File:Collected reprints - Atlantic Oceanographic and Meteorological Laboratories (and) Pacific Oceanographic Laboratories (1968) (20656194132).jpg

Title: Collected reprints / Atlantic Oceanographic and Meteorological Laboratories (and) Pacific Oceanographic Laboratories
Identifier: collectedreprin1972v2atla (find matches)
Year: 1968 (1960s)
Authors: Atlantic Oceanographic and Meteorological Laboratories; Pacific Oceanographic Laboratories; United States. Environmental Science Services Administration. Research Laboratories; Environmental Research Laboratories (U. S. )
Subjects: Oceanography Periodicals.
Publisher: Washington, D. C. : U. S. Dept. of Commerce, Environmental Science Services Administration, Research Laboratories : For sale by Supt. of Docs. U. S. G. P. O.
Contributing Library: Penn State University
Digitizing Sponsor: LYRASIS Members and Sloan Foundation

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SECTION Figure 3: The Sudbury lopolith showing the distribution of the sub-layer (in black) along the margin of the Irruptive and in radial fractures ("offsets"). Diagonal ruling shows the extent of more highly metamorphosed and tectonically disturbed rock associated with the South Range. This metamorphic aureole extends northward from the nearby Grenville front (Souch and Podolsky, 1969). fifty known sulphide occurrences. This may possibly mean that the bolide arrived from the north so that its substance was preferentially splashed against the south wall. Secondly, one wonders if the common mafic and ultramafic xenoliths which are not traceable to known formations could be preserved fragments of the cosmic bolide, and hence "cosmoliths"? By reflection and interference of shock waves along the rear margin of an impacting bolide, fragments may escape shock destruction. This effect apparently explains the preservation of unshocked fragments of the Canyon Diablo meteorite, which created the Barringer (Meteor) Crater in Arizona (Anders, 1965). However, the wide variety of these rock types at Sudbury argiiesagainst this possiblity and makes the deep-crust source more likely. Also, Sidney Pollack (personal communication) has been unable to find any stacking disorder in their orthopyroxenes such as is found in some meteoritic pyroxenes in chondrites. HYPERVELOCITY AND CENTRIFUGAL INJECTION By the proposed impact model, the sub-layer would be emplaced at hypervelocity and injected centrifugally with respect to ground zero — the centre of the Sudbury Basin. Distribution of the sub-layer components would reflect inertial or density differences and would not be appreciably influenced by the gravitational field. Both theory and small-scale experiments show that hypervelocity bolides traveling many kilometres per second upon impact are literally turned inside out. There is almost complete destruction of the bolide as it is converted into a spray of plasma, liquid, and gas phases which sweep up along the walls of the crater. Experiments and the rayed craters on the Moon both indicate that, instead of a uniform sheet, discrete coherent jets are formed. Figure 4, adapted from a diagram of the Levack Mine by Souch and Podolsky (1969), shows the zonation expected with a hypervelocity injection of the sub-layer vectored normal to the gravity field. The densest substances would travel farthest, giving an order of zonation as follows: sub-layer silicate matrix, a mixed zone (breccia with disseminated sulphide and some silicate matrix), and massive sulphide. The innermost zone would be pyrrhotite-rich (Fe at. wt. = 55.8), followed by a zone enriched in pentlandite (Fe at. wt. = 58.7), and finally a chalcopyrite-rich zone nearest the 508

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