysics. The airborne geophysical work is also under preparation.


Carrying out ground geophysics, Kaiserstuhl.
Carrying out ground geophysics, Kaiserstuhl.
Carrying out ground geophysics, Kaiserstuhl.


First meeting with the mayor of the Vogtsburg Gemeinde and heads of councils to introduce the anticipated scientific programme at the Kaiserstuhl alkaline-carbonatite volcano, Germany

View from Eichstetter viewing tower of the Badberg  (middle) and Haselschlachter Buck.

On 13 April 2016 the HiTech AlkCarb project team held a first meeting with the mayor and heads of local councils in Oberbergen at the Kaiserstuhl, Germany. During the meeting, partners of the project (from the University of Tübingen, terratec Geophysical Services GmbH & Co. KG, and A. Speiser Environmental Consultants) introduced the scientific programme and explained why we would like to work at the Kaiserstuhl.

The Kaiserstuhl alkaline-carbonatite volcano is an ideal project area in which to gain in-depth knowledge about how rare earth elements and other critical metals have become enriched in some volcanic rocks during the active volcanic phase. Over the past centuries plenty of scientific work has already been conducted, but now new and more advanced geophysical methods have been developed that will allow us to acquire more details during the project. This information will be used to meet the overall goal of developing new geo-models for international critical metal exploration programmes.

The initial fieldwork entails taking rock samples with a hammer from existing rock exposures and old quarries. Additionally, geophysical surveys will be conducted along tracks. The main focus of these activities will be at the centre of the Kaiserstuhl (Badberg and Ohrberg). This will be followed by an airborne survey during which magnetic and radiometric data will be collected using a helicopter. The area which will be investigated is approximately 12 x 12 km.

Finally, it is anticipated that a borehole will be drilled to obtain a continuous core of rock down to a depth of a few hundred metres. The final location can only be decided once the ground geophysical and airborne data have been analysed. The core will provide samples that we can analyse to study the enrichment of rare earth elements and other critical metals in the rocks at depth.

The mayor and heads of councils are very interested in this scientific research project. However, work can and will commence only once all necessary authorisation documents and permits have been obtained from the local government institutions. The mayor raised concerns following on from previous drilling in the area. Previously, in the village of Staufen, anhydrite layers started to expand after water leaked into that stratigraphic layer during and after drilling, resulting in damage to houses in the area. In Basel hydro-thermal drilling, where water was pumped into the borehole, resulted in some small earthquakes. We explained that the geology at the Kaiserstuhl is totally different to that in Staufen and Basel and that such issues should not occur at the Kaiserstuhl. Furthermore, we are only drilling to obtain a drill core and after further downhole measurements the hole will be sealed off. The University of Tübingen offered to provide a written statement stating that none of the above raised concerns will happen at the Kaiserstuhl. We mentioned that the only problem occurring during the drilling could be that we hit water. If so, we will take care of that and ensure that the borehole is sealed off correctly. Finally, the mayor asked us to provide him with proof of liability from the drilling company and with a long-term liability, which will be arranged by our project team.

To inform the wider public of the Kaiserstuhl area, the mayor suggested that we write a short notice for the local municipality newspaper in which we explain the project. This has been done and was placed in the edition of 22 April 2016.

Subsequently, the documents for the permit to conduct the initial geological fieldwork and geophysical surveys were submitted to the 'Landesbergdirektion' (relevant authority to grant such permits). On 27 April we received an answer that we can go ahead, as no permission needs to be granted in regard to the existing legislation, because the project is only for scientific work. Our geological research at the Kaiserstuhl will get underway in early summer 2016.

Alexandra Speiser 5 May 2016

HiTech AlkCarb kick–off meeting 22–23 Feb 2016 | Mission for Improved Mineral Exploration Underway!

The HiTech AlkCarb project kicked off in London, 22-23 February 2016, at the Natural History Museum. 29 participants attended the meeting, representing each of the 12 project partners. Special guest Michael Le Bas was also present, to guide and encourage improvements from his 1977 model, still considered the standard in understanding carbonatite complexes (see below).

Diagram of a carbonatite-alkaline rock complex (Le Bas 1977) based on observations in Kenya.

The project will:

  • Develop new geomodels to explore for 'hi-tech' raw associated with alkaline rocks and carbonatites, including exploration indicators to target mineralisation at depths to 1 km.
  • Improve and develop of geophysical and downhole exploration techniques.
  • Transfer into Europe expertise gained in African exploration.
  • Give Europe world-leading expertise in critical raw material exploration.

Day One was a project overview, with presentations from Frances Wall, the European Commission Officer, and work package leaders: Kathryn Goodenough (British Geological Survey), Pete Siegfried (Geo-Africa Prospecting Services), Klaus Brauch (Terratec Geophysical Services), and Alexandra Speiser (A. Speiser-Environmental Consultants). Plans for fieldwork this year in Greenland and Mongolia were discussed, as well as the first two Expert Council meetings, one in Italy in June 2016, and the second in Malawi in October.

The theme of Day Two was 'The Science' and started off with a review by Alan Woolley based on his series 'Alkaline Rocks and Carbonatites of the World', the most comprehensive catalogue available.

Presentations

Presentations and discussion then followed six key geological questions:

  • How can we predict what intrusive rocks are present at depth by using volcanic carbonatites and alkaline rocks exposed at the surface?
    Michael Marks and Gregor Markl
  • How can we relate mineralisation in shallow volcanic and sub-volcanic carbonatite and alkaline systems to predict richer deposits at depth?
    Gianluigi Rosatelli
  • How can we better understand the plumbing systems down to 1–2 km (the most important environment for mineralisation)?
    Jindŕich Kynický
  • Can we use the geochemistry and mineralogy of fenite (alteration around carbonatites and alkaline rocks) as an exploration indicator?
    Frances Wall and Holly Elliott
  • How can volatile elements in the roof zones of alkaline complexes (F, Cl, OH, S) be used to indicate if there is a prospective deposit below?
    Adrian Finch
  • Is the unusual element enrichment in scandium in carbonatites found at Glenover, RSA a potential economic resource?
    Pete Siegfried

The final presentation focused on the scientific research site in Germany. By acquiring new geophysical in combination with surface geological data, it will be the most detailed study ever of a carbonatite-alkaline complex.

HiTech AlkCarb kicks off at the Natural History Museum.

Dylan McFarlane 2 March 2016

@HiTech_AlkCarb