A regional lithostratigraphy for southern and eastern , north

ROBERT H. FINDLA Y

Findlay ' R . H.: A regional lithostratigraphy for southern and eastern Sulitjelma, north Norway . Norsk . . Geologtsk Ttdsskrift, Vol. 60, pp. 223-234, 1980. ISSN 0029-196X.

A revised regional lithostratigraphy is described for the Sulitjelma region. T ectonic boundaries occur at two levels i� the lithostratigraphic column; these tectonic boundaries correlate with the soles of the Gasak and P1eske Nappes.

R. H. Findlay, 45 Leitch St., Christchurch 2, New Zealand.

Early work (Sjøgren 1896, 1900a, 1900b, Holm­ Sulitjelma Amphibolites sen 1917), culminating in the regional study of Greater Furulund Group - Pieske Nappe Vogt (1927) identified the major rock types and Inferior their distribution within the Sulitjelma region. SjØnstå Group The Sulitjelma area was visited briefly by Pieske Marble Kautsky (1953) who, on the basis of extensive Sparagmite-Gneiss Formation mapping in Sweden, considered the region to be Lower Mica Schist Formation formed by four superimposed thrust nappes, Basement Gneiss identifiable in Sweden as the Pieske, Salo, Vas­ ten and Gasak Nappes. The regional outcrop pattern (Fig. 2) is domi­ These and later studies (Nicholson 1966, Ma­ nated by large basin-and-dome structures caused son 1967, Wilson 1968, Henley 1970) were ably by interference of two sets of folding on north reviewed by Nicholson & Rutland (1969) who and northeast trends; these folds refold early revised the regional lithostratigraphy, identified recumbent folds. Sulitjelma township Iies in the the sole of the Gasak Nappe, and confirmed the core of an east-west trending antiform with the conclusions of Wilson (1968) that the sole of the basin-like Baldoiavve structure to the south; to Vasten Nappe does not occur at Sulitjelma. the north, in the cliffabove Sulitjelma township, Kollung (1970a, 1970b) and myself (Findlay a tectonised zone intervenes between an overly­ 1972) remapped the region to the east of the ing sequence of high grade schists (Sulitjelma Sulitjelma/ road, and to the south of Schists) and a lower sequence of calcareous Baldoiavve and Balvatnet. This paper aims to garnetiferous hornblendic pelites (Furulund summ�rise our work, revise slightly and add Group). The tectonic contact between these two detail to the lithostratigraphy of Nicholson & formations persists eastward along the northern Rutland (1969), and to describe in the Sulitjelma side of Lomivatnet, and crops out also to the region the possible sole of the Pieske Nappe. I south of Balvatnet (Fig. 2), where it separates modify (see below) the lithostratigraphy of Ni­ the amphibolite facies calcareous pelites of the cholson & Rutland (1969) which formed a work­ Furulund Group from the overlying staurolite­ ing basis for field work, and describe two new amphibolite facies, aluminous and calcareous formations below th Pieske Marble. I have seen Sulitjelma Schists. neither the Marble in its type locality, In the region of Basshaugen (Fig. 2), there nor the Sulitjelma Gabbro. occur two erosional windows exposing a con­ Fauske Marble Group tinuous sequence from the top of the Furulund upper Group to the Basement Gneiss. These windows Sulitjelma Schists - Gasak Nappe lower are the southern 'Kragelva window' (Kragdalen

16-Geologisk Tidsskr. 4/80 224 R. H. Findlay NORSK GEOLOGISK TIDSSKRIFT 4 (1980)

° 67

� Basement Gneiss

25 km Fig. l. Locality map showing Sulitjelma and study region.

inlier of Nicholson & Rutland (1969)) and the synformally folded into the Pieske Marble, the northern 'Knallerdalen window' (Fig. 3). Within Sparagmite-Gneiss Formation (new formation: the Kragelva window three formations underlie this paper), and the Lower Mica Schist Forma­ successively the SjØnstå Group: the Pieske Mar­ tion. I did not tind the base of the Lower Mica ble, the Lower Mica Schist Formation (newly Schist Formation in the Knallerdalen window. described formation) (Kollung 1970b), and a thin In the northern part of the Knallerdalen sparagmite, all of which overlie the Basement window, rocks of the Furulund Group are thrust Gneiss. However, in the Knallerdalen window locally over beds of the underlying SjØnstå the downward lithological succession below the Group, which is thinner here than to the south or SjØnstå Group is as follows: Pieske Marble, a east, and which in turn may be thrust locally gre y-green garnet-biotite-muscovite-chlorite over the Pieske Marble. schist (which I identify as Sjønstå GrouJ?) The granite and leucocratic gneisses often

TASLE l Nomenclature of the major lithostratigraphic groups according to previous workers.

l VOGT (1927) KAUTSKY (1953) l HENLEY (1968) NICHOLSON & THIS PAPER RUTLAND l (1969) --- � Baldoiavve Sulitjelma schist Sulitjelma Upper o. ""�'"' '""�"' o. sch1st Gasak Nappe Upper Gro up � Sulitjelma Baldoiavve sequence with r----- z + with schist Unit Schists Lower "' � Schists Ska ti Sulitjelma Sulitjelma Sulitjelma Gabbro "' """ l � (South) � sch1st Gabbro Gabbro <.9 Gabbro Junction Unit Tectonic Discontinuity Sulitjelma Amphibolite Vasten Nappe Amphibolites Sulitjelma Amphibolites -- +' •ri Furulund � � o. Furulund :> "' Lower � � z Pi eske � Furulund Group Furulund Group 3 " o "' Sulitjelma schist _, Group "' " •ri '" Schists Sjt'lnst� Muorki Sj6nst� Nappe SjØnst� Group Sjlmst� Group Gneiss Schist Gro up

(West l (East l --'---- Pieske Marble l Tectonic Discontinuity NORSK GEOLOGISK TIDSSKRIFT 4 (1980) Lithostratigraphy for Sulitjelma 225

TASLE 2 : Generalised lithostratigraphy of the Sulitjelma Schists.

SULITJELMA AND DUOLDAGOP BALDOIAVVE SKAI TI

Garnet phyllite, calcareous- Graphite schist above Calcareous biotite pelite banded gre y semi-pelites calcareous-banded schists with development of and diopside-bearing unit. diopside, garnet and Marble, quartzites and Granites and trondhjemites. hornblende. Intermittent rust y schists quartzite.

Ul "' Aluminous staurolite kyanite Aluminous schists probably Orange rusty (kyanite) .... "' Ul 0.. schists (Lap he Ueren equivalent to Laphelleren schists, interbedded H 0.. "' => schists) with Furulund schists. Granite sil l. with staurolite schists, (.) Granite and leucocratic staurolite garnet Ul gneiss bodies. schists, biotite schist .,; :>:: and gneiss bodies. ..:1 Trondhjemites low in "' >-, section. .... H ..:1 => "' "' "' arnet calc. ;:. -pelites, o ..:1 bolites, �are'"""''''' marble.

Tectonic breccia and Sulitjelma Amphibolites (Junction Unit of Henley,, 1970)

Pelites of the Furulund Gro up j

known colloquially as 'Furulund Granite', and of the stream of Skaitibukta, beyond Tjerfjellet which occur extensively throughout the lower and towards Storfjell I (see Figs. 2 and 4). part of the Sulitjelma Schists, clearly do not form Two subdivisions are discernible in the Suli­ a unique lithostratigraphic marker (Fig. 2). I tjelma Schists south of Balvatnet. The lower suggest that the term 'Furulund Granite' should formation (Lower Sulitjelma Schists) is com­ remain restricted to that granite seen in the posed of rusty-weathering grey-purple garnet­ Kobbertoppen region (spot height 10 12, Fig. 2), staurolite-biotite schists, subsidiary grey phyl­ above the town of Sulitjelma. lites, and numerous hornblendic amphibolites, and contains also acidic volcanogenic rocks similar to the Inferior Furulund Schists de­ scribed later in this paper. The Lower Sulitjelma Schists form a 'wedge' which although thicken­ Lithostratigraphy ing eastward from Skaitibukta (Figs. 2 and 4), is cut out by the U pper Sulitjelma Schists im­ Sulitjelma Schists mediately to the west of Skaitibukta. South of Balvatnet the schists overlying the Although in the shore section at Skaitibukta Furulund Group are comparable to those form­ the contact between the Lower and Upper Suli­ ing the Baldoiavve Group (Vogt 1927, Henley tjelma Schists is well-exposed, the contact is lost 1970), and have been correlated also with the inland among isolated outcrops of a rusty-weath­ Sulitjelma Schists north of by Ni­ ering, gre y, kyanite-quartz-mica schist, a cholson & Rutland (1969) (see Tables l and 2). sheared diopside-bearing pelite, and a dark au­ South of Balvatnet the base of the Sulitjelma gen-gneiss, all lying within a synform within the Schists is marked by a zone, 6- 10 m thick, Upper Sulitjelma Schists (synform A:Fig. 4). consisting of a tectonic melange of Sulitjelma The lowermost rocks of the U pper Sulitjelma Schists, Sulitjelma Amphibolites, and Furulund Schists are composed of garnet-chlorite schists Group. This zone, identical to that mapped containing limestone lenses and a coarse northeast of Langvatnet as 'Junction Unit' by hornblende amphibolite overlain by rusty weath­ Henley in 1970 and forming the sole of the Gasak ering, grey, kyanite-quartz-mica schists. Overly­ Nappe (Nicholson & Rutland 1969), can be ing these schists and separated from them by an traced west from the lower northern slopes of intermittent thin, black quartzite is a calcare­ Jouska, through a sericite schist near the mouth ous-banded biotite-bearing dark pelite (Diopside 226 R. H. Findlay NORSK GEOLOGISK TIDSSKRIFT 4 (1980)

Kobbe li

2Km. SCALE O

HEIGHTS IN METRES

Boldoiovve

Colcoreous ond kyonite schists

-� - -�./

-- 7 �-/ -...... � ...... l / · l Jousko i 1273 NORSK GEOLOGISK TIDSSKRIFT 4 (1980) Lithostratigraphy for Sulitjelma 227

l i NORWAY j SWEDEN i ' ) il

-,.._; - ,...; - . _/ -r.J --- .7 -- __ / r.J// -7 -r-J

LEGE ND Top not seen

GA SAK NAPPE

Pl ESKE NAPPE

PIESKE MAF:BLE :--o] SULITJELMA GABBRO � - ··: SPARAGMITE- GNEISS FM.

:s_] GRANITE BASEMENT

Fig. 2. Geological map of the Sulitjelma region. Map compiled from Vogt (1927), Kollung (1970), Mason (1970), Fiiullay (1972), and Wilson (1973). 228 R. H. Findlay NORSK GEOLOGISK TIDSSKRIFT 4 (1980)

TABLE 3 : Generalised lithostratigraphy of the Furulund Group.

TO BAL VATNET BAL VATNET TO BASSHAUGEN LOM! VATNET !

Tectonic brec cia and Sulitjelma Amphibolites (Jun et ion Unit of Henley 1970) "' "' Brown fine-grained biotite muscovite pelitic schists; als o thin graphitic and (l) p.. phylli tie interbeds. Black garnets developed near Tjerfjellet, garnets and hornblende ,.. p.. (l) :::> deve loped near Sulitjelma township and in Basshaugen region. H :c p.. u :::> (l) o "' o "' Variable, generally phylli tie schists Grey-brown, generally phylli tie "' z ..J bear ing biotite porphyroblasts. Large schists aften carrying biotite :::> o o ..J o boudins of a meta-gabbro of variable porphyroblasts. z :::> H :::> "' X: grain size. ..J :::> :::> "" "' :::> "' "" "' Calcareous pelitic schist with same Calcareous pelitic schist with meta- phyllitic bands. Same rneta-gabbro gabbro bodies and fine amphibolites. !;;! "' � "' boudins developed locally. At Lairotoppen Occasional thin white quartzites. "' � o a thick graphitic schist is developed, ..J and the calcareous pelitic schist is absent.

o z :::> Schistose aeid effusives, amphibolites, with a sedimentary sequence of calc-peli tes, ..J :::> limestones (near Lairotoppen), metaquartzites and metaconglomerates near the base. "' :::> ""

Rock, Kollung 1970), displaying diopside and a schists. A rusty-weathering micaceous gneiss green amphibole near the contact with the rusty carrying garnet and thin laths of tourmaline schists. This calc-pelite could correlate with the overlies these rocks which, with the gneiss, form Fauske Marble. Trondhjemite lenses occur at, a sequence continuous at least as far westward and adjacent to the contact between this calc-pe­ as Storfjell l (Fig. 2). A few hundred metres east lite and underlying rusty schists. of the southwest corner of Balvatnet the gneiss The Diopside Rock Iies in the core of a tight and underlying Sulitjelma Amphibolites are cut km-scale south-closing synform (synform B :Fig. out by the tectonic boundary between the Suli­ 4) within the rusty kyanite-quartz-mica schists tjelma Schists and the Furulund Group: here on the north face of Salefjellet. The synform (Figs. 2 and 4) the Diopside Rock overlies di­ plunges subhorizontally, the axis tren ds roughly rectly the grey pelites of the Furulund Group. east-west, and the axial plane dips at about 20-30° south. The lower limb of this synform is Furulund Group sheared out in places, evinced by the fact that the kyanite-quartz-mica schists, underlying the The Furulund Group consists essentially of two Diopside Rock, are cut out westward along the formations, a regionally-extensive, apparently southern shore of Balvatnet, thus bringing the uniform suite of grey pelites (Greater Furulund Diopside Rock to Iie directly above the pelites of Schists) overlying a suite of volcanogenic rocks the Furulund Group (Figs. 2 and 4). (Inferior Furulund Schists). In the study region the Greater Furulund Schists contain three fairly-well definedmembers Sulitjelma Amphibolites (Table 3) here called 'upper', 'middle', and In the SW corner of Balvatnet the Sulitjelma 'lower' members. Amphibolites are represented by thin amphibo­ The Inferior Furulund Schists consist of a lites intercalated with calcareous pelites of the regionally extensive sequence of acidic and basic Furulund Group, overlain successively by a fine­ effusives (Kollung 1970a) consisting of amphibo­ grained dark amphibolite only a few metres lites and what may be meta-rhyolites and meta­ thick, a thin zone of grey pelites, a thin intermit­ andesites. Near Lairotoppen (Fig. 2), locally tent quartzite, and graphite schists, and, in the developed limestones and quartzites, occurring region of Tjerfjellet, amphibolites and thin near the base of the Inferior Furulund Schists quartz keratophyres intercalated with pelitic and preceding conformable passage to the un- NORSK GEOLOGISK TIDSSKRIFT 4 (1980) Lithostratigraphy for Sulitjelma 229

TABLE 4 : Generalised lithostratigraphy of SjØnstg Group.

r LAIROTOPPEN-BALVATNET BASSHAUGEN WINDOW

Chlori te quartz schist, with inter- Grey garnet biotite muscovite chlori te 1>: bedded metaconglomerates, quartzites quartz schist, sornetimes garnet-poor, a."' and graphite schists. Greenschists sometimes chlori te-poor. A chlorite a. (meta-volcanic) just below boundary epidote schist occurs close to the :::> with Furulund Group. Furulund boundary in the eastern part of the window. a. :::> o 1>: Brown schistose quartzites, with (.!) _,"' garnet biotite muscovite quartz schist <><( A interbeds. The schistose quartzites E-< A U) H rnay sometimes be feldspathic and z :<: sometimes calcareous. Graphitic 6> schists also are found . U)..,

Gre y to green chlori te biotite muscovite schist. Coarsely-amphibolitic 1>: calcareous amphibolites, and fine- "' grained amphibolites interbedded with o"' _, graphite schists in the lower parts of this subdivision.

derlying SjØnstå Group, contain Ordovician coarsely foliated quartz-chloriteschist, with thin (Vogt 1927, Nicholson 1966) crinoid ossicles and interbeds of graphite schists, occasional bryozoan fragments. amphibolites, rare metaquartzites, and In the Calmebello region (Fig. 2), the lower metaconglomerate lenses (Table 4). Within the part of the Inferior Furulund Schists contains quartz-chlorite schists between Calalvesjavre non-fossiliferous thin white marbles, grey phyl­ and Dorrovatnet, magnetite-bearing metabasites lites, and quartzites of local extent which overlie are intercalated with a fine-grained blue-grey conformably the coarse quartz-chlorite schists of magnetitiferous schist that contains dark green the SjØnstå Grop. At Kong Oscar Gruve a local amphibole in thin chlorite-rich partings. non-economic pyritiferous sericite schist occurs. In the Basshaugen region the Sjønstå Grop Further south, towards Balvatnet, the Inferior consists of predominantly garnet-muscovite­ Furulund schists thin and the limestones and biotite schists, containing small amounts of chlo­ quartzites disappear. rite. I found well-formed 4 to 6 cm blades of blue West of Balvatnet, the Inferior Furulund kyanite in one of the numerous quartzofeldspa­ Schists are exposed in the northem and eastem thic tension gashes common throughout this area. sides of the Basshaugen window. Here, the In­ The kyanite blades possessed no preferred ferior Furulund Schists are formed of calcareous orientation and no kyanite was found in any schists and local meta-conglomerates containing other gash, nor anywhere else in the schists of pebbles of acidic and mafic composition, in­ the Sjønstå Group. The schistosity dose to these terbedded with hornblendic amphibolites, very gashes is redirected to Iie parallel to the gashes, white quartzofeldspathic schists (meta-rhyo­ which are also often surrounded by concentra­ lite?), and probable meta-andesites. tions of large garnets (frequently l to 2 cm The contact between the Inferior Furulund across) and which are often pseudomorphed Schists and underlying SjØnstå Group appears perfectly by chlorite. conformable everywhere, save to the north of The Iower part of the SjØnstå Group contains the Knallerdalen window where the Inferior an extensive sequence of coarse and often Furulund Schists are thrust locally over the calcareous hornblendic amphibolites, interbed­ garnet-biotite-muscovite schists of the underly­ ded with very rusty, often sulphurous weather­ ing Sjønstå Group. ing, graphitic schists. These rocks crop out around the Knallerdalen window, and round the northern, eastern, and southern margins of the Sjønstå Group Kragelva window (Fig. 2). Between Lomivatnet and Balvatnet the up­ permost rocks of this Group are predominantly 230 R. H. Findlay NORSK GEOLOGISK TIDSSKRIFT 4 (1980)

KRAGELVA W!NDOW SOUTH NORTH KNALURDALEN WINOOW

Knolterdah!n 'canyon' Storfjellet 1

to \ake at 416m

r:-:1Bos�•ent P::l Lr f'llico Schist Sparagm_ite gne1ss !taP ieske Sjfnsta Greoter } Furulund E3 Upper Sulitjelma IIJlill Oiopside � Gne•ss I..:::::J For111ahon LARJ Formahon tft!j Marble �8 Group U9 tnfenor_ Group l;:;;;J Sch1sts L.!l.!J Rock

Pl ESKE NAPPE GASAK NAPPE Fig. 3. Sketch block diagram to show relationships in Knallerdalen and Kragelva windows. Thicknesses not scaled. Note recumbent fold containing Sjønstå Group rocks overlying tectonic boundary (toothed heavy line) in Knallerdalen window.

Pieske Marble which, northeast of Basshaugen, takes on a In the study area the Pieske Marble is found only gneissic appearance due to the development of in the Knallerdalen and Kragelva windows, pink quartzo-feldspathic lenses about lO cm by 2 where it underlies the SjØnstå Group. or 3 cm long axis, elongate in the plane of The Pieske Marble is a coarsely saccharoidal schistosity. Although immediately west of marble containing interbeds of biotite-musco­ Basshaugen the Sparagmite-Gneiss Formation is vite-quartz-carbonate schist near the top and only 5 m thick, and although it was not observed quartzites interbedded with coarse mica schists in the Kragelva window, it thickens rapidly and carbonate layers near the base. I suggest northward from Basshaugen towards Knallerda­ that the upper biotite-muscovite-quartz-carbo­ len, where, in the cliff immediately south of nate schists represent an original sedimentary Knallerdalen 'canyon' (Fig. 3), it attains a thick­ transition to the schists of the Sjønstå Group. ness of about 100 m. The abrupt decrease in In the Kragelva window, the Pieske Marble thickness southward may indicate a tectonic rests apparent!y conformably on the Lower Mica boundary. Schist Formation (Kollung 1970b). Immediately west of Basshaugen a recumbent, possibly Lower Mica Schist Formation southeast-closing, isoclinal fold within the This formation underlies the Sparagmite-Gneiss Pieske Marble contains, in its core, grey-green Formation in the Knallerdalen window, and the garnet-biotite-chlorite-quartz schists of the Pieske Marble in the Kragelva window. It is a SjØnstå Group. The Pieske Marble, forming the 120 m thick, rusty-weathering, coarsely foliated lower limb of this fold, is no thicker than l m, muscovite-biotite-quartz schist containing large indicating considerable shearing during or after (2 cm) garnets. Neither chlorite-rich schists, nor folding. This sheared lower limb is underlain by amphibolites, nor graphite schists are known a 5 m thick sericite schist containing epidote and within this formation. Rusty weathering sericite rare biotite and which, separating the Pieske schists (similar to that separating the Pieske Marble from the underlying Sparagmite-Gneiss Marble from the Sparagmite-Gneiss Formation) Formation, crops out around at least the north­ occur on at least two levels, dip parallel to the em and western part of the Basshaugen window. foliation of the schists, and may represent shear The hand-specimen appearance of this schist is zones. very reminiscent of a highly-sheared granitic or In the Kragelva window, the Lower Mica gneissic rock; identical sericite schists also occur Schist Formation is separated from the underly­ at two or three other levels in the thicker part of ing Basement Gneiss by a 15 cm thick dark the Sparagmite-Gneiss Formation forming the quartzite, possibly equivalent to the sparagmite northern cliffof Knallerdalen 'canyon' (Fig. 3). of Nicholson & Rutland (1%9).

Sparagmite-Gneiss Formation Basement Gneiss The Sparagmite-Gneiss Formation is composed The Basement Gneiss is well-exposed in of a light grey schistose feldspathic quartzite Kragelva window, but I did not tind it in Knal- NORSK GEOLOGISK TIDSSKRIFT 4 (1980) Lithostratigraphy for Sulitjelma 23 1

1403 m SalefJelletl

} § i side Up p r g::k e Sul�tjel�t�a Fig. 4. Sketch block diagram to Rusty schists Schlsts show geology of Salefjellet­ § � Lr.Sulitjelllla Schists Balvatnet region. 6ASAK NAPPE lerdalen window. Wilson & Nicholson (1973) Discussion describe this gneiss as a microline-plagioclase­ Gasak Nappe quartz gneiss (containing also subsidiary biotite; R. H. Findlay, per. obs.), assign it an Rb/Sr As described by Kautsky (1953), the Gasak whole rock age of 1180 m.y., and consider it to Nappe lies with considerable angular uncon­ be similar to the basement gneiss of N asafjallet. formity on the Vasten and Salo Nappes (not recognised in the area of the present study), and consists of high grade metamorphic rocks con­ taining 'secondary' oligoclase, kyanite, stauro-

TABLE 5

Rishaugfjellet Vatnfjellet

North South

Absent Fauske Marble Fauske Marble

Furulund Group Hornblende pelite Mica schists, and marble marble and (Furulund) amphibolites

Sj6nst� Group Semipelitic schists Thick muscovite characteristic of schist the Sj6nst� Group Mixed group, including marbles

Mixed group, including well­ bedded calc­ psammite

Furulund Group

Sj6nst� Group

Sparagmite Some few psammites Possibly psammites and micaceous psammites schists

Granite gneiss Granite gneiss Probably granite (east of Rishaugf­ gneiss jellet summit sparagmitic psammites are complexly inter­ folded with granite gneisses below and pelitic metasediments above) 232 R. H. Findlay NORSK GEOLOGISK TIDSSKRIFf 4 (1980)

TAB LE 6 : Illustration of the regional tectonic discontinuity at the base of the Gasak Nappe, and regional interpretation

of that below the Pieske Marble in the Basshaugen window. Broken line indicates tectonic discontinuity.

BASSHAUG EN KAUT SKY (19 53) - TO NORTH RISHAUGFJELLET VATNFJELLET SULITJELMA SKAI TI OF SULITJELMA KNALLERDALEN KRAGELVA

Gasak No li thostrati- Schists of similar Nappe gra phi c Wlit nature to Sulitjelma Fauske I above Sulitjelma Schists Marble Fauske Schists recog------, Group Marble nised Gro up Vasten Dom�nantly \ Sulitjelma Nappe Schists 1 Schists (Upper) ------mafic \ , Sulitjelma ' \ Sala f ' Schists Nappe rocks ', \ '"*�(Lower) ------· ------_·,\_ ------Furulund Group Gt.Furulund Schists Gt. Furulund Schists Furulund Furulund Furulund Furulund Group Group Gro up Group Laotak Series Inf. Furulund Schists Inf. Furulund l Schists Pieske Nappe Stalo Series Sj.Snst� Gp. SjØnst� Sj�nst� Sj�nst� and Gro up Group Gro up psamrnites ---1- ·- ·- -?- -- / . ?- - Pieske Marble/ -� Pi eske Marble Pieske Marble ·- -- _,; - - ·- !------·--- r------Huron Quartzite Sparagmi te- Gneiss Fm. Lr.Mica Schist Fm.

Microcline Gneiss with Granite infolded Sparag- Lr. Mi ca Schist Fm. sparagmitic mitie psarnmi tes psamrnites Basement ? Basement Gneiss

lite, garnet, and biotite. These minerals show the Pieske Nappe effects of retrogression to the epidote-amphibo­ lite facies, the mineral assemblages consisting of As described by Kautsky (1953) the Pieske mainly chlorite and mica. The schists are often Nappe, of greenschist facies, has at its base the gneissic; but orthogneiss is found to the north of remnants of a microcline granite (deeply weath­ Kautsky's area. Kautsky (1953) describes meta­ ered immediately below its covering sediments) andesite and rhyolitic effusives at higher levels overlain by a metamorphic arkose (Huron in the Gasak Nappe; these rocks are overlain by Quartzite), and overlain in turn by the Pieske a uniform staurolite-garnet-mica schist. limestone. Above the Pieske limestone, Kautsky In the present study region the Lower Suli­ (1953) described a conglomerate-sandstone tjelma Schists contain amphibolitic horizons and series, the lower part (Stalo series) of which metavolcanic effusives in a staurolite-gamet consists of psephitic and psammitic rocks schist. The Upper Sulitjelma Schists consist altemating with graphite-bearing schists, and the of staurolite-garnet schists, kyanite schists, upper part of which (Laotak series) consists of diopside-bearing schists (with the reservation various types of schist with frequent intercala­ that this might be an infold of Fauske Marble), tions of limestone and dolomite together with and scattered augen gneisses and trondhjemites. lavas, rhyolitic tuffs, and metandesite. The Both the U pper and Lower Sulitjelma Schists lavas, including the acidic rocks, display a dis­ have suffered some retrograde metamorphism tinet pillow structure. with muscovite and quartz pseudomorphing The rocks comprising the Stalo series there­ kyanite, and chlorite pseudomorphing garnet. fore appear similar to those of the Sjønstå Group Thus, it is clear that both the U pper and Lower in the Sulitjelma region, and the Laotak series Sulitjelma Schists are part of Kautsky's Gasak resembles the Inferior Furulund Schists. Both Nappe which, throughout the study region, the Laotak series and Inferior Furulund Schists overlies more-or-less conjunctively the Suli­ are overlain by the widespread grey pelitic tjelma Amphibolites and Furulund Group. schists of the Furulund Group. NORSK GEOLOGISK TIDSSKRIFT 4 (1980) Lithostratigraphy for Sulitjelma 233

TASLE 'l : Summary of lithostratigraphy in the Sulitjelma-southern Sulitjelma region.

BASSHAUGEN WINOOW BALOOAIVVE­ SULITJELMA LOMIVATNET­ SKAITIBUKTA AND SULITJELMA BALVATNET SW BALVATNET KRAGELVA KNALLERDALEN

FAUSKE MARBLE Not seen

Calcareous Banded calc-peli tes, Calcareous pelites, SULITJELMA banded peli tes, may bear diopside. rus ty psarnmites . Quartzite. Rusty locally bear Upper Furulund weathering kyani te diopside. Granite, staurolite garnet Rusty kyan:iæ SCHISTS Laphe lleren mi ca schists. schists, kyanite schists. Trondhjemites, pods pods of Pods of gneiss. of gneiss, lime- gneiss and stones and amphi­ granite boli tes. Rusty bodies. staurolite schist and amphibolite. Lower \jR �:�i'.olite garnet schist, _ ; e t n c l E_ !______amE_hi_b�li_t�s- _ irea� Gre ater . . . . . Amph�bolJ.tes developed sporadJ.cally at tap. Grey, sometl.mes calcareous, peli tes wi th graphite Furulund schists and boudins of amphibolitised gabbro developed throughout region. Schists FURULUND GRO UP Inferior Acid and basic Keratophyres Meta-extrusives Furulund effusi ves with and greenschists acid and basic Schists limestones and in poorly in nature; cal­ quartzites ne ar exposed outcrops careous schists base. Limestones near base. and Ordovician Occasional meta fossil fragments conglomerate. at Lai ro toppen.

Quart z chlori te Grey garnet biotite muscovite schists, chlorite schists, isolated chlori tie Upper epidote albi te green-schist. schists near boundary with Furulund Group. o Graphite schists. SJØNSTA Brolo'n schistose quartzi tes wi th GRO UP Middle garnet schist interbeds; quartzites are feldspathic. Graphi te schists.

Grey-to-green chlori te mi ca Lower schists. Coarse-grained calcareous and fine-grained amphibolites, gra phite schists.

PIESKE f!ARBLE Coarsely crystalline limestone, with micaceous quartz carbonate sch is ts in� up per part, micaceous Tectonic _ u r z ·t s i o e · ____ _ � � � :\: � : � : _ Break-- :_ Quartzofeldspathic SPARAGMITE-GNEISS Absent mic�-q';lartzite with FORMATION gne1ss1c texture

LOWER MICA SCHIST Rusty-orange coarse garnet mica FORMAT ION quartz schist. No amphibolites. No graphite schists. Thin dark quartzite at base.

BASEMENT Leucocratic gneiss ? .______...J______L ______L______L______L______

As outlined already (Table 5), Nicholson & Pieske Marble in the Basshaugen region (Table Rutland (1969) indicate that, to the northwest of 6). As this boundary therefore would appear to Sulitjelma, the Pieske Marble is either extremely be regionally extensive it could correlate with thin or is absent. This could indicate a tectonic the sole of Kautsky's Pieske Nappe (Kautsky break between the SjØnstå Group and underlying 1953). As the proposed nappe sole between Bass­ rocks in the Rishaugfjellet/Vatnfjellet region haugen and the Rishaugfjellet/V atnfjellet region (Fig. l): this suggested tectonic break could clearly cuts across lithological boundaries (Table correlate with my tectonic boundary below the 6), the Pieske Nappe is disjunctive. 234 R. H. Findlay NORSK GEOLOGISK TIDSSKRIFT 4 (1980)

Conclusions Holmsen, G. 1917: Sulitjelmatrakten. Nor. Geo/. Unders. 81, pt. Ill. A regional lithostratigraphy for southem Suli­ Kollung, S. 1970a: Geologiske undersøkelser. Området mel­ lom Lairofjell og Balvatn. tjelma is presented (Table 7). In the southem Company report held by AlS Sulitjelma Gruber, Sulitjelma. Sulitjelma region two major tectonic boundaries Kollung, S. 1970b: Geologiske undersøkelser. Storfjella Y for exist, a lower one cross-cutting Iithological Balvatn. Company report held by AlS Sulitjelma Gruber. boundaries and separating rocks of epidote­ Sulitjelma. Kautsky, G. 1953: Der Geologisches Bau des Sulitjelma-Salo­ amphibolite facies from sparagmitic rocks and jauregebietes in den nordskandinavishen Kaledoniden. Sv. psammites overlying a gneissic basement, and Geo/. Unders. Ser. C. No. 528, 232 p. an upper one separating rocks of staurolite­ Mason, R. 1967: The field relations of the Sulitjelma Gabbro. amphibolite facies from rocks of apparently epi­ Nor. Geo/. Tidsskr. 47, 365-387. Nicholson, R. 1966: On the relations between volcanic and dote-amphibolite facies. These tectonic bound­ other rocks in the fossiliferous east Lomivatn areas of aries correlate with the soles of Kautsky's Norwegian Sulitjelma. Nor. Geo/. Unders. 242, 143-156. Pieske and Gasak Nappes respectively. Nicholson, R. & Rutland, R. W. R. 1969: A section across the Norwegian Caledonides. Nor. Geo/. Unders. 260, 86 p. Acknowledgements. - The author thanks AlS Sulitjelma Rutland, R. W. R. & Nicholson, R. 1965: Caledonides of part Gruber for permission to publish this paper. Mr. S. Kollung of . Quart. J. Geo/. Soc. London 121, 73-109. between 1970 and 1971 mappeda good half of the area covered SjØgren, H. 1896: Om Sulitjelma-områdets bergarter og tekto­ in this study, and is thanked both for a very thorough introduc­ nite. Geo/. For. Sth. Forh. 18, 346-376. tion to the geology of the Sulitjelma region and for commenting SjØgren, H. 1900a: Enkrinitfynd i fjlillskiffrarne vid Sulitjelma. on the paper. The paper could not have been written without Geo/. For. Sth. Forh. 22, 105-115. recourse to the company reports of Messrs S. Kollung (1970, SjØgren, H. 1900b: 6fversikt af Sulitjelma-områdets geologi. 1971), R. Badkar (1972), J. Cunningham (1971), Stoakes & Geo/. For. Sth. Forh. 22, 437-462. Moorhouse (1969), Needham & Knox (1967), Findlay (1972), Vogt, Th. 1927: Sulitjelmafjellets geologi og petrografi. Nor. and Dr. M. R. Wilson (1969). The author is indebted to Geo/. Unders. 121, 560 p. Professor W. Means, Professor R. N. Brothers, and Drs. Wilson, M. R. 1968: An investigation of the supposed nappe M. G. Laird and G. Warren for useful comments concerning structure on the north side of Langvann, Sulitjelma, North presentation, and to Drs M. R. Wilson and R. Nicholson for Norway. Unpublished Ph. D. thesis, Manchester Uni­ extensively and carefully reviewing drafts of the manuscript. versity. Wilson, M. R. 1972: Strain determination using rotational porphyroblasts, Sulitjelma, Norway. J. Geo/. 80, 421-431. References Wilson, M. R. 1973: The geological setting of the Sulitjelma ore bodies, Central Norwegian Caledonides. Econ. Geo/. 68, Findlay, R. H. 1972: Geological Survey. South of Knallerda­ 307-316. len, and Salefjell. Company report held by AlS Sulitjelma Wilson, M. R. & Nicholson, R. 1973: The structural setting Gruber. Sulitjelma. and geochronology of basal granitic gneisses in the Henley, K. L. 1970: The structural and metamorphic history of Caledonides of part of Nordland, Norway. J. Geo/. Soc. the Sulitjelma region, Norway, with special reference to the London 129, 365-387. Nappe hypothesis. Nor. Geo/. Tidsskr. 50, 97-136.