Geological Survey of Denmark and Greenland Bulletin 33, 2015, 53-56 53 Follow-up on Ujarassiorit mineral hunt finds and outreach activities, South-East Greenland Majken D. Poulsen, Holger Paulick, Diogo Rosa, Vincent J. van Hinsberg, Jonas Petersen and Lærke L. Thomsen In connection with fi eld work in South-East Greenland in 2014, we took the opportunity to examine the geology as- sociated with potentially valuable mineral occurrences found by local rock collectors. Th e initial fi nds were made by local collectors as part of Ujarassiorit, which is an annual mineral hunt competition where anyone in Greenland can submit samples of rocks they have found i n the countryside for closer examination by the Ministry of Mineral Resources (see www.ujarassiorit.gl). In the Tasiilaq region, Ujarassiorit resulted in fi nds of corundum, precious metal and base-metal mineral occurrences. Our intention was to locate the original sample sites with help from the local rock collectors, describe the geological context and assess the potential for mineral exploration. Further work will include laboratory analyses of rock samples and geological reporting. Since the base camp in 2014 was located in the settlement Kuummiut, we made an eff ort to engage the local people in outreach activities. Th e aim was to explain what type of work geologists conduct and how diff erent rocks and minerals can be distinguished. We also visited adjacent communities where the idea was to develop local fi eld guides for teachers, interested citizens and tourists. Fig. 1. Geological map of the Tasiilaq area in South-East Greenland, modified from Escher (1990) and Kolb (2014). © 2015 GEUS. Geological Survey of Denmark and Greenland Bulletin 33, 53–56. Open access: www.geus.dk/publications/bull Ice Quaternary Isertoq Terrane Gabbro (c. 1.7 Ga) Norite, gabbro, diorite, granodiorite (c. 1.85 Ga) Contact metamorphic anatectic gneiss Granite, granodiorite, diorite (c. 1.7 Ga) Orthogneiss (Isertoq) Orthogneiss (+opx) Amphibolite, ultramafic and meta- sedimentary rocks Isertoq unit (≤1.91 Ga) Ammassalik Intrusive Complex Marble Diorite, tonalite (2.2–1.9 Ga) Kuummiut Terrane Brown orthogneiss Meta-anorthosite/-leucogabbro Ivnartivaq Complex (1.955 Ga) Orthogneiss, migmatitic (c. 2.8–3.0 Ga) Amphibolite Kuummiut unit (<2.2–2.1 Ga) Helheim unit (>1.9; < 2.2 Ga) Schweizerland Terrane Ultramafic rock Amphibolite Ujarassiorit locality Greenland 38°W 66°N 65°30´N 38°W 37°W 36°W Se rm ilik 25 km Marble belt Tonalite belt Qiianarteq Sermiligaaq Schweizerland Terrane Nordfjord Kuummiut Aappaluttoq Tasiilaq Kulusuk Tiniteqilaaq Nattivit Isortoq Isertoq Terrane Ammassalik Intrusive Complex Kuummiut Terrane Inland Ice Kangertittivatsiaq 5454 Precious metal mineral occurrence north of Tasiilaq During fi eld work, the winner of two Ujarassiorit prizes, Wil- liam Umerineq from Kuummiut, showed the fi eld team the locations of his winning samples. One sample was described by the Ujarassiorit jury as a sulphide-bearing, garnet-rich am- phibolite rich in platinum-group elements, cobalt and copper; it was collected at Ilitti close to Nordfj ord at the outer part of Kangertittivatsiaq (Fig. 1). Th e rock contains 44.5% Fe, >1% Cu, 5280 ppm Ni, 2340 ppm Co, 804 ppb Au and 284 ppm Pd. Th e other sample was collected near Aappaluttoq in the fj ord of Sermilik; it had been described as a graphite and garnet gneiss and it had a gold content of 11.1 ppm. At the Ilitti locality, a pegmatite lens with coarse-grained calcite was found during fi eld work (Fig. 2A). Th e origin of the calcite is uncertain; it could come from marble remnants within the host gneiss, from a carbonatite occurrence or it could be of hydrothermal origin. Epidote and actinolite- bearing, calc-silicate assemblages developed along the con- tact between calcite and the pegmatite, and small sulphide pods are found locally. Such a sulphide pod submitted to the Ujarassiorit was confi rmed to be rich in precious metals, co- balt and copper during our follow-up work. At Aappaluttoq, the rock collector William Umerineq showed us a garnet-rich (garnetite) horizon (Fig. 2B). Th is horizon seems to belong to one of several discontinuous and foliation-concordant, garnet-rich bodies that are pres- ent within yellow-weathering, graphitic mica schist. Th ese garnet-rich bodies are probably boudins that formed due to deformation of the garnet-rich rock or its precursor. In some areas, these bodies are closely related to subhorizontal peg- matite sheets, which were also dismembered into boudins. No sulphides were identifi ed in these garnet-rich bodies during fi eld work. However, since Umerineq’s sample was very similar in appearance to the garnet-rich bodies that we found, we undertook an extensive sampling eff ort in the area. Other samples were collected from silicifi ed domains, veins and veinlets that contain sulphides or gossanised ma- terial. Laboratory analyses failed to confi rm the presence of A B C D E F Fig. 2. A: William Umerineq (to the left) at the location where he collected a prize-winning Ujarassiorit sample at Ilitti in the Kangertittivat- siaq fjord area. B: William Umerineq standing above the shoreline where he collected another prize-winning, gold-rich Ujarassiorit sample near Aappaluttoq. The locality is only accessible at low tide. C: William Umerineq panning stream sediments to separate possible gold grains on the island of Qiianarteq. D: In the Isortoq area, Dines and Rosa Jonathansen (first and second from left) took the field team to several of the sites where they had collected rock samples for the Ujarassiorit competition. E: The corun- dum locality was found with help from Vittus Sakæussen, the 2009 Ujarassiorit prize-winner. The geologists are examining ultramafic rocks containing veins with pink corundum; Vittus Sakæussen is sitting on the ultramafic rock and a light pinkish granitic pegmatite is seen between them. The vein in the ultramafic rock shows several progressive reaction zones. F: Biotite, amphibole and pink corundum were formed during the final stages in the development of the metasomatic vein. 55 gold in the garnet-rich rock, but anomalous gold values (up to 463 ppb) were recorded in a few of the veins and veinlets. Th is indicates that the original Ujarassiorit sample might also have included such a vein or veinlet and that nugget- eff ects could account for the diff erences in gold concentra- tion between that sample and the ones collected during the follow-up in 2014. Th e collectors of additional Ujarassiorit samples from 1993, 1999 and 2007 with high gold concentrations could not be contacted or accompany us to help locate their sample sites. Th e fi rst two samples were erratics whereas the third was in situ, but its precise location is unknown. In order to follow up on these samples, gold panning was carried out in areas with large drainage basins on the island of Qiianarteq and on the adjacent peninsula north of Qiianarteq (Fig. 2C). How- ever, the panning eff ort failed to show any signifi cant gold. Follow-up on copper mineral occurrences in the Isortoq archipelago Th e area around the settlement of Isortoq is characterised by an archipelago consisting of banded gneiss with amphibolite bodies hosting granite intrusions. Pegmatite dykes and quartz veins are also common. Th e fi eld work focused on visiting is- lands and localities with reported copper mineral occurrences (up to 1.9% Cu) in order to describe the geological setting and assess the potential of these occurrences. Samples from these localities were submitted to Ujarassiorit between 1990 and 2012. Some of the sites were visited with the rock collectors, Dines and Rosa Jonathansen (Fig. 2D), and this proved to be a good approach to explore several sites in a time-effi cient way. We observed a number of diff erent styles of sulphide oc- currences in the area: (1) amphibolite with late-stage brit- tle fractures with quartz, epidote and pyrite with malachite staining, (2) pyrite within quartz veins, (3) pyrite-chalco- pyrite dissemination or veins within pegmatite dykes, (4) sulphide-bearing granitic or gabbroic boudins within banded gneiss, (5) disseminated sulphide in banded gneiss and (6) rounded boulders of sulphide-bearing gabbro in a moraine close to the margin of the Inland Ice. A soapstone occurrence was also identifi ed that is apparently used by local craft smen as raw material for their work. Overall, the fi eld work showed that the known sulphide occurrences are small and commonly lack signs of large-scale hydrothermal alteration. Where sulphide occurrences were encountered the visual estimates of pyrite and chalcopyrite concentrations are commonly around 1–2 vol.%. Hence, our fi eld work gave little encouragement for additional eff orts to explore for economically signifi cant copper deposits in the area. Follow-up on a corundum sample from the Ujarassiorit prize-winner in 2009 Several occurrences of corundum (Al2O3) were investigated, and we focused our eff ort on an occurrence on a small island off Immikkeerteq near Nattivit (Fig. 1). Th is corundum lo- cality was visited with the help of the rock collector Vittus Sakæussen, who initially found it and won the fi rst prize in the 2009 Ujarassiorit competition. A preliminary under- standing of the formation history of the Nattivit occurrence allowed the fi eld team to identify a number of additional co- rundum occurrences. All occurrences share the same characteristics: corun- dum occurs where late-stage felsic pegmatites crosscut and interact with metamorphosed ultramafi c rocks (Fig. 2E). A progressive metasomatic change of the pegmatite took place at the contact with the ultramafi c body, where progressive subsequently varying mineral zones developed with more and more silica-depleted bulk compositions culminating in a biotite zone, followed by a zone with black amphibole and pink corundum at the centre (Fig. 2F). Th is sequence of min- eral zoning was found as a concentric arrangement along the length of the pegmatite dyke with successively increasing de- velopment as the dyke protrudes farther into the metamor- phosed ultramafi c rock. Th e corundum crystals are generally large (locally up to 5 cm in diameter) and anhedral with min- imal fracturing. Th is mode of occurrence as isolated, large grains suggests that metasomatic replacement took place un- der conditions where element mobility was high. Th e source of the aluminium appears to be plagioclase in the pegmatite with removal of silica by interaction with the ultramafi c rock which ultimately led to Al2O3 saturation. Th e process of formation is local and linked to element exchange between ultramafi c rocks and late-stage pegmatite dykes. Both these lithologies are common throughout the fi eld area, and metasomatic reaction zones between them are ubiquitous. However, most of the reaction zones only devel- oped biotite, without black amphibole or corundum. Older generations of metasomatic interaction between pegmatites and ultramafi c rock units are present, but these lack corundum. Th e metamorphosed ultramafi c rocks are mainly sills or dykes that occur as intrusions in a tonalite- amphibolite gneiss basement. Black amphibole rims devel- oped at the contact between the intrusion and the gneiss, but no other mineral zones were observed. General outreach and education Th e geology near Kuummiut, Tiniteqilaaq, Sermiligaaq, Ku- lusuk and Tasiilaq was studied and rock samples collected as 5656 Authors’ addresses M.D.P., Geological Survey of Denmark and Greenland, Nuuk Office, Kivioq 2, 3900 Nuuk, Greenland; E-mail: madp@geus.dk H.P. & D.R., Geological Survey of Denmark and Greenland, Øster Voldgade 10, Dk-1350, Copenhagen K, Denmark. V.J.v.H., Department of Earth & Planetary Sciences, 3450 University Street, Montreal, Quebec, Canada H3A 2A7. J.P.& L.L.T., Ministry of Mineral Resources, Postbox 930, Imaneq 1A, 201, 3900 Nuuk, Greenland. A B Fig. 3. A: A geologist from GEUS teaching chil- dren in Kuummiut how to use a hand lens and how to recognise different minerals. B: Robert Umerineq enthusiastically studies a rock sample. Photographs: Jakob Lautrup a basis for local geological fi eld guides. Th e intention is to en- gage school teachers and other interested citizens to develop a better understanding of the local geology, the science of geol- ogy and geological fi eld work in general. Th e local people are already familiar with their local environment and landscapes, and this will allow them to interpret what they see, and teach this to the next generation. Th e fi ve communities represent diverse geology and cover a wide spectrum of themes, which taken together, can tell a story of a dynamic geological history of this part of South- East Greenland. A variety of geological structures and pro- cesses can be studied, such as relations between intrusions at Kulusuk and Tasiilaq, contact metamorphism at Tiniteqi- laaq, deformation and metamorphism at Kuummiut and an igneous fractionation series at Sermiligaaq. Th e smaller set- tlements are well suited for geological outreach because they show the most interesting igneous and metamorphic geology, whereas a fairly uniform geology is exposed around the town of Tasiilaq. We collected samples that can provide mineral- ogical, petrological and geochronological information, as well as data on geochemical compositions and thin section pho- tographs for the fi eld guides. Th e fi eld guides will be written following analyses of the rock samples, and will contain back- ground information on geological processes and features. Shortly aft er the beginning of the school year in 2014, a geology theme day about basic geology with demonstrations of the typical rock types in Kuummiut was held at the prima- ry school in Kuummiut for 6–12 years old children (Fig. 3). Furthermore, a community information meeting was ar- ranged at the school in Kuummiut, where we presented the aims of the fi eld activities in the Tasiilaq area. Th e meeting and presentations were well-received and more than 30 citi- zens of Kuummiut attended. Conclusions Th e experience from this fi eld season shows that the follow- up of mineralised samples submitted to the Ujarassiorit pro- gramme is best carried out with the help of local rock collec- tors. Th is has proved to be the most effi cient way to quickly fi nd the right areas, since the limited time in the fi eld makes it important to get to the right locations as quickly as possible. Also, we found that engaging the local community members in the fi eld work contributed to a better understanding of what geologists are doing in the fi eld and how this work may ultimately benefi t the Greenlandic community. Our experience shows that especially children enjoy explor- ing their natural surroundings and are eager to learn about rocks and the work carried out by geologists. Field guides and further outreach will be appreciated by the local people and will hopefully lead to a self-sustainable situation where school teachers and interested citizens acquire suffi cient geological background knowledge to explain their local geology. Acknowledgements Th is study is a joint project fi nanced by the Government of Greenland and the Geological Survey of Denmark and Greenland. We are grateful to the rock collectors who shared their local knowledge with us and to the people of Kuummiut and Isortoq for support and for their enthusiasm for our work. Hans Kristian Olsen kindly commented on the manuscript. References Escher, J.C. 1990: Geological map of Greenland, 1:500 000, Skjoldungen, sheet 14. Copenhagen: Geological Survey of Greenland. Kolb, J. 2014: Structure of the Palaeoproterozoic Nagssugtoqidian Oro- gen, South-East Greenland: model for the tectonic evolution. Precam- brian Research 255, 809–822.