NO. 4 TEKTITE SPECIMENS — CLARKE AND CARRON 17 



It should be clearly demonstrated that both of the above hold before 

 specimens are accepted as proven tektites. The natural occurrence re- 

 quirement seems not to have been proven beyond reasonable doubt 

 in the case of Georgia and Martha's Vineyard specimens. Certainly, 

 the history of specimens found to date in these localities is not over- 

 whelming evidence of their natural origin (Bruce, 1959; Kaye et al., 

 1961). 



The data that have been given point to a current weakness in our 

 understanding of tektites. It has not been possible to take two glass 

 objects, found 20 years and 1,000 miles apart, into the laboratory 

 and, after studying their chemical and physical properties, report un- 

 equivocally that they are tektites. Had the specimens under study 

 belonged to one of the major recognized tektite groups, and had their 

 properties been fairly typical of that group, a reasonably certain 

 identification could undoubtedly have been made. However, chemical 

 composition apparently separates the specimens from Martha's Vine- 

 yard, Mass., and Empire, Ga., from known tektite groups. The speci- 

 mens have properties that are typical of tektites but not exclusive 

 for tektites. All the properties that we were able to measure have a 

 counterpart in natural or artificial glasses. Further information on 

 these tektites, particularly their field occurrence, is required before 

 a final judgment should be made. A disproportionate amount of 

 laboratory work cannot compensate for the lack of sufficient field 

 data. A typically geological approach is needed for a problem that 

 remains basically a geological problem. 



CONCLUSIONS 



In the chemical and physical data that have been presented, there 

 is nothing inconsistent with the claim that the Georgia and Martha's 

 Vineyard glasses are tektites — tektites in the sense of the major tek- 

 tite groups. However, there is likewise nothing in these data to 

 prove categorically that only a natural origin can account for the 

 specimens. Conceivably some type of artificial origin, perhaps an 

 accidental one, is possible. Certainly it would be premature to as- 

 sume that Martha's Vineyard is a valid tektite locality. The cause 

 of our inability to solve this problem at present — and this seems to 

 apply also to problems concerning the major tektite groups — is the 

 lack of geological evidence relating specimens to their occurrence. 

 Until the occurrence is understood, speculation as to origin lacks 

 foundation. 



