LPS XXVI 825

MOLDAVITES FROM LUSATIA (GERMANY) 11: A CHEMICAL COMPARI- SION WITH CZECH MOLDAVITES J.-M. Langel, K.T. Fehr2, T. Grund3, M. Langenaue1.4, T. Meisels, H. Palme6, B. Spettel7, D. StBffler8. 1Institut fiir Geologische Wissenschaften und Geiseltalmuseum, Martin-Luther-Universitit Halle-Wittenberg, present adress: Institut fiir Geophysik und Geologie, Universitiit Leipzig, Talstralk 35, D-04103 Leipzig; Wine- ralogisch-Petrographisches Institut, Ludwig-Maximilians-UniversitiitMiinchen; 3Institut fir Planetologie, West&- lische Wilhelms-Universitiit Miinster; 4Laboratorium fiir Radiochemie, Universim Bern; 5Isotope Geochemistry Laboratory, Department of Geology, University of Maryland; 6Mineralogisches Institut der Universitiit Kiln; 7Kosrnochemie, Max-Planck-Institut fiir Chemie Mainz; 8Museum fir Naturkunde, Humboldt-Universitiit Berlin

Abstract: Chemical analyses of Lusatian moldavites confirm previous suggestions con- cerning their affinity to Bohemian and Moravian moldavites. Small but characteristic chemical differences exist between moldavites from Bohemia, Moravia and Radomilice area. Lusatian moldavites cannot be assigned unambiguously to any of the three groups. Some Lusatian molda- vites have compositions matching the Bohemian sub-set others are similiar to the Moravian group. Thus the origin of Lusatian moldavites cannot be explained by fluvial transport from the Bohemian sub-strewn fields alone. Samples and Methods: The major element composition of 69 moldavites (Bohemia 43, Radomilice 3, Lusatia 15, Moravia 8) were analysed by EMA. Trace elements were determined for 24 moldavites (Bohemia 6, Radomilice 3, Lusatia 11, Moravia 4) by INAA, RNAA, ICP, GAAS, FAAS. Results: Our results confirm the observations of [I] of three distinct chemical groups char- acterized by correlations among three groups of elements (Fig. 1.): 1. Ti02, A1203,FeO, Na20, K20 (REE, Th, Zr, Hf, Ga, Rb, Cs, Sb, Cr, Co, Sc); 2. MnO, MgO, CaO (Cl, Br, Sr) and 3. Si02 - corresponding to a target area consisting of clay, carbonates and quartz sand components [I]. Compared to Moravian moldavites, Bohemian moldavites display higher amounts of Ti02, A1203,FeO, Na20, K20, and lower amounts of MnO, MgO, CaO as well. Moldavites from the Radomilice sub-strewn field (SSF) are characterized by high silica concentrations. REE pattern also clearly demonstrate the existence of three Czech sub-strewn fields (Fig. 3). The range of chemical composition of Lusatian moldavites covers the major part of variations of other mol- davites (Tab. l, Fig. 2). In Lusatia types of moldavites occur with chemical signatures of Bohe- mian and Moravian moldavites as well, demonstrated by major and trace element contents. The average REE pattern of Lusatian moldavites is similiar to the REE pattern of Bohemian and Moravian moldavites. In Lusatia moldavites are predominant showing compositions related to a source material with high amounts of clay (Moravian type). An origin of the moldavites in Lu- satia by fluvial transport from the two Bohemian SSF, as assumed e.g. by [2,3], can be excluded because of the occurrence of Moravian type moldavites within the Lusatian samples. Fluvial transport from the Moravian SSF is impossible (e.g. [4, 51). This suggests a primary ejection of moldavite material to the Lusatia region from the Ries impact. Therefore an independent Lusa- tian sub-strewn field within the Moldavite strewn field is postulated. Acknowledgement: We are very grateful to Prof. V. Bodka (Charles Univ. Prague) for the most Czech moldavites and to Mr. H. Wagner (Museum der Westlausitz Kamenz) for the most samples fiom Lusatia. J.-M. Lange's work was supported by the Deutsche Forschungsgemeinschaft (Re 92911-1) and the Sachsen-Anhalt state. References: [l] DELANOJ.W. and LINDSLEYD.H. (1982) GCA 46,2447-2452; [2] ROSTR et al. (1979) Cas. Mineral. Geol. 24, 263-271; [3] BOU~KAV. and KONTAJ. (1986) Acta Univ. Carolinae, Geol., 1-126; [4] UKOVSK~M. (1975) Vest. W~G 50, 27-31; [5] SUK M. et al. (1984) Geological history of the territory of the Czech Socialist Republic, Academia, 400p.; [6] LANGE,J.-M. (1994) unpubl. thesis, 101p.

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MOLDAVITES FROM LUSATIA (GERMANY) II: J.-M. Lange et al.

Table 1. Major element analyses of moldavites from various sub-strewn fields (All data in wt.%, FeO* as CFe) Bohemia (MB) Radomilice area (MBR) Moravia (MM) Lusatia (ML) (n = 43) (n = 3) (n = 8) (n = 15) - - range ji %% range ji %% range x sx% range x sx% Si02 71.9 - 81.0 78.6 2.0 80.0 - 84.7 82.6 2.9 77.5 - 82.5 79.0 2.0 77.2 - 84.1 79.3 2.4 Ti02 0.23 - 0.50 0.31 14.1 0.24 - 0.29 0.26 10.2 0.30 - 0.47 0.40 14.0 0.26 - 0.42 0.34 16.4 A2038.96 - 12.7 10.1 6.4 7.27 - 9.36 8.22 12.9 9.82 - 12.3 11.5 7.2 8.94 - 11.8 10.5 8.7 FeO* 1.28 - 2.86 1.62 16.4 1.00 - 1.41 1.18 17.9 1.44 - 2.56 2.16 18.9 1.32 - 2.51 1.84 23.6 MnO 0.05 - 0.20 0.09 34.5 0.05 - 0.07 0.06 18.2 0.02- 0.05 0.04 32.8 0.03 - 0.11 0.06 38.5 MgO 1.52 - 3.73 2.33 20.3 1.60 - 2.26 1.91 17.4 1.21 - 1.68 1.37 12.2 1.06 - 2.73 1.75 26.7 CaO 2.05-4.48 2.98 23.0 1.80-2.82 2.29 22.3 0.65-1.63 1.25 30.4 0.93-3.85 2.00 42.0 Na20 0.25 - 0.60 0.42 19.9 0.19 - 0.32 0.24 28.0 0.40 - 0.76 0.61 18.4 0.28 - 0.70 0.47 25.0 K20 2.88 - 3.77 3.40 6.5 2.20 - 2.97 2.53 15.6 3.34 - 4.04 3.64 7.5 3.06- 3.75 3.46 5.9

MOLDAWTES: coeflicients of linear regression

correlation coefficient degrees offreedo (IT-2)

- A 0 AD 's 0 0 - 52- 4 062 - - .& o 6 A@$g 0 Fig. 2. Coefficients of linear regression of major elements and other 0 data from moldavites (Bohemia, Radomilice area, Lusatia, Moravia) 1 V I,I, 0 123 4[%1 G CaO loo Fig. 1. Selected major element ratios I Moravia (n - 4) ; - of moldavites I - % lo: Fig. 3. Average chondrite normalized REE pattern of moldavites from different , , , , , , , , , , , , , , , 4 h Ce PI ~d em SI EU ~d ~b DY HO Er ~m ~b LU sub-strewn fields

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