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The Abnormal Penetration of the Norfork, Arkansas, Iron
Author(s) -
Paz Lincoln
Publication year - 1938
Publication title -
contributions of the society for research on meteorites
Language(s) - English
Resource type - Journals
eISSN - 1945-5100
pISSN - 0096-2813
DOI - 10.1111/j.1945-5100.1938.tb00196.x
Subject(s) - penetration (warfare) , meteorite , siderite , geology , astrobiology , physics , mineralogy , mathematics , pyrite , operations research
(and Introduction) The Norfork, Arkansas, iron recently described by Nininger, 1 belongs probably in the select category of North American irons of witnessed fall. While it is a normal siderite in other respects, certain surface features are unusual, and the observed depth of penetration into the earth of four feet is much greater than one would expect to find in the case of a meteorite weighing only 1050 grams. The purpose of this paper is to give some quantitative indication of the discrepancy between the reported penetration of Norfork and the calculated probable penetration of a spherical iron meteorite weighing only 1050 grams. In view of the magnitude of this discrepancy, it seems most improbable that the small iron mass under consideration attained the reported depth by actually forcing its own way into the earth. The most probable explanation of the observed abnormal penetration is that the Norfork fragment entered the earth in the wake of a much larger mass, from which it was disengaged approximately at the instant of impact. From a study of the peculiar form and superficial features of the Norfork specimen, Nininger has already been led to conjecture that it “represents a corner of a large mass which was detached just as the main body penetrated the soil.” It is shown in what follows that the weight of the unrecovered portion of the fall may lie between 27.8 and 286 kilograms.