1 (22)

© Matti SAV

Guide Map for Field Excursion in Central Lapland: Special Refer-ence to Pyroclastic Komatiites

by Matti Saverikko

Appendix to Saverikko, Matti, 1992. Komatiitic Explosive Volcanism, Volcanoes, and Its Tectonic

Significance in Northern Finland, the Fennoscandian (Baltic) Shield.

Introduction

The Guide Map covers the key areas (Fig. 1) of my paper "The Lapland greenstone belt: Strati-

graphic and depositional features in northern Finland" [Bull. Geol. Soc. Finland 59, 2, pp. 129-154

(1987)]. The petrographic explanations in the paper are based on the references cited and a number of

other studies (see Additional references). The key areas were largely remapped by me and my co-workers

Tuomo Manninen and Jorma Räsänen, particularly, and the excursion sites are some of the most

important exposures, lying close to roads, that I used for my geological interpretation.

All the main roads or highways are two-lane paved roads; other roads (e.g. local, private) are one

or two-lane roads with or without paving; forest lorry roads are one-lane unpaved roads with short passing

lanes, some of them being cart roads in poor condition; the cart roads proper are passable for most cars

when driven slowly; the cartpaths are tractor tracks and are passable for cross-country vehicles, except on

wooded or open bogs. As a rule the car must be parked off the roadway also on the smallest cart road! In

the east, the national boundary zone is marked along some roads with blue and white blazes on tree

trunks; access to the zone is prohibited without a special pass.

Useful maps are the Road Maps of Finland (1:200 000) which are sold at service stations, and

book and paper shops. Topographic maps (1:50 000) are recommended for orienteering, because they are

reduced from original maps (1:20 000) and cover an area of at least six original map sheets (Fig. 2);

topographic maps are sold at well-stocked book and paper shops. A road map overprinted with a grid of

the map sheets at 1:20 000 scale may be helpful in conjunction with the topographic maps. The maps of

the excursion sites have been cut from the original maps at scale 1:20 000. Their geographic information

(Fig. 3), along with the 1x1 km quadrates, is given on the topographic maps at 1:50 000 scale.

Excursion sites

8. Peridotitic komatiite: a volcanic vent.

13. Peridotitic komatiite: volcanic structures in cumulate flows.

7. Pyroxene peridotitic komatiite: a block-lava flow.

6. Pyroxene peridotitic komatiite: a cinder cone.

5. Pyroxene peridotitic komatiite: a lava flow and ejecta.

37. Pyroxene peridotitic komatiite: a volcanic neck.

28. Pyroxene peridotitic komatiite: block lava and ejecta.

31. Pyroxene peridotitic komatiite: cinderite or scoriaceous agglutinate.

2 (22)

© Matti SAV

38. Pyroxene peridotitic komatiite: olivine porphyroblasts in a lapilli tuff.

32. Pyroxene peridotitic komatiite: pillow breccia.

11. Pyroxene peridotitic komatiite: tuff and lapilli tuff.

34. Pyroxene peridotitic komatiite: tuffaceous rock along with graphite/sulphide slates.

4. Pyroxene peridotitic komatiite: volcanic conglomerate.

12. Pyroxene peridotitic komatiite: volcanic conglomerate and lapillistone; and komatiitic basalt: pillow lava and volcanic

greywacke.

10. Komatiitic basalt: agglomerate.

3. Komatiitic basalt: a spatter cone.

9. Komatiitic basalt: pillow lava.

12. Komatiitic basalt: pillow lava and volcanic greywacke; and pyroxene peridotitic komatiite: volcanic conglomerate and

lapillistone.

15. Komatiites and a felsic volcanic rock: a volcanic cluster.

14. Felsic volcanic rock: lava and pyroclastics.

15. Felsic volcanic rock and komatiites: a volcanic cluster.

29. Felsic rock: lava toes/pillows/bombs or sandy ball-and-pillow structures.

39. Lower Lapponian quartzite.

40. Lower Lapponian quartzite and Saamian basement gneiss.

27. Lower Lapponian quartzite--carbonate--schist suite and Saamian basement gneiss.

41. Lower Lapponian quartzite: intrastratal breccia-conglomerate.

18. Marker bed: lower-middle Lapponian.

21. Marker bed: lower-middle Lapponian.

16. Marker bed: middle-upper Lapponian.

45. Middle Lapponian quartzite.

30. Middle Lapponian conglomeratic arkose quartzite.

17. Middle Lapponian: Orakoski arkose.

20. Middle Lapponian: Orakoski arkose changing into metapelite.

25. Metapelite: slate.

22. Sodankylä quartzite formation: arkosic quartzite.

26. Sodankylä quartzite formation: sericite quartzite.

24. Sodankylä quartzite formation: arkose-sericitic quartzite.

23. Sodankylä quartzite formation: calc-silicate rock.

19. Sodankylä quartzite formation: calc-silicate rock.

44. Salla greenstone complex: mafic lava.

43. Salla greenstone complex: mafic to ultramafic tuffs.

35. Salla greenstone complex: felsic tuff.

46. Salla greenstone complex: felsic lavas of acidic to intermediate chemical composition.

42. Salla greenstone complex, a weathering breccia, and pyroxene peridotitic komatiite; a stratigraphic gap.

36. Saamian basement gneiss.

40. Saamian basement gneiss and lower Lapponian quartzite.

27. Saamian basement gneiss and lower Lapponian quartzite--carbonate--schist suite.

2. Saamian basement gneiss, Möykkelmä komatiitic greenstone and lower-Lapponian quartzite.

1. Volcaniclastic greywacke--slate and Kittilä greenstones.

33. Banded iron formation.

47. Aatsinki's Fault Valley.

3 (22)

© Matti SAV

Fig. 1. Four key areas of the Guide to the geological sketch map of central-eastern Finnish Lapland, compiled by Saverikko

(1987, 1990). 1=Sattasvaara, 2=Oraniemi, 3=Kummitsoiva–Jauratsi, 4=Salla.

4 (22)

© Matti SAV

Fig. 2. Topographic maps at a scale of 1 to 50 000 (see Map

Sheet 3714) reduced from twelve original maps at a scale of 1:20

000. The western half (Sheet 3714-1) consists of sheets 01-06 and

the eastern half (Sheet 3714-2) of sheets 07-12. The map-sheet

area of the original map measures 10x10 km and is composed of

100 quadrates 1x1 km2 in size; the subareas (A, B, C, D)

measures 5x5 km.

Fig. 3. The most common map symbols used.

5 (22)

© Matti SAV

Key areas

Sattasvaara area

Fig. 4. Excursion sites (1.-16.) in the Sattasvaara area. Map compiled by Saverikko (1990).

6 (22)

© Matti SAV

Maps: Road Map of Finland 1:200 000; GT-17. Topographic Map 1:50 000; Sheets 3714-1&2.

1. Volcaniclastic greywacke--slate. Sheet 3714

03 [A], quadrate x7512-13/y3460. Nuttion Kuu-

sikkolaki, close to a forest lorry road.

A local cross section of carbonaceous green-

schists is exposed on an eroded fault scarp in a

syncline, the fold shape of which is recognizable

on the hillside. The succession is composed of

graphitic greywacke including graphite slate with

or without sulphide laminae, and porous volcanic

interbeds. The greywacke occurs in beds up to 1

m thick. Lumpy volcanics of the Kittilä green-

stones are exposed on the hilltop. See Räsänen

(1977, p.16).

2. Saamian basement gneiss, Möykkelmä

komatiitic greenstone and lower Lapponian

quartzite. Sheet 3714 06 [A], quadrate x7510-

11/y3472-73. Möykkelmä, close to a forest lorry

road.

The Saamian basement of anisotropic gneiss-

ose granitoids is poorly exposed on the top of the

hill and forms a thin deposit of palaeoresidue. On

the southern flank the mafic to komatiitic green-

stones are largely pyroclastic (tuff to agglomer-

ate/blocky tuff) but infrequent lavas appear as

well; the uppermost lava(s) is coarsely vesicular

in structure. On the western flank the lower

Lapponian quartzite is feldspathic, and the fine-

to-medium grained arkosic quartzite contains

quartz-rich laminae. See Räsänen et al. (1986)

and Saverikko (1978).

3. Komatiitic basalt: a spatter cone. Sheet

3714 05 [B], quadrate x7506/y3470. Visakup-

purat, close to a local road.

A pile of lava driblets overlies massive lava

flows. The absence of radial cracks indicates that

the lava driblets are spatters rather than stretched

pillows. Their limited and isolated occurrence

may be due to a rupture of the solidified crust of

a pahoehoe flow. This is suggested by the scat-

tered angular pyroclasts embedded in the

massive flow(s) in close proximity to the spatter

cone. See Saverikko (1985, p.63).

4. Pyroxene peridotitic komatiite: volcanic

conglomerate. Sheet 3714 05 [A], quadrate

x7505/y3473-74. About 2 km north of Sattas-

vaara, close to a cart road on the way to Pahta-

vaara.

2 (22)

© Matti SAV

The volcanic conglomerate is moderately

packed and includes (well-)rounded cobbles of

mostly amphibole-chlorite rock within a talc-

chlorite matrix. The rock is similar to that at

Sakattipahta on the river Kitinen (see Mikkola

1941, pp.58-59); they indicate a hiatus between

the komatiitic basalt and the upper(most) layer of

pyroxene peridotitic komatiite. See Saverikko

(1985, Fig. 12).

5. Pyroxene peridotitic komatiite: a lava flow

and pyroclastics. Sheet 3714 05 [A], quadrate

x7502/y3473. By a cart road on the way to Sat-

tasvaara, a cliff at the junction of two reindeer

fences.

The lava flow displays, from top to bottom:

flow-top breccia, a few vesicles, platy flow struc-

tures, and polygonal jointing; the lava pillows are

as exception. The MgO content increases up-

wards in the flow, which is penetrated by a vol-

canic neck of serpentinitic rock. See Saverikko

(1985, ps. 67-68, 77, Table 3: # 24.-27.).

6. Pyroxene peridotitic komatiite: a cinder

cone. Sheet 3714 05 [A], quadrate x7502/y3473.

Sattasvaara.

[see previous picture]

The steep-sided rocky hill is composed of

pyroclastics which are cored lapilli or lapilli with

chilled margins or both. The remnant hill may

have remained standing because of the presence

of welded pyroclastics, whereas primarily un-

welded ejecta were eroded in the surroundings.

The brown shade of the weathering surface is

lithologic evidence of the most ultramafic pyrox-

ene peridotitic komatiite partial-magma.

Eruption fissures of mafic greenstone cut the

relict cinder cone on the top of the hill. See

Saverikko (1985; 1991, Fig. 14).

7. Pyroxene peridotitic komatiite: a block-lava

flow. Sheet 3714 05 [C], quadrate x7501/y3474-

75. About 1.5 km southeast of Sattasvaara.

The block-lava flow resembles recent ones in

exposed flow morphology, which shows the flow

direction from the vent at Sattasvaara. See Save-

rikko (1991, Fig. 16).

8. Peridotitic komatiite: a volcanic vent. Sheet

3714 05 [C], quadrate x7502/y3477. Mikkuu-

rova, close to a cartpath.

A peridotitic rock forms a volcanic neck and

the associated komatiite flow, the crust of which

is autobrecciated amphibole-chlorite rock, i.e.

pyroxene peridotitic komatiite. See Saverikko

(1985, p.73).

9. Komatiitic basalt: pillow lava. Sheet 3714

08 [A], quadrate x7501/y3484-85.

3 (22)

© Matti SAV

Paloseljänrolli, close to a cartpath leading away

from a forest lorry road.

Lava pillows of spherical, ellipsoidal or flat-

tened shape with or without a tail resemble the

recent pillows in three-dimensional form in the

outcrop. Radial cracks are common but chilled

skins and polygonal shrinkage cracks are rare.

See Saverikko (1985, pp. 63-64, Fig. 10).

10. Komatiitic basalt: agglomerate. Sheet 3714

08 [C], quadrate x7503/y3489. On Main Road 4.

Loose boulders of agglomeratic structure, in

which essential and accessory pyroclasts are

fairly distinct from each other. See Saverikko

(1985, Fig. 11).

11. Pyroxene peridotitic komatiite: tuff and

lapilli tuff. Sheet 3714 08 [C], quadrate x7503/

y3490-91. On a cartpath near the western side of

the river Kitinen.

Local boulders are coarse tuff. An outcrop

on the river bank is crudely stratified lapilli tuff,

the ejecta (φ 1 cm) of which include also

accessory pyroclasts of komatiitic basalt and

accidental grains of carbonate or magnetite. See

Saverikko (1985, Fig. 20).

12. Pyroxene peridotitic komatiite: volcanic

conglomerate and lapillistone, and komatiitic

basalt: pillow lava and volcanic greywacke.

Sheet 3714 11 [A-B], quadrate x7504-05/y3491.

Sakattipahta, eastern bank of the river Kitinen,

close to a forest lorry road. (Obs! Currently

under dammed basin.)

On the road to Sakattipahta: a volcanic grey-

wacke is talc-chlorite slate with strong foliation

but changes into thickly-bedded pebbly siltstone

underlying pillow lavas of komatiitic basalt. The

lavas are capped with volcanic conglomerate of

tightly packed and crudely stratified cobbles and

boulders of pyroxene peridotitic komatiite and

komatiitic basalt; the conglomerate has changed

into lapillistone about 200 m to the south. See

Mikkola (1941, pp.58-59), and Saverikko (1978;

1985, Fig. 12).

13. Peridotitic komatiite: volcanic structures in

cumulate flows. Sheet 3714 08 [D], quadrate

x7505-06/y3489. Mataravaara, on a cartpath.

4 (22)

© Matti SAV

Clearly distinct massive flows of

serpentinitic or peridotitic appearance. In

addition, the serpentinitic rock contains lava

driblets and displays incipient flow breccia,

whereas the peridotitic rock

shows polygonal jointing. The (almost?) com-

plete cumulate texture is evidence that the peri-

dotitic komatiite poured out as a crystal mush.

See Saverikko (1985, Fig. 27).

14. Felsic volcanic rock within graphitic slate

zone. Sheet 3714 08 [D], quadrate x7509/y3490.

Beside Main Road 4, on a path.

The rock is mostly structureless in the fresh

surface but the weathering surface displays fea-

tures of lavas and ejecta in some places. This is a

type locality of the albite rocks which caused the

adinolization of the adjacent argillaceous meta-

sediments (Mikkola 1941, ps. 66-67, 253-256).

The exposure is one of a group of small albite-

rock outcrops by the river Kitinen, of which one

has been dated (O. Kouvo, pers. commun. 1986)

to 2.70 Ga or (M. Vaasjoki, pers. commun. 1991)

2.05 Ga.

15. Komatiites and a felsic volcanic rock: a

volcanic cluster. Sheet 3714 12 [C], quadrate

x7514/y3497. Vaiskonpalo, about 1 km from the

end of a forest lorry road, along a cartpath.

In the northern part, a peridotitic komatiite

contains numerous idioblasts of pyroxene as

contact-metamorphic evidence of the border

against the Koitelainen gabbro complex (Save-

rikko 1985, p.73). Its contact, according to Iso-

maa (1978), lies beneath the adjacent narrow

strip of bog: thus, this rock is older than the

Koitelainen complex (2.45 Ga). In the southern

part at the volcanic minicentre, a felsic volcanic

rock displays a vent (φ 2-5 m) in the form of

foamy shapes or strongly contorted beds and

discordant feeder cracks; the extremerely dense

rock is usually stratified with parallel thin beds

(see exposures by the small lake nearby). The

rock is overlain by a peridotitic komatiite pene-

trated by a few volcanic necks (φ 10-30 m) of

komatiitic basalt. The felsic rock changes into

albitite--chlorite-rock association, as is seen in

outcrops about 700 m southwards down the path.

See e.g. Saverikko (1978).

16. Marker bed: middle-upper Lapponian. Sheet

3714 07 [A], quadrate x7490/y3481-82. 2 km

west of the village of Sattanen, close to a cart

road.

Volcaniclastic greywacke of fine-to-medium

grained mafic material containing (sub)angular

coarse grains. It is stratified due to the alternating

massive beds (h 10 cm) and slumped laminae.

Marker characteristics, i.e. graphitic and jaspery

interbeds (Saverikko 1987, p.137), disappear

from this banded cap rock of amphibolite, but the

overlying graphitic slates can be recognized in

adjacent swampy lands.

2 (22)

© Matti SAV

Oraniemi area

Fig. 5. Excursion sites (17.-27.) in the Oraniemi area. Map revised by Saverikko (1988).

3 (22)

© Matti SAV

Maps: Road Map of Finland 1:200 000; GT-15, GT-17. Topographic Map 1:50 000; Sheets 3713-2,

3731-1, 3732-1.

17. Orakoski arkose. Sheet 3713 08 [C], quad-

rate x7471/y3487. Orakoskenvaara, close to a

local road.

A very coarse-grained arkose quartzite char-

acterized by current bedding in the form of large-

scale festoon and channel-fill cross-beds and

rarely of embryonic megaripple bedding.

Blastoclastic texture has developed in graded

bedding and channel-lag gravel in the channel-

fill cross-beds. The lower-middle Lapponian

marker bed appears as a deposit of amphibolic

greywacke to graded sericite-quartz slate on the

eastern bank of the river Kitinen. See Saverikko

(1977, p.24; 1988, Fig. 7).

18. Marker bed: lower-middle Lapponian. Sheet

3713 07 [C], quadrate x7464-65/y3487-88. Close

to the road (9624) to Luosto.

Two or three felsic pebbles in volcaniclastic

greywacke. A well-rounded cobble of granitoid

is met with in a small outcrop on the bottom of a

sand pit beside the road. See Saverikko (1988,

Fig. 5b).

19. Calc-silicate rock beneath the Sodankylä

quartzite formation. Sheet 3713 11 [C], quadrate

x7473/y3498. Near Lake Orajärvi, close to a lo-

cal road.

Epidote and amphibole form banded texture

in an arenaceous quartz-albite rock. Sharpstone

conglomerate and soft-sediment breccia are ex-

posed in the western part. See Saverikko (1977,

Fig. 16; 1988, p.197).

20. Orakoski arkose changing into metapelite.

Sheet 3731 01 [D], quadrate x7467/y3508-09. A

rock cutting on Main Road 5 between Sodankylä

and Pelkosenniemi.

The feldspathic quartzite of finer grain size

and increasing mica content exhibits a composite

bedset with ripple-bedded, variously massive,

laminated or cross-bedded sands. See Saverikko

(1988, p.194, Fig. 8).

21. Marker bed: lower-middle Lapponian. Sheet

3731 01 [C], quadrate x7464/y3507. Peuralam-

minmaa, about 1 km north of a private road.

2 (22)

© Matti SAV

Gravelly volcaniclastic greywacke

displaying very low-angle planar cross-beds. The

underlying mafic volcanic rock is pyroclastic in

structure and belongs to the Salla greenstone

complex. See Saverikko (1977, Fig. 5c).

22. Sodankylä quartzite formation: arkosic

quartzite. Sheet 3713 11 [D], quadrate x7474-

75/y3498. Near Lake Orajärvi, close to Main

Road 5, on a cart road leading to a reindeer

fence.

A coarse-to-medium grained arkosic quartz-

ite resembling the Orakoski arkose in lithology,

except for a rhythmic bedset with alternating

laminated finer sand and parallel-bedded to

cross-bedded sand. See Saverikko (1977, pp.41-

44; 1988).

23. Calc-silicate rock changing into the overly-

ing Sodankylä quartzite formation. Sheet 3713

11 [D], quadrate x7475/y3497. Near Lake Ora-

järvi, 250 m north of Main Road 5.

A silty albite-quartz rock that is frequently

ripple-bedded; mud-draped ripple marks which,

at their thickest, include andalusite idioblasts

within the biotitized muddy fill. See Saverikko

(1988, p.197).

24. Sodankylä quartzite formation: arkosic

quartzite member changing into sericitic quartz-

ite. Sheet 3713 11 [C], quadrate x7475/y3496.

Near Lake Orajärvi, Tepsanniemi, about 200 m

south of Main Road 5.

A feldspathic quartzite of bimodal detritus

comprising laminated fine sand to silt with float-

ing grains of coarser sand that also form distinct

laminae. See Saverikko (1988).

25. Metapelite: slate. Sheet 3713 09 [C], quad-

rate x7482-83/y3487. Kommattilampi, close to

the road (967) from Sodankylä to Tanhua.

An andalusite slate with thinly bedded,

graded mud and interlayered clay and silt in tabu-

lar beds or laminae. See Tyrväinen (1983, Fig.

7).

26. Sodankylä quartzite formation: sericite-

quartzite member. Sheet 3731 03 [C], quadrate

x7482/y3507-08. Numerous local boulders and a

few outcrops along a forest lorry road on the way

to Nuolikirkko.

3 (22)

© Matti SAV

The sericite quartzite consists of interbedded

silty and muddy detritus in the form of laminae

alternately rich in quartz or sericite and of seric-

itic flasers associated with quartzose lenticular

beds. Bouma cycles and mud cracks are also

encountered. See Rask (1978, pp.22-24) and

Saverikko (1988, Figs. 12, 13).

27. Saamian basement gneiss and lower Lappo-

nian quartzite--carbonate--schist suite. Sheet

3732 01 [D], quadrate x7499/y3508-09. North of

Suksivaara, close to a forest lorry road.

The Saamian basement consists of conglom-

eratic arkose gneiss and mica gneiss; an inferred

palaeoresidue can be seen on a boulder. The

gneiss exposure is overlapped by a brecciated

calc-silicate rock at the SW border. An ortho-

quartzite with feldspathic zones and interbeds

borders the basement gneisses in the north. On

the northern and western flanks of Suksivaara the

quartzite includes interlayers of sericitic schist

and calc-silicate rock. See Saverikko (1978;

1985, Fig. 29).

2 (22)

© Matti SAV

Kummitsoiva--Jauratsi area

Fig. 6. Excursion sites (28.-36.) in the Kummitsoiva–Jauratsi area. Map compiled by Saverikko (1990).

3 (22)

© Matti SAV

Maps: Road Map of Finland 1:200 000; GT-15. Topographic Map 1:50 000; Sheet 3644-1&2.

28. Pyroxene peridotitic komatiite: block lava

and pyroclastics. Sheet 3644 03 [D], quadrate

x7458/y3546-47. 2 km northeast of Saukkovaara,

very closy to a forest lorry road.

A lava flow shows autobrecciated structure

and encloses larger blocks which appear to be

air-fall in origin. Adjacent ejecta contain

magnetitized pyroclasts. Secondary magnetite is

concentrated on fissures. See Saverikko (1980)

and Saverikko et al. (1985, Fig. 4b).

29. Albite-quartz rock: felsic lava toes/pillows/

bombs or sandy ball-and-pillow structures. Sheet

3644 03 [B], quadrate x7458/y3543-44. Southern

bank of the river Kemijoki.

A mass of pillow-like felsic lumps whose

megascopic structures indicate volcanic origin

but which are microscopically clastic. If the al-

bite-quartz rock is of volcanic parentage, it may

be a felsic volcanic of the Salla greenstone com-

plex. See Saverikko (1980).

30. Middle Lapponian conglomeratic arkose

quartzite. Sheet 3644 03 [B], quadrate x7456/

y3541. 2 km south of the bridge over the Kemi-

joki, on a local road.

Arkosic quartzite of very coarse-to-medium

grained sand is intermingled with cobbles or peb-

bles of granitoid and quartzite. See Saverikko

(1980; 1987, p.136).

31. Pyroxene peridotitic komatiite: cinderite or

scoriaceous agglutinate. Sheet 3644 03 [A],

quadrate x7453-54/y3541. About 2 km west of

Pyytövaara, very close to a forest lorry road, on a

path.

The pyroclastic rock is composed of bomb-

to-lapillus sized ejecta which are usually densely

scoriaceous and welded together. See Saverikko

et al. (1985, Fig. 5d).

32. Pyroxene peridotitic komatiite: pillow brec-

cia. Sheet 3644 03 [A], quadrate x7451/y3545.

Northwest flank of Rahkavaara hill, unearthed

outcrops very close to a forest lorry road (rather,

cart road).

2 (22)

© Matti SAV

Pillow breccia and a few lava pillows with a

fluidal-shaped flow breccia in their core. See Rä-

sänen (1983) and Saverikko et al. (1985, Fig. 4c,

d).

33. Banded iron formation. Sheet 3644 02 [B],

quadrate x7446-47/y3541-42. Jauratsiselkä, on a

forest lorry road.

The Jauratsi BIF forms a pod-shaped deposit

trending W-E, right on a volcanic vent

underlying Kummitsoiva hill (2 km north). Small

hillocks nearby are also exposed and there the

jaspilitic rock shows boudinage and slump folds.

See Rieck et al. (1967) and Saverikko (1980;

1983, Fig. 26).

34. Sulphide slate and tuffaceous komatiite

along with graphitic slates. Sheet 3644 02 [D],

quadrate x7445/y3547. Siulionpalo, on a forest

lorry road.

A sulphide slate is exposed in a sand pit

with black slate and carbonatic rock visible in

the wall. In the eastern part, a tuffite of pyroxene

peridotitic komatiite contains interbeds and intra-

clasts of graphite slate, intercalations with dis-

seminated graphite and/or micas, and calc-

silicate idioblasts; lapilli tuff is also interbedded.

See Saverikko (1980; 1983, pp.121-122).

35. Salla greenstone complex: felsic tuff. Sheet

3644 05 [B], quadrate x7445-46/y3552. About 1

km southwest of Kunkuttama, on a forest lorry

road.

Thinly stratified tuff with alternating quartz-

feldspathic or micaceous laminae/thin beds and

containing euhedral plagioclase crystals. See

Manninen (1981, pp.28-29).

36. Saamian basement gneiss. Sheet 3644 02

[C], quadrate x7441-42/y3548. About 3 km north

of Vuotosselkä, along a forest lorry road.

Anisotropic gneissose granitoids are unlike

the K-feldspathic granites in the surroundings.

The gneisses and a biotite gneiss or schist farther

north display some hornblendic bands. The

biotite gneiss may belong to the pre-Lapponian

paragneisses. See Saverikko (1980).

2 (22)

© Matti SAV

Salla area

Fig. 7. Excursion sites (37.-46.) in the Salla area. Map slightly revised after Saverikko and Manninen (1981).

3 (22)

© Matti SAV

Maps: Road Map of Finland 1:200 000; GT-15. Topographic Map 1:50 000; Sheets 3644-1&2, 4621-

1&2, 4622-1&2.

37. Pyroxene peridotitic komatiite: a volcanic

neck. Sheet 3644 08 [A], quadrate x7441/y3562.

Känespella, close to a forest lorry road.

On a steep-sided rocky hill the rock is erup-

tive breccia with tightly compressed fragments of

block-to-lapillus size; some blocks may be mafic

greenstones. Volcanic fines virtually disappear,

and the rock clearly differs from the lapilli tuff or

lapillistone exposed in the surroundings. See

Saverikko and Manninen (1981), and Saverikko

(1983, pp. 116-117, Fig. 6a).

38. Pyroxene peridotitic komatiite: olivine por-

phyroblasts in a lapilli tuff. Sheet 3644 04 [D],

quadrate x7437-38/y3557. Koutelokumpu, close

to a forest lorry road.

A large outcrop area where a lapilli tuff of

pyroxene peridotitic komatiite shows (contact?)

metamorphic features within numerous olivine

porphyroblasts present as rusty spots of coin

size; the metamorphic olivine is common only in

exposures adjacent to a granite province. A

granite and a lower Lapponian quartzite are

exposed on the top of Koutelokumpu hill. See

Saverikko and Manninen (1981, Fig. 21), and

Saverikko (1983, p.122).

39. Lower Lapponian quartzite. Sheet 3644 04

[A], quadrate x7433/y3552. Close to the Ahven-

selkä–Vittikko local road.

A feldspathic quartzite is thinly bedded:

quartzose laminae and calc-silicatic stripes pro-

duce a banded structure that is accentuated by

banded calc-silicate rock interlayers. See Save-

rikko and Manninen (1981).

40. Saamian basement gneiss and lower Lap-

ponian quartzite. Sheet 3644 04 [A], quadrate

x7430/y3554. Close to the Ahvenselkä--Vittikko

local road, on a cartpath.

At left: an anisotropic gneissose granitoid

resembling palaeoresidue, showing structures of

bedding planes and weathering breccia; however,

the rock is granoblastic instead of blastoclastic in

texture. At right: the lower Lapponian quartzite

is orthoquartzite with thin parallel beds. See Sa-

verikko and Manninen (1981).

41. Lower Lapponian quartzite: intrastratal

breccia-conglomerate. Sheet 4622 07 [A], quad-

2 (22)

© Matti SAV

rate x7433/y3573. Varpuselkä, close to a local

road.

A brecciated quartzite that was originally

thinly stratified, alternating quartzose and feld-

spathic sands which now include disseminated

calc-silicate minerals. The breccia-conglomerate

led me for a while to interpret the quartzite area

at Varpuselkä as middle Lapponian in origin (Sa-

verikko 1987, p.136). See Saverikko and Manni-

nen (1981, Fig. 5).

42. Salla greenstone complex, a weathering

breccia, and pyroxene peridotitic komatiite; a

stratigraphic gap. Sheet 4622 10 [B], quadrate

x7436-37/y3584-85. 1 to 2 km east of Tuohi-

vaara, close to a local road.

A mafic greenstone is exposed nearest to the

road, whereas a felsic volcanic of intermediate

chemical composition is present as quartz-

plagioclase-biotite rock on the hill. In the west, a

mafic greenstone (present in local boulders) was

the source of flagstones in a breccia-

conglomerate with talc-chloritic groundmass; the

tuffitic matrix derived from a lapillistone of the

overlying pyroxene peridotitic komatiite in the

west. The breccia-conglomerate is considered to

be a weathering breccia indicative of a

stratigraphic break between the lower and upper

Lapponian successions, as the middle Lapponian

rocks and even the graphitic slates present at

Tuohivaara disappear. See Saverikko and

Manninen (1981, Figs. 18, 19), and Saverikko

(1983, Fig. 6b).

43. Salla greenstone complex: mafic to ultrama-

fic tuffs. Sheet 4621 12 [D], quadrate x7426/

y3586. Mäntyvaara, close to a private road.

A group of small outcrops where the ultra-

mafic tuff has a brownish to greenish grey

weathering surface. The mafic tuff dominates

and displays slump folds in places. Some lavas

are also seen. See Saverikko and Manninen

(1981, Fig. 10), and Saverikko (1987, p.135).

44. Salla greenstone complex: mafic lava. Sheet

4621 12 [A], quadrate x7422-23/y3582. Liemu-

vaara, about 2 km west of the village of Aatsinki,

on a forest lorry road.

A mafic greenstone consists of lava flows

coarsely vesiculated. Amygdales are

concentrated mainly in conformity with flow

structures, in places forming the frothy skin of

lava flows. See Saverikko and Manninen (1981,

Fig. 8).

45. Middle Lapponian quartzite. Sheet 4621 09

[A], quadrate x7420/y3576. Puu-Matovaara,

3 (22)

© Matti SAV

close to highway (82) between Kemijärvi and

Salla/Kelloselkä.

On the top of the hill, strong

recrystallization and foliation have obliterated

the thin parallel bedding of an orthoquartzite.

Down on the northwestern flank, the quartzite

grades into carbonaceous sericite quartzite

displaying large-scale units of well-developed

foreset laminae – either megaripple bedding or

planar cross-bedding in origin. Beneath the

quartzite an uralite-porphyritic greenstone

contains a few amygdales in finer-grained rock.

The sericite-quartzite–orthoquartzite suite is

regarded as middle Lapponian (Saverikko 1987,

p.136) as the palaeogeographic environment

clearly differs from that of the lower Lapponian

province; further, (Puu-)Matovaara hill differs in

topography from the surrounding lowland and

may thus be a remnant hill. See Saverikko and

Manninen (1981, Fig. 6).

46. Salla greenstone complex: felsic lavas of

acidic to intermediate chemical composition.

Sheet 4621 11 [B], quadrate x7416-17/y3584-85.

V-shaped valley between the Koutoiva and

Petservaara hills, very close to a forest lorry road.

At left: an acidic lava that is vesicular albite-

quartz rock associated with magnetite-striped

chert. At right: an intermediate lava that is flow-

structured quartz-plagioclase-biotite rock with

amygdales (Ø up to 10 cm) in planar arrange-

ment. See Saverikko and Manninen (1981, Figs.

11, 13).

47. (i.e. 43./46.) Aatsinginhauta: "Aatsinki's

Fault Valley".

The 30 km long fault valley is a fairly recog-

nizable landmark. Parallel vertical diabases and

thick quartz veins are seen beside the valley

which separates the tightly folded tract of Salla

greenstones in the east from the rather flat-lying,

quartzite-dominant strata in the west. See Save-

rikko and Manninen (1981), and Saverikko

(1988, p.205, Fig. 17).

References cited

Isomaa, J., 1978 Keski-Lapin liuskemuodostu-

ma Petkulan alueella Sodankylän

pohjoispuolella. M.Sc. Thesis, Dept.

Geol., Univ. Oulu.

Manninen, T., 1981 Savukosken Akanvaaran

alueen geologiasta. M.Sc. Thesis, Dept.

Geol., Univ. Turku.

Mikkola, E., 1941 Suomen geologinen yleis-

kartta. Kivilajikartan selitys. Lehdet-

Sheets–B7-C7-D7, Muonio–Sodankylä–

Tuntsajoki. General Geological Map of

Finland. Summary: Explanation to the

map of rocks. Geol. Surv. Finland,

Espoo.

Räsänen, J., 1977 Kaarestunturi-muodostuma

ja sen sijainti Keski-Lapin liuskejaksossa.

M.Sc. Thesis, Dept. Geol., Univ. Helsin-

ki.

--, 1983 Keski-Lapin komatiiteista. English

summary. Geologi (Finland) 35, 25-29.

--; Hanski. E. & Lehtonen, M., 1986 Komati-

ites and tholeiites in the Möykkelmä area,

2 (22)

© Matti SAV

northern Finland. In: Lång, K. (ed.)

Abstracts. 17e Nordiska Geologmötet,

12.-15.5.1986, Helsinki. p.167.

Rask, M., 1978 Kivilajeista ja metapeliittien

progressiivisesta metamorfoosista So-

dankylän Kelujärven alueella. M.Sc.

Thesis, Dept. Geol., Univ. Helsinki.

Rieck, K.-H.; Borchert, H. & Anger, G., 1967 Lagerstättenkundliche Untersuchungen am Eisenerzvorkommen Jauratsi in Finnisch Lapland. Geol. Surv. Finland Bull. 226.

Saverikko, M., 1977 Oraniemen liuskeiden

kerrostumisjärjestys ja stratigrafinen

sijainti Keski-Lapin liuskejaksossa.

M.Sc. Thesis, Dept. Geol., Univ.

Helsinki.

--, 1978 Keski-Lapin liuskejakson stratigrafian,

sedimentaation ja rakenteen pääpiirteet

Sodankylän, Savukosken, Pelkosennie-

men alueelta. Rep. 6/78 (unpublished),

Lapin Malmi, Rovaniemi.

--, 1980 Keminniemen kallioperän stratigrafia,

rakenteet, evoluutio ja malmikriittiset

vyöhykkeet. Rep. 7/80 (unpublished),

Lapin Malmi, Rovaniemi.

--, 1983 The Kummitsoiva komatiite complex

and its satellites in northern Finland.

Bull. Geol. Soc. Finland 55, 2, 111-139.

--, 1985 The pyroclastic komatiite complex at

Sattasvaara in northern Finland. Bull.

Geol. Soc. Finland 57, 1-2, 55-87.

--, 1987 The Lapland greenstone belt: Strati-

graphic and depositional features in

northern Finland. Bull. Geol. Soc.

Finland 59, 2, 129-154.

--, 1988 The Oraniemi arkose--slate--quartzite

association: An Archaean aulacogen fill

in northern Finland. Geol. Surv. Finland

Spec. Paper 5, 189-212.

--, 1991 Synopsis. In: Saverikko, M., 1991, Ex-

plosive komatiitic volcanism, volcanoes,

and its tectonic significance in northern

Finland, the Fennoscandian (Baltic)

Shield.

--; Koljonen, T. & Hoffrén, V., 1985 Palaeo-

geography and palaeovolcanism of the

Kummitsoiva komatiite complex in

northern Finland. Geol. Surv. Finland

Bull. 331, 143-158.

-- & Manninen, T., 1981 Keminniemi/Saijan

osa-alueen kivilajit, stratigrafia, rakenteet

ja malmikriittiset vyöhykkeet. Rep. 8/81

(unpublished), Lapin Malmi, Rovaniemi.

Tyrväinen, A., 1983 Sodankylän ja Sattasen

kartta-alueiden kallioperä. Lehdet-3713,

3714-Sheets, 1:100 000. Summary: Pre-

Quaternary rocks of the Sodankylä and

Sattanen map-sheet areas. Explanation to

the maps of Pre-Quaternary rocks. Geol.

Surv. Finland, Espoo.

Additional References

Gehör, S., 1982 Kittilän manganosideriitti-lius-

keiden petrografia, mineralogia ja geoke-

mia. M.Sc. Thesis, Dept. Geol., Univ.

Oulu.

Haimi, M., 1977 Luoston alueen geologia.

M.Sc. Thesis, Dept. Geol., Univ. Helsin-

ki.

Kallio, M.; Kärkkäinen, N. & Sarapää, O.,

1980 Keski-Lapin liuskealue Itä-Kittilän

ja Länsi-Sodankylän osalta, Osa I: petro-

grafinen kuvaus ja kallioperäkartta. Re-

search report (unpublished), Dept. Geol.,

Univ. Oulu.

Kröner, A.; Puustinen, K. & Hickman, M.,

1981 Geochronology of an Archaean

tonalitic gneiss dome in northern Finland

and its relation with an unusual overlying

volcanic conglomerate and komatiitic

greenstone. Contrib. Mineral. Petrol. 76,

33-41.

Lehto, T. & Niiniskorpi, V., 1977 Pohjois- ja

Itä-Suomen rautamuodostumat. Sum-

mary: The iron formations of northern

and eastern Finland. Geol. Surv. Finland

Rep. Invest. 22.

Leppänen, T., 1985 Savukosken Kiurujärven

alueen kallioperän rakenne ja metamor-

foosi. M.Sc. Thesis, Dept. Geol., Univ.

Oulu.

Mäkelä, M. & Räsänen, J., 1986. Pyhätunturin

kvartsiitin paleosedimentologia. (Abst-

ract). In: Laajoki, K. & Gehör, S. (eds)

Suomen kallioperän sedimentologia. Res

3 (22)

© Matti SAV

Terrae (Dept. Geol. Univ. Oulu) B, 9, 28.

Mattila, H., 1974 Karelidit Savukosken Tan-

huan alueella, Keski-Lapissa. M.Sc. The-

sis, Dept. Geol., Univ. Oulu.

Niemelä, M., 1976 Pelkosenniemen alumiini-

rikkaat kiillegneissit. M.Sc. Thesis, Dept.

Geol., Univ. Turku.

Nikula, R., 1985 Sodankylän Virttiö- ja

Värttiövaaran metasedimenttien paleo-

sedimentaatioympäristöt. M.Sc. Thesis,

Dept. Geol., Univ. Oulu.

Paakkola, J., 1971 The volcanic complex and

associated manganiferous iron formation

of the Porkonen-Pahtavaara area in Fin-

nish Lapland. Geol. Surv. Finland Bull.

247.

Papunen, H.; Idman, H.; Ilvonen, E.; Neuvo-

nen, K.J.; Pihlaja, P. & Talvitie, J.,

1977 Lapin ultramafiiteista. Summary:

The ultramafics of Lapland. Geol. Surv.

Finland Rep. Invest. 23.

Pekkala, Y., 1970 Aluminiumsilikaattitutkimuk-

set kesällä 1969. Rep. M82/3643,4713/-

69/1 (unpublished), Geol. Surv. Finland,

Espoo.

Peltonen, P.; Manninen, T. & Pihlaja, P., 1986 A late Archean volcanic conglomerate in Peurasuvanto, northern Finland. In: Lång, K. (ed.) Abstracts. 17e Nordiska Geologmötet, Helsinki 12.-15.5.1986. p.146.

Pulkkinen, E.; Rahkola, P. & Saverikko, M.,

1983 Case study of a geochemical

anomaly in a komatiite area in northern

Finland. In: Björklund, A. & Koljonen, T.

(eds) Abstracts. 10th IGES - 3rd SMGP,

29.8.-2.9. 1983, Espoo/Helsinki. p.64.

Puustinen, K., 1977 Exploration in the north-

east region of the Koitelainen gabbro

complex, Sodankylä, Finnish Lapland. In:

Davis, G.R. (ed.) Prospecting in Areas of

Glaciated Terrain. Inst. Min. Met.

London. 6-13.

Räsänen, J., 1984 On the Archean and Pro-

terozoic komatiites in the Savukoski area,

NE-Finland. In: Armands, G. & Schager,

S. (eds) Abstracts. 16e Nordiska Geolo-

giska Vintermötet, 9.-13. Januari 1984,

Stockholm. p.189.

Sarapää, O., 1980 Keski-Lapin liuskealue

Itä-Kittilän ja Länsi-Sodankylän osalta,

Osa III: vulkaniittien geokemia. M.Sc.

Thesis, Dept. Geol., Univ. Oulu.