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Re: Tektites: Hypthetical Terrestrial Ring & Possible Lunar Source Cr aters
Varricchio, Louis schrieb:
> A news article published in the Sept./Oct. 1980 issue (pgs. 92-93) of
> the defunct SCIENCE 80 magazine, titled "An Earthly Ring?" reports on
> J.A. O'Keefe's (NASA Goddard) controversial theory of an Eocene
> tektite ring around the Earth (the result, he claimed, of one or two
> lunar volcanic events).
> Can anyone steer me to sources of published papers, by O'Keefe et al,
> regarding the tektite ring theory? The papers must have appeared in
> scientific journals around late 1980 or early 1981.
Hello Louis, hello List!
I've just finished browsing my database and my search yielded the
following sources:
J.A. O'Keefe (1964c) Water in Tektite Glass (J. Geophys. Res. 69,
3701-3707).
J..A. O'Keefe et al. (1973) Tektite Ablation: Some Confirming
Calculations (J. Geophys.Res. 78, 3491-3496).
J.A. O'Keefe (1976) Tektites and Their Origin, Elsevier Scientific Publ.
Company, Amsterdam, 254 pp.
J.A. O'Keefe (1978) The Tektite Problem (Sci.Am. 239, 116-125).
W.L. Melnick, J.A. O'Keefe (1990) On the Ablation of Flanged Australian
Tektites (Lun.Plan. Sci. Lett. 21, 783-784).
S.R. Taylor et al. (1994) Comment on "Origin of Tektites" by O'Keefe
(Meteoritics 29-5, 1994, 739).
J.A. O'Keefe (1994) Reply to Taylor and Koeberl (Meteoritics 29-5, 1994,
743).
Sky & Telescope, May 1987, p. 481: Tektites and Lunar Volcanoes
The origin of tektites - glassy stones unevenly distributed over the
Earth's surface - has not been an easy puzzle to solve. Australian
tektites often exhibit an ablated appearance, which means they partially
melted while passing through Earth's atmosphere. The two surviving
theories have suggested that they either originated from volcanic
outbursts on the Moon or are bits of terrestrial rock splashed from the
impacts of comets and asteroids with Earth. Such interpretations depend
heavily on tektites' structure and composition. One recent analysis
supports the idea that a particular group of them came from the Moon.
Darryl S. Futrell examined the mineral structure in samples of the Muong
Nong-type tektites found in and around Thailand. His study indicates
that the glass had a prolonged, multistage formation at its site of
origin. All of the samples appear to have undergone two episodes of
melting separated by several minutes of cooling. This implies a volcanic
source, Futrell notes, because an impact would have fused material
instantaneously.
Furthermore, tektites differ greatly from Earth's igneous rocks,
especially in their lack of water. Thus, Futrell concludes that if the
Muong Nong samples are volcanic, they are not terrestrial. The Moon is
the only choice since it is accepted that tektites originated within the
Earth-Moon system. If so, it must have been active less than a million
years ago to match the Far East tektites' geologically youthful age.
This evidence lends support to a theory that material volcanically
ejected from the Moon had more of an impact on our planet than just
dotting the surface with glass particles and stones.
John A. O'Keefe of Goddard Space Flight Center contends that an
accumulation of lunar material in Earth orbit coalesced into a r i n g
which altered the climate by blocking the Sun's light. O'Keefe suggests
that several r i n g-f o r m i n g episodes disrupted Earth's
seasonal changes and caused mass extinctions of life, such as the rapid
disappearance of the dinosaurs.
Best wishes, Bernd
P.S.: See also the contributions to the List by JJSwaim, Matt Morgan,
and Martin Horejsi (Thu, 30 Apr 1998) + search the List archives because
there is a lot of info to be found in the archives on that subject.
References: