Gases in Tektite Bubbles

Abstract-Tektites, natural silica-rich glasses produced during impact events, commonly contain bubbles. The paper reviews published data on pressure and composition of a gas phase contained in the tektite bubbles and data on other volatile compounds which can be released from tektites by either high-temperature melting or by crushing or milling under vacuum. Gas extraction from tektites using high-temperature melting generally produced higher gas yield and different gas composition than the low-temperature extraction using crushing or milling under vacuum. The high-temperature extraction obviously releases volatiles not only from the bubbles, but also volatile compounds contained directly in the glass. Moreover, the gas composition can be modified by reactions between the released gases and the glass melt. Published data indicate that besides CO 2 and ⁄ or CO in the bubbles, another carbon reservoir is present directly in the tektite glass. To clarify the problem of carbon content and carbon isotopic composition of the tektite glass, three samples from the Central European tektite strewn field-moldavites-were analyzed. The samples contained only 35-41 ppm C with d 13 C values in the range from )28.5 to )29.9& VPDB. This indicates that terrestrial organic matter was a dominant carbon source during moldavite formation.

Section: A Review Of Available Data On Volatile Compound Content and mentioning

confidence: 89%

A review of volatile compounds in tektites, and carbon content and isotopic composition of moldavite glass

Žák

Skála

Řanda

et al. 2012

“…Although they occur in all types of tektites (Muong Nong or layered, splash-form, and aerodynamically ablated tektites on land; microtektites in deep-sea sediments), bubbles are most abundant (and largest) in Muong Nong-type tektites. O'Keefe et al (1962) studied the gas of a bubble in a bediasite using electrodeless discharge spectroscopy and detected Ne, He, and°as main constituents. They concluded that the Ne and He had probably diffused into the bubble from the atmosphere because of the high permeability of the tektite glass for these gases but also noted that the°may be "atmospheric oxygen incorporated into the tektite during its formation."…”

Section: Introductionmentioning

confidence: 99%

Noble gas study of a philippinite with an unusually large bubble

Matsuda

Maruoka

Pinti

et al. 1996

Abstract— A philippinite with a large bubble (volume ⋍5 cm3) was crushed in a specifically constructed device under vacuum. The total pressure, the major gas components, and the concentration and the isotopic composition of noble gases in the trapped gas were measured. The total gas pressure was found to be low, ∼10−4 atm. Compared to terrestrial atmosphere, the abundances of He and Ne are considerably more enriched than the concentrations of the heavy noble gases. Unusually high 20Ne/22Ne and 21Ne/22Ne ratios were measured in the bubble gas. These ratios are higher than values expected for any steady state process and are interpreted to reflect very fast nonsteady state diffusion in the early stages of tektite formation.

“…Because metal depletion does not appear to correlate with water depletion, it is possible that water in the molten tektites was buffered by water vapor in bubbles within the molten rock and/or in a hot, moist enveloping cloud formed during impact. However, given the lack of correlation between bubble frequency and water content, along with earlier studies which did not find water vapor or condensed water droplets in tektite bubbles (O’Keefe et al. 1962), it seems unlikely that water present in the bubbles could have buffered water dissolved in the molten material.…”

Section: Discussionmentioning

confidence: 82%

“…2003). Determination of the composition of bubbles within tektites has also been attempted (O’Keefe et al. 1962).…”

Section: Introductionmentioning

confidence: 99%

Exploration of tektite formation processes through water and metal content measurements

Watt

Bouchet

Lee

2011

Abstract-Impact events are a significant surface-modifying process on solar system objects lacking frequent resurfacing by atmospheric or igneous processes. To better explore the effects of impacts on surface materials, we measured the water and trace element compositions of tektites from Da Lat, Vietnam. Fourier transform infrared spectroscopy was used for water measurements and laser ablation inductively coupled plasma mass spectrometry was used for trace element measurements. Consistent with previous investigations of tektites, we found that the samples are depleted in volatile metals (e.g