Water in Tektites and Impact Glasses by Fourier-Transformed Infrared Spectrometry

Autor(en)

Anton Beran, Christian Köberl

Abstrakt

To improve the scarce data base of H2O

content in tektites and impact glasses, we analyzed 26 tektites from all

four strewn fields and 25 impact glass samples for their H2O content.

We used the Fourier-transformed IR (FTIR) spectrometry method, which

permits measurement of areas of .apprx.40 µm in diam. The results show

that the tektites have H2O contents ranging from 0.002 to 0.030 wt.%

(av. 0.014 ± 0.008 wt.%). Ivory Coast tektites have the lowest H2O

abundances (0.002-0.003 wt.%); the Muong Nong-type indochinites and some

North American tektites having the highest contents (up to .apprx.0.03

wt.%). Impact glass samples (from the Zhamanshin, Aouelloul, and Rio

Cuarto craters) yielded H2O contents of 0.008 to 0.13 wt.% H2O. Typical

impact glasses from the Aouelloul and Zhamanshin craters have low H2O

contents (0.008 to 0.063 wt.%). Libyan Desert Glasses and Rio Cuarto

glasses have higher H2O contents (.apprx.0.11 wt.%). We also analyzed

glasses of unknown origin (e.g., urengoites; glass fragments from

Tikal), which showed very low H2O contents, in agreement with an origin

by impact. Data confirm that all tektites found on land have very low

H2O contents (<0.03 wt.% H2O), while impact glasses have slightly

higher H2O contents. Both glass types are very dry compared to volcanic

glasses. This study confirms that the low H2O contents (<0.05 wt.%)

of such glasses can be considered good evidence for an origin by

impact.

Organisation(en)

Institut für Mineralogie und Kristallographie, Department für Lithosphärenforschung

Journal

Meteoritics and Planetary Science

Band

32

Seiten

211-216

Anzahl der Seiten

6

ISSN

1086-9379

Publikationsdatum

1997

Peer-reviewed

Ja

ÖFOS 2012

104026 Spektroskopie, 105116 Mineralogie

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