Geochemical Journal, Vol. 10 , pp. 1 to 11, 1976 1

Major elements and REE in tektites and three probable shock-metamorphic rock series of the Baltic shield

TAPIO KOLJONEN' and R. J. ROSENBERG2

Department of Geology and Mineralogy, The University of Helsinki, 00170 Helsinki 171 and Reactor Laboratory, Technical Research Centre of Finland, 02150 Espoo 152, Finland

(Received February 28, 1976)

REE contents of four tektites from separate strewn-fields have been determined and the REE and major elements in ten shock-metamorphic rocks from lakes Lappajarvi, Saaksjarvi (Finland), and Tinisjarvi (Soviet Karelia). Neither the impact of meteorite or comet nor secondary weathering seems to change the REE content or distribution pattern in rocks. Therefore, where the texture and major element compo sition in country rock has changed through impact and after it, REE can be used as indicators of the original rock or sediment type. The surfaces of the Moon and each planet, including the earth, probably have unique REE distribution patterns as a result of the prevailing endogenic and exogenic processes. The distribution patterns of REE in tektites, are quite similar to those found in sediments, sedimentary rocks and shock-melted rocks. Accordingly, the origin of tektites from silica-rich clayey sediments or silicic rocks through impact is strongly indicated.

INTRODUCTION METHODS Rare earth elements, being a rather coherent The major elements have been analyzed geochemical group, can be used advantageously according to the classical wet method and REE in studying the genesis of rocks. This is espe by activation analysis as described earlier (cf., cially true of shock-metamorphic rocks and KOLJONENand ROSENBERG,1974). The normali tektites because REE volatilize at elevated tem zation of REE is made against chondrites as peratures and migrate with difficulty from the proposed by MASUDA(1962) and CORYELLet al. brecciated rocks formed through impact. (1963), and because some fractionation has been REE contents of shock-metamorphic rocks observed in chondrites, against Leedey L/6 and tektites have been studied in the Bosumtwi chondrite (MASUDAet al., 1973). Normalized Crater area in Ghana by SCHNETZLER et al . graphs are represented in decimal rather than (1967). They compared the REE distribution logarithmic scale because the former are more patterns found there with those in Ivory Coast easily read. As is usual, the separate REE are set tektites. COHEN (1963), BousKA (1972), and out at equal distances (atomic numbers) instead BOUSKA et al. (1973) compared the REE con of according to their ionic radii because the tents of moldavites with those of rocks in the graphs appear to be smoother when presented in Ries area in Germany, TAYLOR (1968) and his this way. This possibly indicates that REE pres coworkers compared the contents of australites ent in trace concentrations behave as if the ionic with those of Henbury impact glass, and WINZER radii from La to Lu change gradually and not et al. (1976) have studied REE in the shock according to their calculated ionic radii (cf., melted rocks from the Wanapitei Lake in Cana WEAST1971, F-171). da. HASKIN and GEHL (1963) and CHASEet al . (1963) have also studied REE in tektites. OCCURRENCE OF ASTROBLEMES In this study, major element and REE con IN FENNOSCANDIA tents of tektites and common silicic rocks are compared with the contents of three probable In the midst of Precambrian terrain , ESKOLA ( shock-metamorphic rock series of Middle 1921, 1927) observed rare occurrences of Precambrian terrain (Fig. 1) young "volcanic" rocks as islands in the lakes 2 T. KOLJONEN and R. J. ROSENBERG

0*1 30° IIIII ~I Iii

MMIL 2

3 j 4

pr.rr ® 6

C0 G t 2 0 m

61° w O 61° Lake I+ r++++ Ladoga +++ O

Finland Gulf km

20° 25° 30°

Fig. 1. The sites of the shock-metamorphic rock-series presented on a generalized geological map of Finland (SIMONEN,1971), to which is appended part of the geological map of Soviet Karelia (HACKMANand BERGHELL, 1931). Presvecokarelian rocks: 1. Gneisses. Svecokarelian rocks; 2. Karelian and Svecofennian schists; 3. Volcanogenic schists; 4 Orogenic plutonic rocks (1.8^1.95 Ga). Later Precambrian rocks, Postorogenic; 5. Rapakivi intrusions (1.7 Ga); 6. Jotnian sediments.

Lappajarvi and Janisjarvi. He was especially in Finland, Dellen (SVENSSON, 1968b), Mien puzzled by the resemblance in chemical compo (SVENSSONand WICKMAN,1965; SVENSSON,1969; sition between these rocks and the surrounding STANFORS, 1969), and Hummeln (SVENSSON, schists. Moreover, the roundish form of the 1966) in Sweden, and Lake Kaali in Estonia, lakes distinguished them from the typical USSR (ESKOLA, 1937) were later interpreted longish lakes of Finland, which formed in as astroblemes rather than extinct volcanos. brecciated fault zones from which Pleistocene The diameter of Lake Kaali is only about one glaciers evacuated crushed rock material and hundred meters and it is notable that as early melt waters the sediments. as in 1922 KALJUVEE (1933) recognized it as Eskola compared Janisjarvi and Lappajarvi a meteorite crater. with the lakes Dellen and Mien in Sweden. Astroblemes (see also CARSTENS, 1975; Mostly on the basis of morphological and WELIN, 1975), whose age in Finland is not petrographical features, Lappajarvi (MCCALL, known, appear to be more common around 1968; SVENSSON,1968a, 1971; LEHTINEN, 1970, the Baltic than elsewhere. This suggests that 1976) and Saaksjarvi (PAPUNEN, 1969, 1973) at least some of them were formed during Major elements and REE in tektites 3

the same cosmic event. volcanic-like, shock-melted rock, karnaite. LEHTINEN (1976) has described the rocks near GEOLOGY OF THE LAPPAJARVI, JANISJARVI, AND the lake. In fallout and impact breccias he has SAAKSJARVI AREAS found: coesite, maskelynite, diaplectic quartz and microcline glass, planar features in quartz Lappajarvi Lake Lappajarvi is located in and feldspars, and kink bands in biotite and the Bothnian schist belt (Fig. 2). The dominant graphite. The impact origin of the lake is well rock around the lake is biotite-plagioclase gneiss established. which is migmatized by small granites and The petrography of the specimens used is granodiorites and silicic pegmatites. Near the displayed in Table 1 (Nos. 1-6) and major ele lake in its northern and southern parts there ment and REE contents are laid out in Tables are outcrops of small synorogenic muscovite 2 and 3. granites and granitic pegmatites in gneiss (cf., LAITAKARI, 1942; LEHTINEN, 1976; SAKSELA, Jdnisjdrvi Lake Janisjarvi, Soviet Karelia, 1934, 1935, 1949). The bedrock is mainly is located in the Karelian schist belt (Fig. 3) silicic, corresponding approximately to that of where mica, andalusite, and staurolite schists granodiorite. In the northern part are islands, with some garnet prevail (cf., HACKMAN, 1931; Karnasaari and others which are composed of HACKMANand BERGHELL, 1930; HAUSEN, 1930). The bedrock is homogeneous and only a few small silicic veins are found in the lake area. The specimens studied here were collected by E SKOLA (1921). In the middle of the lake are two islands, Pieni (small) and Suuri (large) Selkasaari, which are composed of dense shock-melted rock. The petrography in the specimens studied is dis played in Table 1 (Nos. 7-9) and major element and REE contents in Tables 2 and 3 . The specimens are those used by ESKOLA (1921, p. 6; I is No. 7, II is No. 8 in Table 1). The characteristic textural features of shock metamorphic rocks are barely detectable in small-grained mica schist because mica serves to reduce the effect of an impact. Shock-lamellae in quartz typical of impact-produced rocks, however, have been observed in veins (LEHTINEN, pers. com.).

Sdaksjarvi The bedrock in the Saaksjarvi area is like that near Lappajdrvi but more silicic , containing mostly quartz diorite, granodiorite , and veined gneisses (Fig. 4). Shock-metamorphic 0 5 10 km rocks have not been found as outcrop , but brecciated glacial boulders with some shock metamorphic features have been found in gravel = 1 2 3 pits. The rocks have been described by PAPUNEN (1969, 1973). He reports planar features in quartz and plagioclase, kink-bands in biotite, ,~ 4 5 and partial transformation of plagioclase to glass. The petrography, and major element and Fig. 2. Geological map of the Lappajarvi area (SAKSELA, REE contents of the studied specimen are dis 1934). 1. Migmatized biotite gneiss; 2 . Hornblende played in Tables 1, 5 and 6 (No. 10). biotite gneiss; 3. Gneiss granite; 4. Pegmatite and mus covite granite; 5. Shock-melted rock, karnaite. 4 T. KOLJONEN and R. J. ROSENBERG

Table 1. The samples studied from Lappafdrvi, Jdnisjdrvi, and Sadksjidrvi(Nos. 2-5, cf., LEHTINEN, 1976, Table 9).

No. Rock type Texture Mineral assemblage Location 1 Shock-melted rock, Dark, dense, vesicular, glassy, Fragments: granitic pegmatite, Finland, Lappajarvi, karnaite microcrystalline rock in which quartz, feldspars. Microlites: Karnasaari fragments of minerals and sanidine, albite, orthopyroxene, rocks are found partly pinitized cordierite, biotite, zircon, opaque, amphibole. Cavities: calcite

2 Shock-melted rock, Dark, dense, homogenous, Fragments: quartz, feldspars. Finland, Vimpeli, karnaite. Boulder on glassy, microcrystalline rock Microlites: feldspar, pyroxene, Kotkaniemi the S shore of the lake in which only a few fragments amphibole, cordierite. Cavities: of minerals are found chalcedony, calcite

3 Shock-melted rock, Grayish, glassy rock with Like No. 2 contains zeolites Finland, Alajarvi, karnaite. Glacial more cavities than Nos. 1 and Hietakangas boulder 2

4 Shock-melted rock Dark gray, brecciated rock Quartz, plagioclase, and potas Finland, Alajarvi, (breccia). Glacial well preserved against second sium feldspar which are partly Hietakangas boulder ary alteration. Contains more altered to glass fragments of country rock and minrals than Nos. 1 3. The composition of glass varies according to the rock or mineral from which it has originated

5 Fallout breccia (suevite). Gray, brittle, and much Like No. 4 but contains zeolites Finland, Alajarvi, Glacial boulder weathered rock in abundance Hietakangas

6 Mica gneiss Lepidoblastic Quartz, plagioclase (An 25), Finland, Vimpeli, biotite, sillimanite, muscovite, Ahola microcline. Accessory minerals: apatite, zircon

7 Shock-melted rock Dark, very dense, glassy, micro Fragments: mica schist. Micro USSR, Karelia, crystalline rock in which frag lites: oligoclase, quartz horn Ruskeala, Janisjarvi, ments of minerals and rocks blende, chlorite, ilmenite. Pieni Selkasaari, are found Cavities: chalcedony, carbonate W-shore

8 Shock-melted rock Dark, dense, glassy, micro Microlites: oligoclase, quartz USSR, Karelia, crystalline rock in which frag orthopyroxene, biotite. Accessory Ruskeala . Janisjarvi,~ ments of minerals and minerals: carbonate, chlorite, apatite, Suuri Selkasaari amygdales are found sericite. Cavities: chalcedony

9 Staurolite-mica schist Lepidoblastic, fine-grained Biotite, mostly cruciform twins of USSR, Karelia, Harlu, rock with staurolite porphyro staurolite porphyroblasts with Laskela. About 5 km blasts poikiloblastic quartz, quartz, S of Janisjarvi chlorite. Accessory minerals: zircon

10 Breccia (suevite). Highly weathered brecciated Fragments: quartz, oligoclase, Finland, Saaksjarvi Glacial boulder rock with glassy microlitic sanidine, spinell. Groundmass: groundmass quartz, chlorite. Cavities: chalcedony

STUDIED TEKTITES MAJOR ELEMENTS AND REE IN SHOCK M ETAMOR PHIL ROCKS AND T EKTITES The specimens are from the meteorite col lection of the University of Helsinki. The types The major element contents (Table 2) of chosen for comparison with shock-metamorphic shock-melted rocks in Lappajarvi and Janisjarvi rocks are ones whose REE contents have seldom closely resemble those found in the surrounding been analyzed. bedrock. In particular, the presence of several The general features of the tektites are des percent of corundum in CIPW-norms suggests cribed in Table 4 (Nos. 13-16) and the REE the chemical composition of clayey sedimentary contents are displayed in Table 6. rock. The composition of rocks in Janisjarvi Major elements and REE in tektites 5

Table 2. Chemical composition (weight percent) and CIPW-norms of shock-metamorphic rock from Lappajdrvi and Jdnisjdrvi (Table 1, Nos. 1-9).

1 2 3 4 5 6 7 8 9 SiO2 65.09 65.86 62.20 67.88 62.42 73.92 59.63 60.92 62.22 A1203 16.38 15.46 13.63 14.81 14.39 11.51 18.11 19.08 18.05 Fe203 3.02 0.97 3.89 3.11 4.80 1.52 1.12 1.64 2.06 FeO 2.48 4.41 3.33 1.65 0.26 1.88 5.67 5.47 6.36 MnO 0.12 0.05 0.06 0.02 0.05 0.02 0.14 0.13 0.06 MgO 1.42 2.24 2.74 1.27 1.42 0.79 2.15 1.41 3.84 CaO 2.94 2.72 2.34 2.20 2.28 1.33 3.06 1.92 1.66 Na20 2.76 2.45 2.22 2.80 0.27 3.82 2.17 2.54 1.45 K20 3.22 3.37 2.51 3.05 2.S8 3.07 3.75 3.36 2.74 H2O+ 0.65 0.71 3.10 0.69 S.37 1.04 1.15 H20 0.55 0.70 2.11 2.22 5.22 0.03 3.68 2.84 0.08 P205 0.14 0.49 0.93 0.08 0.38 0.03 0.17 0.20 0.11 TiO2 0.48 0.64 0.65 0.48 0.75 0.73 0.97 0.70 0.82

Total 99.25 100.07 99.71 100.26 100.19 99.69 100.62 100.21 100.60

CIPW-norm s

Q 28.01 28.04 32.32 33.54 45.05 35.80 19.67 24.10 30.35 or 19.03 19.91 14.83 18.02 15.25 18.14 22.16 19.86 16.19 ab 23.35 20.73 18.78 23.69 2.28 32.32 18.36 21.49 12.27 an 13.67 10.30 5.54 10.39 8.83 5.19 14.07 8.22 7.52 cor 3.34 4.01 5.23 3.09 7.92 5.32 8.25 9.94 di 0.98 by 5.03 11.91 8.76 3.16 3.54 2.52 13.49 11.28 18.29 mt 4.38 1.41 5.64 3.99 2.20 1.62 2.38 2.99 he 0.36 4.80 ii 0.91 1.22 1.23 0.91 0.65 1.39 1.84 1.33 1.56 ru 0.41 ap 0.32 1.14 2.15 0.19 0.88 0.07 0.39 0.46 0.25 H20 1.20 1.41 5.21 2.91 10.59 1.07 3.68 2.84 1.23

Table 3. REE in the shock-metamorphic rocks from Lappajdrvi and Janis/drvi (Table 1, Nos. 1^•9)and in Leedey L/6 chondrite (MASUDAet al., 1973). The values in parentheses are estimates (cf., MASUDA,19 75).

No. 1 2 3 4 5 6 7 8 9 Leedey La 40 40 32 44 37 38 39 38 32 0.378 Ce 77 84 78 80 79 97 95 91 69 0.976 Pr (0.138) Nd 33 37 29 31 36 39 41 40 30 0.716 Sm 4.9 5.1 4.0 5.2 4.7 4.7 6.7 6.3 4.4 0.230 Eu 1.1 1.1 1.0 1.2 1.2 1.0 1.6 1.3 1.2 0.0866 Gd 0.311 Tb 0.56 0.58 0.55 0.62 0.67 0.77 0.97 0.86 0.64 (0.0568) Dy 3.0 3.2 2.5 3.0 4.0 4.3 5.4 5.1 3.8 0.390 Ho (0.0868) Er 0.255 TM (0.0399) Yb 1.5 1.6 1.5 2.5 1.9 2.2 3.0 2.7 2.3 0.249 Lu 0.35 0.40 0.29 0.31 0.40 0.34 0.61 0.57 0.44 0.0387 REE 179 189 163 184 181 177 214 205 159 3.95

La/Yb 27 25 21 18 19 17 13 14 14 1.5 is specific and probably very uncommon because position no longer represents the original one. astrobleme has been introduced into homo The potassium content is exceptionally high. genous mica schist in which only the grade The REE contents and distribution patterns of metamorphism varies. in each rock series are alike, indicating similar The rock from Saaksjarvi (Tables 1 and 6) chemical composition before impact and is highly zeolitized and the major element com weathering (Fig. 5). Even in Saaksjarvi the REE 6 T. K OLJONEN and R. J. ROSENBERG

Table 4. The tektites studied.

No. Specimen General features Site of occurrence 13 Indochinite Form: disc-shaped, depressed in Thailand centre. Surface is corroded and etched. Color: black. Size: breadth 25mm, thickness 10mm

14 Billintonite Form: spheroid. Surface shows Indonesia, Belitung flow lines and pits. Color: Island black. Size: diameter 15 mm

15 Bediasite Form: disc-shaped. Surface is USA, Texas, Grimes County, pitted. Color: black. Size: Carlos area breadth 20mm, thickness 12mm

16 Libyan Desert glass Form: wedge-shaped flat piece, United Arab Republic, which possibly is an artifact of Sand Sea, lat. late neolithic or Pre-Dynastic 25°17'54"N, long. man (cf., CLAYTON and 25°34'0"E SPENCER, 1934). Surface is broken along conchoidal faces and the edges in places are pitted, probably by blowing sand. Color: pale greenish-yellow

Table 5. Chemical composition (weight percent) and CIPW-norm of a specimen from Sadksjdrvi (Table 1, No. 10) and some average compositions (see Table 7): 11a. Plutonic rocks in the Tampere area, SW Finland (K0L JONENand CARLSON,1975, Table 1); 12a. Finnish clays (KOLJONENand CARLSON,1975, Table 1). The average is calculated without water and organic matter. The average water content is 5.41 %; 16a. Libyan Desert glass (O'KEEFE, 1963, Table 13); 174. Tektites (O'KEEFE, 1963, Table 13).

10 11a 12a 16a 17a I % Si02 59.30 66.98 61.89 98.20 73.87 Jinisjarvi A1203 18.24 15.35 18.00 0.70 12.69 Fe203 3.94 0.87 3.89 0.53 0.47 FeO 1.13 3.48 3.72 0.24 4.16 MnO 0.03 0.04 0.08 0.10 MgO 3.99 1.35 3.05 0.01 2.18 CaO 0.08 3.11 2.12 0.30 2.23 Na2O 1.58 2.27 3.30 0.33 1.38 K20 6.86 3.76 3.02 0.02 2.28 H2O+ 2.54 0.81 0.06 H20 1.64 P2 05 0.23 0.18 0.20 TiO2 0.58 0.51 0.81 0.23 0.75 2 E 3 4 Total 100.14 99.71 100.08 100.62 100.11 CIPW-norms Q 23.17 21.51 95.79 46.27 6 7 • . a 07, 5 or 22.22 17.85 0.12 13.47 ab 27.67 27.92 2.79 11.68 0 5 10 k m an 14.25 9.21 0.37 11.06 9 cor 0.68 5.93 3.90 di 0.05 Fig. 3. Geological map of the J inisjdrviarea (HACKMAN wo 0.44 and BERGHELL,1931). 1. Presvecokarelian gneiss; 2. by 8.26 10.03 11.63 Quartzite; 3. Metamorphosed volcaogenic rocks; 4. mt 1.26 5.64 0.11 0.68 Limestone and skarn rocks; 5. Dolomite; 6. Mica schist he 0.46 i1 0.97 1.54 0.44 1.42 and phyllite; 7. Staurolite, andalusite, and garnet schist; ap 0.42 0.46 8. Pegmatite granite; 9. Shock-melted rock. H20 0.81 0.06 Major elements and REE in tektites 7

Table 6. REE contents of (see Tables 4 and 7): 10. Breccia (suevite). Saaksjarvi, Finland, lib. Graywacke, Kangasala, Finland (WILDEMANandHASKIN 1973, Table 1); 12b. Kinzigite, Helsinki, Finland; 13. Indochinite; 14. Billintonite; 15. Bediasite; 16b. Libyan Desert glass; 17b. Average in tektites; 18. Average in shock-melted rocks and impact glasses; 19. Average in granites; 20. Average in sands (USSR).

10 11b 12b 13 14 15 16b 17b 18 19 20 La 30 28 38 39 41 34 9.5 31 38 50 16 Ce 56 52 88 88 84 72 20 66 75 96 30 Pr 6.6 7.8 8.6 11 4.1 Nd 29 26 40 35 31 30 7.6 27 34 41 16 Sm 3.6 3.7 5.5 5.4 6.1 5.8 1.2 4.5 5.8 10.8 3.8 Eu 1.2 1.12 1.1 1.2 1.1 1.3 0.20 1.1 1.2 1.1 0.8 Gd 3.1 4.0 4.0 7.3 3.2 Tb 0.59 0.46 0.59 0.93 0.87 0.79 0.15 0.67 0.78 1.7 0.55 Dy 3.5 3.24 3.6 5.9 6.5 5.9 1.0 4.3 4.2 6.0 2.7 Ho 0.65 0.9 0.9 1.6 0.6 Er 1.78 2.5 2.3 4.3 1.6 TM 0.28 0.38 0.36 0.7 0.2 Yb 2.0 1.77 1.7 3.0 2.9 2.6 0.53 2.3 2.1 4.8 1.2 Lu 0.43 0.30 0.44 0.69 0.65 0.52 0.12 0.39 0.40 0.7 0.1

REE 140 129 196 199 193 170 44 153 178 237 81

La/Yb 15 16 22 13 14 13 18 13 18 10 13

The REE contents and distribution patterns of all tektites are similar. The results of this and earlier studies indicate that REE contents vary only slightly in the most common types of tektites. In particular, the REE contents and distribution patterns in Far East tektites are Saaks nearly identical, which points to their genetic jarvi relationship (cf., FLEISCHERet al., 1969). The most conspicuous discrepancy is the La content (SOppm) of australites (TAYLOR, 1968, Table 1).

CONCLUSIONS AND DISCUSSION

REE and major element contents do not 0 5 10 change observably after meteoritic or cometary km impact. The REE are especially well preserved, and much better than the major elements , in rocks which have been brecciated by the shock I I2 wave and whose composition has changed after ward through weathering. In general, therefore, Fig. 4. Geological map of the Skaksjarvi area REE distribution patterns could well be used Gneiss granite; 2. Mica gneiss. (SEDERHOLM,1903). 1. for the identification of rocks and other mate rials in which texture and major element com distribution is like that in Svecofennian schists. position has altered. Moreover, because REE This, as such, does not prove a shock-metamor content and especially the distribution pattern phic origin; but if magmatic solutions had are stable under a wide variety of physical and caused the change in chemical composition the chemical conditions, they could be used for REE distribution probably would have changed general identification purposes. Industrial pro too, because in most late magmatic differen ducts, for example, could be trade-marked tiates the REE distribution is typical of the rock through the inscription of artifical patterns of type, even in low-temperature solutions (KOL, REE in trace concentration. JONEN and ROSENBERG, 1974 and unpublished The REE contents and especially their dis data of carbonate-rich rocks). tribution are alike in all the shock-metamorphic

8 T. KOLJONEN and R. J. ROSEMBERG

110 A 110 100 e 100 w 90 0 1 w 90 0 W 7 x W 80 2 0 80 W 80 70 J 70 W 3 x W 9 . 60 4 A 60 050 50 Z 50 x 40 x 6 . 40 U U Y30 U Y 30 20 20 Y 10 10 0 a

La Ce Pr Nd PmSm Eu Gd Tb Dy Ho Er Tm Yb Lu La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Fig. 5 a. Fig. 5b.

110 110 100 100 0

W 90 0 10 x W90 13 0 W 60 O w 11b o 60 14 x A 70 12b 0 W 70 15 A 60 166 0 F 60 Z \x 50 Z 50 U 40 40 ~[30 x 30 20 0__ • ¢ 20 10 10 0 0 0-c 0-0 La Ce Pr Nd Pm Sm Eu Gd Tp Dy Ho Er Tm Yb Lu La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Fig. Sc. Fig. Sd.

Fig. 5. REE contents normalized against chondrite

110 (Leedey). The numbers in the graphs indicate the

100 analyses shown in Tables 3 and 6. a. Lappajc rvi rock W 90 c 17bA series (Nos. 1-6); b. Jc nisjarvi rock series (Nos. 7-9); W so W 16 c. Breccia from Sadksjdrvi (No. 10), graywacke (No. W 70 19 0 ~60 20 o 11b), kinzigite (No. 12b); d. Indochinite (No. 13), 50 Billintonite (No. 14), Bediasite (No. 15), Libyan Desert X40 glass (No. 16b); e. Averages for tektites (No. 17b), Y 30 `off impact glasses and shock-melted rocks (No. 18), granites 20 10 (No. 19), and sands (No. 20). 0 La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Fig. Se. published analyses of tektites La and Gd con tents are slightly increased and Eu content is de creased in the normalized graph, which changes rock series (Fig. 5), which indicates a similar are characteristic of silicic igneous rocks. These original composition and the formation of melts features may be fossil patterns inherited from without magmatic or metamorphic differentia silicic sediments or host rocks. Such REE pat tion. terns as are found in taktites need both magmat The REE distribution patterns in tektites are ic and sedimentary processes for their forma like those in impact glasses. This similarity tion. This is because the REE differentiated in supports the proposed terrestrial and sedimen magmas are again evenly distributed in sedi tary origin of tektites (e.g., TAYLOR, 1962; ments. The total REE content is high and the BousKA, 1968), especially because the differen light elements are enriched into the upper crust tiation pattern typical of silicic magmatic rocks and are depleted in the upper mantle. REE is not at all or only slightly observable. In some contents and distribution patterns appear to be

0 Major elements and REE in tektites 9

Table 7 Calculation of some of the averages in Tables 5 and 6. lla. The averagechemical composition of plutonic rocks in the Tamperearea, SWFinland (KOLJONENand CARLSON,1975). The differentiationseries includes rocks from peridotites to granites. The chemicalcomposition, which corresponds to granodiorite, has been calculated on the basis of the chemicalcomposition and distributionof rock types on a geologicalmap. The orogenic plutonicrocks in CentralFinland may have been formed through the anatexisof basementand geosynclinalsediments (KOLJONEN and ROSENBERG,1975). 12a. The average chemicalcomposition of 43 Finnish clays. Clays contain much unweatheredmineral detritus because the weatheringtime of the sedimentshas been short ( 10,000 years) and the climate is cool (KOLJONENand CARLSON,1975). 17b. REE content of tektites calculatedfrom the averagesfor: a. Australites,average given by TAYLOR(1968). b. Bediasites, averageof one specimenof HASKIN and GEHL (1963) and Table 6, No. 15. c. Billintonites,Table 6, No. 14. d. Indochinites, Table 6, No. 13. e. Ivory Coast tektites, compositeof 10 specimens(SCHNETZLER et al., 1967). f. LibyanDesert glass, Table 6, No. 16b. g -h. Moldavites,average of the Bohemianand Moraviantektites (BOUSKAet al., 1973). i. Phillipinites,one specimen (HASKINand GEHL, 1963). For the averages(a .i) the elementsnot presentedin analyseshave been calculatedfrom smooth graphs. 19. AverageREE content of granites. The 55 analysespresented in graphform by KOLJONENand ROSENBERG(1974, Tables 1, 3, and 4, Nos. 14-21, 29 41, 43'.44) and the analysesof BOWDENand WHITLEY(1974), and BUMAet al. (1971) are used. Only valuesgiven by separateauthors are used in the calculations.Only a few analysesof Tm (9), Ho (14), and Pr (17) have been reported in the literature and many of them, although they seemto be accurate,are old. The averagediffers only a little from that presented by HERRMANN(1970). 20. The averageREE content of sands is calculatedas the averageof the averagesRONOV et al. (1974, Table 5) present for Mesocenozoicrocks from the USSR. unique to the surface of each planet and even temperature of the tektite material was further to the Moon. Also probable are different increased through atmospheric friction as it was original total contents, although the relative hurled through the atmosphere: most of the contents of separate REE must have been nearly characteristic textural features of sediments and the same in the primordial Solar System. It rocks were erased and minerals were melted (cf., seems that the chemical compositions of the RANKAMA, 1965). The high silica, aluminium, undifferentiated celestial bodies were different. potassium, and calcium contents typical of The contents of REE in Earth and Moon are tektites presumably increased the viscosity of higher than in chondrites, which probably origi the melt; glassy droplets formed while the melt nate from the Asteroid belt. The difference is was hurling through the atmosphere were such also observed in the selenium content which as not to disintegrate under friction (see UREY, should, as a mobile element, be strongly enrich 1963). Tektites low in silica do not form ed into the upper crust. The selenium content because such melts are less viscous. The com of L-type chondrites is 1.4 16 ppm (PELLY and position and behavior of tektite melts resemble LIPSCHUTZ,1971) and in abyssal igneous rocks the composition and behavior of the melt of the it averages 0.05 ppm. Therefore, if the content glasses used in chemical laboratories. The dif in the undifferentiated Earth had been the same ferences in REE contents and distribution pat as in chondrites, selenium contents of the upper terns, e.g., in Libyan Desert glass compared with crust should be much higher than those observed other tektites, arise from the differences in the (KOLJONEN,1973, 1975). Possibly refractive chemical composition of the original sediment elements have condensed more to the inner part or rock. Clayey sediments, for example, contain and volatiles more to the outer part of the Solar more REE than quartz-rich sands. Likewise, System (see also ANDERSON,1972). the REE contents in graywacke and kinzigite The REE distribution pattern is a result of (Table 7) and in the sedimentary rocks and geological processes and through them depend sediments containing clay analyzed by HASKIN ent on the size and chemical composition of et al. (1968), W ILDEMAN and HASKIN (1973), the differentiating celestial body and the ex and RONOV et al. 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textures in the erratics of the Lake Saaksjarvi area in astrobleme in southern Sweden. I. The bottom southwestern Finland. Bull. Geol. Soc. Finl. 41, topography. Sver. Geol. Unders., Ser. C 608. 151-155. SVENSSON,N. B. (1968a) Lake Lappajarvi, central PAPUNEN,H. (1973) Chemical composition and origin Finland: A possible meteorite impact structure. of the shock metamorphic rocks of the Saaksjarvi Nature 217, 438. area, Finland. ibid. 45, 29-34. SVENSSON,N. B. (1968b) The Dellen Lakes, a prob PELLY, I. Z. and LIPSCHUTZ,M. E. (1971) Selenium able meteorite impact in central Sweden. Geol. (34), in Handbook of elemental abundances in me Foren. Stoch. Forh. 90, 314-315. teorites, ed. B. MASON, 271-278, Gordon and SVENSSON,N. B. (1969) Lake Mien, southern Sweden Breach Science Publishers, New York-Paris. a possible astrobleme. ibid. 91, 101-110. RANKAMA,K. (1965) Origin of australites. Nature SVENSSON,N. B. (1971) Lappajarvi structure, Finland: 207, 1383. morphology of an eroded impact structure. J. RONOV, A. B., BALASHOV,Yu. A., GIRIN, YU.P., Geophys. Res. 76, 5382-5386. BRATISHKO,R. KH., and KAZAKOV,G. A. (1974) SVENSSON,N. B. and WICKMAN,F. E. (1965) Coesite Regularities of rare-earth element distribution in the from Lake Mien, southern Sweden. Nature 205, sedimentary shell and in the crust of the earth. 1202-1203. Sedimentology 21, 171-193. TAYLOR, S. R. (1962) The chemical composition of SAKSELA,M. (1934) General geological map of Fin australites. Geochim. Cosmochim. Acta 26, 685 land, 1:400,000, sheet B3, Vaasa. Pre-Quaternary 722. rocks. Geological Survey of Finland, Espoo. TAYLOR, S. R. (1968) Geochemistry of Australian SAKSELA, M. (1935) Uber den geologischen Bau Siid impact glasses and tektites (Australites) , in Origin and Ostrobothniens. Bull. Comm. Geol. Finl. 110. distribution of the elements, ed. L. H. AHRENS,533 SAKSELA,M. (1949) Das pyroklastische Gestein von 541, Pergamon Press, Oxford. Lappajarvi and seine Verbreitung als Geschiebe. Bull. UREY, H. C. (1963) Cometary collisions and tektites. Comm. Geol. Finl. 144, 19-30. Nature 197, 228-230. SCHNETZLER,C. C., PHILPOTTS,J. A., and THOMAS,H. WEAST,R. C., ed. (1971) Handbook of Chemistry H. (1967) Rare-earth and barium abundances in and Physics, 52nd ed., The Chemical Rubber Co., Ivory Coast tektites and rocks from the Bosumtwi Cleveland. Crater area, Ghana. Geochim. Cosmochim. Acta 31, WELIN,E. (1975) K-Ar dating and Sr-isotope com 1987-1993. position of rhyolitic rocks from Lake Mien in SEDERHOLM,J. J. (1903) General geologicalmap of Sweden. Geol. Foren. Stockh. Forh. 97, 307-311. Finland, 1:400,000, sheet B2 Tampere,Tammerfors. WILDEMAN,T. R. and HASKIN, L. A. (1973) Rare Pre-Quaternaryrocks. GeologicalSurvey of Finland, earths in Precambrian sediments. Geochim. Cosmo Espoo. chim. Acta 37, 419-438. SIMONEN,A. (1971) Das finnische Grundgebirge. WINZER S. R., LUM, R. K. L., and SCHUHMANN, S. Geol. Rundsch. 60, 1406-1421. (1976) Rb, Sr and strontium isotopic composition, STANFORS,R. (1969) Lake Mien -an astrobleme or K/Ar age and large ion lithophile trace element a volcano-tectonic structure. Gepl. Foren. Stoch. abundances in rocks and glasses from the Wanapitei Forh. 91, 73-86. Lake impact structure. ibid. 40, 51-57 . SVENSSON,N. B. (1966) Lake Hummeln a possible