THE CONDITIONS OF BLACK SHALE DEPOSITION AS 



ILLUSTRATED BY THE KUPFERSCHIEFER AND 



LIAS OF GERMANY. 



By CHARLES SCHUCHERT. 

 {Read May 7, 1915.) 



Stratigraphers do not agree as to the conditions under which the 

 black bituminous shales so often met with in American Paleozoic 

 marine deposits were laid down. Among the more striking of such 

 formations may be mentioned the Quebec, Martinsburg, Colling- 

 wood, Utica, Maquoketa, Genesee-Portage, Ohio, Chattanooga, and 

 Caney, formations ranging from the Ordovician to the Pennsyl- 

 vanian. To aid in the interpretation of such black shales, the writer 

 presents herewith the main results set forth by Professor J. F. 

 Pompeckj, of the University of Tiibingen, in a publication that will 

 not be of wide distribution in America.^ The following is a decided 

 condensation and in part a free translation of his exhaustive paper, 

 which is replete with bibliographic references. 



The Kupferschiefer of Germany are of Middle Permian age, 

 and occur near the base of the Zechstein, the time of marine in- 

 vasion over the previous continental series known as the Rotliegende. 

 In general, the bituminous dark shales occur above the basal Zech- 

 stein conglomerate and below the Zechstein dolomite, and occupy an 

 area of at least 60,000 square kilometers in middle and western 

 North Germany. The average thickness of the copper shales over 

 wide areas is about 30 inches, but varies from nothing to a maximum 

 and exceptional local thickness of 35 feet. However, in many places 

 there are no black shales and then the equivalent deposits, or the 

 basal strata of the invading Zechstein, may be conglomerates, sands, 

 shaly limestones, or dolomites. In other words, the black bitumi- 

 nous shales do not prevail everywhere, and the same is true of the 

 metal sulphides. 



1 " Das Meer des Kupferschiefers," Branca-Festschrift, 1914, pp. 444-494. 



259 



