Detection, identification, and structural analyses of tektite

Okeefe, J. A.

English

NASA Technical Reports Server

. c 
x 
National Aeronautics and Space Administration 
Goddard Space Flight Center 
Contract No. NAS-5-12487 
ST - IM - 10561 
T E K T I T Y  
John A. O'Keefe 
[USA] 
Translation of the Introduction 
by E. L. Krinov 
Editor of the Russian Version 
13 FEBRUARY 1967 
https://ntrs.nasa.gov/search.jsp?R=19670016501 2020-03-16T18:18:10+00:00Z
~~ ~~ 
S T  - IM - 10561 
T E K T I T Y  
PREFACE 
Bythe Editor of the translated edition of the book by 
Dr. John A. O'Keefe, entitled Tektites 
The small glassy formations, preserved in large quanti- 
ties in numerous world collections of meteorites, are known un- 
der the denomination of tektites. They have the most diversi- 
fied shapes: round, oval, pearl-like, cylindrical and so forth. 
When looking at them against light, one may notice in the thin 
plane parts of separate specimens, a green,brown or yellowish 
coloring, making them look like the ordinary dark bottle glass. 
Most of the tektites have dimensions of a hazel nut and weight 
in tens of grams. The coarsest ones reach the size of a chick- 
en's egg and a weight to 0.5 kg. 
At first, tektites having been called moldavites were 
found in the western part of Czechoslovakia (in Southern Bohe- 
mia and Western Moravia). The exact time of their finding has 
not been ascertained; it is known, however, that they were en- 
countered by local natives as early as in the second half of 
the eighteenth century. 
Subsequently, tektites were also detected in other parts 
of the terrestrial globe: on the island of Tasmania (tasmanites), 
in the Central and Southern Australia (australites), on the Billi- 
tori Island (Indonesian Archipelagos), in the Philippines (philip- 
pinites or risalites), in Indochina (indochinites) and also in 
West Africa and North America. They were all found to be simi- 
lar to moldavites, differing from them only by the coloring, 
when looked upon through light. It should be noted, however, 
that despite its enormous territory, not a single tektite has 
been found to-date in the Soviet Union. This is probably ex- 
plained by the fact that in our country very little and even 
practically nothing is known about tektites. 
Despite the fact that tektites have already been known 
for a sufficiently long time, the question of their nature is 
still unresolved, and the discussion of their origin is still 
under way at the present time. Some researchers, however, con- 
sider them to be peculiar glassy meteorites, while others ne- 
gate their cosmic origin and consider them as terrestrial for- 
mations. One must say that until very recently tektites drew 
the attention of only very few scientists. The situation 
changed abruptly in the course of the last few years. This 
2 
began with the reports on special symposia on tektites held in 
Washington (1957), New York (1963) and also at the Florence 
(1961) and Washington (1962) Cospar Symposia, during which the 
audacious hypothesis was brought forth that tektites are frag- 
rieiits of the M~cn's smface layer, ejected dllring the fall on 
the Moon of sizeable meteorites. 
It should be stressed that quite reasonable foundations 
were laid at the basis of this hypothesis. The low critical 
velocity for the Moon (of the order of 2 km/sec) and the absence 
of atmosphere lead to the fact that when sufficiently coarse me- 
teorites fall on the lunar surface (the impact velocity for me- 
teor bodies meeting head-on may exceed 70 km/sec), the fragment- 
ed and pulverized fragments of the Moon's surface layer acquire 
speeds above the critical velocity and escape the sphere of gra- 
vitational action of the Moon. Part of them will unescapably 
hit the Earth's gravitational sphere and at the very end enter 
the terrestrial atmosphere, decelerate and probably fall on the 
ground. Tektites may precisely be those fragments of the Moon's 
surface layer having undergone modifications on account of the 
impact and atmosphere modeling. Therefore, if this hypothesis 
is valid, by investigating the chemical composition of tektites, 
we in essence carry out the study of the matter of the lunar sur- 
f ace. 
Resting upon the fact that no tektite falls were observed 
to-date and considering impossible the conservation of glassy or 
glass-like formations at deceleration in the Earth's atmosphere, 
the adversaries of this hypothesis relate the origin of tektites 
with the so-called silica-glass (or impactites), found in meteor- 
itic craters in the form of pieces of glassy matter, having 
emerged during the impact melting of the terrestrial silica-sand 
during the falls of crater-forming meteorites. It should be men- 
tioned that contrary to tektites, the fragments of silica-glass 
always have an irregular, fragmental shape and are either painted 
in light yellow color or are generally colorless. At the same 
time, the partisans of this viewpoint agree with the idea that 
the origin of tektites is somehow linked with the impacts (on 
the Earth or on the Moon). 
The above referred to reports have stimulated the study 
of tektites by scientists of numerous lands of the world, and 
the number of published works devoted to tektites sharply in- * 
creased. Nevertheless, it cannot be said that enough attention 
is presently being given the tektites by researchers of the So- 
viet Union. The decisive word in the problem of tektites un- 
doubtedly belongs in contemporary geochemical methods, and first 
of all, in the establishment of the exact isotopic composition 
of tektites, the determination of their age by the potassium- 
argon method, and the aerodynamic analysis of conditions of en- 
try into the atmosphere and shape-modeling of tektitic bodies. 
3 
I .  
# 
This is why the edition of a symposium of works on tektites, pub- 
leading NASA specialists, appears to be quite timely. 
c lished in the United States in 1 9 5 4  by John O'Keefe, one of the 
The object of the symposium, its problems and principles 
of composition, are sufficiently fully characterized in O'Keefe's 
preface, and this is why we shall limit ourselves here only to 
a brief enumeration of the works entering into the book. 
Chapter 1, written by J. Baker, is devoted to the shape 
and the sculpture of tektites. In Chapter 2, V. E. Barnes con- 
siders the fields of tektite scattering. Chapter 3 ,  belonging 
to E. Chao, acquaints the readers with the petrography and che- 
mical properties of tektites, and Chapter 4, written by C .  C. 
Schnetzler and W. H. Pinson, presents the tektites' analytical 
chemistry. In Chapter 5, I. Friedman describes the physical 
properties of tektites and J. Zahringer considers in Chapter 6 
their isotropic composition. Chapter 7 is devoted to the prob- 
lem of aerodynamic analysis of tektitic shapes (E. W. Adams). 
Chapter 8 ,  written by J. A. O'Keefe, gives a critical analysis 
of the merits and shortcomings of various hypotheses relative 
to the origin of tektites. Finally, in the concluding Chapter 9 
belonging to A. J. Cohen, the fields of moldavite scattering in 
the light of hypotheses on tektites' origin are considered in 
detail. 
Thus, the symposium provides a sufficiently complete 
picture of the contemporary state of the problem of tektites. 
In conclusion, a few words about the circle of readers 
of this book. It will be indispensable, first of all, to spe- 
cialists-astronomers, geochemists, geologists, taking interest 
in extraterrestrial matter and its terrestrial manifestations. 
A large amount of valuable material will be foundhere also by 
specialists in aerodynamics, working on the problem of entry in- 
to the atmosphere with cosmic velocity and the atmospheric 
braking at high speeds. The book, however, will also be read 
with interest by representatives of a broader circle of readers 
showing interest in literature devoted to meteorites. One may 
be assured that these readers will face with interest a book 
devoted, according to its creators, to the attempt of knowing 
what tektites really are. 
It would be also desirable that this book provide the 
incentive for the detection of tektites on the territory of 
our country and stimulate the development of tektite research 
in the Soviet Union. 
August 1 9 6 5  (Signed) E. L. Krinov 
* * * 
Volt Technical Corporation 
Washington, D. C. 20036  
Translated by 
ANDRE L. BRICHANT 


Tektites

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server