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Tittel Geologyof the Alta Kvenangen window(Kvaenangen side).

Forfatter Dato Bedrift GAUTIER A. 1975 . Sulitjelrna Gruber AJS

Kommune ' Fylke Bergdistrikt 1: 50 000 kartblad 1:250 000 kartblad

Fagområde Dokument type Forekomster

Råstofftype Emneord

Sammendrag Geologiske undersokelse av Alta - Kvenangen vinduet i Nordtroms og Vestfinnmark. Generell skildring av berggrunnen, detaljerte petrografiske beskrivelser av de forskjellige bergartene i grunnfjellet og Raipas -dekket. Metamorfose, geokjemi og geokronologi gnmdig diskutert. Mulighetene for mineraliseringer vurderes som sma. Del av doktorarbeide. Skyvedekke. Tektonikk. fift Sulitjelftn 6nehr tnp Sta /TiFin Mese No. (

61-01067 o TRE 817.fieAW9N6Fir WINDOW (ktesnemfes slå)

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SpIre4 Sve/t Awderlosd • No.. 10 0 21 A/S SULITJELMA GRUBER N - 8230 SULITJELMA NORGE

GEOLOGY OF THE ALTA - KVAENANGEN WINDOW (Kvae nangen side )

N - Troma and W-Finnmark, Norwa Regional mapping to the scale 1/ 50.000

Field work : summer 1974 and 1975 • André M. Gautier Licencib és sciences gbologiques et mintaalogiques (at B. Sc. ) UniversitE de Genbve/Dept.Min‘ralogie 13, rue des Maratchers CH - 1211 GENEVE 4 Sveits - Switzerland

November 1975 2

Content papae

CH. IINTRODUCTION 1. 1. Location I fl 1. 1. 2. Topography I c 1. 1. 3. Outcrops IC 1. 1. 4. Climate I

1. 2. Geology I G 1. 2. 1. General Geology I 6 1.2.2. Previous work IJ

1. 3. Old Mining Area I L.

1. 4. Survey: why and how I L- 1. 4. 1. Geological motives I L 1. 4. 2. Field work Iti

CH.IIPETROGRAPHY

2. 1. Upper units II 9 2. 1. 1. Allochthonous II I? 2. 1. 2. Autochthonous H fl

2. 2. Basement II g 2. 2. 1. Subgroup of Upper Raipas H 8 2. 2. 1. 1. Dolomite interbedded w. sand- stones and shales II 8 2. 2. 1. 2. Greywacke II D 2. 2. 2. Subgroup of Lower Raipas II D 2.2.2. 1. Argillite ll p 2.2.2.2. Black Sqldsts II£ 2. 2. 2. 3. Carbonate rocks II F 2. 2. 2. 4. Basaltic tuffs, tuffites and tuffo- genic sediments II6 2. 2. 2. 5. Basaltic tuffs w. dolomite lenses ll if 2. 2. 2. 6. Greenstones: Introduction H fl

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CH. IV TECTONIC

4.1. Polarity IV fi 4.2. Tectonic style IV /9 4.3. Tectonic map: explanation IV 8

CH. V LOCAL DESCRIPTION 5. 1. Middavarre

CH. VI ECONOMIC GEOLOGY VI

CH. VII DISCUSSION

7.1. About the thickness of the series VI I) 7.2. About the sedirnentation conditions and their relation w. tuffs/tuffites etc. VII 8 7.3. About a patticular pillow layer(marker) VII 7. 4. About the extension and the volcanic vent of the lava stream VII 7.5. About the limit between Lower and Upper Raipas VII 7.6. Comparison of the Lower Raipas with a type scheme for the"greenstones belt" VII H

CI4.VIU FURTHER WORK VIII

CH. IX CONCLUSIONS Ix

CH. X 10.1. Bibliography (references) X f/ 10.2. Maps and air photos X F 10.2.1. Maps NGO X F 10.2.2. Air photos X F 10.3. Equipment list X G 10.321. Office work and drawing X 6 10.3.2. Field work X H 10.3.3. Camping and bivouac X h s-

Cll. XI MISCEL LA.ECUS XI

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). rir Generally, the rock has a weathering crust, oxydation crust, up to 1/2 cm thickness. Even more, the rodc is covered by lichens, whose thickness varies from some tens of mm. to some cm. But anyway, these two facts are enough to mask completely the petrography, the limits between rock-types.

The rock is often broken, with lots of joints whose surfaces are weathered, rusted, or with a chloritic coating. li might be difficult to get a good hand-specimen with a fresh cut.

From go )d, the outcrop conditions are getting very bad when onsiclering detail structures such as in a fine-grained greenstone, or as gradded beddings, cross beddings, in banden rocks.

Glacial streaks might also mask primary features of the roc,):.

1.1.4. CLIMATE

Generally the snow disappears at the beginning of June in low areas; some zones, covering important surfaces, might be snow-covered during all summer.

The melting of snow causes strong flood of the rivers, so that there are man; river-crossing problems for the geologist.

Snowfall might occur at any moment in summer time. Temperatures range from 5°C (or less) up to 30°C within a few hours.

The wind may be very strong. It happens that it is very strong in altitude and inexistant in the valley, causing an irregular gradient of pressure that should be takei into consideration when using an altimeter.

According to floatplane piots, wind up to 50-60 kt/h are not uncommon. When the observatorium of Sukkertoppen was still operating at the beginning of the century, winds up to 60 m/s have been measured. I. E

The summer 1974 was rather favourable concer1, ng the snow- conditions;the consequence of a winter with little snow and a warm wave at mid-June was that the area was free of snow. Our field experience from previous years indicates that such case is seldom.

In 1975 the situation was very unusual, much more unpleasant in terms of working conditions: at mid-June the whole field above 400 rn was still snow-covered and the lakes were frozen, excepted in a zone of 2-3 km from the shore of the fjord. Mid-July the lakes were still frozen above 400 m and crossable some tens of meters higher. End-July even big lakes such as Storelvan ( 634 m) were still frozen. Baddervan ( 575 m) was free of ice, with important floating ice. Nikkeluob'baljav're (675 m) was frozen, except a small zone of some tens of meters on one side, and a very strong ice on the other side.

The ice broke after a heavy storm and rain on August 6th. The lakes we found above 800 m kept frozen all the summer.

The snow cover was important too. End June / beginning July it was very strong on slopes to the E (50 - 80%) and 20-50% on slopes to the W (above 400 m). Later, the snow melted, but important zones still remained covered, at the foot of cliffs or on the bottom of the valley.

Big tunnels up to some meters high were taking shape above the streams and rivers flowing under the snow, forming dangerous snow-bridges, invisible until they were broken. This fact represented an additional danger for the work.

Epzt of August some snowfalls happened above 700 m. At the be- ginning of September there was a period of 4 days of windstorm and snowfalls above 570 m. -,•—=—Sternay LEGEND SCALE 10 km.

~-••••• , Gneiss (allochthonous) r-7,1 Cambrian sedimentary rocks

- Eocambnan sedimentary rocks 4 'Y-2( 1..•• Eocambnan tillite ,4 IK ° ,‘ 1I \ Upper (sandstone)subgroup1 Precambr . • Lower tgreenstone,slate..) . sg. Raipas %

group 1,4 yy: j I Dolomite and limestone

Basic rocks...(Caiedonianzone)

SimpIllied from NGU no 208 Geological map of Norway I. 6-

1.2. GEOLOGY

1 2.1. General eolo of the W art of the Alta-Kvaenan en window.

The fig.p r F• modified and enlarged twice from the geological map of Norway ( 1/1.000.000) shows the general geological outlines. The nurnerous Caledonian "nappes" (allochthonous gneisses) have been grouped together.

There are 3 main tectonic units, from th_e bottorn to the top: 1) the basement, 2) the autochthonous, and 3)the allochthonous.

The Precambrian basement, called Raipas group, is divided into 2 sub-groups: the Lower Ralpas subgroup, consisting mainly of a folded sequence of volcanic and volcano-sedirnentary rocks: metadiabases as sills, lava streams, often with pillow-lava structure, exceptionally with columnar jointing, with basaltic composition, sometimes with a spilitic tendency, associated with tuffs, tuffites and tuffogenic sediments, and also some pelitic or carbonate layers. There is in one place an ultrabasic outcrop (se ,ifitinised lherzolite).

the Upper Raipas subgroup, consisting mainly of a thick sequence of sandstone - quartzitic and a formation of interbedded dolomite and greywacke and shales.

The autochthonous (sensu stricto) consists mainly of white, bluish etc. quartzites, with sorne shales, tillite layers, etc. Around Alta, where it has been studied in detail, it is divided into 2 distinct groups: /(1arenanyen window Geo/og/ca/ and leclonic owIhnes

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-the Boseekop group ( late Precambrian), mainly white quartzite, laying with an angular unconformity on the base- ment; - the Borras group ( eo-cambrian), characterised by a tillite and different shales and quartzite, slightly unconformable on the Bossekop group.

li is not possible to correlate the typical stratigraphy in Alta with the autochthonous rocks all around the window.

3. The allochthonous. The latter is made of all the Caledonian nappes.

1. 2. 2. Previous work.

During the last century the area has been studied. (Russeger, 1849, (Pettersen, 1874), (Reusch, 1890).

In 1915 a first stratigraphy has been established for the precambrian formations of Alta, called Raipas group (Holtedahl 1915, 1913).

At the same time, a geological map and a report were written about the mining district of Alta & Kafjord and Kvaenangen (Zenzen 1915), to the scale 1/100.000 and 1/50.000, and this already for Sulitjelma Gruber! In tLis report there is reported the presence of numerous lavas with pillow structures, but without tectonic interpretation.

More recently, a rough surveying was done in the Talvik-laijord area (Geukens & Moreau 195d). This publication is useless. Another survey was undertaken at Riiddevarne and Klubben close to Bur- fjord. (Milnes and Ritchie, 1962). This publication is useless too, at hast in the Precambrian.

A detailed mapping around Alta has been done, in correlation with the tillites met in other localities in Finnmark (Fbyn, 1963).

A general surveying of the window has been done to the scale 1/50.01 in 1965. This work is mainly a photo interpretation and should be considered as such, with too muci extrapolation and geological borders following a "reingjerde'' On the other hand, apart from published papers, several in- vestigations, more specific and located on small surfaces, and some drillings, have been done at different periods on and around the old mines of Kvaenangen.

The paragenesis of the old mines of Raipas, on the Alta aide, have been studied in detail ( Vokes, 1956).

The area of the old copper mines of ddjord was a diplom subject for two students (Mfrk, 1969; Stacke 1970).

l'he area of Bergmark anticline (Badderen) has been studied in 1970 for Bleikvassli Gruber (we have not seen the report).

We have personnally done the geological mapping to the scale 1/50.000 ofthe E and NE part of the Alta-Kvaenangen window (Alta side), this for Elkern Spigerverket (geological map Alta 1334 I, NGU 1973 Zwaan & Gautier).

In 1972, part of the window was mapped in Kvaenangen for Sulitjelma Gruber (S.Laux). Unfortunately the interpretation and the tectonic conclusion did reveal wrong.

The allochthonous units (Caledonian nappes) have been mapped between Alta and Kvaenangen in 1971, 1972, 1973 by NGU (K. B. Zwaan)

111 In 1974 a study of Quaternary geology was done for the evaluation of gravel, sand and economically valuable construction material(NGU).

During these last tens of years, a geological mapping of the precambrian window of Komagfjord, between Altafjord and Hammerfest (Reitan 1963), of the Altenes window, on the N- side of Altafjord (NGU, Eareth 1974) has been done.

In 1975 the autochthbonous and allochthp1onousaround the window, especially North of it, was done by NGU (Inge Bakke and Zwaan) to complete the 1/250.000 Noreisa mapsheet. During a one-month- work for NGU, we personnally mapped the autochthonous between Badderen-Kjaekan and the Bergmark area. Some soil sampling has been done around Cedar mine by Mr. Grammeltvet . I. L.

F'rom 1972 to 1975, Sulitjelma has proceeded with the stream- sediment geochemistry of the window.

We should mention that many old mining reporta from the XIX and beginning of the XX centuries might be found in the archives of N.G.U.

1.3. OLD MINING AREA .

The Alta-Kvaenangen window is well-known for its old mines.

On the Kvaenangen side, the old rnines are: Middavarre EC 460542 EC 468536

Bergmark anticline : Sedars EC 472475 Kisgangfjellet EC 457450 (area) Ruk'sesgsPrro EC 429472 EC 429430

Apart from these mines, we found some exploration works, trenches, shafts, tunnels ..e. g. in the "canon" between Riiddevarrevatnet and F jellbukta (EC 352556), on the left side of the strearn, or at Randberg, on the shore ( area of EC 332595).

The last tentative of evaluation and production of the znineralisation, except the recent and probably last exploration works ( see previous work) have been done in Middavarre before World War II.

Sand and gravel are worked out here and there at a small scale for local use.

1.4, SURVEY WHY AND HOW

1.4.1. Geolo ical motives The only "general" map - except some local surveyings - of the precambrian window is the geological map of Norway, scale 1/ 1.000.000 (!t.'. ), which is useless for the problems of regional geology. M

Mines were in production at the end of the XIX and at the beginning of the XX century, in Raipas (Alta), Kafjord, Kvaenangen. F'urther North, in the Komagfjord tecton4e window, there is a new copper mine since a few years (Reppafjord). There is another new mine in Bijjovagge ( with an uncertain future due to the actual economic conditions ) on the other side of the Caledonides, in precambrian formations, which are similar - if not the sames- as in the window.

It seems from all these facts that the Precambrian might contain mineralisations.

It was important for this reason to have more detailed tectonic and stratigraphic knowledges and this for two reasons: to try to find a "similar" control with the former mines

to interpret the geochemistry results ( stream-sediments method) of sampling done since 1972 up to now, The pre- liminary results of the geochemistry are not yet known.

The present work was therefore the logical continuation of the work done on the Alta side of the window for Elkem Spigerverket during summer 1971 and 1972 ( the latter work being our Ph.D. subject, University of Geneva, and being the main material for the precambrian part of the new geological mapsheet Alta 1334 I, 1/50.000 NGU).

1.4.2. Field work Summer 1974 Our basis was in the boarding school of Burfjord, from 15.6. to 30.9.1974. We mapped alone from 15.6. to d. 8. the area West of the vertical coordinate (N-S) line EC 430, including the mountains Fltiddevarre, Daurnanstind, Rastufjellet, Grönlifjellet. Starting August ath, we got the help of an assistant, Mr. John Harrisson, geologist, who - after a short period of introduction in this volcano-sedimentary area - showed himself as a great help and a good friend. We mapped first, walking from the road, the Badderelva valley, Middavarre ( - in collaboration with Mr. Per 131‘e, "ammanuensis" (rom NTH, who was carrying out some personal researches on the mineralisations ). I. N

The mapping of the inland has been done with the help of the floatplane (two camps of 5 days each, nne at Flintfjellet, EC 500480, one at Holmvatna, EC 621551).

After these two camps, the weather becar ie very bad( cold, rain, stormy wind ...) especially on the high plateaus, preventing an efficient work to be done there. For this reason we started with the mapging of the N-part of C'aikavarre (EC 460500), and also Lille Blafjellet (EC 500525), that we could reach daily from the top of Middavarre ( it is possible to drive to the latter top, but not recommended at all for the vehicle). This wav of doing was the only one to save time and to map, in spite of the daylight getting shorter every daf. Due to the weather it was irrealistic to try to establish a camp in the working area.

The field work ended at the end of September with snow storms. • We think that the end of the field work in this area should be around 15th to 20th September for future work.

Mr. Jan Fr. Holten, Box 75, 9501 Alta, was the pilot of the (A-flight lice-se)floatplane, and used to take off from Storelvdalen/Alta. Despite the fact that we consider him as a good pilot, we would counsel to fl; with professional pilots for field work: he happened to forget appointments.

If a very detailed work has to be done later in the Middavarre area or even as far as Fiskervatnet (EC 498540), or in the 134trgmark anticline area (EC 460470), we can agree with and emphasize the proposition of S. Laux in his report about the use of mopeds.

For the two camps we used two small bivuac tunnel tents (one roof), which were just enough, the weather conditions being not too hard • during these camps. I. 0

Summer 1975

F'rom the 15th of June to the 15th of July ve were mapping the authocthonous units between l3adderen and Kjaekan, and also the Bergmark anticline area which was claimed by other mining companies. This work was ordered by NGU ( cooperation A/S Sulitjelma Gruber - N. G. U. ). During this time we had our base at the boarding school of Burfjord.

From the 15th of July we were working for A/S S.G. We had the chance to get as field assistant Mr. Arfinn Johansen from Øksfjordbotn ( geology student in Troms4, lst. year). His interest for the mountains around his homeplace , for the geology and also his "local" knowledges ( e.g. for the shopping before every camp) were of a great help for our work, which was very difficult this summer due to the weather.

After some working days in Badderen ( Uldaidvarre, EC 435445) we moved to Alta, where we could stay in the house of Mr. Dahlen of Norsk Nefe'in ( to the 27th of August). Later on, we found a roozn with a friend.

We established the following camps from Alta by floatplane (sea-plane)

22. VII. - 26. VII. Fiskervan (0ag'gujav'ri) EC 656523 30. VII. - 7. VIII. Baddervan (Nikkelubb'baljav'ri being frozen ) EC 556422. 14. VIII. - 22. VIII. Lake West of Holmvan EC 575536

5. LX. - 9. IX. Djupvan EC 511464 (cabin with fuel oil stove).

We mapped the area of Sedars Gruve (EC 470480) and the end of the Bergmark anticline, walking from Burfjorddalen and bivouaqing.

The experience teached us that 1 1/2 - 2 days are necessary to pre- pare a camp, including planning the food, the shopping - especially in Alta where we have to go frnm one end of the city to the other, to fMd everything we need - ... the refrairing cf the equipment damaged during the previous camp, the preparation of the "mapping strategy" on the air photos, ordering the plane, etc. The flights were done by Norwing (Alta airport). We had some problem at the beginning due to a new office man. On the other hand the pilots have been very helpful and cooperating. I.P

Camp:each of us had at disposal a 2-men bivouac tunnel tent, with one roof (Fjellteltet tunnel-enkelt, Hell Sport, Trondheim). They reveal to be real "wind channels", the wind blowing through the big ventilation openings.

During the first camp we tried to put the 2 tents in front of each other, with approx. 1 - 1, 2 m between them, and with a plastic sheet as shelder to cook between the two tents. This method should be developped with a proper tent cloth. Our plastic sheet has been teared by a wind blow

After this experience, we could use an ordinary mountain tent for two persons, "doppelt". We used only the external tent, whose borders joining the ground were loaded with stones, this as kitchen tent and wind shelter. It was then possible to have a higher temperature • inside the shelder with the help of 2 candles and a butane lamp; the cooking was less heroic but it was possible to warm the food.

We had problems with the butan cookers: they were working very badly because of the cold weather.

The use of the kitchen tent improved the cooker's working too.

For a similar work we would advise in the future the use of 3 tents ( or 2 tents with a shelder in between), but the tenta should be models with 2 roofs, as we were working sometimes nnarly in " late winter" conditions. • •

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;:7-;bnuder -»•,r ,v31king 2. 2. BASEMENT ( Rai as Grou )

This basement is divided into 2 subgroups.

2.2.1. Sub rou of U er Rai as

2. 2. 1. 1. Dolomite interbedded with sandstone and shales

1,1s formatt )(1is similar to the nnt mapped in Luovusvarri, St Ikkatadfjellet ( Alts mapsheet 1834 I), coord. 755555.

There is an interbedding of dolomite beds and greywacke to greenish schist-wacke. This dolomite has a light colour in fresh section, pinkish, whitish or purple. The weathered colour is light brown. This formation might not be recognized on medium to lost slopes, the dolomite forming a negative relief and being covered by moss, lichens, etc. and id seems that there is only greywacke.

Small cliffs or crevices ( joints) perpendicular to the strike let discover these dolomite layers.

The main outcrop of this formation is on Middavarri (EC 530490) - do not confuse with Middavarre (EC 470540). There is a thick layer ( 10 - 20 m ) of quartzite at the bottom, forming a wall in the landscape when the dip increases. Over the quartzite, there is a first thick layer of dolomite, very characteristic in the landscape, with a light yellowish brown colour. ( We put this basal dolomite layer as an individual layer on the map, and another colour for the whole rest of the formation ).

The upper part of this formation contains much less dolomite layers as the lowest part. On another hand, the greywacke is grading to a schistous wacke, light green with sedimentary figures that might be confused with some layers of tuffites of the Lower Raipas ( see below).

This formation is probably the top of the subgroup of Upper Raipas, and thus outcrops as middle of the synclines. Jr

ToN s

AC-R es --

------""------Ouartzwacke ,„------5 /-. -- -' ---- , „------Ouartz Ouartz arenite Sublith-#.- Suborkose S arenite 25 t "Ot / 4.' RANy es( , / EktwAck / ‘5 tkI5 t 5 s(' cc V ,61‘,R1(1°SIC Volcanic FE RENITE LITH/r 2tVOLCANIC ARENITE IDSINE ARENii; 50 Rock C CALCLITHITE PHYLLOARENITE rkkGPIDITs •50 SO Srdimirdwy Metamorphw

Classificationofterrigenoussandstones(modifiedfromDott1964,fig.3) Pettijohn,Potter8 Siever(1972) (p.158)

Pettijohn,Potter8.Siever1972 Sandand sandstone SpringerVerlag Cnr.wacke ( sandst me with some argillaceous layers.)

- this sandst me is grev-greerish at the bottorn nf the

formati in, getting gre higher up and is blue-purple

•in tht. t )p.

It is yer ,gendus, massiwe. t•nw thin secti,hts studied

ut th( ,\Ita side it sh )uld be classified as lithie c'rejr, acke

(Pettij )hn, etal. It is p)ssible to observe sedimentary

iigures sueh as ripple-marks, cross beddings, etc., with

s uretirnes mdre argillaceous layers ni s )me meters thickness.

Ii pinees there are sorne layers •:-ith fossile traces, s une of • therr ;L)-; ermeentric structures cm )f diameter. )\ce) )rdiag to:ers. Siedlecka CU there are not stromatolites

( pyrsmini1SL assi ug.

his sandst inc appears as dark-green r mks in the landscape.

Very at.e). the surface weathering is masking sedinientary

struetures, and schistosit::. 2\s) fresa sections, these structures

ean hardly be seen - if the). can -Fhe best outerups are

surfuees bleached

It diffieult and time consurning t look after these sedimentary

structures to resolve the detailed structures, as the study of

the inter )p is s bad. Such a work in detail is useless in that

thesc sandst.mes have n ) econdmic value.

Oubcrr iup v.0 I niias

ArgiUlite ( shales)

Ihis rock is dark grey, sometimes claret and has a little

luster, rather schistms. It might grade to a lithie v acke.

'JH a la c r argillite containing o

ratl)m) ixnn)rtnut lurnber of septarian mDclules" (ef. dieti'mar7

))( tcrms, T) dphird, this e. g. at coord. i C 4.).3(15...:0

— est )): II.

lnciç s,»Iists

etual r ick t:pes might be designated as black sehists":

tuffs, tuffites ni even argillites impregnated with

black and/or rusted oxydation products (probablv hx :dation

tic, t.pe is recognized,

it is nidpoeti onUer its arinc. .uften ute enn observe a black schist zdne of s ure dm.

nt the contaet hift.erent rock types, xith gre(mst-)nes (Invas :)t• think these are either contaet

Iretarnorphism phen men ,ns or zones sheared anh

• x dised, due to tne differenue in the rock-competenee

(1uring the tect ni- m.)vernents.

Idlack aud massive schistous, heavy, pr )bably minbralised, witn t As of rusted surfaces )n it and

around the outerob, e. g. in [Cisgangfjellet in tne biergmark

anticline (I C 456456). rhis rock has been designated

granintic schist' in s me earlier wprks. Up t i now and

far as we kn,)\‘ n) analyse has been done to elleck if

ftur is (. (earbdn1 n n vt. )r detail v.)rk it sh )uld be Jr-eked ,f the c :Ipur and the y-eight is nDt due tr, iron

II ,a blnek r )cktype t schist 1J5, sometimes

s metimcs erushed in thin plates. This

t uchist scems t us te be ver: important f the to L H1L. iii fact v e find sueh r )cks as "joints" between

v deano-sedinientai mcm clinal units, and very often

vet, irr.-?guhlr forms in cross sections, like wedges

e. g. ur locatidg thrust faults. these cross secti ins etc.

ght b, bserveb in ealleHs perpeudicular the tectonic

.rt.ructures.j see ebapter 'tectunicH -€) nat think that this r is characteristic

a Jefinit): strhtig,rapniu 1 r. It seems that this is the

resalt •if a tectanic grinding ;f several sedimentary ;)))1):ftagenic raHcs. "'e sarnetimes found lime zanes grey

1n- 3r.

aru ic;;;.-; ( ci 1;mitc -

i-hesei ck type:-) are f negative in the landac;:ne due t their high ;)ften tillee iF qua“

Lit ‘;11 tmder this berciing v.t. niapped difTment r ick type)3:

raaosive dal nnit‘ aite esh sectians, light br )\*.1

v-eathered sdrfa‘T•is, caatiiining )ften veirdets and

n 4.;ie d Tiartz. chert ,

slam, ( t. J cm Car ,ne slate).

t7e firsn (1escriLeJ )91.amites cccur ;ften figethE'r.

del:mite made )f a r.-1) -1()•)f spherulitie nr pisnlitic like

eice cijis, fvari size, frun; s inie hirci t..) the em.

:ne mairM 1 If thc sir nn*)it1n as thi); Elen,:nts,

he cal )ur is faintlY greenish e. 4. at co )1:d. •'"))H5:

est and f;)uth )f the enauntain )C i;iddevarre there are same

sbapolite hearing dalmnite ;-4 inn; in cross

secti• . and l•mg. de Itter -)p V est af 1),iiddevarre

bas bceidescribed b :\)ilnes 1962.

int c ear.samr t:?as of

i; Hiat • ;..1.2 156456 contains verr nurneraus

), inm in size.

iMmc samv Li••1mith nr lirse layers, ,iever

tHaker thnn JalLe meters, -ary irregular (lenscs ^') and thus

suck.yi. (). 9-..Stuffsjtuffites v•. d il.imite lenses. 2. 2. 2.4, Basaltic tuffs, tuffites and tuffo enic sediments. The volcano-sedimentary formations show important variation on short distances. It is not possible for this reason to map in detail and separately the different types of tuffs, tuffites, etc. For the same reason the term includes sometimes rocks more pelitie (tuffogenie sediments), thin lime layer in tuffs/tuffites, and also some green and greenish black schist associated with tuffs/tuffites.

l'he terrn tuff, tuffite and tuffogenic sediment is described here according to the work of Blokhina & al., 1959. These authurs established a classification for the ancient clastic rocks and might be shortened as follows:

Tuffogenic Pyroclastic rocks Tuffite Tuffs and volcan.ic sedimentary breccras rocks

Uniform composition: 'Predominantly Pyroclastic tuffd pyroclastic mat. < 50% Non uniform composition: mat. > 50% a lomerate tuff sedim. mat.<50°,:, Sedim. mat.> 50%

This formation is showing sometimes good polarity (way up, sedimentary facing) usable for tectonic, such as cross bedding, gradded bedding, or the angle between the strati- fication and schistosity.

Thesc rocks are forming generally negative relief in the landscape. When the dip is high they have a tendency to outcrop as "schists".

f3anded rock: this rock shows a banding of light green and dark green bands ( sometimes even greenish black) on fresh cuts. On bleached surfaces the light green bands ere getting whitish and the dark bands light green.

The thicïlness of an individual band is of a magnitude of 5 mm, but might reach 2-3 cm. The size of the grain is small up to invisible (aphanitic). type ni silow ,j1"):S bucic:irvY anct/or

cyaajed bedding, )E. a cy..117.

'5? rippraFr-ice oT this . t.-ne is sindlnr

ts..cy.0

- • n ncihlo tr,

, CO)1")1,-itH

, 7u-L :Hcs, viiCh

bat sLhan thies.Jez-ss

t.21sli- j.eLçlre xt012( zJat Lise, yei'e uch,

mcip.sble. t;ic- .

2.2.2.6. ' :st )sc-3 : E.ttc.-4.

s

use

tri.saltic c si- L}pluti, t :ture

1-.1 ;;1,RIn ni2taiiabase

n.re trcia the sriojcfj1I in 0 )ssii:yration. II.

distinguished 2 main groups of greenstones: - thtoarse grained metadiabases ( or tmetagabbron after the use of Canadian field geologists, considering only the appearance of a hand specimen and not the occurrence, as sill, dyke or plutou ...)

the medium to fine grained greenstones named I tt fi ne grained etadiabasesm• or metabasaltes .

Pillow-lavas belong to this group.

• or all these greenstones", except when the occurrence is very clear ( pillow-lava or other tipical volcanic feature, or when the intrusive character is certain), there is always a doubt: sil or lava flow?

A sill nuight intruse in consolidated rocks, or in non-consolidated r.nd still water-saturated sediments; a lava flow ( submarine or subaedal) might be massive. Fhe distinction between sill and lava is a problem in man:, cases. ( Ihis is a general problem in ancient volcanic area cf. 11. Vurnes in the Solund area).

No typical intrusive contact feature has been determinated safely, as the contacts are very ofteu masked by talus, or are strongly weathered....

We shall mention that the sediments close to these lava-flows or sill are very often crushecl on the contact; this is due to the competence difference during the tectonic movements.

According to the great lateral extent of most of the greenstone levels and their regularity, we do presume that thev are mastive lava flows, aud probably submarine, without pillow-lava forma- tion.

In the field, these r ieks are brownish russet on weathered sur- faces, dark green to light ni same polished or bleached surfaces. The weathered crust ( surface) and the lichens ( and moss in some cases) might mask completely the surface look of the rock, so far that it happens to go over a rock boundary without notieing it.

K

2. 2, 6. I. Caarse :;rainca greenst )ne C metag:dibr ;

char‘mter zed a meta-pphitic na:ta-

inka-sert,d tacture. i s:.orph might

differ, jinpeadim4 !):1 ournlitisati:rn,

rs.tabiHy.t•itiJati

Ceaeralle me can )bservu on s are eathered surfaces

the ht:t f aliuite micr ditt:s oac t )n oifferential etehing

ecery mineral t- P.

:aarai;wu basaltic tuf: $i tIlffitcs _ C.I

a I a beea used to inuicate c -)arse

i tti t.ins) sttp:trate.1 ' tuffs,

rwrites ,rt1HJCllU LZ t ttatekl tett t ) smail t,, be

t.:. ttt ,:naraeteristic n air ph4tos

LL.t.

2. 2 tabr_salt e.-meta air!, ; !y: metaaiabanea, s

it) Ices reeta-)phitic t nmta-intersertal

tey ta

xcent is ettptItr1( t lavit fl ef. 2. 2. "?. 6),

f charaytta Htic valetcde reatures:

pipn lava stream fl.ays wer a wet

anbstratum .--;•M-1,-;)li fl 10w deptn suPrearine

vlnnnir the )re stream rises inta the lava flow,

e-ith a vatm).:abb iorce, lorming "pipes. ,) ha:at eaen )ther, larming an

-; t ; fi;ure

idiavarre ani surnunding

slibit ver: gaad autcrops

tL tl:i feati,H; 1:c tbe tnp of :t•idinvarre "F'it nn the sketch

iddayarrc, see :)elow) ftsere is n laya surface

hnIcn, their nvere being between

?-5 rmr. attain i cm . In

vertical seetinn*; this Invc sul'fnce, nne ,tbserves

the pipe vesic1 along their length; some of them have

beu refilled tte several see pndar-; minernIs. (:thers

ren.ain ernpH, as hand samples resemble a coarse

sciten made f lnya.

-

ninl- in an6 alsn th

lpenlities surfncet: tsith pnlegt mal nets with a

- cm ntibt he observed. l'hey

reee:-1 thoy: =;1:1 ts, be lava fley,t vith c ilumnar

jointing. Lhe trenches pf the old mines in it iddavarre

let sce thesecdurnns in view. 'fne

tcxtnre the rine t;) medium grained. Up to ds regar_leti b:. .Jc );; crie geo-

logists PS a gatiori pluton, according to the appearance

a hand spectc en, this gabbro e.zplaining the presen-

ce of the minerailsatinn

thci nt1-1 inet bat.,citie lnvc y-ith

cedumnar jninting in santiTyien bet‘et,cn tuffs, tuffites

nnd pillow-lavas.

in 21(.:.fje1-Lt 5 G - aL ennobserve if the cylTimus, forming carved

sliccs up t cm thick, perittn.r.2icular to the axis the colum.n. ( l'hese slices snnuld ant be confused

'T.ith the I. e .4n nIs ) present in the

enlumns fl snme

t il tir thcse deserihed valscanie fT;atm•es, and the fall v --Tava ( er. aext paragraph(

ata ..[[)milutely sure, aud ark very fresia-Inaking, as

r,n0(1P5 flflV n[ia-ht be nix:_et• :d q[r::)dern valeanie

area, such flS Islau[t Ital

crn t11:11. ' ; i)in.ces the

,tt .feea Frti hclvv. bhev had the

7-.0c1h ti

L 'rt-j112. - sfrurtun:.

Tt y0gri,zrel tert y vrmed

[e[ at IcpI ijs 01,J ana[-s.iturated

siare vel[ 1113c-mtributed L1(.1; :j1t1

eit( yia .(.): the n:i icati n 1).[."--1. •

Cisth“. ti t:i lItt I ti .t

k "J4L, ‘HI;y:»1.11 lv vAtv5zeri ,

p s nrt. <111,1 1,t'l in the .L ainas

hoy nis er 1.11^17)-wtLint

layeus" ipht foll0W( I fr fl ine i, the ptber side of the

ahDuT , perhapn cven ire). T;'ne t[..)

Le partl )1[.. tect alang

ii - it is uat to guess thir extent al[ang

tile GrAtif.[ig it ectiiri. hc,". are gence[ally arearring as

con[iple.0 .21[[\[,[: th, v ttuai my the t p eil ut Inea stream has

sichv stla.L.tui[e; tvu re.it vf the ..2treara cau. Istihg DI massive

lava; accurs hI tween lava.r..a'ers

il. twIlfaYite fd-between.

is onn of tht most iniprtnnt of the

ar )ozi p ond tois ?n. Long

all t?-1, parts of tHc appea area

es er bedding

-nuauties and

:,:partant

th: tectrei oo3, the fieln :reo.] aid rlDt

,-;ocod lot timn onterops to find

ut r"-t lava strealt ap detcrmiaa-

A fJ1r D1 tiie ruci: tne

re the

10: ol' Luspected

fl roek: sna. green

it is it r,)suible ta rc4e, t pt: is

oc -nn: 57 practleed

raUvoell joiilted and separated

•Yher 'e the ctisass• ceusl, about bet,yeen

CtlCIt chert i5 rMU)(:. nsion nf

ra;iges frorr. about ein iii diameter

one 5 to i , 5 - , r;"ni , but

theno are betweea (i".)to

are shnv:ing deformatfon

es:eept in one zuiri, in

t•hree (limensional, the pillo,.vs appeor as elangated

sISCS, the eross section af. abiuL (..hanges very

duickly, from a circular ta a flottened forrn', and vdth all rne Lclassiealr seetioas sac) as herw' , balloon",

with one ur several stems.

:.;(nr,ctimes a belb ...;nnledmes

the.- ,,e.;.[ paft3,thus the chreetion nI

teF- uv. v Liag,-e-,t iiji.dSzerh it is even

Te-FI :".1af; been

itinT1 ,1

jiliwo irs1

a.,-.I.struu- L.L., J: (,,a.. r.e2.1-,

:i..:,te.. i i toidc to ti. IriuiIe, nr, 2 Cilt

:

i. litie )ee.

, i e.ither,

the-,-: jr zone ( or rj ned the-y appear

s z)„fe 13

a b- ut tac),

r all t': the e pt wberc:, i3tenc .); the

s .air fillo. Tvita very

rer,--e•e nu±nerous an6 muel, lens visiblel.

ary-gclules

in the ary-.: tee ueatt.r

, the

tbe. ii:socc1r3 rt: zDries,

- :ring in tee euatter.

fine intersertal

: tnl v-ith a

btf .1

albitisadon, ehloritination,

the tenjeley to reast: the original anne- r i Iiit( it .‘appe,-)s tirit thc yeea!!les 1-11'

tne ii.l.nr!!!!"(!f121:11.•:

eec: ese with tre.!

r

ert,

i!!! asil!;-

H(!„! L1 1

!!!•!..! !! ;.!! kI1 xsLaiiding

brian

in.tt !

ers.

. t ;-; hrc hcr.r.

tir,!!

\ iJ'NI11 JR t th''r

el;" Y103C

: '".: 1. 1 tcatures pillow-lava flow

crust of

— the pillow

hole in the crust 11. of the illow

It is possibletoobservethemodeof formatiomofa pillow-lava alongthe riverGammeelva the crustof the pillowhasbeenplerced (probablydueto the internallavapressure)anda new pillowhas beenformedfromthishole.ltisan evidencethatpillowsareprima- rilyinterconnectedandare not isolatedbags(=pillows...). Cf. recentspapersaboutsubmarinevolcanismandthe filmof Tepley& Moore.

NOTIC£ 450‘17" PILLOW-ZAVA

kke ca//ed pl/opi-/ava 0,7/7 rocks _roikving deady sonie

11, charanieriilic e/emeats- ot. fillow-s/niclute Field report- 1971 .

cAP for Chrish'aw4Striefk filta cifecf) pliow.Lnw l et egfrad- _

• z w,lif 'ej $41.4.> • 1 41 to, (CAT.eff C DowN \sfew

rfrery /9/VP 11 ni ,OsSiNe, kre axed tdlow to 4.1ernilite

pcsiNem 01 sede (normed or 6//e9-.17k4down) 6enercd/y A-dows- 79.-mcd/onxhave ar fed06.-rA kowil

weaMer1/218 ca/or .(krign. /ook>iy FreiA fecl/wfx

111/:94/ (47-k yreen, eve), knillout wril/e fhwricgre g

2, 2. 2. 6. 6. Metadiabase "interbedded"(?) with marble "la ers". We found in a single locality, as elongated hillock (EC 355610 - EC 373602) a mediumf coarse grained metadiabase alternating with coarse grained carbonate (marble). The melanocrate minerals (dark) are elongated along the structural direction. On cross sections, one recognize a blasto-ophitic structure, with lots of veinlets and epidote zones.

The marble occurs as bands of 30 - 50 cm thickness (sometimes 10 cm only) with a "layer" every 2 to 10 meters. As for all the carbonate layers, these are difficult to localize on smooth slopes. They are easy to be seen on vertical joint surfaces perpendicular to the structure. The dip is about 400 to the NE and is getting steeper to the South ( to 60 - 700), where the frequency of the marble is increasing ( one zone every 2 m ). When observing the marble zone on the cliff surface, it seems that there is some "boudinnage". The metadiabase seems to have been deformed, elongated (tectonically); this is well observed along the foot of the cliff.

There is a little problem with this outcrop: does it belong to Lower Raipas or already to the autochthonous ( this latter containigg tectonized greenstone lenses in the Kvaenangen area)?.

The position of this outcrop along the border of the window and the fact that this rocktype occur4nowhere else didn't give us the upportunity to resolve this problem. 2. 2. 2. 7 Ultrabasic We found outcrops of a met4ltrabasite, probably a partly seppentinised, tectonised and metamorphised lherzolite in a " tectonic zone" as a geological "scar", in a single zone, following BfElfjellet to the W, emerging out of quaternary deposits. (EC 487531)

The weathered surface of this rock is orange-rusty coloured, with lots of serpentine veinlets running in all directions.

On fresh cut this very light grey-greenish rock seems to be monomineral, made of tabular cristals of approx. 2 mm size. In fact we can observe serpentinised pyroxenes and (?) olivine in thin section ( see ch. 3).

This rock is the only ultrabasic inet in the window, from Kvaenangen to Alta.

The closest outcrops around this ultrabasic body are black schists. Our hypothesis about the role of these schists seerns to be confirmed.

This ultrabasic body disappears to the South, in the direction oPflintvan. T

0/ doode IS .911

horzburplo —frvehr/de

/herzoIde

Ig 4.9

art4oppo- midne ,reinte offSe webslerde ckhopyro- xende Al

Opx tve slen e arthopyroxemle ch»oppoxeode Fig. 2. Classification and nomenclaturc of ultramafic rodss. 01 -4- Opx -t Cpx 4 1-11)1 + Bi -f Gar 4- Sp) 95; Opaque minerak ...„ 5. Fig. 2a. Ultramafic rodxs composed of oUvane, orthopyro.ere, and clinopyrosxne.

0/ doode JO

) k pyfaxeoe kornNende • pendoldes— perldoldes ppoxene- hornb/ende pendobles

IO oin»e ppoxe- tz, alikvhe- offil»e ndes horoNende ppoxene hornb/en- dde pyroxendes hotob/enade kat' fl

tt,'L se libl - ,oporeodesharnNende pyroxene »orod/endde pyroxendes hotob/endlle Fig. 211. Ultramafic rocks that cmstain hornblxndr. Ah rføø. 1U6SSwkomillitheon ifre 4slentx lysteat, IS nalidtcati*,and konacbbne0Ç Olukkic4h , sencsnyesdaimuP

(far/ 6/Yon er fhciic rok z 2 2 .-?)

151: Subcornm1ssio1 n the Systenprics of Ign. Rock. Ir distification and Nomonclature of Plytonic Rod:s 15,9

Go1 or - 8.< 0/ . _ $.4 17 (7 -c; c Thc Schcommistion scoa•eY,s udnd the prefixes 17:(7.1- and felfe0- to 1,11)11.111. lite Inone feber acd, 1,1f1 typos F erb :rda comc ditec ..\,/ 21 / Wi1}1 11,,1111,11 (, runz.”1,. e1y the leu.-0- and n1 • . y,rns of

// 11» c.10.1 rotk group. proti \ es loceo- acd ncla- procetle t.he oot nrce:

leccdto louLogracile, homildonde-biotite cledvarano ir,”he letc o- \ // Ilnarty diorito, ;nola ulivnilt .Wbro, nuela -nopl, • le diot ute, nepho!:no-bcar-

.ccd melasycnito, etc.

At ncrtovite, apatitc, primary ca Onl3WS, etc. arc considered commonly

fe/at winerab, color miii t's,\s delinei .11 bui:1111“,:

Opx N1" \ — attovitc, apatite, prcnary carldwart, oted.

ocks Olav so be c,rouped accordCr; to cot,or indot: into IC!!("OCIJr,1:

(N1' 5', ”:c>, (,.iinc (NI. --65), nnef.zw.crark (NV : 65-1(17.1, an/1

rocks (NI1

/ 4 0/ /9/ bsplandcion to 111g. 4 (p. 1581). Opx 1 (lun1le (iiiiVIT11te) Cpx 2 welnlire • 3 nu:7olile /burire 11, p1,1n,- cipnt 5 roxenity 6 websteri(e 7 o1...,ne “(-(11pm \ en1re

1r1.11.1.1,Hel

/7,/ Op x •.• 0/ ' % - Cpx ..... -- r inx A ••• 11 inp(:, 111.., 4 ( r.1),•1, 111,-1 .1.,,I npine.,(1.11we ilf g.11,1.rp1, and (11ir.u11aln locks 111 (11(• 14 11•11-1“1, iepep , tne11-) 1,-r.111,-,1rpn pl p:rin.1.1.c — or(hop‘rpsune — 1111111;/1In \ ent. -- ohvine. 15 1-1 in,n,(1.1se belring dclitp‘ro \ enire of 111,- ipp 11R-,1ron. 16 plp1ne ;1.11-1,p, hU:n-,1., 1,1 Sc,ItIlll 0 f Ii11 1, P.,11,-,1rup .dping the 1111( 1\ 11 .C. 17 pl (1.111(y)lornite ne,Inni il/ the p p 111,-,Iplp p.p.111(.1 in (11(' 1)4.1. pl op sO percen( p1.1e,10- 11( jrli0.ut1ap.- bl 11,11111'e .1.1.,• .(n.:(c.p iipprincli1.111‘-e fur pl.n.m..11,(. “n1(c11P, ('1 10 --93 pen-c,,,1• 19 (.1 1:21:1 isn-1,c.(11n111'"Ii't"r) l'1'1;',C ppr1te (.‘ d . cula harna..4.4itr-g-s a. 22 ./(tti.u.c innitz p11.1fle pyinn,n.ro en1,e .rhe flot a ttbeine for 1,t sLi I eLnrrim,...li. are (tel1c(r.“1, ((i . .l'tn r::'-‘ ihe

IINNist;i ne pin nnk t(11.1n1.• .9,4111 4/11),31 441 r».41/1)379 -111 f ititn.4.9)W

• • • • METAMORPHISM, GEOCHEMISTRY and GEOCHRONOMETRY

3. 1. Metamo hism (rom thestud of thin sections)

3. 1. 1. Introduction Most of our (meta-) diabases have a primaryiophitic or intersertal texture. The recrystallisation during the metamorphism did not affect the same way all the rocks. Some of them still exhibit rather fresh primary textures ( blasto-ophitic or blasto- intersertal), some others recrystallised textures ( grano-nematoblastic).

The effects of the metamorphism are as follows: The plagioclase have been transformed in albite; The augite are partly or completely ouralitised (actinolite). Actinolite crystals did grow in all directions and everywhere, and also epidote S ome zones in actinote have darker outlines and cleavage border. This is due to the formation of hornblende, showing variation increasing of the metamorphism, to the upper part of the geeenschists facies; this is confirmed by the apparition of biotite.

3. 1. 2. Usual ara eneses and metamor ism rade Some parageneses found in the basic sequence are : albite/ augite/ ouralite/hornblende/ leucoxne/biotite/carbonate albite/ chlorite/ epidote/ quartz albite/ Ti-augite/ ouralite/ chlorite/ epidote/ leucoxéne/apatite albite/ augite/ chlorite/ actinolite/ leucoxène. In some cases the leucoxène ( from ilmenite) is dissethinated in very small grain and in such a way that the optical determination of the thin section is getting impossible.

In the pelitic sequence ( also in the tuffs/tuffites etc.) there are some neocrystallisations of idiomorph crystals of tourmalin, interpenetrat- ing the neighbour minerals. (Schorlite).

All these parageneses indicate that the rocks of the window belong to the greenschist facies, and that there is a little variation in the metamorphism to the highest part of the facies.

3.2. CHEMISTRY ( main o des)

3.2.1 Introduction It has been established from the microscopical study of thin sections that the meta-volcanites of the window are roughly metabasaltics ( - metagabbroic).

This fact is confirmed by chemical ar zlyses. We plottet the results of analyses from the N-NE side (Alta-side) of the window (number 1 - 11, marked on the diagrams with circles) with the results from the Kvaenangen side of the window, to show a full view of the window's chemistry. The results W of Oag'gujav'ri have the number 12-22 and are marked with full squares on the diagrams.

The results are monotonous. On the Alta side there is a tendency to spilitisation.

The analyses have been made on: pillow-lavas ( border and center) fine grained metadiabase coarse grained metadiabases tuffs/ tuffites

3.2.2. Data from the rocks on the Kvaenan en side of the Alta-Kvaenan en window .

' eL

G Enour. fllCAL AKaLYSES Rne Fl«ore;cepte, • DEPARTMEWT OF PETROLOGY, U.G. .44 ...... 441,41,44,*.¥1,

OONCE211 11049 louE

SPECIMEN 51027102 AL203 55203 FE0 /190 850 CAO 11820 K20 19705 1120- 1120. CO2 SUKOX. (1,,,,d4)4 Di,grarn numier l2 1128 A9.11 0.95 13.39 3.13 11.39 0.29 6.02 5.92 2.77 0.45 0.18 0.01 2.43 0.23 99.21 /7 1265 46.63 1.47 14.18 3.42 11.51 0.22 6.34 8.24 3.83 0.37 0.19 0.03 3.63 0.19 100.65 /4 1333 47.11 1.40 13.66 3./9 11.64 0.23 5.43 10.35 2.26 0.15 0.16 0.00 2.15 0.29 99.64 15 1365 45.69 1.15 12.75 4.84 9.22 0.18 2.52 0 .13 0 .1 5 0.13 3.54 2.97 103.21 /6 1115 49.15 1.33 12. 39 3.51 11.35 0.:// ').:3:2 1 1.41 2.75 11.64 5.19 C.3) 2.77. 1.16 123.56 /7 1153 47.33 1.05 12.43 2.51 7.95 0.22 13.19 13.37 11.16 0.11 0.16 3.13 1.62 3.46 100.54 19 1289 49.14 1.05 14.04 3.30 9.77 0.22 6.52 13.11 2.13 0.11 0.13 0.10 2.61 3.1. 99.55 3 01183 43.92 8.95 11.95 2.55 9.97 0.19 9.52 9.32 2.23 3.31 0.14 0.03 3.25 11.39 99.71 20 01153 49.45 0.95 11.94 2.4S 9.81 2.19 9.51: 8.51 2.72 0.01 8.15 0.20 3.25 0.51 99.52 2/ 91185 45.93 1.33 14.19 2.92 10.64 0.25 9.91 8.89 1.61 0.,6 0.17 1.03 3.83 ..1.21 99.54 22 01185 46.79 0.97 12.51 3.33 11.00 0.25 10.63 9.23 0.90 0.03 0.17 0.13 3.57 5.21 99.37

o( rir) furtor

dr.10:“ 0)

hernblerde coxeneth:otite

ene

o: r-2.1 18 no 1 1 tethorr.tdend ploo-e 1 or i trf 1 ruroxene

19 467531 p

crunolite pidote,rhlori'mraibite4leuroxeneig.:a i 71 EC 34254 pillo• (or,ier)

h:a 'er.mrtn1 (center)

u11/-4135530 ultrabasic Lorp,ifitiffised tromolitefclinochlor~lHorte:phantom of olivin in trpmult” (no diudyse) krorpletely pinlIlI0111 ot pyroxqn (r.rrrioulorpho,,H in armhbol)fleur,oxrnefowl,we toctøni nedi iiiPn showing old cry5trds borders p

A113KanortMe

zoisite

60141 : (pidote

1 d 9,11'fit ...... tchlorees ..(faittl au 0- 72-lbrte.... Basattes // gockr \ -',...... i .... / ..-1 .... , nepheline\ -.. .r./ amulUbtes 1 i .,,/ \ pyrox nesi ! ...____ pEndots silice, quartzskipte -200 '..<-\ \-100s minemis100/ AI/3-Na

orthose 460orthaie leucite

Fig. 2. Diagramme Al, Na, K. Domaine des basaltes et champ des asso- ciations spilitiques

AW3-K **s.nFtr À.

200

---- 1 I "-.."..ffnardlonitar ---- i ---- Vhiellite .z.. I ---- frOi« .--- i rment..--Gjr AIN i 1 '9,;fites asfel•oilitic \ i ,.. /,.. \ .•• ' , tocksn t (419 / \ . ‘ 5, aite 5‘. ,,,..t.31.• i 4,.., -T.T.,--,r`-Nyte • -c,..co cit.., fl'ecLrez . cer .etc+itti f0 700 -et iraiites i d e... •:es Fr. rt:trsis AI/3-Na o- i / / atiotite I m s Zone des bosa0es \ .re.: /:-. secteur s4dirnenlan \ i ; v..conite 112 W1canisrne spitrt.que / rzt tkIcartsrne cicc'n sodiqueAraitique \ / ' • 'e( prercces 01.100.01~5) Votcaname ccOcoakatrt Ftrtique / LEa VolcrirsineUlcieLlAue et orcwnces p(Jtartca:at almdines) -2()0 / Voicanames rtterniores let PliZzlismes m me chrnie) "10, Fig. 1. Diagramme Al, Na, K. Disposition gen'eraledes associations volcaniques. Leur opposition par rapport aux associations sédimentaires. D'aprés H. de la ROCHE (1968)

g)(ple of Pheofra9rarn(27.3.22,1) fl

i SI/3-(Na.K.2Ca/3) Quartz

/ \ / \ / 400 \ \ hypersthIne \ / „ ._ / mwmei200 \ \

chtorite / \ fro#: easaltes Plagloclases i minercus \ Orthose l, -800 -600 -40Q1° 1 -200 *Sfitle, ard Siejlfic 200 1.00 epidote / augite K- I tua+cal — Roch< / ° -200 leuate / igala• igh1,411.37/1

I. nephefine

Ihn4f 11•00C1411. Stoluie •

• " Btoc-Diagramme avec Na.K en Altirnelrie Micas,hornbrende,auate sur la droite 0 r-An Hyper.,oliv.,mmerals,carb.x, dons plan 0 Feldspothoaes x sur prolongement plan Q-Ab-Or vers le haut. olCak2e x mineraux situs en avant de la figure. non reprfsentek.

Fig. 7. Diagramme Si, K, Na, Ca. Domaine des basaltes et champ des associations spilitiques

?< of the dric(9'rcfrn (cf F

3,2. 3. Dia rams

3.2. 3. 1,Dia ram asd

(114 k 6p) (441 6,» 3

These diagrams, established by h. de la Roche, G. Rocci and Th.Juteau 1974, allow to put in evidence and to show the specific character of basalts and spilites, better than the classical diagrarns, such as Harkey, Niggli, Peacock, Jung, Kuno, Murata

The parameters have been calculated with the number of milliatomgram in 100 grams.

3.2. 3. 1. 1. Diagram (4/ - z_- ().11 N4)

This diagram shows the differential " behavour" of the alcalis compared to alumina; it is possible to distinguish the "sedimentalty weathering" ( "degradation sedimentaire) from the igneous differenciation("differenciation ignee").

" fact, part of the rocks of the window are in the basalt field, the other one beingighe spilitic field.

ifro 4 ,e4 Cai 7/(k— (FatC4)) 3.2, 3. 1.2, Diagram 3

The interesting fact with this diagram is that the vector showing the transition anorthite—~albite is projected on the diagram as a very short line, that might be assimi- lated as a spot. This latter fact allows to avoid mistakes, in the case of modal analysis e.g., due to a too high albite content in spite that the basic grade of the rock did not change in the case of spilitisation and metamor ism s' ..(Na.K+2Ca 7 3

200

517rui a 100

V 03 .4 a K-(Na•Ca) -400 -200 100

• -100

02 100

14 .18 e21 al3 ig°3 o7 ,11 12 •22 519 or .17 8 20 or

04 50

N 7-a 150 -100 -50 50

-50 One observes that the rocks of the window are grouped together, showing no tendency of differentiation along one of the classical igneous serie.

The dotted line on the diagram indicates the limit between tholeiitic ( above) and alcaline (under) series.

The tholeiitic character of flie wIndow appears clearly.

3. 2. 3. 2. Dia ram FMA ( total iron oxyde, Mg0, total alkalies). This diagram shows the " monotony" of the rocks of the window, and the very tholeiltic composition of the columnar basalt of Middavarre ( no.17).

3. 2.3, 3. Dia ram Ca0 NaO M 0 This diagram shows the decreasing Ca0 to the benefit of Na20 in the spilites. The rocks of Kvaenangen are in the tholeiitic area.

3.2. 3. 4. Dia ram Ca0 NaO K 0 This diagram shows the very low content in .

3. 2. 3. 5. Diagram C4 0 - r 01) L 0 j0 li is possible to put a limit in this diagram for the apilites. Fiala 1974 ( in "Spilitic rocka") proposes Ca0/ Na20 + K20 < 2 for spilites. 03 09 1512.14

ci‘ >16c41 ? 188711862 1122 .019 20 02 v• •

• Ca0

o2

Mg Na2

Ca0

17 22

7

o< 2

Na20

Ca0

o 6

1,21 5 05 oll 14 79 4 o/

o6 3 20 I2 oli2 2

o9 o 7

oh o 2

Si02 111 4.0 45 50 55 60

Na20+K20

o2 6 04

5

ol o7/ 9/3 0/19 4 SI ./

o/0 16 3 09 .12"/ 20' .15 og,A06 o74 / .78 71 2 05 .2f," o 3

22

I7 SiO 40 45 50 55 60 2 I• LI

sy -)I1TUSCC metamorphism is smaller. The preliminary age is . 9 approx. 1,4 10 years. Due to the metamorphism, this age is certainly too young.

The following work will be done: isotopic dilution - analyse for some samples due to the very low content of K.

some Rb/Sr age determination, this method being less sensitive to metamorphism.

The full results will be published later in Norway, after the agreement of A/S Sulitjelma Gruber.

• •

•

•

•

, 1.* C f IC

i'he p darit rva up) eritergns 1:sed t I res •lec the tectgnie is:

lava ( se€ :. G. 4. ). he pillahrs as mentioned

bef ‘re, irae the main tectonic element, as the lava-fla:es

are rather r€galer and rhight be long distanee.

hese as Pl'et therefore the la the tect nie ( for the stratigraph : the pill vi lavers -wour

nt dificrent stratigrapaic levels);

)ther tiaatures, ci. ntirmi1g in ceel ease the polarit )b-

SEil'\ ed i pillas, in tuffs, taffitea md turf agenic beas,

051e als , arc greowacite:

gradied bedding

Ci SS; beairilig

angle b‘ftv•een sehist :site and la e ing.

i-ectonic st ja

It is not pos:-;iblc to rec ignize ana t i ase the asual teet-)nic

elements ( sucn as drag iglas

the teetonie st le is rather hard, ricarli; nut pliant. fhe dips are

verv aften steep, the structure isoclinal, r as "schuppenu

( lindn It is rather seld jn to find a real sHnelinal .or anti- elinal f1a, execpt the svaeline

( IlL :5•3u49] - C

ften the tect )nic units are separated zancs black sehistsi

that seen: tG be erashed z )nes more than lith 1 gicri facies. ihe

ibservation )1' the cliii in the end thc Hadderclva valley

4 54 t.) ,nNrrn it. 4. 3. Tectonic ma E lanation to the tectonic ma The circled numbers ® • ® are referring to the tectonic map.

Montclinal unit of mainly coarse grained metadiabase and black-greyish sediments ( also some scapolite bearing dolomite to the W). Steep dip to the W, way up not known. Laying on unit number with a thrust fault.

Monoclinal unit of mainly lavas and volcano-sediments: pillow-lavas, tuffs, tuffites, fine grained lavas and some layers of coarse grained metadiabase. Steep dip to the SW. Way up: up-eide down, shown by pillow-lava layers and sedimentary structures in tuffs/tuffites. Between units 0 and 0 : zone of black schists, stnIrgly tectonised. Between units 0 and 0 : important fault;

Monoclinal unit. Stratigraphy ( rock types) similar to unit 0 Steep to the W (SW dipping), leas steep to the NE. Close to the limit between units ® and ® , strongly tectonised zone, shown by deformed pillow-lavas ( being elongated);

Monoclinal unit of mainly coarse grained metadiabase, tuffs/tuffites and some dolomite. Low dipping to the NW, wayup unknown; 0 Monoclinal unit of coarse grained greenstone, dolomite layers and some tuffs/tuffites. Many faults in this unit. Way up probably normal.

Between units fl and fl and C) and (i), zone of black schists; 0 hnportant monoclinal unit; upside down. Volcano-sedimentary unit: important serie of pillow-lavas layers interbedded with usual lava streams and tuffs/tuffites. Way up shown by pillow-lavas and some good features of lava stream's bottom ( gaz pipes ...), and also by sedimentary structures. Dipping: low to the W, steep in the middle and to the E. Between unit ® and 0 zone of black schists and pelites. Monoclinal unit. Cnuld be upper part if unit (-6-\ , but this is

not sure. Consisting mainly of lava stretars inderbedded with

tuffs/tuffites; the lowest lava-strearn is sh :wing a pillow-lava

structure. Steep dipping to the \V; upside c:cwri. Between

unit '7; and (r9-'),3C".") black schists

Yold along anaxis, dividing an anticlinal structure in two:

6.21) and.

Anticline, both limbs dipping to the W. The anticline axis is

probably a Malt, at least in thepart of this enticline.

1;ock-tpes: meta-diabases,streams, tuffs/tuffites • and some in.p.,ftant dolornite layers.

Important volcnnic sequence of columnar basalts,

interbedded with tuffs/tuffites, pillow breecias. Dipping rather

flat to the , steep to the S. rhis zone is forming an anticline, which --as in fact the same as

the Bergmark antieline ( nb but has been individualised by

a folding alang a axis;

'fhis zone is strongly covered by quaternar:; deposits. It consists

of sedimentar, la,yers (gre., wacke etc.) uith septarian nodules,

and black l'robably a teetnnic discontinaity between

111 unit 10 and 11 . T..ltrabasic rocks (lherzolite, partly serpentinised, outcrops as hills);

Lavas, pillow-lavas, tuffs/tuffites-

Very tectonized area, v-ith many faults, thrust faults, etc.

General dipping to tht. , ver1 steep. Wav upside down to vertical

( way up to the 1:);

(13 tavas (. with columnar basalts), tuffs/tuffites.

Dipping - vertical, way up t.) the V.

Between unit and L black schists and tectonized zone;

between unit and 4,, probably normal contact; IV. D

Sandstone of the blpper Raipas sub-group. Way up to the E. The upper part of this sub-group consists of interbedded sandstone and4)lomite ( see 0 );

Formation of interbedded dolomite and sandstone, with a quartzitic layer of about 10 m - 20 m at the bottom. The number and thickness of the dolomite layers decrease to the top of the formation and the greywacke is getting more wacke, and the colour changes from grey to greenish. The formation is forming a syncline, whose fold might be observed from coord. point EC 545513 to the NE on the side of Didnoidhar'ji. formation is disappearing to the South because of an axial dip to the North on the Southern part of Middavarri- Nikkeluob'balat (EC 530470). This unit h overlayed to the E, (rom the South to Didnoidhar'ji (EC 570515) by autochthonous and allochthonous units. On the North of Didnoidhar'ji, there is a fault between tlds formation and the next tectonic unit to the E; 0 Unit of lavas, pillow-lavas, tuff/tuffites, dolomite & Lower Raipas), and the beginning of the Upper Raipas greywacke. Dipping steep to the W; way up normal. Very complex tectonic: this unit is laying over (?eo-carnbrian ?) white quartzite ( thrust fault); 0 Mountain of lava ( fine grained) on which no structure has been found in the Northern part. To the South, a pillow-lava stream and gradded bedding in tuffs/tuffites indicates that this zone is the front part of an anticline fold, the middle of the fault being faulted and the Eastern flank upside down;

Serie of lavas, pillow-lavaa, tuffs/tuffites, forming the limb 4 an anticline. The other limb is covered by the Bossekop quartzite in

this area. Tlds zone is the continuation of 3 , but is locally inter- rupted by faults;

Dolomite and sandstone of the Upper Raipas sub-group; 111.E

Same formation as , forming here a syncline too, but much more isoclinal in this case. To the N of Bavtavuolesjav'ri (EC 625520) the syncline axis disappears slowly in the air above Botnelvdalen, bending to the ENE. The Lovosvarre formation between Mattisdalen and Botnelvdalen is the continuation of this anticline-middle; 0 This unit consists of the Lower Raipas sub-group. li is forming an anticline whose Eastern limb is upside down. The Northern part of the anticline has been strongly deformed during the folding, this showed by the folds in the dolomite to the North;

"Island" of Lower Raipas meta-volcanites limited by a fault on the NW and unconformably covered by autochthonous tillites and quartzites tbthe E and S;

Zone of Lower Ralpas meta-volcanites, corresponding probably to unit 0 , as other Iimb of the syncline whose syncline-axis is in the 0 unit. The structures ( pillows, gradded beddings ) are difficul.t to be found and are in a bad condition; 0 Limited by faults, zone of aittochthonous ( tillites and quartzites) and allochthonous ( nappes) covering the precambrian;

Pleteau with an important cover of boulders, showing some outcrops of Upper Raipas greywacke and some of a nappe made of quartzitic sandstone very similar and difficult to distinguish from Upper Ralpas: ( cf Ch. II nb. 2.1.1. );

Very tectonized zone, with lots of tillite beds and tectonized greea- stones. It is not certain that these greenstones are belonging to the window's structure, or if they are ( precarnbrian) tectonic lenses within the autochthonous as it occurs ia the autochthonous units North of Buy'ravhgiera river (EC 550540) - (personal communication from Mr. Inge Bakke, NGU). Iv. F

To the South, E of Baddervan, a zone of greywacke, probably Upper Raipas. But it cannot be completely excluded that there is + here a - quartzitic greywacke belonging to a nappe ( cf. 0 and Ch. 11 nb. 2. 1. 1. ) ;

@ On the flank of Didnoidhar'ji white quartzite with a dip slope. To the E and SE of Storelvvnt (Cav'dajav'r1), folded rocks, quartzitic ( - gneissic), belonging to the nappes. •

• •••••... • , *;• • „.

.74 v. v•<

...... ,,,, '''''...... #.# .(:)""(;):

"

1 4.

7- 1 _Z

D 49 •

4

'PI

•_-*•••• • 9 •

•

:5.4‘

9 Definde llssomed

4‘ _41.41A.L. LÅ.L Thrusf pkine Lineamen/ 24 L -L lingu/or unconformify D1» normal AAA _a Foull (1hr ri.r/9 side down Fatd, or joinf Di,o,no'rroyi.",„indicabon Syndine Zone of:O/ack sk-h/sic-„ Y Rnlicline Ro/f2os sub9roulo - - 13x/o/dip Zower Rolyos slivkyvroujo Pillow showing ;‘,ax (9„ 1 , 2 el'c See descroofion (re,00rf)

1-• TECTONIC MAP Of THE AZTA-IWAENANGEN WINDOW (AraenatIgenside) ,Norbs,ay Scale 1/50.000 Alopsheels Kweniwz9e/7/734 I / 834- /515 ilmir‘. Opi.de tn1n1ra1091e Gevus,ve Is r.c/es Nciredchers 6RUBERCH—/21/ GENEVE 4'

c::1) Siae: 790 5‘62 a

V LOCAL DESCHIPTIONS

5,1, Middavarre (f.0 460540) Lx lanations to the eo10 ical eketch of Middavarre based on the air hotos (E 7) E 3 (F' 9), ni ht 2025 from P'ellan er-Wider e A S.

a - b way followed to establish the profile ( next figure) from the cart track on the top of Middavarre to Gammeelva. the river has digged its bed in a flow of pillow-lavas; Vurther clownstream from b the river has made a canon in the lava flow,. go')d and didactic outcrop showing a pile of pillow-lavas with a characteristic "younging" or sedirnentary facing" ; cliff made of pillow-lavas. rhe cliff allows one to see the pillows in a three-dimensional view and to study the formation of a pillowed flow. The bleak plateau at the foot of the cliff ( approx.between point b and d ) is made entirely of pillow-lavas; on the track, cleaned from the lichens etc, by passing tractors, a typical outcrop of pillow breccia; L. glacier-polished surface cutting a flow in no particular direction, showing the internal structure of the pillow. About 10 rn from there, a lava surface "covered" with the holes from the pipe vesicles; a pillow-lava breccia outcropping just on top of Middavarre; several good outcrops showing a polygonal pattern, which is a perpendicular section of columns of basalt ( basalt with columnar jointing) at the end of the cart track to one of the old mines, outcrop free of lichens, "polished"; on a small hillock, close to the lake; on some rock's surfaces outcropping close to the track; trenck of an old mine, with columnar jointing as a wall. WMMN eneT-mOTI1 WM6 OT3DaJ2 MOTIT. kffia •••e';inntl‘n.n: >1.202,1 neygin.1 ;uiJo.;uopunJeInuu crcr cyl;z;Jpn- moTeg aUfiri 11~ u; uaneLe:dx;, J; No&fl ' Noe1 lIeD AJetuc,9 leall

E 8 2025

rApauturee /U/r$1.0/`,.:

8-7F filidelayQpre c

carttrack Gammeelva Afiddavarre

600 clIff clIff

400

4 / 2

° 00 200 0 0° 0 ° ° 0 -0 o 2 00 tet In •44 468535 0 EC

tufttuffite f younging direction 111111111columnar lava lava , one layer on themap pillow lava j

ri I

1)pillow-lava2)bandedtuffite3)pillow-lava4)massivegreenstone(1ava) 5)smallpillow-lavaOpmassivegreenstone(lava)7)tuffite,withsome carbonatebeds 8)tuff/tuffite9)massivegreenstone(lava) 15)tuff/tJffite with crossbedding 11)pillow-lava,difficulttorecognizeon polished& weatheredsurfaces12)bandedtL.ffite(swamp)13)massivegreenstone(lava) 14)columnarlava yt“I1.4TA

• • • • VI ECONOMIC GEOLOGY

As mentioned before (cf. "1.2.2. Previous work", "1. 3. Old mining area" and r 1.4.1. Geological motives") the Alta-Kvaenangen window was an old district for ecornmic geology. See Vokes (cf. references ch.X) for the description of mineralisations in Raipas /Alta.

Generally the greenstanes are containing disseminated pyrite , as very small cristals.

The study of thin sections indicate the presence of le uc oxene with

traces of ilm e nit e ( eL" 3. 2. 2. geochemical datas"): the green- stones c•mtain I - 1, 5°/, Ti02.

One can find "coating", "film" of m al a c hit e , disseminated in the field.

These spots have )ften as origin a veinlet f caleite with one or two cristals of chalcopyrite, of some mm'S onlY. In the Ee'rgmark anticline area, and also South of Djupvan, there are sorne clolamite layers containing quite a lot of idiamorph cristals of m agn et it e (actahecir,ms), often pseudomorphased in limonite They have a size of some 1/10 of mm.

Traces of m æl achite associated with oxydation r oducts might be seen in the "black schists" in tectonizéd zones.

Malachite c )ating can seldom be found higher than the tree-line; this is probably due t ) the bleaching ( snaw and rain ).

In sheared zanes ( faults), as between Lille and Stora Riiddevarre, there are some joints filled with as bestas (amphibol). No d olomite layer is pure and/or thick enough to allow any expl utati m for this mineral.

Yle shall mention that all the visible traces of mineralisations have al-

ready been discovered during the active period of mining, end of XDC, beginning of XXth century. This is deduced from works met in the field, such as trenches, shafts etc.

The conclusion is that if there is an economic mineralisation itrour

research field, it is not visible just with "nacked eyes-, but can be found •nly by geochemical or geophysical methods. •

•

•

• Vfi

VII. DISCUSSION

7.1. About the thickness of the series. Due to the tectonic, it is very seldom to observe the stratigraphic pile continuously. The favorable zones for the evaluation of the thickness of the series are the Bergmark anticline on the Kvaenangen side of the window and the Kvaanvik area on the Alta side.

In the Bergmark anticline (Lower Raipas), the problem is the following: on the W, the series disappear under a zone of black schists (tectonic zone). Over this zone there are always rocks from the Lower Raipas. To the W, the anticline is followed by the highest part of the Lower Raipas, then by the beginning of the Upper Raipas. Now there is a tectonic "accident" further North, so that ultrabasic rocks are to be seen. This "accident" is going in direction of Flintvan, where it seems that is disappears. If this is the case and if it doean't exist anymore at the level of Badderelva river, then it is possible to evaluate the thickness from the middle of the Bergmark anticline to the top of Lower Raipas. In this case ( the most likely), the minimal thickness of the Bergmark anticline is approx. 1,5 km. (approximation due to the variation of dip along a profile).

If, on the contrary, this "accident" should go further than Flintvan, to the South parallel to the structures, up to a point where it would disappear under the overthrust, then we w)uld not have a continuous series anymore and the evaluation of the minimal thickness would be indeterminated ( due to the lack of marker layers).

The thickness evaluated in Alta by Holtedahl for the Lower Raipas was approx. 0, 8 km. In Kvaenvit we estimated approx. 1 km But it seems that the series is not completely present at tits, bottom.So the real thickness should be much more. About Upper Raipas, between Bla fjellet and Middavarri (included the doltimite and greywacke/shale formation at the top of Upper Raipas), it is possible to evaluate, with the dip variations, a thickness of 1 - 1,5 km. This is of the same magnitude S the thickness mentioned by Holtedahl and Zenzen, Upper Raipas in Alta ( ni 1 km). 7. 2. About the sedimentation conditions and their relation with tuffs tuffites tuffo enic sediments .

As mentioned in the chapter "Petrography", the term tuffs/tuffites/tuffogenic sediments includes rocks of different aspect ( descriptive).

Now we should also consider the genesis of these deposits.

As a matter of fact, it is possible to have different formation mechanisms for the same final result.

We shall consider here two main possibilities:

Primary volcanic origin: hyaloclastites. Submarine volcanoes can produce, apart from lava streams, important ampunts of hyaloclastites. They are formed b; the fragmentation of the lava when it is in contact with cold water (Tazieff 1972). If the volcano is close to the surface, these vitreous fragments might be ejected in the air before felling down again in water.

This shows that purely volcanic rocks can be deposited in water as an usual sedirnent, this explaining sedimentation figures in tuffs/tuaf ites such as cross bedding, gradded bedding, Bouma sequence (turbidite). Erosion "in situ" : we can also imagine the erosion and the deposition nearly "in situ" of local volcanic rnaterial, coming from a line of volcanic islands e.g. The result would be a kind of volcanic greywacke. In this case too the de- position happens in water producing the usual sedimentation figures.

The metamorphism, in the "greenschists facies" induced many transformationc: the volcanic glass has been devitrificated, the rock has been homogeneisated, weathered; the structures, in a fine grained rock, disappeared. For these reasons it is not possible to distinguish frozn each other between these two possibl e origins of the rocks. ( The chemical composition of these rocks is typically basaltic).

We personnally think that the first mode of formation was the most important: for the second one, a too big emerged area would be necessary. According to the numerous pillowed flows (= submarine) it is not the case. als ) dth innicate on the rnop thnt ree nt:s/tuifites ete.. are getting

1Å'')re prl cte enrh anate'. ;Lese nained tuffogenit.-, and Rrc s ,netin es tontaining rwrel- n.e.decs.

iatt- prctoti in is the

Lite as tid seuinientation f the b dton. as nail yer f_Hc sho-: ing centain didtanee the -re Thc- varinwt s nsites Di the upper part of Boipos indicatc t,pe zsale in pinces. ihe sedimentation ratio shoul.d bo vor

tt , : niring tae sucn“. pt riod Yrta:-It valeaoid c ple dlii eetr.

is evleat that i; p )ssibit to ecmpare a lava strnnn: snme rdet, )(jastite dep )sit up to senre tens af ncters, n, less, ciiL tne ciepositions u Einoinients ;if s ede ern

Lhe diwentor. n,aterial has bees POiissaivecr. in the eoloanie isaterial.

But if thc iicani activit dcert ases A» temporaril-, brodk, thet, the dep tsitioa rpupe sedheents ;nle.bt visible again. .111is ia the :;:plonati

‘,ero tine, iinaRnwar beas )f setlinwnts.

Another dat is t , nsick‘r depdsiti nlacc rrorn the volcanie fissure:

Vor thc iii 'dastites c.g. vicent that far it li fr.yil their as imporlant the dep )sit be. 'dt(.1 n,uch ,re iii g; av as fr UY! this as less traterial ii1l be; ean then eprisider that after ecrtain iti,tit ice tin deposition v deanic martial viii be the same rragnitude that sedirdeatttn- c:t is then possible to have all the inter- ritediate stepa ;ietv pantdd and pureir sedimentar roeks, and it rnight h. diYieult t.c.artac Iiit;31' the eiassirication and field neupn4no: t ot--; terf , t.r.fitcs, drzillites, etc:. L)

Nrticnia n11).o,s lava layLr

f-,und sevtIai a barticulal lavc lmer \-hose

structure is sor t \Y-11:• visible, anC. vei Jifficult t•)

detect, vith pillo)cs uuparated from each other by 1-2 em of chert.

he arnygoules appro. i cm inside i'rcur the outer border of

the pillow, charae.- • tae piJlav s af the )-indo)!, is absent.

Instead, there is a z,ale 2—: cro with dissemiaatc, numer-ris, very

little, black r rI-•iavisible. i hese pillov: lavas are associated \-ith lavas ).-ith r.r; utrueture ami ver fine grnined (like the

In some localitiE.s c.g. in at

1..useskardet L - Blfjellet , at Ruolla6k'ka 623560), on

a yr:ountain vithaa. ry-Jca, (LE 60:55)5), it is certain that this lava

stream is tI.L last :11] strnim .'aaybe it is not

the same, consideriag the distance, but anyYT.; sister-lava-streams,

bel0nging to the same volaanic event ano in the same environment.

I hese lava strcan eac covered b.• the rather thiar< sequenee of

tuffajtuffites etc. the tob )f 7. )v-er Raipas.

lriva stream, itb 71,-S direction, running

_rom •"..55••-;5) t rldaidvarre (TlC 4::5445), with an

upside-doy n p.;sition, aoci being cut in its go 17gicn1 upper part

to the T in the fieli by n shear-zone ( v. black sehists), sa that it

is not p )ssible t ) se- the upper part af ver Lginas and Lbper Raipas.

ur goal is to prove that if re accept the pill•)» lava morphology

- dosoribed at the begi.ming of this paragraph - as characteristie of a

partieular horiz n ( = n arker layer), then the ridge Gr3n1ifje1let -

Uldaidyarre vill belong t-) the upper part of I ower Raipas. ,

ht the exte.—:inie. the vo•lcanic vent ••:' s trehic.s.

fl has been snib her•e•••• thnt the njricov j chn. act

ilimad•Jus anc. t.ohni lava streams ( in spite cu: the fact that in

s )1111•('nst s the.• • i » doubt betwccd ji- s i -nm and sill). dieficl mappid recenlecI pilloved laeers tl t,uld be

t • :i»

the -)ther •-n€,c•2):ildc:.n the etherit is fl IsHhle to

eontino )usl a pillhwed strearn 1 :tree.)gnised arr)und

th- p .ir)t. I ." -55cT.the 3, turning arma •:1 ;ukkertpppen

(1 1.:)5IIthen •••):$'uotil it dtsnppears uneerautuebtr„)H•has,

norn••.x, at the pedtit(30:;50•). fhe full distnhec is hece of ahout • :5 kin(thi.--•:er• iser )ssing' :5•.1).•Vh.thesis Cilu / hppian,th.• ''j'1i th1 nrr.

mapphdtlitielmF) f7ru1jer).

rhest .5 ke are lcngth measured 0long me extensi.m dire ti iii

, .••••0,5 )1•1.z is ndt Di sylbl t :n )). tht

along the see 51R. in t asion fi the plane becanse n: the tectanic structu-

F1'S folds, Its ete. i \-ith strong dips.

.evertheless the stud.: pf some areas such as the Bergmark anticline,

Mbavd tlie. lkem 5piger),•erk; bct•-.71 n I 1....:2Lag'gi (! ( 6705(I)) and Vasbotndalen (inefficd), sh ees drawing inter- 111 pretation prpfiles vdth the synclines, anticlines etc. that this lnternl e:cteasi i of tl:e lava fl iws sh )uld be at lenst •)f sevc ral kilhwafters

( i i l l• 11. 11'e) .

if admit hat hos been diseussed before ( cf. 7. ••. that there

is 7 special pilloy•ed lafer that might be used ns marker layer, this

mean thnt • t•KIn• an nctunl prcjected •h. 011

axis perpendicula the strictures ( = fold asis, faalted folds,

t 'Schuppen" vdth ut defolding nnd flattening again these

structures, oï appih). • - 43 km. ( from crIalihjellet I C

ti lenvil; I :11 77 VII. f

Although one can consider our way of calculation as not adequate, anyway it is ehowed that the two horizontal directions of extension are very big. For this reason we consider - according to the latest volcanic litterature - that these lavas cannot be emitted from a central volcanic mouth only, but from a volcanism of fiseural type, such az the one observed and studied presently on the ocean floor (Atlantic, Pacific, Red Sea, Afar - today emerged - etc.)

In conclusion we consider that our field was an ocean floor This hypothesia fits with the chernistry of the lava (tholeiitic, like the • actual ocean floors) This would be an explanation to a certain copper anomaly in some sedimentary rocks of the window associated with lavas ( cf. D. Rickard in Bartholom 1974).

• VII. 6

7.5. About the limit between Lower and U r Ral as

The upper part of Lower Raipas is made of argfflite with dolomite layers; the base of Upper Raipas is a sandstone. The transitional zone between these two sub-groups is always covered by quaternary deposits. The dip and strike are concordant. Reitan 1963 mantions an " assumed erosional unconformity" between these two sub-groups in the neighbouring Komagfjord window (NGU no.221 p. 9). In the Alta-Kvaenangen window we found no element to confirm or contradict this unconformity.

Another way is to consider the paleographic relations between argillite • and sandstone. But we don't know the source of the Upper Raipas sand... this happens beyond the limits of the window and we only can assume things and facts. So we can admit that an " assumed erosional unconformity" can.. occur.

• VII. Fj

7. 6. Com arison of the ty e scheme for the '' reenstone belt".

tried here to compare the greenstones series of Lower Baipas with the type scheme for the "greenstones belt'' established by G.Allard. This latter, who found important Cu .)re bodies ( sulfides) in Canada, e.g. Chibougano ( Lac Dor, Quebec ) developped a type scheme, after coirparison with the big "greenstones belts" of the world; the observations concerning the mineralisation are confirmed.

rom this model it can be stated that mineralised lenses of little economic interest aan o‘.cur at everv level, coming generally from the feeding dykes of acid intrusives. But economically important ore bodies are el)se to the acid intrusives, just above a chert layer whose thicknes s might vary ( some cm. to some m 1).0n another hand it seems that the importance of the mineralisation is in relation with the thickness of the series.

In the Alta-Kvaenangen tectonic window, compared to Allard's model, we can state: the thickness of the serie is one magnitude smaller than greenstones belts ( 1 to 1,5 km against li5 - 25 km ) the tectDnic divides the units in "small" fragments, so that it is not pDssible to "follow" a laver. there are no acid intrusives in the window.

From these points we can deduce either that we have here a greenstones series with a small thickness, or that we have only a part of a thicker series.

Brom the second criteron ( tectonical) we think that the second hypothe- sis is more likely, as follows: during the folding phases the series has been cleaved along a plane more or less horizontal; the part above and under this plane have been tectonised apart.(cf. ch. IV, paragraphe 4. 2. ). rhe upper part bas been then divided into rather rigid blocks that have been nearly not deformed ( this is proved by

71/10/ca/ sIraligra/ohy of fhe yreefisiones beiV„ Ihd2

wor/d„from Ihe begrnn/ny of 14e farth ulo

.12/egmodil cr( g areeicdonJ est Qt/:/ned" .11 >9

le.IPC1/-CA:1 y n ,'»es'sre icrr > L > 1tvFrI/;2 sege,, 5/2,, ny. , ,;--„;(7 giaye / eji-Q,J;6'r;ea1 777 C/,o4q1O 2 411c-- ,OPrer

-21-1e6e.". (1.%7M4G4 70L-Q or: kr, _r-Q, r0,62:2airg'd („L'f c)/i4--

.68 2,7 /4e 4a2r,ial

2 od

fed„,,,emis sc

rtot70, o -/ tAl 011d dassee A o a a C,5er;` ,asti Åttnat:-t fc-1,(Kief rderv4-e7-3z-

ansir— 9aa dame paritril-e

- Cic pyroC/o.,../,eJ ^ lot„-as,s, .q o n

- Q —, c. -a a s c' , : n ..0 n — a° a° ° ania° °0°. ,3 ° 9,-,"'o,,-- 'a yg s (2.; a, ell ,le rl 0 a L P P ia P 0 0 a 0..._, 0 0

- ,tatr; c ter xxga np.Å sxt v•ttl-{ • • •• a semenf

c recks

/47(2,,cinfal-Pc resre(

A--„nnet.A,/es- ,iltrasnaleic /awa_r Stsr/cley itruc,r.c/e lifele•J ty la 50c-~

±221. a.w 4erk ine ary /ook,..y /fre cs); Ven- Aremi 017;1‘$,Ver qrnqsairc (aqq: 4eitv ;.•Mi iiftergA(Ae 77.-.4ye-ratute er).l /69-/t.ro 'C. cl bar;Ae • P) o éra,?,0-2cc,‘ a.nci 14

- f..)eponts

St•ta,' (": ST.,-!,-o-:..Cal2),(j 64e 7.2 crec k"-;

Se- iefosm fed•wrfaey rw c'n.et1 r;e4, to o",),d e oo- igifesh•dari',•5 Or‘ 412yin4t- rac,b 4>vb./ jAe. ,/49le ei.ila 19.0” ia.1.0k, 0.4*

C) r4y e/Ie fly1/71- 9 "f/-eert 4/'. rye...) :+1 0 Cr4'r

,V :- bef`A-ee »ne ,t/&° ,n7.27 a,<-offre /70 Aftermere r‘;‘="k: _fq 71.-1Ye.f ^e

,in1/2-A--)yerr cnn,areveri"1:14(1ÆC9./ C.-y9 70 - 25-

//: are 4,29,70 x to% /-=1 gs'er7 icv

:69tniir 50r, 95 dl9ra Yeal gre.'0,,,9rp-_--ed ‘-'>Cred. . VII. K

the observation of non tectonised and deformed primary structures such as pillow-lavas and sedimentary structures), except some "hinge" zones, which are anyway often faulted. All these platy-blocks did slip over each other. In such a model we can even consider that the observed ultrabasic rocks, coming from much deeper, did not intrude as "warm bodies", but as diapyric intrusion, "cold" , as it is usual with serpentines.

These facts would prove that the ideal conditions to locate important ore bodies are far to be realised, or at least very much perturbated. For this reason we think that there is very little chance that the Alta-Kvaenangen window become a modern mining district.

• •

•

• VIII. PUliTHER V;(,1-(K

coasider that we have described the structures aud the stratigraphy of

the window, mapped ta the scale 1/53. 300 ( regimal geology).

Acadernicall>, speakin man researches might still be done in the area:

detailed petm)graphical stud •, metam)rphism, n-.agnetical parameters ot

the different greenstanes, stud., of the structure or the lava streams, geo-

chemistry of trace elements, etc., etc...

Practically speaking H mining industr. ): ev-em.thing is depending frorr the

results of the geoehen-istry. If they are negative, et think that this area • should be considered as iainteresting ( for mining purp )ses), according the ar2tual ge ,chemistry aa(1 pr )speeting meth us. If these geocnemitr

results are positive and n detailed ge 1 )gical rnap nceded later, to a

scale such as 1/13. UOU, 1/5.303, l/ 2(Yl I etc., then wer suggest: to divide iinte

the terms of our legead, cspecially the ''tufrs, tuffites and turfogenic r

ahd als.) the "greenst 1-iesn, that sir)uld be clasaified according to their

detailed mineralogY. This Juld be a long-time and hard -nork, t i be done with

.eith thethelp" of a great numbee af thin sections. Uhe geolugist in charge of

such a should first have to at the t.-pical r-)cktnpes ciescribed f the y ind-,v-,first along typical prefil such as the mc of :\iiddavarre

(ef . 5. 1. ). But such detailed mapping can and shall be done only cin • small surfaces, directly en• and around the target. •

•

•

• JÀP

IX. CONCLUSIONS SorLe 1500 to 2000 million years ago, the studied area was a sea bottom, probably a part of an ocean crust. The sedimentation was pelites and carbonates (limestone and dobmite), with an assumed small sedimentation speed. An important volcanic activity occurred on this sea bottom: volcanism (submarine) characterized by the formation of massive lava streams, lavas with the typical "pillow-lava" structures, pilow-breccias, interbedded with tuffs, tuffites and tuffogenic sediments. ( cf. discussion). Some parts of the area were in shallow waters or as island; this is showed by columnar lava strearns. All this volcanism, of fissural type, produces lava flows of big extent. The end of this volcanic period is marked by a more important deposition of tuffites, tuffogenic rocks and finally the sedimentation of an argillite bed.

This very fine pelitic material indicates a zone far from the shore or a shallow.

Associated with this argillite, there are beds of dolomite (dolomitised limestone ?) whose thickness and facies are variable ( massive, brecciated etc. ), and could be recifal-like. .. All the rocks formed during the described period are forming an unit called Lower Raipas Subgroup, and are 1 to 2 km thick.

Later - and we cannot state if there is an "erosional unconformity" or not - the sedimentation is building a thick sandstone of about 1 km thick. This could be, as we think, a kind of "molassic bassin". A pure quartzite layer has been deposited on the top of this sandstone, containing some jaspis grains, on which lies a pile of alternating dolomite and sandstone/ argillite. These rocks are forming an unit called Upper Raipas Subgroup.

The Raipas group as a whole was folded a first time. The folding was of isoclinal type, with thrust faults, "Schuppen", monoclinals etc. so that in one localiti it is possible to see ultrabasie r ocks from the underlaying upper mantle (of the earth).

tuat )Ct. I ti

IL r •_ L

thea bil..kcal eatne, 131.ars rikk i r1.11121.

aults ,t;t11 hig ni httit rattik thic. 1.) ct

is Lii iuL. j. h C•ILlit1 11/4_,

r Sti'LL-ti • . r:;31..pir .1 ILU 1.: • iii

L1-SL

presunat that the ntia n phasu fnult

breettin etc. is frf)n• tht. peri Flie "gret thetan. )rphisn;

py kaahr.) )r t,, tlita riyst p ancl c tcyl-nic

ei si ,n pnase )11 t '1)4 ":"1:,

tii•i.k.. p gr

ii .\ it ti thr

,1111111. I, 3tit

en:nnai g ;nat 3 -i , ).; thi;trc liia,

thttpan-th•T.1 •

" nnt n; pp-a.; Ic; -t.1 ntci t..c.' dt...,) siU .ii i: ti... L._, ', tlL 13 irran

g.r,),..:p is LitiAt si. tia. s r i•),• ,,,,, »i ,,r, writs, U),,_,

-.!e I-1,-,,e ( , 1 Ir•r 5, ...-,1.1, -- CS .1. •SI. .'. ),. St u .IL. L1 u) cl.., )r,..1FIL ir.

(trii,L 1( r• ...,

Ansytac, all up t 1,r1ta:

acambritai) Ilits beeu foldeci t ,gether, vtith rug ,F) spite

s inatinans rathir str ing dips, tra_ I.)up.,

C ea ,ugh tu kt ep tia aflunat " aut :1/4kar

..e a);:surre that this prinre is 211 ac cau: t the Lalt d inian tragen.

This latter is niarited in tre studicd artaL b)- tra ;acclitrusting af big nappes

that covered bas)sment anct •ut )cht1rutp11s (or.)geu: Li'!! i ta 4 0,) )

75(L-

lo.rp -tant fe.alts are running thr:nigh both basement + autoehtiLm)us

tdiuII )chth-m+us. idey havt probabl) been mahe at the ead of the

, gun (readjustings), maybe later.

emersion phase, erosi m and peneplaliation succeeded ti) the building-up

oi the Caledonides, revealing some preeambrian zones: the preeambrian

wine ( ,ve shall mention that in some cases where observed a

tectonie limit: fault).

nvich mpre recent tirre, at the end of the Tertinr (ersinozic), tbd

Scandinavian area urdift:d, eadsing z reactivatio_i :f the reJief, • ge miorpholoy ( vnlIecs ), the.i c ,vered h the rmatern{H‘. glacin.tiods ( in the last 2 ), with -s gutting deepe:‘, compliete

change of the ge )rin irph 1 igV, u, dui ing thd dep+sition of

imp,rtant miraines covering big surfaces, masri-ing clic bed-rock, and

finrdl upiift I the SeantMlavia tisostasie readjustniedt), with formatipn terras.-“, etc . ( and gravel. ders,its).

As last remard and CUJiUSiOjI, Y c anall tnat the i'reeambrian •.)f

the -)f Scaludid2via , ndanu, is kn-AV11 vCl little. Vem- 'eological, geocilrun-dagteal ete. -,•orics nave bee.i (.1)Lie in these wide we. havE aol, Lelate our • á ( The most imp )rtnnt ones are rnarked with a • in the left column. )

- merican Geological Institute

flictionary of geological terrns, Ed. 1962 Hc.,Carden • ni 1 n :00S1(111.)

•

-.clature of the

).1') Dec.1959

•

- ,Hiadra Island,

sediments ahj. 1:,111etin

2 1. nliclastite b-octu with Ordovicinian in the %orv.a.‘. »Jirst; ri6d2K1b:, pp. :)[15 - 407, Oslo 19' t:S

S. 19621

he tillite bearing f -)rmati-ns af the Alta district - a u n-relati ,n with T astern innmark and the interi)r t: innmark. \CL

Gautier

leie rep ,rt and ge il igical map af the I and NE part the .\Ita- Kvaenangen te,dt tic Christirdha Spigerverk Ikem) c r: Dr. II. F. Ceis, chief ged ,gist unpublished • Ge 4 gical map /53. ALTA I 334 I, Precambrian

(Zaan/Fygliaug, byn, Gautier, fiGU 1L7d, Universitåtsforlaget)

Geul ens I . & reau 3. 1600

Contributi )n la géalagie de la re.gian de innmark, ..nrvege Intern. Geol. Cangr. hep:il.t ;I' the 2ist. sessidn Drden 1963 Part IX Precarnbrian, Stratigraphy and correlation.

fl dtedahl al. 3:61

Aspect )f the ge dag-• \ n-thern 3 -n-way Int. Geal. Cangress sessi n \Irden 196] Guide ta excursions Ç A

• ,:acdonals G. A. 1972

Valcanaes (5,1) p. ) I'rentice Hall, Inc. , Lnglewo3d . J.

G. 67

1.e tutiti. Italiana Linerabgia e Petr )logia, "hiilano '97 (d) pp. 4; - 426

ilnes tst„Lichties

.)are . 1965

Pctr dag deep-sea basalt near Iiawaii Arn,Jaurnal of Science Val. 26. J anuar.: 1965, pp. 43-52 e tj. Crist*F-)lini E. & Ciudice A. 1:evel)prnent of pill)tvs tin the submarine exteusiin recent hva fl i s, .Vt.fitna, Sicily

Tci .„ztedl Survdv .:esearch .L:71 1.S. let: i. .1',1.11vev T'2_per 75:1- c pp. c -

it7.)

Iit )gsdpgave i n geol)gisk unders.tikelse av. •,rn rftdet drnicr ing Ka fjord K•)bbergruve, Afj.)rd,

Vniversitet s1 vNren 1970 unpublished

I

Precambrian f rthern 7 drway, ‘vinddv-s in the Caled ,nides in the c:f )ten district, Troms and innn\ark, in df :irvav"

pp. G7 72

The geoldgy of the K:a-itagf'j-n-d tedt.:nic indd\ df the haipas suite, Hinnmark,

ILG\

• Kittmann

\ ulkane and ihre I Ntigkeit

erdiaand 11-nke, Stuttgart

i05.;

Volcan)es and their netivitv

ile Interscience Publisher V. p.

ILd

Les volcans et leur activitc( 72. rnriçaise par il tazieff) _vasson et Cie. l'aris 796

11153

Il wecanismd di formazipne delle lave a pillow e dei c )sidetti tufi palagonitici.

hill Accad. (Si)enia Sc.'at,,Catania (V)4,pp.

r. ave a ed ialdclastiti

Italiana e Petrdlogia,:Ciland Ih7d \V

Shrock R.R. 1948 Sequence in layered rocks Mc Graw Book Co. Inc. , N.Y. 1948

S tache 1970 Diplornarbeit : Die Geologie des Kupferbezirkes Kaafjord in den unteren Raipas Formationen von Nord Norwegen Universitåt Clausthal-Zellerfeld, Febr. 1970 unpublished

Tazieff 11. 1972 About deep sea volcanism 2 Geol. Rundschau 61. 2 pp.470-480 Stuttgart , Aug. 192 1972 Les volcans et la derive des continents. Collection S. V. P. Presses universitaires de France 1972

Tepley L. 1975 (?) (Movies Film 16 mm. 20 min. colour + optical souna "Fire under the sea", the origin of pillow lava. A dramatic documentary of man's first observations of red hot lava flowing underwater" Filmed by Dr. Lee 1Depley, scientific consultant Dr. James G.Moore (Kilavea, Hawall) • Distributed by Moonlight Production, Dr. Lee Tepley 2650 California Street, Dept. GT, Mountain View, Calif. 94040

Vokes F. N. 1955 Observations at Raipas Mine, Alta, Finnmark NGU no. 191, 1955 1957 Some copper sulphides parageneses from the Raipas formation of Northern Norway NGU no. 200 pp. 74-111 Oslo 1957 1957 On the presence of minerals of the linnaelte series in some copper ores from the Raipas formation of Northern Norway NGU no. 200 pp. 112 - 120 Oslo 1957 X, E

Vuagnat M. 1946 Sur quelques diabases suisses. Contribution å l'tude du prdblåme des spilites et des pillow-lavas. Bull. suisse mineral. petrogr., 21Z pp. 116-228, 1946

Vuagnat M. & Pustaszeri L. 1965 Råflexions aur la structure et le tnode de formation des coulåes en coussins du Mont-Genièvre (Hautes-Alpes) Arch. Sc. Genåve, 18, pp. 686-689 1965

Zenzen N. 1915 • "Rapport öfver en geologisk undersEkning at Alta Koppargrufvors umråde i Kvaenangen (Troms8amt Norge) + 1Carter till rapport 1915, Sulitjelma Aktienbolag NGU Bergarkivet, Rapport no. 105A and 105 B

• I F

10.2. MAPS AND AIR PHOTOS

10.2.1. Ma s NGO (Nor es eo rafiske o m?din ) Mapsheet 1/50.000 Series M 711 Edition 2 - NOR Sheet 1734 I Kvaenangen Sheet 1834 IV Flintfjellet Sheet 1834 I Alta

10. 2. 2. Air otos used : Fjellanger Widercle A/S Flight 490 J 24 - J 28 • K 46 - K 53 Flight 2025 C 1 - C 4 1 - D 11 E 1 - E 12 F 1 - F 12 1 - G 14 1 - H 14 J 1 - J 11 2 - K 10

Flight 1800 J 1 - 8 • 1 - 8 L 1 - 9 10. 2. EQUIPMENT

10.3.1. Office work and drawl Mirror/ stereoscop (Tcpcpn) Iron plate + magnets for dito Office lamp Kodatrace (acetate sheets) for air photo Rapidograph 0. 2 0. 4 0. 6 0. 8mm + ink and cleaning liquid A pair of compasses Graduated rule (30 - 40 cm) Pencils • Colour pencils Magic Markers (different coloura) to colour the map Soft rubber Transparent tape MaskIng tape (pressure sensitive tape) Tracing paper -->-2 80 gr/m2 Paper A 4, white and squared Cover C 5 and C 6 Fixed punch ( DIN standard size) Sorter A 4 with dividing sheets • Stapler and staples (r) tt

tfl

ir)(iket sttre (Zeiss) n-roasx th ulinnmeter (Silen)

tsr ( 5 ) !i)

rrugnificati Iulj n)ajfe•i !'entSI nrcr ( hanap1(..f.:

glas:"(-s) x 4 -) or

t!-776..n )ifie :"(e)

Hac.

Bag f )r. nir pI(..ture

Sel )(' ?ar pidtarea

..;et GI t

"flucksask"

dradi G n'tahle st .ve s Jid faca r inethri(aca

Safett

lares set

histle

alet lior n'(a) fr. first aid safet. (-fpnee ulatei-acet

Yamping arri Sernoun(2

persnn -.flaterpr ,af rr )untain tent i,une for ei(sn' Kitchen tent ( trur ".• Llpr;C=. " )bbeltH

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Butan :.-t.,ve (i'riir •s) 't burners igE f-s to 0.) os Set of pans Spoon, fork, knife, plate, cup x x I3ucket 10 1 with cover Kitbags (seaman-bag) for all the camping equipment Butan lamp (Primus) + reserve of burning elements Rubber torch x x Repair kit for tents: roll of "Norges plaster" string etc. • Plastic sheet approx. 2 x 3 m Mobiltelefon

Walkie-talkie when the assistant is a geologist too

• •

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' AICTri t:"S "brc ;fte, j' Vulkansk i Kvænangen

— Av I3Jorn Aage Krane — Han si, lite om hva som kunne -7* tie 4 ••••/t.4 tenkes å finnes av mineralfore- f% komster i fjellet, den sveRsIske geologen André Gautler som I sommer har foretatt geologisk kartlegging av fjellene ovenfor Burfjord på oppdrag av Sull- tjelma Gruher. Med seg i sommer har han hatt geologistudent Arn- fInn Johansen fra øksfjordhotn. Derimot er han mer enn villig til å fortelle at de har funnet ut at fjellet Middavarre for en stor del består a lava som er dannet un• der havosertlaten for minst 1,4 milliarder år siden. I Preram. brIum, om det har interesse, og las aen kalles putelasa på grunn av sin karakteristiske form. Men det som mer interes- serer folk og mvndigheter i Ksa-n angen. er om de finner minera- ler det kan bli gruvedrift av. le Det kan jeg ikke ssare på, • sler Gautier og ser opp over kaffe- koppen på Kaasen Gård pensjo- nat i Burfjorddalen. Jeg har taus- 441:.14:.4 • hetsplikt — skrevet under .• rIng, så nnin munn er lukket. Men 19. Jeg håper det ikke hlir. i I. 0:?f: ØKOLOGISKE s/ ,4 .4 s• KONSEKVENSER 1-Ivordan det? Jeg kommer fra et industri- alisert land, og har sett de oko- 1 logiske konsekvenser gruvedrIft j r ., har l:lempene er store, spesielt <* it11.11 i arktisk klima, der gjenveksten er langsom. Men hvis jeg finner ..:44% noe, må jeg selvsagt rapportere ! 4. det til nune oppdragsgivere. imsforstå meg ikke Gautier har mange somre bak seg i Nord-Norge. Området han trbeider tned kartlegging regner han som spesielt interes. sant. Itet kalles Alta-livamangen vmduet. Forsto vi ham rett, betyr det itt man her finner atskillig eldry fjell enn i området omkring Men geologi er ikke vår sterkesty side, selv otn Gautter og Johansen gjorde en stor mnsats for å opp lyse ets forovrig ta med at Gau- tier nettopp i sommer i ferd med 0 ta sin doktorgrad i geologi p;len avhandling nettopp om Alta- Kværtangen-vinduet.

INGEN FARE 411 Når dere tmer lava. betyr det altsa at Kvamangen ligger pa volkan Nnr kan vf vente hrudd” Ingen s'anst-r ak de roligste verden l'thrud Geolog Andre Gautler og stu- dene her sktedde ved at ,tv,tert dent Arnfinn Johan•en satte strommet ut g».nnom store sprek Men hyr medarheider på kondisjonsprose kyr i ftellet ug flet er fngen s:anse sed å klatre opp til dette os rr- for gientake.se sltk at i.bkr tbt- ber henget. for å fram et eksern- litorningeo. det Gautter ster at det er gede mu pel på ts pisk ulkansk aske.IPutr- ifgheter far santle stem ug mme las aen lå utenfor sår rekkevidde sa :agt han nuk svg glor, raler den dagen. ktenner Mrhaatene Isafttarbefd sloone katt le-Mys med . Burf»-rd bar nin smt. ker the ot t,. dyne lvt, ,aget en me med 4 - 5 mine stil slirn irgpl te•g nty s st ,dent tte s st funnyt i Hmftord-ornradet nytt,,,b og Hir drr, ed skal monteres shk at mån kan se :erne, g Jen for Hin er hvilken type de forskJelbge er og ferd:g Vor snukke hvor de er funnyt fjell kld!re •

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-,••••," 2 light brown , 3 light brown with blue symbols • 4 rosa 5 rosa with red spots

11.4 • • 6 rosa with blue spots • I . 7 light blue *. - , -._ •, ; r•M , r 8 light green ..• .., - , .. \ ------',(7,i —„ 1S I 9 light green with blue spots • . 4 / 0 10 dark yellow 7- -- I •• 1 j f It 1 11 dark blue 1/. 4 •1' • - r ..".t. .- . 12 light yellow , 13 lilac-colour 14 light & dark yellow bands 15 light grey

'' 03 • 1 ". .‘ -.4-pc• „ • I ;

o 8

---cS's?'-'' e, , pl._• - LEGEND klii,ø1 7 pi ii 1 's t •I it: , ' i • 4 07 4, 134 Quaternary cover (sand,gravel,swamp...) P . GEOLOGICAL MAP i ' t,c.'/' (: V ALLOCHTHONOUS 41, 1„1 ,----not mapped except : Scale 1/50000

N‘11 I . .., ... o• - "^-...i ... 671 Dolomite Alta-Kvaenangen window . . ø .., see report : .../ / /' (Kvaenangen side) AUTOCHTHONOUS tectonic map, ,- 4% N.-Troms,w. 4'innmark ( no 24,25,26,27 ) 12 1-1Main1y white quartzite Norway „. L-27*EiContortedquartzite q re, 12 Mapsheet : 4, t t• 1_.O Tillite , • . sgzLb- 13 Kvaenangen 1734 I " • ‘L , quartzite see report : Flintf'ellet 1834 IV s tectonic map,(no 25) Qfl , C • and Ch.I1,2.1.2. Field work : ± BASEMENT „ 1 181 Upper Raipas subgroup (stratigraphic order) Summer 1974 & 1975

• o . et Ig C,73 Luovusvarri formation Dr.Andre- M. Gautier Individual dolomite 1ayers showing •••• I Il Pr:41 Dept. of.mineralogy ' I , structural trend at til 13 r. des Maralchers 4.3 k 4,4 7. 0 11 Dolomite interbedded with sandstones and shales 1211 GENEVA 4 r 7 Basal quartzite (dots)and thick dolomite layer e st Switzerland

------Quartzite layer 0 le ' •T--'•;) Geneva,1976 103 Skoadduvarri formation ,• 10 Greywacke with some argillaceous layers

i 7. Lower Raipas subgroup (not in stratigraphic order) " • C:, Black schists g Argillite with septarian nodules Is Argillite ' l3 Argillite with dolomite lenses 2 • 04 72.91 Dolomite and dolomitic schists ' 7 . cå' 5 Basaltic tuff and tuffite 0/. " • r. — Basaltic tuff and tuffite grading to tuffogenic sediments

‘•-• .0 SBY , 6 Basaltic tuff and tuffite with small dolomite layers ,r Metabasalt and fine grained metadiabase , ' 4•• ; n aa Metabasalt with pillow-lava structure (convexup-side sIde showing direction) s • 0 0 0 Metabasalt with pillow-lava structure (position unknown)

Metabasalt or fine grained metadiabase(snowing with tuff structurai layers trend)

„ 501 -• 2 Coarse grained motadiabase

\--• 0 — 2 - Coarse grained metadiabase with tuff layers (showina stru--turaI treno)

3 Metadiabase "interbedded" with marble "layers" 9,8 (tectonostratigraphic position uncertain -see report )

0, b! Ultr,lbasic DEFINITE ASSUMED/PHOTOGEOLOGICAL ------Rock boundary ..../nr Strike k dip (in 0/360) Axial dip & syncline axis or joint /4.1(.. A- JL Thrust fault/thrust

48 68

E.(J.20m ALTA NORGES GEOLOGISKE UNDERSØKELSE 18341 BERGGRUNNSKART 1 : 50 000

50 r15 TEGNFORKLARING .71 Legend

OVERDEKKETIVESENTLIGSAND OG GRUS, Govered i mai fly sand and graveIt

ALLOKTONE ENHETER Allochtonous units

NALGANAS-DEKKET (?EOKAMBRIUM) Nalganas Nappe (?Eocambrian)

GRANATGLIMMERSKIFER Garnet-mica schrst

META-ARKOSE 511191.›.5.,51-17— Meta-arkose

2,312 GLIMMERSKIFER : I Mica sthist

GARGIA-DEKKET Gargia-Nappe

NALEJELLGRUPPEN (UKJENT ALDER) Nalgell Group (unknown age)

GNFIS GeIss

ULTRAMAFISKE PERGARTER Ultramalic rocks

KALKGLIMMERSKIFER ( aIe enca rust

HORNBLENDESKIFER Hornblende schmt

NVARTSKERATOFYIT Ouarld keratophyre '

GNEIS Gnees

KOMSAGRUPPEN (?E0KAMBRIUM) Komsa Group (?EocambrIan)

GLIMMERSKIFER M ca schm,

META ARKOSE Mela arkose

AUTOKTONE ENHETER Autochthonous units

/ // 3 , it e BORRAS-GRUPPEN ('EOKAMBRIUM OG YNGRE) i Borns Group ('Eocarnbrian and younger) , / , I, // fr T1'13-e- ara . ,125:: i: KVARTSITT OG SKIFER / ,./. il Cluartade and shale ' / /, BTA OG GRONN SKIFER Blue and green Shale 2, ' 1/.1 ', i , I '.t,i4:',/ ,,, KVARTSITT KONGLOMERAT Sp ' / o o o o ,/ 00000 Ouareitic conglomerate '''' '/ TILTITT i: " 7,111te ),, ,..,__ t11:11' .1:1:1:111:1; : /;:111‘ [1::1'; : „„,.._, ,_,,,,, ,,,, BOSSEKOP-GRUPPEN (SEN PREKAMBRIUM) , iy . ,„. Bossekop Group (Late Precambnan) ,,, 2 , _-, _, ,,t4,./ KVARTSITT -_ , ,- -..„1/_-?„, ,./,), OkIarIzite / ---// - ,,,,/ RAIPAS-GRUPPEN (PREKAMBRIUM) „_, , , ‘( „, , ,,:„..„-} , Raipas Group (Procambrian) ...\ =,..1,;,, DOLOMITT I VEKSLING MED SANDSTEIN .,z--.\-/, , DoIomite ,nterbedded ArtI, sandstone „._ ti SANDSTEIN MED NOEN LEIRSKITERLAG 5andstone with some argillaceous layers

DOLOMITT OG KALKSTEIN Dolornite and Ionestone

LTIRSKIFER Argillee

I FIRSKIFER MED DOLOMITTLINSI fl 3?(. Ar (611de wts MalOMIte erises

BAISATMSK F OG FITT F3ssa Ttrt .snet tut' te

FIALALTISK TUFF OG TUFFITT MED LEIRSKII THLAG L, Rys s tic Ist end IMITe eito argillas eous lavers

RATA T11151( TUFF OG TEIFF ITT MFD DOLOMII TLINSER Hosallic tuf I ano tuf I ite avith eglomite lenses

METABASALT Metabasa t 456 ME t ABASALI MED PUTESTRUKTUR Metabasalt eth prlioe•struclute

MI 'ADASAL I- MED PUTE5TRUKTUR UTEN OPP-NED KHITERIER MeldhasaIt eith puIovs structure onsrig ng unknoen

METABASAI T MED TLIFEL AG MetaLasaIt eit51uP mers

611 "AGABBRO Me!agabbro

ME TAGABERO MED RASALTISKE I UFFLAG Mylagabbro etih hasaltic toll iayors

GEOLOGISKE SYMBOLER Geological symbols

STROK OG FALL LAGDE LING IVLITTIKALT HORISONIALT ton ke ard Mg Iayering tverb001 noripontal,

ST HOK OG ALL SHIFRIGHET IVERTIKALT HORISONTAI T SIpke and (51, sshistosey mertmal horuontah

FOLDINGSAKSERITIORISONTALli Trsio exes iIr,rr,nontall

R46 KONT-RUFBIL SKTRIGHETS LIN IER onstr, æled p HISM

SIKRE DATA USIKRE DATA/FOTOGEOLOGISKE DATA Definge Assumed /phatogeological

IILPGARTSGRENSE Rock bodudary

FORKASTNING ELLEIT SPREKK F duIt nr 00000 / 000 00betoÇ de. SKYVERIAN 0 0000000 Ihrust oIane -0 0 e o e o 0000000 o o c KOBFIERKIL SVOVELK1s, o L:r.,lcoo,m,tlr pyrie

Sh Ie ERBRU0D -t's--\Z Ar---.: Flalstone 0 urer r - / 1 / MAONETITTFORENDE N3.151netile-!»,, 59

Errala Gult lelt I profil J-K ved Peskenasenskal arkeha sorleprikker Yellow area InsectionJ-K at Peskenasen should not have black dots

Gecilegrsa kaolagr av 5 Foyn INGU pub nr 228 1964) A M Ga uher ,Ecole des selenees cle a terre instett de mineralogie Geneve og TIkem r buger aerkel A S 19-1 -2) og NGU tNord Norge Drosiektet 19-1 17, Redmert av K R Zeaan NGU I 1972

A M GauTer

tI Zeaan Pvg114,9

4)3T -,55 •

BRUK AV UTM RUTENETT FOR REFERANSEPUNKTER Instruction in using UTM grid for reference points

15110ILVISING ICACI CEIERENSEI I SONIOMeala 51ANDAKT e, et erSt (1-6 F- 0710 ZrONE 01IGNETION 1151I55110 i TO 5551101 550 ME T1175 NAERMESI5 100 rn 34W krrose 0 ROSTEN ers rre Yerr 5AMPLE POINT o 175/511I, 1515SF St SQUAVI IDest,Itcam,oN ar t al 2 grri ra lEtter kr, ntr nd read I ARGI 5gyrer rrie r, er erner, r,„y,„ er R651-55 Bateo5 en ihe lere r/seIl Mers at komma eIoyfes og a000 kni Itlene Esirmale tenors rrom ged I,rrea voirri de sni talleve 5 iusl 7'nere lett skal tas ned EC loraie IhrsillORI/ONIAL grrdIrre BILlree scen, and read I Ale0 figures la5eling tee Vedmeldingee stereet mcc km elIer heis merre rine er,,, le rhe lerr ar ,e t eielree,treir Sv trvttrrateeetmtemer het p kårtetstar ei„mar, tenrhe iram rei he, te ogse 100 km fuler angrs

0 ercrraa EC832545 SAME0tE REFFEENel 451515 IGNOet the 551C1 I ER ItareseIel reproefing ser, 0 100 000 meter-rer 5heel I Ved eneIdingerr utover 95 ered syd eIler 18. grra nurnser Inese are tor finarng teare are averlaseing gril Prell• 100 000 aus, rest shal ori seneonuide anvis the lall rovid.neles Use ONEr the hasssts M erer 55uare ide555,5Q5 ev LARGER ligures ol tne Era nambei. bei„de5p, o i IS yrr 41 ecamvie 1155t00.25.15 7740000 Crra lorre Denanation as liw(c..32545I

4/13

..80 1, 85 1 90

Malestokk,Scale 150 000 1/2 0 1 2 3 4 5Km

.31

Hou meter 1000 KARTBLADINNDELING .31 Location diagram

e memee 3.3 , Kvænve 500 500 LIIIe RelpfletIet

Kveenvily Ovre Alta Tverrelvdellen Allaelva 1811315 1835 1935 Vassbotnelva Kaltorden

0-

500 1834 1834 1934 500 IV IV

1834 1834 1934 7;:t fif,i~d~ Rantasvarn meter er A- Stuom Ramas 500 500 Altdelva 1115. Peseenasen

s ty3T d'an cr an~ - <

500 500 hi Kartgrunnlag Norges geogratiske opornalings kart etter tolatelse Reprografi Norgesgeologiske undersokelse - 1973 Trykk Nordenbelske Lito A/S - 1973 For Mg Uroversitetslorlagel Geochronolo of the Alta - Kvaenan en Window rocks (northern Norway).

André GAUTIER, Fazil GULACAR and Michel DELALOYE, Mineralogy Department, University of Geneva, Switzerland.

RESUME

Une approche Teochronom6trique par la méthode K-Ar a été tentée sur les roches vertes de la fenêtre tectonique d'Alta- Kvaenangen en Norvåge septentrionale. C.esroches ont livré des åges minimum compris entre 1400 et 1500 m.a. confirmant l'åge Précambrien de ces séries onhiolitiques.

1. TNm-onnurrmToN

Precambrian terranes of Northern Norway are not well known particularly from the geochronological point of view. Many factors contribute to this fact. Among them, the lack of fossiliferous fonnations and an uncomplete knowledge of the geological evolution can be pointed out.

The mapping of the area known as the Alta-Kvaenangen Window (Zwaan et al. 1973; Gautier 1977) has been carried out by one of us (A.G.) during four sommers from 1971 to 1975. In the same time, samples of pillow lavas and metadiabases have been collected to be dated by radiometric methods. We present here the results of this work.

2. GEOLOGICAL SETTING

The geological frame of the Alta-Kvaenangen Window is the following: - 2 -

a Precambrian basement, the Raipas Group, with an overlaying sedimentary Eo-Cambrian cover, the Bossekop and Borras Groups, occur in a window below the Caldeonide nappes.

The Raipas Group is 2000 to 2500 meters thick and can be divided in two sub-groups: the Lower and Upper Raipas (Holtedahl et al., 1960). The Lower Raipas Group shows in- trusive as well as ocean floor-type metavolcanic rocks of basaltic composition with a spilitic trend. They are inter- bedded with tuffs, clays and dolomites. Locally ultramafic bodies have been incorporated tectonically to this assemblage which is metamorphosed in the greenschist facies.

The Upper Raipas Group consists of the Skoadduvarri sand- stones and the Luovusvarri sandstones and dolomites (Gautier 1977 and unpublished data).

As fossils are absent, the stratigraphic and tectonic relations between the different formations described above have been established in using the polarity criteria of pillow lavas and of sedimentary structures such as ripple-marks, gradded bedding, etc.

On a general point of view, the tectonic style of the area is characterized by large isoclinal foldings and of thrust sheets. Major vertical faults cut across the whole window.

The Bossekop and Borras Groups of the overlying cover (Føyn, 1964) are composed mainly of quartzites, schists and tillites,

The Caledonide nappes of Norway rest over this basement and its cover.

3, TYPES OF ROCKS USED FOR DATING

Radiometric dating by the Potassium-Argon method has been carried out on three different types of ignous rocks from the Lower Raipas Group: pillow lavas, fine grained metadia- - 3 -

bases and coarse grained metadiabases. The chemical compo- sition of these rocks is given in table 1.

3.1. Pillow lavas

Field evidence shows bona fide pillow lavas which are not or only slightly deformed. Their typical texture is well recognizable; a rim of chloritic material followed by a thin variolitic shect and an important amygdulitic zone of inter- sertal structure are typical. Plagioclase has an acicular habit and the matrix is made mostly of actinolite and chlorite. Chlorite is less aboundant toward the center of the pillows where cpidote and leucoxene are also pesent.

3.2. Metadiabases

The structure of these rocks is ophitic or intersertal but is usually erated by the secondary development of meta- morphic minerals.

The major mineral assemblages observed are the following: albite - augite - epidote - chlorite leucoxene ± actinolite ± biotite. albite - ouralite - leucoxene ± hornblende albite - actinolite - epidote - leucoxene ± chlorite. It is evident from petrographic studies that the fine grained diabases were more affected by the metamorphism than the coarse grained rocks. Primary minerals like augite are found only in coarse grained samples.

3.3. Tuffs

Tuffs having the same bulk composition than the diabases are common in the Window. These rocks have a relatively high specific gravity (2.86 to 2.94) but show clearly cross beddings and other sedimentary features. - 4 -

4. EXPERIMENTAL PROCEDURES

4.1. Potassium-Argon method

Radiometric dating using the K-Ar method has been used extensively in this study.

Potassium has been determined by flame photometry or by X-Ray fluorescence spectrometry, while argon composition has been measured by isotopic dilution using an AEI MS10 mass spectrometer. The 38Ar spike is from Schumacher, Bern -1 (purity 99.99%). The decay constant used is = 5.544.10-10 v Analytical procedure as well as statistical data on error calculations are described in Delaloye et al. 1974.

Potassium content of rocks with less than 0.1% K20 has been measured by isotopic dilution on a mass spectrometer. This procedure increases the accuracy so that the ages ob- tained of these rocks have also a significance.

The spike used in this technique is prepared with enrichcd KC1 (39K = 61.10%, "K = 35.71%, 411<= 3.18%) from Oak Ridge Laboratories. 100 to 300 mg of rock is digested by 1 ml HC104 conc. and 3 ml HF 40% in a Teflon bomb during 24 hours at 110°C. A known weight of spike is added before the acid attack. The ratio weight of sample versus weight of spike is calculated in order to have on the mass spectrometer a ratio 40K/41K close to one.

The isotopic analysis is carried out on an Atlas-Bremen CH4 mass spectrometer. A tantalum thermoionisation filament is used. The isotopic ratios of K are measured for 6 different temperatures of the filament. At each temperature 10 swipes are registred. The accuracy on the K content varies between 0.3 and 0.6%. The blank of the overall procedure gives a K content of 0.288 w g. - 5 -

4.2. Rubidium - Strontium Method

An assay has becn made with this method on the same samples used for the K-Ar age doterminations. The rubidium concen- tration was very low (< 2 ppm) on all measured sambles from this area and while on the contrary the strontium content was relatively high (> 100 ppm). This unfavourable ratio in- troduces an analytical error which is very large, so we cannot attribute much significance ot the Rb-Sr calculated ages.

5. DISCUSSION OF THE RESULTS

The rocks of the Alta-Kvaenancen Window have low potassium concentrations which strongly limit the choice of the samples for K-Ar dating purposes. It was also impossible to carry out minural separations because of the ophitic texture: metamorphic minerals arc inclosed within primary minerals. Consequently only whole rocks have been analysed.

5.1. Pillow Lavas

Radiometric ages obtained for the lavas (Table 2) are spread over a very large period of time. The explanation has to be found in the various stages of alteration which must have caused possible loss of argon in variable amounts. The alteration is visible under the microscope. Some kind of a plateau at 1200 m.y. as it is shown in Fig. 1. points pro- bably toward a maximum apparent age for the pillow lavas as the samples no KA-820 to KA-823 are less altered than the others.

5.2. Fine grained metadiabases

Except for the samples no KA-579 (2509 m.y.) and no KA-748 (1947 m.y.), the ages of the fine grained metadiabases are grouped between 640 and 840 m.y.. It is possible that these diabases were rejuvenated under the green-schist facies metamorphic conditions. It seems that the loss of radiogenic argon has been more or less homogeneous for most of the dif- - 6 -

ferent outcrops of fine-grained diabases. Sample no KA-579 seems to us to be without any statistical significance. Sample no KA-748 comes from a typical columnar basalt flow from ?4iddavarre.Its granulometry is intermudiate between coarse and fine-grained diabase. In the coarse-grained group, the 1900 m.y. age obtained on this flow would fit better with other samples, particularly no KA-749.

5.3. Coarse-grained metadiabases

It seems clear, as shown by the petrographic observations that the coarse grained diabases are less altered than the other rock-tynes. They show a cluster of ages betweeh 1300 and 1500 m.y. in spite of the fact that they have also under- gone a certain metamorphism. As pointed out above, the age of about 1990 m.y. appears twice. This suggest that 2000 m.y. is the true age of these formations but we have no other evidence to verify this hypothesis.

6. CONCLUSIONS

Field evidence shows that coarse grained diabases are interbedded with pillow lavas, tuffs and also fine grained metadiabases. Consequently these rocks must have approxima- tely the same age. From the table 2, we see that the coarse grained diabases yieldsthe oldest ages. A possible expla- nation of our results is that the pillow lavas and the fine grained metadiabases were strongly rejuvenated by the green- schist facies metamorphism. The coarse grained diabases in contrast, resisted better to the same metamorphism lossing much less radiogenic argon.

As a general conclusion, it is possible to say that the ignous rocks of the Alta-Kvaenangen Window have a minimum age of 1400 to 1500 m.y. so that they are probably of Middle Proterozoic age. A formation age of 1800 to 2000 m.y. ac- cording to some of our data is also probable. - 7 -

Acknowled ments

We thank A/S Sulitjelma Gruber and Elkem Spigerverket A/S for permission to publish these results and the Swiss National Foundation for financial assistance.

Critical reading of the text and helpfull suggestions have been made by Professor Roger Laurent, Laval University, Quebec. • - 8 -

Delaloye, M. and Wagner, J.J. 1974: Potassium-Argon Dating: an automatic equipment with digital output for computer processing. C.R. Soc. Phys. Hist. nat. Genåve, 9, 66-74.

Føyn, S. 1964: Den tillittførende formasjonsgruppe i Alta- en jevnføring med øst-Finnmark og med indre Finnmark. Nor. Geol. Unders. 288, 139-150.

Gautier, A. 1977: Gåologie de la fenêtre pråcambrienne d'Alta-Kvaenangen (partie NE), W-Finnmark, Laponie norvågienne. Thåse no 1740, Université de Genåve.

Holtedahl, 0. et al. 1960: Geology of Norway. Nor. Geol. Unders., 208.

Zwaan, K.B., Gautier, A.M., Føyn, S. and Ryghaug, P. 1973: Berggrunnskart Alta 1834 I (M:1/50.000). • Nor. Geol. Unders.

Table 1. Chemical anal ses of datellsamoles

KA 573 576 583820 821 822 823 560572575579580

PILLOW LAVA FINEGRAINEDMETADIABASES

SiO2 52.33 42.37 48.92 49.48 45.93 46.79 50.4550.3149.8147.97 Ti02 1.13 2.14 0.96 0.95 1.03 0.97 1.241.281.341.54 Al203 12.45 14.18 11.96 11.94 14.19 12.51 11.3013.1813.0113.84 Fe203 4.30 6.20 2.55 2.40 2.92 3.08 3.054.213.706.09 Re0 9.48 14.03 9.97 9.81 10.64 11.00 7.258.229.418.33 Mn0 0.23 0.50 0.19 0.19 0.26 0.28 0.140.190.200.23 Mg0 6.64 7.05 9.82 9.61 9.81 10.63 5.896.388.056.72 Ca0 6.87 5.36 9.32 8.50 8.89 9.23 10.3011.169.308.23 Na20 4.32 3.25 2.23 2.72 1.60 0.90 1.862.182.013.31 K20 0.03 0.01 0.15 0.01 0.01 0.06 0.03 0.170.170.760.021.38 P205 0.09 0.18 0.14 0.15 0.17 0.17 0.100.130.130.13 1120+ 3.10 6.12 3.25 3.25 3.83 3.57 3.712.963.573.96 CO2 0.05 0.32 0.39 0.51 0.21 0.21 3.500.210.000.08

SOMME 101.02 101.71 99.71 99.52 99.54 99.37 99.05100.58101.29100.45

KA 581 744748 559 574578582 743745 747 749 746 FINE GRAINEDM. COARSEGRAINED METADIABASES TUFF

SI02 46.6047.33 48.83 48.5249.7e 49.1147.11 49.06 49.14 45.69 Ti02 1.471.05 1.31 2.091.81 0.951.40 1.33 1.08 1.15 Al203 14.1812.43 13.74 11.5211.83 13.3913.66 12.39 14.04 13.75 Fe203 3.422.50 3.56 5.0911.18 3.133.79 3.51 3.30 4.54 Fe0 11.517.95 8.99 11.206.86 11.3911.66 11.36 9.77 9.22 Mn0 0.220.22 0.20 0.220.11 0.290.28 0.20 0.22 0.18 Mg0 6.8413.19 6.97 5.286.18 6.026.43 6.42 6.82 5.03 Ca0 8.2413.37 10.89 10.594.49 8.9210.35 8.90 10.11 11.34 Na20 3.800.16 2.11 1.574.91 2.772.26 2.76 2.13 2.52 K20 0.70 0.370.10 0.61 0.06 1.150.32 0.400.10 0.64 0.11 0.13 P205 0.190.16 0.12 0.190.17 0.180.16 0.19 0.13 0.15 1120+ 3.631.62 3.27 3.682.08 2.432.15 2.64 2.60 3.54 CO2 0.190.46 0.00 0.170.16 0.230.29 0.16 0.10 2.97 SOMME 100.66100.54 100.60 100.18 100.66 99.2199.64 99.56 99.55 100.21

Table 2. Potassi=-Argon Pgta and

Ar40, No Rock type/location %K1)% Ar40 rac rad Age (m.y.) moles/g Pillow lava

KA-573 EC 661595 0.039964.1 0.501(10-10 600 ± 80 -10 576 EC 796581 0.057881.3 0.186.10 172 r12 583 EC 797622 0.130887.9 0.259.10-9 872 t61 820 rim -: 0.0580 77.8 0.183.10-9 L EC 462531 1257 ±58 821 corej 0.0874 85.0 0.214.10-9 1043 ± 81 822 rim -! 0.2000 90.6 0.470.10-9 . EC 342541 1011 t 38 823 core i 0.1270 89.8 0.268.10-9 930 ± 38

Fine crainecl :gatadiabases

KA-560 EC 813598 0.1489.9 0.196.10-91641 t22 572 EC 708616 0.1892.8 0.320.10-9 801 t55 575 EC 778581 0.6995.2 0.115.10-8761 t78 579 EC 712622 0.069092.8 0.645.10-9 2509 ± 128 580 EC 736690 1.1596.3 0.181•10-8 737 t33 581 EC 791705 0.585395.6 0.110.10-8 840 t38 744 EC 435550 0.345294.9 0.481.10-9 664 t23 748 2) EC 461540 0.086094.6 0.522.10-9194771

Coarse crained retadiabases

KA-559 EC 792600 0.5697.0 0.917.10-9 746 t 77 574 EC 797647 0.105978.3 0.427.10-9 1488 ± 170 578 EC 776602 0.9699.9 0.376.10-s 1457 t 70 582 EC 776605 0.274888.2 0.106.10-8 1444 103 743 EC 401542 0.335184.0 0.114.10-3 1324 t 141 745 EC 342552 0.109196.5 0.457.10-9 1533 ± 52 747 EC 409581 0.540592.5 0.178.10-8 1297 ± 44 749 EC 334602 0.114996.0 0.724-10-9 1990 t 71

Tuff

KA-746 1 EC 464533 1 0.1629i 93.6 1 0.444-10 1130 ± 40 I -9 I

K values with 4 digits were determined by isotopic diluticn and values with 2 digits by flame photcmetry.

Columnar basalt of Middavarre. ALTA-KVAENANGENPRECAMBRIAN WINDOW 70 410tOGICAL KAP. SPIPIRWO AITER SAWKR All I973 AND UPPWRISFRO 17A7.4

ALIAKJORDEN 183501 163. 111934 0 1734 183411,

ALIA lifec 00 nr.r1

uu nee. : te/c-

3 3 3 3 - 3 3 C • 3 / 13 C 1 3 I• 1--41. ..* _ IC- rc,y3 LEGEND 5 RM tOrt CC1v.1:1 3 COVER Itrit C AUTOCHINONOUS• ALLOCHN ISOMX RAPAS GROURMASEMENT1 EJ UPPER RAPAS SUB6ROUP I=1 LOWER RAPAS St8GROUP fl PALOW-LAVA (IPRIGH71 FAULT ANIELK SYACLIIIt 44 _ aittOSICAL POUNOARIES • SAWIKCLOCALIIES