 INVESTIGATING POSSIBLE BELIZE TEKTITES - REQUEST OF AN EXTENDED DATABASE ON MAGNETIC AND RAMAN SPECTROSCOPICAL SIGNATURE OF NATURAL GLASSES. V.H. Hoffmann1,2, Kaliwoda M.3, Hochleitner R.3, M. Funaki4, M. Torii5. 1Faculty of Geosciences, Dep. Geo- and Environm. Sciences, Univ. Munich; 2Dep. Geosciences, Univ. Tuebingen, 3MSCM, Munich, Germany; 4Tokyo, Japan; 5Okayama, Japan.   Introduction Since 1992 findings of possible tektite glasses havebeen reported from Tikal region, Guatemala, and later from Belize, here most likely in situ. Therefore the  existence of a Central American tektite strewn field was proposed [1,2]. Ages of between 780 and 820 ± 40 ka have been determined for Belize glasses [3-5].  The radiometric age constraints are indistinguishable from the ages of the Australite-Indochinite tektite strewn field (~770 ka). However, additional investigations on Belize glasses reported different geochemical signatures in comparison to the Australite-Indochinite tektites [6-10]. Pantasma structure in Nicaragua was proposed as a possible impact crater [11]. The KTB impact is therefore hypothesized as a double impact.  Several years ago we have started to develope an extended database on the Raman Spectroscopy signature of natural terrestrial and meteoritic glasses [12], including a first Belize glass sample [13]. Background were the findings of the Mars Phoenix mission, namely numerous in part highly magnetic spherules of still unclear origin and formation [15]. A likely impact or volcanic background was hypothesized.  The most important result of was the clear requirement of an extended database based on a selected set of properties of natural glasses: magnetic signature of natural glasses was never investigated systematically, and we decided to significantly extend in parallel our existing database on Raman Spectroscopical characteristics. The focus of our contribution is a first step towards a database of the magnetic signature of natural glasses, whereby a selection of samples will be reported here.  Amongst others, the following types of natural glasses are under investigation in our project:  1. Tektites 2. Impactites 3. Volcanites 4. Tectonic glasses 5. Fulgurites 6. Frictionites / hyalomylonites  Tab. 1: MS of Belize glass samples, error in log MS is +/- 0.05.    m (gr) MS (10-9 m3/kg) Log MS Belize A 1.35 123.5 2.09 Belize 1 0.61 131.5 2.12 Belize 2 0.67 128.5 2.11 Belize 3 0.42 178.7 2.25 Belize 4 0.33 212.8 2.33 Belize 5 0.53 168.3 2.23 Belize 6 0.52 195.4 2.29 Belize 7 0.36 170.5 2.23 Belize 8 0.56 129.0 2.11 Range  123.5 - 212.8 2.09 - 2.33 Average  159.8 2.20  MS values and therefore Fe-content of the investigated Belize glasses show significant variations which is not really typical for tektite glasses. These variations are also reflected by the magnetic remanence parameters of which, in addition, the absolute values are much higher than for other investigated tektite glasses [13]. This facts point to a significant and varying content of ferro(i)magnetic microparticles such as native iron or iron-oxides (which can carry a magnetic remanence), again not typical for (known) tektite glasses. Very rarely iron-like micro-droplets are reported from tektites [Philippinites, 15].  Tab. 2: MS database of natural glasses, all data are new and original: (a) tektites, (b) impactites, (c) volcanites, (d) Tectonic glasses (pseudotachylites), (e) fulgurites and (f) frictionites/hyalomylonites. Each reported sample represents a number of (sub-)samples of different size/mass, and log MS (in 10-9 m3/kg) is mean/average value of a number of (sub-)samples and measurements each. MS error is +/- 0.05.  (a) Tektites MS / Log Moldavites / Bohemia / Czech Republic  34      1.54 Moldavites / Moravia / Czech Republic  28      1.45 Moldavites / Lusetia / Germany  28      1.45 Moldavites / Eger Basin / Czech Republic  30      1.48 Muong-Nong Moldavites / Czech Republic  40      1.60 Tektites / China (various locationa)  84      1.92 Muong Nong (layered) Tektites / Indochina  65      1.81 Ivory Coast Tektites / Ivory Coast 105     2.01 Bediasites / Texas / USA  92      1.97 Georgiaites / Georgia /USA  34      1.51 Thailand - Tektites / Thailand  86      1.94 Billitonites /Indonesia  78      1.89 Javaites / Indonesia 110     2.04 Philippinites /Philippines  86      1.94 Australites /Australia  82      1.91    (b) Impactites Log MS Suevite Glass (bl) / Riescrater / Germany 2.52 Suevite Glass (br) / Riescrater / Germany 3.00 Lonar Impact Rocks (Basalt) / India 3.63 Lonar Impact Glass / India 3.48 Zhamanshinite / Kazakhstan  2.27 Irghizite / Kazakhstan 2.08 Wabar Glass / Saudi Arabia 3.11 Aouelloul Impact Glass /  2.66 Dakhla Impact Glass / Egypt 1.49 Lybian Desert Glass / Lybia MS<0 (diamagn.)    (c) Volcanic Glasses Log MS Obsidian / Little Lake / California / USA 2.32 Obsidian / Wyoming/USA 2.85 Obsidian (Mahagoni) / Georgia 2.75 Lamellar Obsidian (white) / Armenia 2.32 Lamellar Obsidian (black) / Armenia 3.10 Obsidian / Myvatn / Iceland 2.62 Dacitic Pumice / Haruna / Japan 4.38 Andesitic Pumice / Hekla / Iceland 3.13 Ash / Eyjafjälla eruption 2010 / Iceland 3.93 Ash / Grimsvotn eruption 2011 / Iceland 2.99 Pelee Hair / Hawaii / USA 2.44 Pelee Tear / Hawaii / USA 2.18 Reticulite / Hawaii / USA 2.28    (d) Seismo-Tectonic glasses Log MS Pseudo-Tachylites 1 / S-Bavaria / Germany 1.05 Pseudo-Tachylites 2 / Silvretta / Austria 1.90    (e) Fulgurites Log MS Rock-Fulgurite Taymir / Siberia /Russia 3.28 Fulgurites Sahara / Lybia 3.56 Fulgurite Oregon / USA 3.50 Fulgurite Nevada / USA 3.15  (f) Frictionites / Hyalomylonites Log MS Pumice (b) Koefels / Austria 3.11 Pumice (w) Koefels / Austria 3.00 Hyalomylonite / Koefels, Austria 2.20  Our new database will significantly extend existing databases of magnetic signature of natural glasses, mainly focused on tektites and/or impactites [15-17].   Comparing Belize glass MS with tektite or impactite MS signature seems to place Belize glass more to impactite glasses.   References [1] Povenmire H. et al., 2011. 42nd LPSC, #1224. [2] Cornec J., Cornec L., 2010. The Sequel. [3] Povenmire H. et al., 2012. 43rd LPSC, #1260. [4] Schwarz W.H. et al., 2012. Paneth Coll., #0210. [5] Gantert N. et al., 2012. Paneth Coll., #0190. [6] Povenmire H., Cornec J., 2015. LPSC, #1132. [7] Schwarz W.H. et al., 2013. LPSC, #1888. [8] Giuli G. et al., 2014. LPSC, #2322. [9] Koeberl C., Glass B.P., 2014. Metsoc, #5034. [10] Koeberl C., Wegner W., Glass B.P., 2015. Metsoc, #5320. [11] http://www.pantasma.com. [12] Hoffmann V.H., et al., 2013. NIPR Antarctic Meteorite Conference, abstract. [13] Hoffmann V.H. et al., 2013. LMIPE V., #3086. [14] Goetz M. et al., 2010. J. Geophys. Res., 115, E00E22. [15] Senftle F.E., Thorpe A., 1959. GCA 17, 234-247. [16] Werner T., Borradaile G.J., 1998. PEPI 108, 235-243. [17] Rochette P. Et al., 2014. Metsoc, #5040.     Acknowledgements J. Cornec, Denver / USA is thanked for providing a large set of Belize glasses for our investigations. We highly acknowledge the continous support of NIPR. Additional samples were provided from various private and public collections.       
