NGU-BULL 436, 2000 - PAGE 15

Natural stone in : production, deposits and developments

TOM HELD AL & PE ER R. NEEB

Heldal, T. & Neeb, P. R. 2000: Natural sto ne in Norway: produc tio n, deposits and developments. Norgesgeologiske undersokelseBulletin 436, 15-26.

The natural sto ne industry has, during the last two decades, experienced a tremendous growth both on a glo bal scale and wit hin a Norwegian context. At th e present time, the natura l stone industry contributes significantly to total Norwegia n mi neral production and export. The production of larvikite is, by far, the most important part of the indu stry, followed by slate and metamorphic flagstone . Future reserves of these important resources are considered to be large. In addition, a diversified natural stone industry aimed for local and dome stic markets is growing in most parts of th e country, driv en by an increased useof stone fo r building sdome stically, and by th e need for paving stones in urban areas. There exists a considerable pot enti al for th e develop ment of new natu ral stone depo sits, as well as revitalising old quarries in the light of the expanding and increasingly diversified use of sto ne. However, t he possibilities for th e develop ment of new deposits for export-oriented produ ction is probab ly limited to a few geological provinces containing unique rock types. Environmental issues and land use regul ations will undoub tedly influence natu ral sto ne exploitation in Norway, and there are conside rable futur e challenges concerning the handling of waste from product ion,'peaceful' co-existence between industry and community, and th e integration of informat ion on natural sto ne deposits into plans fo r land use.

Tom Heldal & Peer Richard Neeb, Norgesgeologiskeundersekelse, N-7491Trondheim, Norway.

depend s mo re on t he consumer's personal taste and on fash­ Introduction ion tre nds th an t he chemical and physical quality of the Building sto ne differsfrom ot her mineral resources in several material concerned . ways. First of all, sto ne quarrying isabo ut the art of collecti ng In many places around th e world, t he stone industry is w hole, massive pieces of rock, w it hout the need for crushing based on the collect ion and shaping of field stones and sim­ and grinding and separation of individual minerals. Furth er­ ple quarrying of soft and hard sto ne for local building pur­ more, stone pro cessing does not includ e removal of poses. For small-scale. local-market production of stone, the 'unwanted' compo nents from t he rock; it simply deals with a basic requirement s are rocks th at are easily worked wit h a more or less advanced way of shaping pieces of rock into fin ­ min imum of labour (Shadmon 1997). An attractiv ely col­ ished products . In addition, th e market for stone products oured granite is not of commerci al interest if it takes an excessive number of working hou rs to shape a block or a Natural stone brick for construct ion. A 'boring', grey granite may, however, be very interesting if th e cleavage properti es facilitate th e shaping of the blocks. This perspective differ s comp letely from th e search for stone for the internat ional market. Most of th e expo rt quality stone of th e wo rld ends up as polished slabson floors, walls and astom bstones.The aesthetic aspect (e.g. th e colour and st ruct ure of t he rock) is here far more important in th e pricing of stone th an physical prop erties. Predominantly, rare colours such as blu e, yellow, pu re white and deep black are high ly priced, w hilst rocks of mor e 'ordi­ nary' colours obtain lower prices. For raw bloc ks, t he most exclusive rocks may be 20 times more expensive th an the cheapest. All over the world we have seen, during th e last decades, an expanding business in stone, both for local/ domestic and for int ernational markets (Conti et al. 1990). This is not only because of a short-term fashion able tr end, but rather more a 'catching up' on 70 years of concrete hegemony in const ruc­ t ion. Building ston es are often classified according to their Fig. 1. Industrial classificatio n of natural stone (ty pes found in Norway) . technical quali ty and usability. A standardised, internation al NGU-BULL 436, 2000 - PAGE 16 TOMHELDAL& PEERR.NEEB

classification scheme do es not exist, but it is common, as tate the extracti on process. The structural features are also of shown in Fig. 1, to differe nt iate between massive stone importance to the commercial value ofthe fin ished products. (extracted in large blocks) and slabby stone, extracted as Foliated or layered rocks will obviously have improved tech ­ slabs which are cleaved along a planar str ucture,such assedi­ nical properties when cut parallel to the lami nation instead mentary layerin g or metamorphi c foliation . Massive stone is of perpendicular to it. In addit ion, the colour and structure, further divided into 'soh' varieties such as carbonates and which contri bute to the aesthetic qua lity, vary accordin g to serpentinite, and 'hard',essentially quartzo-feldspath ic rocks. cutt ing directions. In some extreme cases, rocks must be cut in a specific direction to have any com mercia l value at all, such as the Norwegian larvikites. Exploitation of natural stone Another important aspect in the production of rough The most important aspect in th e exploitation of natural blocks for the intern ational market is the need for heavy stone deposits is th e need for ext racti ng large and whole machinery in the qua rries (Fig. 2). A standard size for trad e bloc ks and slabs of rocks w ith a uniform quality. This is don e blocks is 2.4 x 1.2 x 1 m (ca. 8 tonnes ). Most suppliers will be by wedging, careful blasting and primary sawing, or a combi­ asked for even bigger sizes, up to 30 tonnes, to feed the giant nati on oft hese met hods (Figs. 2 and 3). Sawing, especially by frame saws in Italy or oth er coun tr ies pro ducing finished diamond w ire, is most applicable to rocks wi th low or inte r­ products. The bloc ks should be well-shaped and rectangular, mediate hardne ss, such as limestone, marble, slate and ser­ with no veins, cracks or inclusions. For small blocks and pentin it e, but is also wi dely used for feldsp athi c igneous bloc ks with such 'faults', the price may be reduced by up to rocks and, to some extent , also for granit es. However, blast­ 70% if one is fortunate to find a buyer for them. ing and wedging is still th e mo st common extraction method The need for large blocks creates a waste problem in nat­ for hard siliceous rocks. Some of these rock types have excel­ ural sto ne qua rries, and generally the percentage of waste is lent natural splittin g prop erties due to more or less visible well above SO%. In some Norwegian quarries, it may be as structural anisot ropic feat ures, such as directionally distrib­ high as 95%. The prop ortion of waste is a good ind icator of uted minera ls or microfractu res. Experienced quarry workers extract ion costs, whi ch in Norway vary from USD 150 to USD know how to make use of t hese directio ns in order to facili- 1000 per m3 for commercial blocks, reflect ing differences in uniformity, fracture density and splitting properties.Only the most exclusive rock types can be produced at such a high 3 unit cost. For most granites, prices (per m ) are lower than USD 500, and thu s the waste ratio should be below 80 % and the deposits hom og enous and massive. The varying price for raw blocks is highly dependent on t he colour of th e rocks; rare colours give higher prices on the world market. Blue, yellow, deep black and pure wh ite are among the most expensive colo urs, whilst pink and grey rocks are low-priced. Generally speaking, all rocks showing an attractive play of colou rs, such as iridescence in feldspars, are highly priced.

Fig. 2. Larvikite quarry, close to Larvik, Southeast Norway. A combination Important geological aspects in the of drillin g/bl asting, diamond wi re sawing and wedging is applied in th e evaluation of natural stone deposits extractio n process. Given the comp lex market mechanisms for natura l ston e, including local needs for raw materials, as well as trends and behaviou r of the glo bal market, some knowledge of markets for finished products is a prerequisite in geological investiga­ tions ofstone deposits. In any case, there are some important geological aspects that need to be focused upon, includin g: Geological aspects influencing the uniformity ofrock col­ our and structure, such as veins and dykes, inclusions and segregati ons, foliations and layering and other structural eleme nts. Geological aspects influencing the block and slab size, such asfracture density, folds,'open' foliations, remanent st ress field s and weat heri ng and deloading features. Geolo gical aspects influencing the quality ofthe rocks, in th e shorter or long er terms,such as deteriorating miner­

Fig. 3. Diamond wire sawing applied in th e Lovgavlen marb le quarry, als and minerals causing staini ng oft he rock (e.g. sul­ Fauske(). ph ides and oxides), po rosity and mineral texture. TOM HELDAL &PEER R.NEEB NGU -BULL 436, 2000 - PAGE 17

Geological aspects influenci ng the workabili ty ofth e rocks, such as preferred orientations of minerals and Massive stone microfractures. ---~~~~-' Geometry and size of the deposits

The testing of physical propert ies of rocks can be ofassist­ ance, especially fo r t he docume ntation of quality to custom­ ers and end -users. A variety of standardised testsexist, cove r­ ing th e streng th ofthe rocks to loading and oth er mechanical infl uence, to resistance to weat hering and chemical attacks (Alnzes 1995). At present t ime, test methods and product 80 % requirements are being harmonised at a European level. Fig. 4. Slate/flagsto ne and massive sto ne pr oduct ion in Norway, 1999. How ever, th e tests are not of any significant help for evaluat­ Larvikit e produ ction contribut es t o approxim ately 88% of the total mas­ ing t he commercial value of th e deposit s. sive st one product ion. Figu res are based on prod uction value from pri­ mary producer (blocks o r slabs), thus exclud ing proce ssing com panies buying raw material from ot her prod ucers.

Norwegian stone production produced by smaller companies around the country as Aft er a significant growth in th e 1980's, the production of show n in Fig. 7. natural sto ne in Norway remained at a fairly stable level Most Norwegian stone companies are very small, even in th roughout th e 1990's, alt hough a small increase has been a Norwegian context; only 10 companies have more th an 20 noted in the past few years.The total production value isest i­ employees. However, th e few large companies are expand­ mated to USD 100 million in 1999 (Fig. 4); th e export value ing th eir share ofthe market. Tod ay, for example, almost 90% was approximatel y USD 85 million (Figs. 5 and 6). Import of of th e flag stone and phyllit e prod uct ion is controlled by Rie­ stone amounted to only USD 5 million. The export of raw ber & Son ASA, and the largest larvikit e producer (Lundhs lab ­ bloc ks oflarvikite contributesth e major part (close to 80%) of radarAS) controls approximately 70% of larvikit e prod uct ion. th e total exports. This attractive type of monzonite with a Of great importance for parts of th e sto ne industry, in recent bluish play of colour, which is quite unique to SE Norway, is years, has been the deliveries of 50,000 m2 of slate and mar­ used for flooring and building facades all over the world. ble for th e new Oslo Airp ort at Gardermoen, w hich op ened Production of quartzitic flagstone and phyllite is also of on October 8t h 1998. great importance, essentially for domestic use, although a There have been several dev elopment s of small-scale part of th e production is exported. Some exclusive types of production units of granite and flag ston e for local markets in marbl e are exploited in Fauske, northern Norway (e.g., the recent years, due to an increasing use of roughly hewn and pink and w hite 'Norwegian Rose'), whilst several other types hammered stone in urb an environments. Of greater interest of granitic gneiss and also serpentinite and soapstone are for th e export market are two depo sits ofexclusive st one th at

300

250

200

150

50

Industrial minerals (including ilrnenite) Metallic ores 1991 1993 1994 1995 1996 Year 1997 1998 1999

Fig. 5.Expo rt of Norweg ian mineral resources during th e last 11 year s. NGU-BULL 436, 2000 - PAGE 18 TOM HELDAL & PEER R. NEEB

have recentl y been put into regular product ion. One is the duction of this quartzite was started in 1999 by two compa­ LabradorAntiq ue anorthosite (brow n w it h a blue play of col­ nies, Fuchsite AS and Masikvartsitt AS.The emerald-green col­ our) in SW Norway (Heldal & Lund 1995). produc ed by Granitt our is due to a high content of a er-bear ing mica, fuchsi te. 7893 AS since 1996. The other is an emerald-green massive Ongoing prospecting activ ities include soapstone and mar­ quartzite (Masi Quartzite) from nor thernmost Norway. Pro- ble. All in all, the Norwegian ston e industry is mov ing ahead, albeit at a slower rate th an in the 1980's, backed by the expo rt of exclusive rock types and a continuing increase in the size of the domestic market.One trend isclear: large com­ panies are gro wing larger at the expense of smaller produc­ ers who are being bought out by th e larger compa nies w ho dominate the industry and market. C S latell agstone i Mill. use 41 , iO Masshe stone I1 :I) / Resource po tential Norwegian bedrock geology pro vides a considerable variety of lithologies, although predominant ly metamorphic and Producto n E x ~ rt igneous rocks, which have either been extracted as bu ild ing sto ne in th e past, are being extracted at present, or may be of Fig. 6. Production versus export for Norwegian natural stone commodi­ future interest as sources of building sto ne. ties.

PERMIA N ROCKS (250 - 290 Ma) Gra nite, Nordmarkite, larvikite Basa lt, Rhomb porphyry DEVO NIAN ROCK S (350 - 400 Ma) Sandstone . C onglome rate CA LEDO NIANNAPPEROCKS (400 - 1650 Ma) Granite. Tonalite Gabbro, Anorthositc, Ultramafic rocks Mica schist Marb le Mctabas alt M etarhyolitc, Metar hyodacite Sandstone . S chist. Conglome rate PRECA MBRIA N ROCKS (600 - 2900 Ma) G ra nite, Tonalite Gabbro, Anorthositc, un ramanc rocks Mctabasalt Metarhyolltc. MetarhyodaClte Natu ral stone quar ries (in ope ration) Sa ndsto ne . Mica schist Gne iss, M igrn,j,tltc o Larvikite o Anorthosite / mangerite / syenitc Granitc/trondhjcmite ~ Gneiss o Marble ~ Scrpcntinite / soapstone o Slate / phyllite / mica schist o Flagstone ~ Sandstone / conglomerate / quartzite

Fig. 7. Distribution of Norwegian natu ral stone qua rries. TOM HELDAL & PEER R. NEEB NGU -BU LL 436, 2000 - PAGE 19

Igneous rocks occur in all three main units of Norwegian Scandinavian markets . Farther north, in Nord land county, bedroc k geo logy; in the Precambrian basement, the Caledo­ th ere are a number of large intrusive bodies of grey and pink nian mountain chain and th e Perm ian Oslo rift (Fig. 8). Pre­ granite.There are no operati ng qu arries in these granites, but cambrian granite s occur predom inantl y in th e sout heast part a number of pot ential deposits, especially of porphyritic vari­ of the cou ntry. Colour generally varies from grey to pink and eties (Fig. 9F), are known from SW Nordland (Heldal 1994). red, and both fine-gr ained and coarse-grained typ es occur. Smaller deposits of Early Palaeozoic granites occur on th e One of t he best know n deposits, t he grey Iddefjo rd granit e west coast of Norway and include pin k, grey and green typ es. (Fig. 9A), has been quar ried for 150 years (Gaut neb et al. The youngest igne ous rocks in Norway are found in th e 1999). Other Precambrian granites of interest, alt hough cur­ Oslo area. Production of larvikite is today the most important rently not under exploitation, include t he red granites part of the Norwegian stone industry, and around 20 quarries around the town of Grimstad (Fig. 9Bl, South Norway (Heldal are operati ng in this area. Best known are the light coloured 1992), and the pink and green, epidote-bearing porphyritic Blue Pearl (Fig. l OA) and the dark Emerald Pearl (Fig. l OB) vari­ gran it es described from several localities within th e Precam­ eties, but other types are also extr acted (Fig. 10C, D). Several bri an basement of southern Norway. Large massifs of feld­ research projec ts in th e area are being carried out to investi­ spat hic igneou s rocks occur in northern Norway (t he Lofoten gate t he possibiliti es for underground quarrying and the massif) and in th e southwe st (t he Rogaland Igneous Com­ futu re resource pot ent ial of larvikite (Heldal et al. 1999, Kj011e plex). A black mo nzonite is quarried in th e Vesteralen area, et al. 2000). Farth er north , pink and brow n granite and syen­ Nord land (Fig. 9Cl, and a brown anort hosite contai ning ite are foun d. There is a lon g tradition in the ext raction and chatoya nt labradorit e in Rogaland (Fig. 90) . In bot h areas, use of t hese rocks, but only two quarries are st ill in operation there is considerable potential for the deve lopment of ot her in t he brownish Reyken granite (Heldal & Gaut neb 1996; Fig. deposits (Heldal & Lund 1995). 1OE) and one in t he Grorud syenite (Fig. 10F). Lower Palaeozoic granitoids occur main ly in Central and A huge part ofth e Norwegian bedrock consists of variou s North Norway.The composition ranges from granite to tonal­ typ es of Precambrian gneiss (Fig. 11). Granitic gneiss and lep­ ite and granodiorite, and the colou r is mainly white to grey, tites, predominantly pink, are common rockswithin th e base­ with some pink varieties . In Central Norway there are several ment in both southern and northern Norway, and thre e small bodies of w hite trondhjemite (Ieuco-tonalite). Two deposits are being extr acted on a small scale, in the Steigen deposits are ext racted today, at Steren (Ser-Trendelaq: Fig. area (Nordland: Fig. 12C) and the Flisa area (Hedmark: Fig. 9E) and Tolga (Hedmark), though mainly for domestic and 120, E). Several ot her deposits are being investigated. Migm ­ atites have become increasing ly popular in the international market du ring the last decades, du e to the wavy structure of such rocks, their attractive colours and excellen t techn ical properties. In Norway, special atten tion shoul d be paid to th e eastern most parts of t he Precamb rian, such as in th e Varang­ Feldspathic igneous rocks erfjord area in north ernm ost Norway . Here, in th e Varanger (Lofoten province) ~ GneissComplex, th ere are several deposits of red, blu ish grey 'sl:>J :~~ 1 and grey migm atites. Two quarries in th e area have recentl y been opened, at Nyelv (Fig. 12B) and Buqoynes (Fig. 12A). Migm atites of dim ension sto ne quality are also foun d in the sout heastern gneiss regio n. Augen gn eiss ismainly formed by . dynamic metamorph ism and deforma tion of igneous rocks. Usually, large feldspar grains occur as 'augen' in a fin e­ ~~. I ) grained and folia ted groundmass,and such gneisses may dis­ play a great variety of colours (Fig. 12F). However, because of .f, ~ the strong planar layering, slabsshould be cut only parall el to ~. " , Metaga bbro/ •- rl I { this . In the Norwegian bedrock, augen gneisses occur in sev­ anorthosite ~ / . ,,~~ . 'I. ..' eral localit ies; and there are many varieties - 'serizzo' typ es, <' . . pink, violet and greenish in hue (Heldal & Lund 1993). Today, ~ ~.~,-p':.. _ -. '- , ' i only 2 small operating quarries exist, in th e vicin ity of Ferd e, ; '" e:»: ~ " on the west coast of Norway. ~..f>=:'~.. ' , ~ . ? Alth ough marble is not a dominant rock type in Norwe­ .~ .. Gra nite gian bedrock, t here are several deposits of attractive marbl e Lt! . ,t( ,17. _ ; (Protcrozoic) which have been exploited for more than 100 years. Most of 0 ~ . r ' . ,~ . '-.:M;, \ t hese occur withi n th e th ick marble for matio ns of nort hern . , ., ~ ., Norway (Fig. 13). Best known abroad is the pink and w hite \ , ) -\ Larvikite, granite. syenite Norwegian Rose from Fauske (Vogt 1897, Held al & Gaut neb \~ ~ (TIle Oslo Igneous Province) ' 1995, Melezhik et aI., th is volume: Fig. 14A). Oth er, less well Anort hosite (Rogaland ligneous Province) known types includ e massive and layered, pin k (Fig. 140, El. Fig. 8. Igneous rock provin ces in Nor way. grey (Fig. 14B) and greenish calc-silicate marbles (Fig. 14Cl, NGU-BULL 4 36, 2000 - PAGE 20 TOM HELDAL & PEERR.NEEB

• > - '

Fig. 9. Selection of Norwegian igneous rocks used as natural stone from the Caledo nian and Precambri an provinces, polished samples. A: Iddefjord granite, 0stfold (Precambrian). B: Grimstad granite, Aust-Agd er (Precambrian), C:Loding en mang erit e, Nordland (Precambrian), D: Helvik anorthosite, Rogaland (Precambrian). E: Vevelstad granit e, Nordland (Caledonian). F:Steren tro ndhjem ite, Ser-Trend elaq (Caledonian). Sizeof images appr. 70% of sample. Colou r may deviate from th e original. TOM HELDAL & PEER R. NEEB NGU-BULL 436, 2000 - PAGE 2 1

Fig. 10. Select ion of ign eous rocks fro m t he Oslo Ign eou s Province used as natural sto ne, polished samples. A: pale larvik ite (Tvedalen), B: dark larvikite (Klastad), C: dark larvi kite (Bergan-type), D: pale larvikite (Malerod-type), E: granite (Reyken), F: syenite (Grorud). Size of images appr. 70% of samp le. Colour may deviate from th e orig inal. NGU -BULL 436. 2000 - PAGE 22 TOM HELDAL & PEERR. NEEB

Augen gneiss

Meta rhyolit e. leptite

Fig. 15. Slate and flagstone dep osit s in Norwa y.

and white dol om it e (Fig. 14F) and calcite marbles. Limestone Fig. 11. Gneiss provi nces of Norway. and fin e-grained marble occur to a lim ited extent in South­ east Norway, close to Oslo. There isstill a considerable poten­ tial for th e exp loitat ion of interes ting depos its of both marb le f!it~Jt:; and limestone. Production and use of slate and flagstone for roofing, cladding and paving has long traditions in Norway, and dur­ JJ,~ ~ ing t he last decade Norwegian indu stry has become a world ~\~/~ j ~ . leader in the production of metamorphic flagstone. Large deposits of grey, flaggy quartzite, black phyllite and mica ?~ ll le Ofoten area schist are fou nd in many parts of the country (Fig. 15), espe­ cially within t he Caledo nian nappes in Central and northern ,':1ft,n , Fauske - S,I

Fig. 12. Selected gn eisses from di fferent regions in Norway used as natu ral stone, po lished samples. A: migm atite Sor-Varanger , , B: Migma tite , Finnmark, C: granitic gneissSteigen, Nordland, D:gr anitic gneiss Flisa, Hedmark, E: rhyolitic gneiss Flisa, Hedm ark, F: augen gnei ssOppdal, Ser­ Trond elag . Size of imag es appr. 70% of sample. Colour may deviate from th e ori ginal. NGU-BULL 436. 2000 - PAGE 24 TOM HELDA L& PEER R. NEEB

Fig. 14. Selected Norwegian marbles used as natural stone. polished samples. A: calcite-dolomite marble Fauske, Nordland, B: calcite marb le Fauske, Nordland, C:ophi-calcitic marble Bindal, Nordland, D: calcite marbl e Skjer stad, Nordl and , E: calcite marble Namsos, Nord-Trondelag, F: dol omite marble Fauske, Nordland. Size of images appr. 70% of sample. Colour may devia te from the original. TOM HELDAL & PEER R. NEEB NGU-BULL 436, 2000 - PAGE 25

Fig . 16. Selected Norwegian slates, flagstones and ultramafic rocks used as natural sto ne. A: Alta flagston e, Finnmark (cleaved surface), B:Opp dal flag­ sto ne, Ser-Tronde laq (cleaved surface), C:Ott a phyllite, Op pland (honed surface), D: Vossflagston e, Hordaland (cleaved surface), E: Otta soapstone, Op­ pland (honed surface), F:Sparbu serpenti nite, Nord-Trondelag (polished surface). Size of images appr. 70% of sam ple. Colour may deviate from th e origi nal. NGU -BULL 4 36, 2000 - PAGE 26 TOM HELDAL& PEERR. NEEB

green min eral serpentine is th e dominant constitu ent. In th e regional planners are able to consider the se possibilities in sto ne indu stry, serpenti nite is often called 'green marble' terms of designati ng future pote ntia l indus tria l areas. It is because of its struct ure and similar technical properties. also necess ary to identify potent ial envi ronmental impacts, Deposit scommonly occur tog eth er w it h soapsto ne deposit s. and to sugg est solution sto wardsthe ir mit igati on. In th iscon­ Only one dep osit is extracted today, namely t he Solberg ser­ text the considerabl e databases held at NGU can play a signif­ pentinite in Centr al Norway. Two varieties, a dark gree n and icant role. a pale green variety (Fig. 16FJ, are produ ced and are popu lar flooring materials in Scandinavia. Both in thi s and in ot her Ackno wledgements parts of Norway, the re are large serpent inite provinces, in The aut ho rs w ish to t hank Dr. Lisbet h Alnees (SINTEF) and Prof. Davi d which the likelihood offinding new occurrencesistho ug ht to Robe rts for read ing and corr ect ing th e manuscript. Furtherm or e, we are g rateful to t he large number of Norwegian natural sto ne prod ucers who be quite considerable. Of special int erest are 'oxidised', red have supplied us w it h p roduction and expo rt figures. serpentine conglomerates in the Ott a area. Massive qu artzites are foun d in many places. The mo st References att ract ive type is the emerald-green quartzite (Masi Quartz­ Alnees, L. 1995: Kvali tet og bestandigh et av naturstein - oavirkninqsia«. ite) from Finnmark, from w hich a trial production has begu n. torer og pre vemetoder. Dr. Ing . Thesis, NTH, Tro nd heim, 438 pp . Two companies are now pro spectin g th ese resources. Large Cont i, G., Mannoni, T., Mo ntani, C, Pinzari, M., Pucci, R. & Ricci, A. 1990 : 11 occurr ences of red quartzite and quartz-rich sandstone are marm or nel m ondo. Ind ust ria e com me rcio dei materiali lapidei. Societe Editrice Apuana. 253 pp . fo und in Southeast and northernm ost Norway. Con glom er­ Gautneb, H.; Heldal, T. 1994 : Nat urstei n i No rd-Tro ndelag . Norge s qeolo­ ates occur in a great variety in Norway from the Devonian giske undersekelse Rappo rt 94.053,31 pp . 'multicoloured' (polymict) conglome rates on th e west coast, Gautneb, H., 0 vereng, O. & Heldal, T. 1999: Granitt forekom ster i Halden to greenish and reddish varietie s in ot her places such as east­ ko mmune. Norges geologiske undersekelse Rapp ort 99.061, 17 pp . ern Finnm ark, in the far north. Heldal, T. 1992: Nat urstein i Ser-Norqe: Befaring av Grim stad og Herefoss gr anitt, Aust-Agder. Norges geologiske undersekelse Rapport 92.217, 14 pp. Helda l, T. 1994: Nat urst ein i Nor dl and : Sydlige Helge land . Norges qeolo­ Perspectives for the future giske undersekelse Rapport 94.055, 62 pp. The natur al stone indu stry in Norway can be expected to Helda l, T. & Lund, E. 1993: Blokksteinsundersokelser i Sogn og Fjor dane. increase both in term s of the volum e of produc tion of estab­ Norges geologiske underseketse Rapport 93.059, 125 pp. lished stone types and in the develop ment of an increased Heldal, T. & Gaut neb , H. 1995: Ma rm or i Salten-Sorfolda ornrad et, No rd­ land . Norges geolog iske undersekelse Rapp ort 95.041, 46 pp . range of products. However , the type of extreme gro wth th at Helda l, T. & Gaut neb, H. 1996: Nat urst einsfore komste r i Buske rud . Norges the indu stry experienced dur ing the 1980's is unlikely to be geologiske undersekelse Rapp ort 96.047,78 pp. repeated in th e future. Helda l, T. & Lund, B. 1995: A reg ion al stu dy of the dimension-stone There wi ll probably be continued growth of small-scale poten ti al in labradorite-bearing ano rhos itic roc ks in th e Rogaland Igneo us Compl ex. (Exte nded abst ract ) Norges geologiske under­ production units for local and do mestic markets, working on sekelse Bulletin 427, 123-126. an increasing number of rock types and deposits. The large­ Helda l, T. & Stu rt, B. A. 1996: Skifer ved St orvassbe rge t, Dovr e kommune. scale production aimed for export w ill probably be furth er Norg es geolog iske undersekelse Rapp ort 96.097, 16 pp. concentrated in the hands of fewer and larger compa nies, Heldal, T., Zwaan, K. B., Tegner, C, Hoist, B. & Karlst ro m, H. 1997 : Geolo­ and due to the increasing competition in th e market only th e gi ske und ersokelser av Alta skifer en. Norges geologiske unde rsekelse Rapp ort 97.064, 11 pp. most exclusive rock types will be of future interest. In Norway, Helda l, 1., Kjo lle, I., Beard, L. P., Tegn er, C.& Lynum, R. 1999: Kart legging some of th e most int eresting areas for natural stone pros­ av larvikitt mello m Sandefj or d og Porsgrunn. Norges geologiske pecting are t he provinces of feldspat hic igneous rocks, and undersekelse Rapport 99.059, 68 pp. we will probably see th e developm ent of new commercial Heldal, T. & Lund, B. 2000 : Fabrics and str uct ure of met amorphic flag ­ typ es of ano rt hosite and larvikite in th e futu re. Granite and sto nes and implicati on s for ind ustr ial qu alit y. Norges geologiske undersokelse Bulletin, t his volume. gneiss occurrences w ill mainly be of int erest for dom estic Kjolle, I., Heldal, T., Tegner, C.& Lynu m, R. 2000 : Dim ensio n sto ne po te n­ markets, wit h few exceptions, whilst som e new, exclusive ti al of larvikite s between Sandefjord and Porsgrunn , Oslo Igneous marble types may st ill be possibl e to exploit. Province, Norway. Abstra ct, Nordic Geological Wintermee ting, Trend­ The focus on environmental issues in Norway as in ot her heim. Geonytt 112000, pp. part softhe world, is grow ing, and th e mineral indust ry is par­ Lund , B. 1979: Geolog isk kartlegging og vurdering av skiferress urser innenfo r Dovre skiferind ustr is kon sesjon somrade ved Hornsje-Stor­ ticularly sensitive to thi s. The product ion of natu ral stone is, vassberget, Dovr e kommune. Norges geologiske undersekelse Rap­ in a global sense, sustainable, 'clean' and consumes less por t 1745, 17 pp. energy th an synt hetic building materials, but better solu­ Lund , B., Heldal, T. & Nissen, A. 1998 : Geol og iske un dersokelser av Opp­ tion s for t he handling of waste are clearly needed . Furthe r­ dalskiferen. Norges geologiske unaerseketse Rapport 98.044, 21 pp. more, wit h th e expansion of urban areasand regu latio ns con­ M elezhik, V.A., Helda l, T., Rob ert s, D., Gor ok hov, I.M. & Fallick, A.E. 2000 : cerning land set aside for agricu ltur e, recreation and natu ral Dep ositi onal en vi ro nment and ap parent age of t he Fauske carbon­ ate co nglomerate, North No rweg ian Caledonides. Norges geologiske habitats, land-use conflictsare increasing. It isthu s important undersekelse Bulle tin , this volume. to identify bot h th e reserve potentia l around know n dep os­ Shadmon, A. 1997: Ston e: an introductio n. Int erm ed iate Technology Pub­ it s, and t he localiti es and/ or areas in w hich inte restin g sto ne lication s, 172 pp. typesoccur. This is of parti cular im porta nce, so that local and Vogt, J.H.L. 1897: No rsk ma rmor. Norges geologiske undersekelse 22,364 pp.