摘要:

AbstractSome principles of the scientific method of reaching conclusions are reviewed and applied to West Hawk Lake, Manitoba, and lead to its interpretation as an ancient meteorite crater. The feature is 12000 feet in diameter, with water depths as great as 365 feet. A gravity survey indicates a negative gravity anomaly of 6 milligals associated with the lake. This is interpreted as due to a breccia zone overlain with sediments.

ISSN:0026-1114    

DOI:10.1111/j.1945-5100.1964.tb01414.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractFive of the six known craters in the vicinity of Cabrerolles and Faugeres, ranging in diameter from 200 to 55m were examined on the ground while additional studies of the same craters were made on aerial photographs. The topography of the five craters and their relationship with their surroundings suggested a relatively recent origin.A comparison was made of these craters with others of recent origin whose formation by meteorite impact was regarded as substantially beyond doubt. All of the comparison craters (including the Barringer Crater, diameter 1.3 km, and the Kaalijarv Crater in Estonia, diameter 200 m) showed the phenomena of raised rims and uplifted strata around their edges so clearly as to suggest a definite diagnostic feature. Since no indication of raised rims or radially uptilted strata was found in any of the five French craters it seems justifiable to doubt that any of these interesting features was formed by meteorite impact.

ISSN:0026-1114    

DOI:10.1111/j.1945-5100.1964.tb01415.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThe four craters, New Quebec, Clearwater Lakes (two craters) and Manicouagan are compared. New Quebec shows evidence of slow uplift accompanied by hydrothermal activity, possibly culminating in a minor volcanic outburst. Clearwater East is interpreted as the result of regional uplift followed by local collapse. Clearwater West shows similar features accompanied by a central peak and considerable volcanism. The latter two features are believed to be related. Manicouagan has a well developed central peak and an extensive volcanic pile. The characteristic cycle; upwarp, collapse, volcanism is beautifully shown. None of these craters can be explained either by ‘classical’ impact theory, or by analogy with known volcanic areas. New ideas are nee

ISSN:0026-1114    

DOI:10.1111/j.1945-5100.1964.tb01416.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractA recent field reconnaissance by one of us (ECL) has tended to support the view that the Lonar Crater, India, is probably a Quaternary meteorite crater. This origin is suggested by the high degree of circularity, the depth to diameter ratio, the breccia of crushed rock revealed by drilling, the quaquaversal dip of the surrounding country rock, the mounds of debris lying around the crater rim, and its regional uniqueness.Although developed in the Deccan flood basalts, the crater cannot be genetically related to these traps, as they were laid down in the Cretaceous, whereas the crater is physiographically young, probably Pleistocene. Cryptovolcanic phenomena (steam explosion, diatreme action, etc.), caldera subsidence and solution collapse cannot adequately account for this depression.

ISSN:0026-1114    

DOI:10.1111/j.1945-5100.1964.tb01417.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractIn the course of the 1961 Perseid shower, ten faint spectra were obtained with one spectrograph. The spectra can be classified into four groups, which form a continuous sequence. The forbidden green line of neutral oxygen at 5577A is visible in the two brightest spectral classes, but appears weaker in the spectrum showing the H and K lines of ionized calcium than it does in those that do not. The green line appears to be relatively stronger in the spectra of faint meteors. An attempt is made to explain some aspects of green line behaviour with the aid of the Whipple comet model.

ISSN:0026-1114    

DOI:10.1111/j.1945-5100.1964.tb01418.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractObservers located as much as 300 km from the ground trace of bright fireballs have sometimes reported hearing swishing sounds simultaneously with the fireball passage. These sounds are anomalous because the geometry of fireball path and observer locations requires that the effect producing the sound sensation be propagated at the speed of light. The great number and striking similarity of these sound reports, which have appeared in the published literature for several centuries, are difficult to attribute to coincidence or psychological suggestion. The description of the anomalous sounds as a hissing or crackling and rare reports of odors which may be ozone suggest that the sounds are caused by electric discharges near the observer. These discharges may be the result of perturbation of the geopotential gradient by the fireball. The occurrence of other electromagnetic disturbances during fireballs, such as deflection of compass needles, induction in long lines, and radio interference, support this inference. It is also possible that the anomalous sounds are due to strong electromagnetic radiations from the fireball which are transduced by natural objects, perhaps even the human brain.

ISSN:0026-1114    

DOI:10.1111/j.1945-5100.1964.tb01419.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractGamma spectrometry is a useful substitute for chemistry in the activation analysis of meteoritic specimens. After irradiation, instead of dissolving the sample and chemically extracting particular elements, the sample is instead placed in a scintillation counter and its gamma spectrum analyzed with the aid of a multichannel analyzer. By a suitable choice of irradiation conditions, various nuclides can be made to stand out clearly against the background of the irradiated meteorite. As examples, recent data are presented for aluminum and fluorine analysis of chondrites.

ISSN:0026-1114    

DOI:10.1111/j.1945-5100.1964.tb01420.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractA recently discovered, thin, flanged, boat‐shaped australite weighing 0.711 grams and measuring 27.2 mm by 10.5 mm by 1.8 mm to 2.4 mm from Port Campbell on the south coast of western Victoria, Australia, consists of approximately sixty five to seventy per cent circumferential flange glass which is relatively smooth and attached peripherally to an elongated, flow‐lined central core. The form is a rare and unique specimen representing the final ablation product of an originally somewhat larger, thicker, elongated primary australite shape, probably a biaxial ellipsoid of revolution, that became modified by aerodynamical heating during non‐rotational, high speed transit through the earth's atmos

ISSN:0026-1114    

DOI:10.1111/j.1945-5100.1964.tb01421.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractAluminum bumpers (Type 6061‐T6) with thicknesses of 0.1875, 0.125, 0.090, 0.063, and 0.032 inch have been subjected to impact with a 0.57 gram cylindrical steel projectile traveling at 9,400 to 21,700 ft/sec. In addition, the 0.032 inch bumpers were subjected to impact with 0.21 gram cylindrical steel projectiles traveling at 11,800 to 14,700 ft/sec. An aluminum (6061‐T6) vehicle hull was used in all experiments. For any given thickness of bumper, the vehicle hull was varied in both thickness and distance of separation from the bumper in order to establish the total weight and thickness of the structure necessary to prevent complete penetration by a given high velocity particle.It appears from the experimental data that spaced plates offer more effective protection from high velocity particles than a single plate of the same material and total mass. Moreover, it appears that thinner bumpers require less total weight in the vehicle to provide the same protection efficiency. This weight advantage provided by the thinner bumpers is reduced as the space between the bumper and plate is decrea

ISSN:0026-1114    

DOI:10.1111/j.1945-5100.1964.tb01422.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractData on the 64 new meteorites which fell or were discovered in the past ten years are analyzed in terms of type, weight, number per year, and geographic distribution. The type and mass distribution of 76 meteorites not entered in the Prior‐Hey catalogue before 1962 is also presente

ISSN:0026-1114    

DOI:10.1111/j.1945-5100.1964.tb01423.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY