THE ALETAMORPHISM OF GLACIAL DEPOSITS.^ 

 Frank Carney 



Introduction 



Field Data 



Color of the altered drift 

 Its texture and structure 

 Folding, jointing-, faulting 

 Weathering 



Agencies of Alteration 

 Chemical 



Saturated condition of sub-glacial sediments 



Oxidation and deoxidation 



Carbonation ; hydration 

 Pressure 



Weight of superincumbent drift 



Weight of superjacent ice 



Due to hydration 



Summary 



INTRODUCTION 



Glacial drift metamorphosed to a conglomerate has been 

 studied in several parts of the world. A detailed description of 

 such a conglomerate in South Australia, identified as a Cambrian 

 tillite, has recently appeared;" glacial formations of the same period 

 have been studied in China.' In India.* Africa,^ and South Aus- 

 tralia,* glacial conglomerates of Permian age have been carefully 

 investigated. 



The ])resent brief inquiry is confined to glacial sediments of 

 the Pleistocene period. The conclusion arrived at, from a field 

 study of these sediments in central New York and in northern and 

 central Ohio, is that locally, at least, the alteration of a part of the 



1 Published by permission of the Ohio Geological Survey, but the author is respon- 

 sible for the opinions expressed. Read before Section E of the American Association for 

 the Advancement of Science at Baltimore, 190S. Reprinted from the Journal of Geology, 

 vol. XVII, No. 5, July-August, 1909. 



2 Rev. Walter Howchin, "Glacial Beds of Cambrian Age in South Australia." Quart. 

 Jour. Geolog. Soc, vol. LXIV (1908), pp. 234-.59. The same author made a preliminary 

 report in 1901, Trans. Roy. Soc. of South Australia, vol. XX\\ p. 10. 



3 Willis, Blackwelder, and Sargent, Research in China, vol. I (1907). 

 Carnegie Institution, Washington. 



4C. D. White, American Geologist, vol. Ill (1SS9), pp. :?0r,.n. Chamberlin and Salis 

 bury. Geology, vol. TI (1906), pp. ()33-,35. 



5 C. D. White, f/'. cit., pp. 303-0. Chamberlin and Salisbury, op. cit.. pp. 63.5-38. 



