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All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Chemical systematics among the moldavite tektites

The compositional variations that occur among the moldavite tektites are caused principally by incomplete mixing of two components during fusion. With the possible exception of silica, there is no evidence for significant losses of volatile species by fractional vaporization. Chemical constraints have been calculated for the two source-materials that contributed to the moldavites. If these tektites were formed by impact fusion, as is commonly believed, then the compositional systematics preserved within the moldavites suggest that hypersonic flow and ejection of impact melts are orderly processes. Insights gained from the study of tektites should prove useful in interpreting the chemistries of impact glasses from other bodies in the solar system.

Delano, J. W.↗
NASA NTRS1983

Preliminary discussion on the origin of Lei-gong-mo (tektites)

The specimens of lei-gong-mo (tektites) were collected from Hainan Island and Leizhow Peninsula during the period from 1963 to 1975. The distribution, forms, sculpture, abration surface (bald spot), internal structure and chemical composition of lei-gong-mo are discussed. Studies of these materials lead to the following conclusions: (1) the specimens of lei-gong-mo can be morphologically divided into eight types; (2) the sculptures on the surface of lei-gong-mo are probably due to the corrosion effect of volcanic gas, and the abration surface due to the aerodynamic corrosion; (3) the folded structures in the layered lei-gong-mo (Muong Nong-type tektite) seem hardly to be formed by an impact of meteorites, but they might be produced in the magma flow process when the lei-gong-mo was melting within the crater vent; and (4) the comparison of its chemical composition with that of basalt from Hainan Island does not show that lei-gong-mo came from the local volcano. The hypothesis of the lunar volcanic origin of tektites is examined.

Baoyin, Y.↗
NASA NTRS1993

Osmium isotopes in Ivory Coast tektites: Confirmation of a meteoritic component and rhenium depletion

The sensitive negative thermal ionization mass spectrometry method was used for the measurement of concentrations and isotopic ratios of osmium and rhenium in four Ivory Coast tektites. These tektites have crustal major and trace element composition, as well as large negative epsilon(sub Nd)(-20) and positive epsilon(sub Sr)(+260 to +300) which are characteristic for old continental crust. Os concentrations ranging from 0.09 to 0.30 ppb were found, clearly much higher than average crustal values, Os-187/Os-186 ratios of about 1.2-1.7, and low Re-187/Os-186 ratios. These results show unambiguously the existence of a meteoritic component (on the order of 0.06%) in the Ivory Coast tektites. Low Re abundances are the result of fractionation of Re during the impact.

Koeberl, Christian↗
NASA NTRS1969

Origin of tektites.

Tektite origin theories, discussing Surveyor experiments effects on lunar geology and Tektite origin

Okeefe, J. A.↗
NASA NTRS1972

Search for carbon 14 in tektites.

An attempt was made to detect cosmic-ray produced C-14 in australites and far-east tektites. No C-14 activity was found outside of statistical fluctuations. If a terrestrial age of 10 thousand years is assumed for australites, a maximum cosmic-ray exposure time of one thousand years is obtained for these tektites on the basis of a 2-sigma statistical error.

Boeckl, R. S.↗
NASA NTRS1973

Tektite ablation - Some confirming calculations.

The calculation of tektite ablation has been redone, taking into account transient effects, internal radiation, melting and nonequilibrium vaporization of the glass, and the drag effect of the flanges. It is found that the results confirm the earlier calculations of Chapman and his group and of Adams and his co-workers. The general trend of the results is not sensitive to reasonable changes of the physical parameters. The ablation is predominantly by melting rather than by vaporization at all velocities up to 11 km/sec; this is surprising in view of the lack of detectable melt flow in most tektites. Chemical effects have not been considered.

O'Keefe, J. A., III↗
NASA NTRS1975

Tektites - Volcanic ejecta from the moon

The possibility is considered that tektites are lunar volcanic ejecta, and lunar regions are examined from which tektites could be ejected with the necessary velocities and trajectories to reach the earth. The examined regions include areas around the Lunar Transient Phenomena sites near Censorinus, Messier, Messier A, and Taruntius, the area of Mare Foecunditatis near Secchi X, areas near Cauchy and Capella, and the eastern part of Mare Tranquillitatis. Evidence of acidic volcanic activity in these regions is described in detail, including possible calderas, mudflows, and endogenous domes. It is suggested that the moon is still gently degassing and that more violent eruptions of material may still occur on rare occasions. Remotely-sensed evidence of recent lunar internal activity is noted.

Cameron, W. S.↗
NASA NTRS1975

Study of the ablative effects on tektite

The tumbling and surface roughness effects on the trajectory of entry tektite were studied in both free molecular and continuum flows. It is shown that, while surface roughness has negligible effect on trajectory, the tumbling may play an important role in tektite trajectory and the consequent ablation, provided the body shape is different from a sphere. A shape factor B was proposed to measure the shape irregularity and is found to be a good parameter for correlations between body shape and tumbling effects.

Chen, K. K.↗
NASA NTRS1975

Study of the ablative effects on tektite

The tumbling and surface roughness effects on the trajectory of entry tektite are studied in both free molecular and continuum flows. It was concluded that, while surface roughness has negligible effect on trajectory, the tumbling may play an important role in tektite trajectory and the consequent ablation, provided the body shape is different from a sphere. A shape factor was a good parameter for correlations between body shape and tumbling effects.

Chen, K. K.↗
NASA NTRS1979

Some effects of gas adsorption on the high temperature volatile release behavior of a terrestrial basalt, tektite and lunar soil

Mass pyrograms obtained from high-temperature, mass psectrometric pyrolysis of a glassy theoleiitic submarine basalt and a tektite, ground in air to less than 64 microns, have shown N2 and SO release patterns very similar to those from the pyrolysis of mature lunar soil fines. The N2 and CO release behavior from the terrestrial samples reproduces the biomodal, high-temperature (approximately 700 and 1050 C) features from the lunar samples. Unground portions of the basalt and tektite show no release of N2 and CO during pyrolysis. Grinding also alters the release behavior and absolute amounts of H2O and CO2. It is suggested that adsorption of atmospheric gases in addition to solar wind implantation of ions may account for the wide range of values in previously reported concentrations of carbon and nitrogen from lunar fines.

Graham, D. G.↗
NASA NTRS1982

Beryllium-10 in Australasian tektites - Evidence for a sedimentary precursor

Each of seven Australasian tektites contains about 100 micron atoms of beryllium-10 (half-life, 1.53 million years) per gram. Cosmic-ray bombardment of the australites cannot have produced the measured amounts of beryllium-10 either at the earth's surface or in space. The beryllium-10 contents of these australites are consistent with a sedimentary precursor that adsorbed from precipitation beryllium-10 produced in the atmosphere. The sediments must have spent several thousand years at the earth's surface within a few million years of the tektite-producing event.

Pal, D. K.↗
NASA NTRS1983

Nickel-iron spherules in tektites - Non-meteoritic in origin

The concentrations of several diagnostic trace elements were determined in two comparatively large NiFe spherules extracted from tektites. The purpose of the study was to obtain some clues about the chemistry of the projectile that is presumed responsible for the formation of these tektites. However, the trace element pattern is distinctly terrestrial implying that the spherules are the result of in-situ reduction of the host rock and are not meteoritic in origin.

Ganapathy, R.↗
NASA NTRS1988

Source of the Australasian tektite strewn field - A possible off-shore impact site

Although there is a preponderance of evidence that tektites were formed by asteroid impacts on the earth, no source crater has been found for the largest and youngest of the strewn fields - the Austalasian strewn field. A combined Seasat/Geos 3 altimeter data set of sea surface heights in the northern portion of the Australasian strewn field has been examined for negative gravity anomalies on the continental shelf and slope which might be related to the source crater for these tektites. A large negative anomaly called the Qui Nhon Slope Anomaly is a sea surface depression of approximately 1.5 meters over an area of 100 km diameter. It corresponds to a gravity anomaly of about -50 mgal. It is proposed that this anomaly may be due to the impact structure that produced the Australasian strewn field.

Schnetzler, C. C.↗
NASA NTRS1988

New approach to the origin of the tektite in China

The tektites in China are distributed on the north part of Australia - Southeastern Asia strewfield of tektite: Leizhou Peninsula of Guangdong Province and Hainan Island, and located exactly at the boundary between Zanjiang Formation and Beihai Formation. A new hypothesis is suggested: During the end of Lower Pleistocene, a comet of special components from the outer part of the Solar System approached the Earth, and then it was captured by the Earth, when it came approximately to the Roche's limet. It was crushed into countless fragments, detritus and dusts, which rotated around the Earth, probably far above the Earth's atmosphere, as a cloud ring. Under the action of crushing energy they could be in the situation of liquid-melt drop in the almost vacuum circumstances and the flow and bubble structure were formed. During their rotation the climate became anomalous and the violet Fe-Si concentration were formed on the surface of sediments. After a rather short time of rotation the unstable ring was broken and the fragments impacted on the hard ground instantaneously.

Qin-Wen, Zhang↗