摘要:

Great showers of tektites fell upon certain parts of the earth at widely separated geologic periods. The four major geologic groups are:The typical forms—spheroids, disks, or oval, cylindrical, dumb‐bell‐shaped, and pointed, drop‐shaped bodies—suggest natural shapes assumed by molten glass revolving in the atmosphere or a similar gaseous medium. The Australites show a partial re‐fusing of the original glass sphere and backward flow, producing a peculiar button‐like appearance.Group three, which includes the Philippine tektites, may be divided into four major subgroups: (1) Indochinites; (2) Rizalites; (3) Billitonites and Malaysianites; and (4) Java Tektites. The characteristicsetc. of these bodies are discussed in some detail.Of the various theories of the origin of tektites, three are still worthy of consideration. These are: (1) the theory of volcanic or other earthly origin; (2) the burning, light‐metal meteorite theory; and (3) the meteorite explosion‐crater theory. An astronomical theory of tektites, proposed by Dr. W. Carl Rufus, is summarized and briefly criticized,proandcon.The Philippines present a unique opportunity for the study of the richest known deposit of tektites in their natural environment. The only local students of the problem are the writer and Dr. Miguel Selga, S.J., joined recently by Mr. J. Van Eck. To stimulate local interest, the present outline was presented to the Philippine National Research Council.1The Ivory‐Coast deposit, believed to be Mesozoic;2The Moldavites, or European, from the Helvetian strata of mid‐Miocene;3The Indo‐malaysianites, undoubtedly mid‐Pleistocene; and4The Australites, believed to be p

ISSN:0096-2813    

DOI:10.1111/j.1945-5100.1940.tb00306.x

出版商:Blackwell Publishing Ltd    

年代:1940

数据来源: WILEY

摘要:

It is supposed that the small, natural‐glass bodies known as tektites were originally derived in major part from the glassy basalt, or tachylyte, which forms the deeper crustal layer of the earth, exposed chiefly on the floor of the Pacific basin, at the time of the fissional separation of the moon; furthermore, that the earthly tektites represent only a small section of the vast swarms of tiny satellites which remained revolving about the earth within the Roche limit, and particularly that section of the satellites having a revolutional period closely coinciding with the period of the earth's rotation. Such swarms would have remained approximately above the Pacific basin, but would have gradually fallen behind and tended to be drawn to the earth, on account of perturbations resulting from the gradual retardation of the moon. Cumulative perturbations and other related factors have caused swarms of these bodies to come down to the earth at widely separated geologic periods in the earth's history, such falls having been particularly extensive along a great‐circle route crossing the western edge of the Pacific basin. This circumstance would account for the great quantity and wide distribution of the Indo‐malaysian tektites ***espeoially, which are of almost identical chemical composition, while other showers of tektites came at different geologic periods and varied somewhat in composition and physical appea

ISSN:0096-2813    

DOI:10.1111/j.1945-5100.1940.tb00307.x

出版商:Blackwell Publishing Ltd    

年代:1940

数据来源: WILEY

ISSN:0096-2813    

DOI:10.1111/j.1945-5100.1940.tb00308.x

出版商:Blackwell Publishing Ltd    

年代:1940

数据来源: WILEY

摘要:

Two photographs, taken 1939 April 29, by Mr. John H. Spikes (photographer) and Capt. D. Z. Zimmerman (pilot), from an altitude of 9,300 feet about 20 miles east of ***Galem, Alabama, show what the writer interprets as a meteor train. The train is about 13° long on the first picture and 8° on the second. It shows marked distortion and some “doubling.” There are apparently insufficient data and too many unknown variables of motion involved to allow any satisfactory computations of the train's true position, height, or drift, but the upper‐air winds were probably from the west and/or north. No confirming observations of the daylight meteor which presumably caused the train have been secured. Nevertheless, the object shown is thought to be certainly a meteor train. If it is, the photographs are unique in having been taken from an a

ISSN:0096-2813    

DOI:10.1111/j.1945-5100.1940.tb00309.x

出版商:Blackwell Publishing Ltd    

年代:1940

数据来源: WILEY

摘要:

An elliptical depression, about 80 × 110 feet, in a wheat field which has been cultivated for about 35 years, just east of Chickasha, Oklahoma, was investigated in a preliminary way by photographing it from an airplane, checking its local history, and digging three test holes in it. No positive evidence of any single mode of origin was adduced, although there seems to be at least some slight possibility that it is meteoritic

ISSN:0096-2813    

DOI:10.1111/j.1945-5100.1940.tb00310.x

出版商:Blackwell Publishing Ltd    

年代:1940

数据来源: WILEY

ISSN:0096-2813    

DOI:10.1111/j.1945-5100.1940.tb00311.x

出版商:Blackwell Publishing Ltd    

年代:1940

数据来源: WILEY

ISSN:0096-2813    

DOI:10.1111/j.1945-5100.1940.tb00312.x

出版商:Blackwell Publishing Ltd    

年代:1940

数据来源: WILEY

ISSN:0096-2813    

DOI:10.1111/j.1945-5100.1940.tb00313.x

出版商:Blackwell Publishing Ltd    

年代:1940

数据来源: WILEY

ISSN:0096-2813    

DOI:10.1111/j.1945-5100.1940.tb00314.x

出版商:Blackwell Publishing Ltd    

年代:1940

数据来源: WILEY

摘要:

The densities of specimens of the meteorites Holbrook, Arizona, Llano del Inca, Atacama, Chile, Xiquipilco (Toluca), Mexico, and Admire, Kansas, have been determined (v.Table 1,post, for results). The influence of the immersion‐liquid on the value of the density obtained is discussed, and examples are given. This influence is small but definite; it is especially important if the meteorite is in the form of filings or powder. The maximum error for some of the densities determined for this report is calculated and discussed. It was found to be small, particularly when the meteoritic specimen was large and the immersion‐fluid was relatively dense. Lastly, rational methods of determining densities of meteorites are discussed and suggestions are offered for a method of calculating the densities of meteorites that are not suitable for immersion in liqu

ISSN:0096-2813    

DOI:10.1111/j.1945-5100.1940.tb00315.x

出版商:Blackwell Publishing Ltd    

年代:1940

数据来源: WILEY